Resources
Tyres
Technical Discussion Page
| OEM tyres shown with green border |
IMPORTANT: the use of H-rated (<130mph) and/or non-OEM tyre sizes is by rider choice so these are displayed for interest only &
should not be considered as recommended tyres for the bike.
Legend
¹ – available as a matched pair if you use a non-OEM size
² – non OEM size or H speed rating
³ – tyre sizes listed but potentially un-available in Australia
Note. although different generation bikes have different rims & tyres, the OD (outer diameter) of the tyres remains the same, hence the overall frame geometry is also *generally* unchanged.
Overview
The greatest tyre challenge with the GPz is the 18″ rear rim and the 16″ front rim of 1st gen bikes.
In 1984 all GP bikes were using the 16″ front so this simply translated across to the sports bikes of the time. Interestingly there are more matched tyre sets for these bikes than the later generation!
I haven’t found any definitive reason for a 18″ rear but this was certainly the standard for earlier bikes and as such there would be no logical reason for Kawasaki to try and change the wheel (pun intended) here. Also the limitations of bias-construction may be a factor here, radials only arrived in 1987 for motorcycles so perhaps the additional rubber of the larger tyre was a physical benefit (heat?) for the tyres. 17″ rims front & back are the modern norm, so even 2nd gen bikes with a 17″ front have limited tyre choices especially if you wish for matched sets.
Having greater tyre options is an often quoted argument for changing the rear rim.
As mentioned although the rim sizes vary on the two generations of bikes the calculated diameters of tyres for all version is virtually identical. Given the bikes potential performance I strongly suggest V-rated tyres (150mph) would be the minimum specification for safety & insurance, there is even an unexpected Z-rated (168mph) option for +A7 bikes (curiously an adventure not sports tyre!). However there are far more tyre choices available if you include H-rated (130mph) tyres that some owners choose to fit, so I’ve also listed these for interest.
| Version | Front | Rear |
| A1-A6 | 120/80/16 (∅598mm) | 130/80/18 (∅665mm) |
| A7+ | 120/70/17 (∅600mm) | 150/70/18 (∅667mm) |
Tyre Pressures (cold)
The service manual specification (1990-93 model radial tyres) is to run F: 36psi & R: 41psi. IMHO you need to take these with a grain of salt, because in 2020 with my Dunlop RoadSmarts I cannot run anywhere near that pressure at the front – it feels like you are riding on a solid piece of rubber. Might be fine on the race-track but on the road I drop to 29psi, as anything below that the front begins to get ‘squirmy’. I then set the rear by the same 5psi offset, so 34psi. And that is still so firm I had to drop the rear shock pre-load!
V vs H-rated tyres
The minimum specification for the GPz900R is a V-rated (149mph) tyre, which is logical for a 150mph bike and of course higher speed rated tyres (Z or W) would be perfectly suitable as well. However….many riders use tyres that are only H-rated (130mph) such as the 130/80/18 Pirelli sport Demon. I would personally not use anything rated less than V, however others may choose to do so based on their riding. So I have included these for interest.
I would also strongly recommend confirming using a H-rated tyre doesn’t negatively affect your insurance!
Smaller diameter tyres
Smaller tyres reduces clearance, shortens the gearing (note speedo runs of front wheel) and changes the geometry of the bike to be even more tail heavy. If you haven’t done it already you can rotate the rear chain adjusters to raise the rear axle.
Folks who modify to the ‘easy swap’ ZZR600 rear rim may need to consider more significant modifications (such as longer rear shock length) to correct the geometry and gearing effects of the even smaller 160/60/17 tyre (∅623mm).
Note: +A7 bikes have no ability to lower the triple-clamps on the front forks.
Wider tyres
There’s handling arguments against wider & lower profile tyres, the most obvious is that the greater profile radius means the bike won’t naturally turn in as easily. But that is potentially balanced by the ‘pinching’ effect you would get putting this onto the smaller rim and the original profile of the tyre itself – which can vary significantly between products. The greater contact patch also potentially creates ‘push’ especially when cornering – analogous to understeer in a car.
On the positive side a wider tyre typically is softer riding due to more material.
150/60/18 (∅637mm)
This is a same-width but lower profile option, provides a few different matched set options for +A7 owners. As discussed drops the rear quite a lot.
160/60/18 (∅649mm)
A wider & lower profile that again drops the rear. I suspect this tyre could be challenging to lever on/off a rim and given the sidewall distortion that would likely occur hard to assess. But for +A7 owners (MT3.5″ rim) if you use this rear size that gives you many more Z-rated (even W) radial tyre options.
The general consensus of public opinion is that a rim can run up & down one standard size – manufacturers might think differently of course. As there is minor dimensional variances with tyre manufacturers specifying in the middle is the correct choice – or better yet specify a particular product that fits perfectly, which is exactly what Kawasaki did.
Tyres obviously vary between manufacturers, likely within as well. One group member mentioned how he used a Dunlop Track Endurance way back in 1985 – the 130 looked as wide as other brands 150’s! Of course none of the OEM spec tyres are available now, so it’s possible that a ‘slim’ modern 160 tyre might fit better than another ‘fat’ modern 150 – I simply do not know.
The only way to confirm would be to test different 150/70 & 160/60 tyres on different width rims and compare the tyre profiles. Kinda difficult…
Note: to fit wider tyres/rim you may need an offset front sprocket and replace the swing-arm, this is discussed in more detail here.
190/55/18 (∅666mm)
FYI the 4.5″ rear rim of the ZX-10 Tomcat (ZXT00B) can run this tyre which is identical in diameter to OEM, however not in the stock swing-arm. I find it difficult to believe that this rim/tyre combination is lighter but have some feedback is that it actually is.
Bias (cross-ply) vs Radial tyre construction
Radial construction is a ‘newer’ design and due to better heat dispersion and different contact patch orientation is the default choice of rubber for sports bikes, however many modern bikes still have bias tyres as OEM. It’s not an apples-vs-apples comparison, as variations of rubber, profiles, weaves & materials all combine to a different result. Of course each manufacturer considers their design to be the ‘best’, but then again over 50% of drivers think they are better than average…….
Link discussing the two types of construction.
Also the early 1980’s were a significant time in tyre development. Michelin introduced radials into racing in 1984, and released the first road bike tyres in 1987. Although the A1 had the widest tyres *ever* fitted to a Kawasaki (130 – lol!), from the service manual specifications it looks like it was only with the 2nd gen bikes (+A7) that radial tyres (Michelins) tyres were specified as OEM. So the GPz was probably designed to use bias-construction tyres, maybe a factor as to why the geometry is ‘slow’ compared to modern bikes.
Designed for Bias
I’ve read online *experts* who debunk the “:designed for bias” theory, and always simply state that radials are “better” because of blah, blah, blah.. However I have four counter arguments.
- Even in 1984 EVERYONE knew that bias tyres struggle with heat build up at speed, the often quoted figure is +100mph. The 150mph GPz had a 6 year development process highly oriented to handling & control at speed, so suggesting that the impact of tyres wasn’t a significant design factor is dismissive of the Kawasaki engineering talent and just plain ignorant IMHO.
- My A8 rides far harder on radials than bias, so with 2nd gen bikes being released with radials Kawasaki softening the front forks to compensate for the harder ride makes perfect sense.
- Unlike these *experts* I emphasise that *my* personal evaluation of tyres do not comply with scientific method nor are statistically significant.
- Manufacturers *still* (in 2022) are developing bias tyres, the new Bridgestone BT-46 only being released in 2020.
The first vehicle to have radial tyres fitted as standard was the Citroen 2CV in 1948 (or 49) – a cool car but hardly fast or ‘sporty’!
It stands to reason that not only have radial tyres developed a lot further since then (so have greater influence on modern bike engineering) but also that the GPz900R engineering would be happier with modern bias-construction tyre, which would *hopefully* be much better than what was available in 1984! This is a ‘score’ of the original rear tyre Dunlop K727 – hardly confidence inspiring numbers!
Although still bias construction the ‘ancient’ Bridgestone BT-45 (only superceded in 2020 with the BT-46) is one of the universally recommended tyres for A1-A6 bikes and I have personally run the 120/70/17 front without any adverse handling issues at all.
As such you can do your own research and decide which tyre construction suits your riding style – IMHO radial gives sharper handling but a much firmer ride.
Lastly although it is generally NOT RECOMMENDED to mix the two tyre constructions, they are still offered OEM on some bikes (eg. choppers) and interestingly in the early days sometimes racers did just that. Just as the Yamahas R1 wasn’t simply about pure power, this just goes to reinforce an important factor in motorcycling racing as to how a rider can get the best out of the machinery. Never black & white.
Need to do homework
One of the complexities we have is that manufacturer or retailer sites do not always recognise the different generations of bike or even the bike full stop!
For example when searching (Nov 2020) www.bridgestone.co.uk and choosing the GPz900rR you cannot select a year, and the only tyres returned as suitable are the BT45 with no listings at all for the either the BT46 or the BT016, despite these being available in Australia for both 1st & 2nd gen bikes. So if a major manufacturer from a major country can’t get be bothered to get their online site right for our bikes – that gives insight into the challenges of hunting down tyres!
Other sites like Pirelli only offer searching by bike make & model, so if there isn’t OEM tyre sizes available you won’t get any matches.
Local online sites
I’ve added the manufacturer marketing ‘blurb’ for interest and for comparative pricing I also have snapshots from an Aussie online supplier motorcycletyrewarehouse.com.au. Personally I purchase tyres directly from my local Adelaide tyre fitter – dcmotorcycles.com.au
84-85 Service Manual Tyres
Front: 120/80/16 V250 Dunlop F-17 Cold Pressures : US/Canada – 32psi elsewhere 36psi
Rear: 130/80/18 V250 Dunlop K727 Cold Pressures: US/Canada – 36psi elsewhere 41psi
86 & 88-89 Service Manual Tyres
US/Canada specs only specify the Dunlops as per 84/85 models. Europe has a couple of extra tyre options though.
Front: 120/80/16 V250
| Dunlop F-17 | Metzeler ME333 Laser | Avon Super Venom AM17 |
|
 |
 |
Rear: 130/80/18 V250
| Dunlop K727 | Metzeler Perfect ME99A | Avon Super Venom AM18 |
|
 |
 |
90-93 Service Manual Tyres
Front: 120/70V17-V250 or 120/70ZR17 Cold pressure: 36psi
| Dunlop K25F | Metzeler ME333 Laser | Metzeler ME1 COMPK | Michelin A59X |
| Amazingly
no image! |
|
 |
 |
Rear: 150/70V18-V250 or 150/70ZR18 Cold pressure: 41psi
| Dunlop K275 | Metzeler ME1 COMPK | Michelin M59X |
 |
 |
 |
First Generation : A1 to A6
Front: 16×2.50 – 120/80/16 Rear: 18×3.00 – 130/80/18
Note 1. All these options are BIAS, as of Jul 2022 not been able to source a RADIAL tyre option.
Note2. as of Jul 2022 it seems OEM sizes are often unavailable in the US despite still being manufactured & available in other markets. Bummer.
Metzeler Lasertec (V)
REAR: 130/80-18 66V
Heritage tread pattern and modern technological solutions to enhance style and performance of the motorcycle
Feb 2021
Bridgestone BT-46
REAR: 130/80-18 66V or 140/70-18² 67V
The Battlax BT46 is set to replace the iconic Battlax BT-45. Since its introduction 22 years ago, the Battlax BT-45 has been the go-to tire for touring. Now, Bridgestone has upgraded this design with modern technology.Wet performance has been upgraded from the BT-45,with no impact on the predecessor’s well known dry handling performance and wear resistance.
From Bridgestone is the replacement for the ancient BT-45V (though not as old as the GPz!) with matched V-rated tyres for the A1-A6 versions.
I suspect this tyre will follow on from the BT-45V reputation as a reliable touring tyre (I found it very ‘comfortable’) and it uses exactly the same tread pattern, so it remains to be seen if the tyres suffer the same side-wall scuffing/scolloping that afflicted the BT45’s if they are ridden with spirit through the twisties.
Feb 2021
There are tyres listed as available for the later +A7 bikes but curiously the 120/70/17 front is only H-rated (210km/h). Also the rear is not currently available on motorcycletyrewarehouse.com.au
+A7 availability unconfirmed.
Dunlop GT501 (4th Gen Arrowmax))
REAR: 130/80-18 66V or 140/70-18² 63H²
Australian (most states) Importer Link
- The Tasmanian importer is a link to the 2016/17 Dunlop Catalogue PDF – 99% sure many sizes are no longer available in Australia.
- Tread looks identical to Dunlop Streetsmart but the listed available sizes slightly vary and they come up as different products below.
The fourth generation of the famous Arrowmax line incorporates all the lessons learned over 15 years of Arrowmax development . State of the art Aramid fibreglass belted designs give precise steering and handling as well as greater mileage by bracing and stiffening the tread area . Large range of ‘V’ &’H’ speed rated sizes to suit bikes from 250cc upwards. All sizes tubeless.More value and mileage than previous Arrowmax models by increased tread depth.
According to Dunlop all sizes are available for both generations of bikes, however this particular tyre IS NOT listed AT ALL at the Australian (most states) Importer Link – the closest they have is the 150/70/18 rear GT502, a V-rated tyre for Harleys. So although there are sizes to suit +A7 bikes listed as available at motorcycletyrewarehouse.com.au it’s likely that this is old stock.
Feb 2021
Pirelli Sport Demon
REAR: 130/80-18 66V or 140/70-18² 67V
AN X-PLY TYRE FOR MOTORCYCLES DESTINED FOR TOURING
Uniform and progressive performance in all riding conditions thanks to the rear multi-radius profile
High grip on wet and dry surfaces with excellent mileage
A safe and reliable tyre in all riding situations, with a particularly favourable cost/quality ratio suitable for Sport Touring motorcycles
The Pirelli site is pretty good matching the available tyres to the bike however being so specific and only being able to search by bikes means you can’t easily search for any ‘close’ matches with the 160/60/18. Note that the front is V-rated, the rear H-rated, though again I suspect it is a close call.
Feb 2021
It is available online at motorcycletyrewarehouse.com.au
Dunlop Arrowmax StreetSmart
REAR: 130/80-18 66V
2022 INFO. Curiously not listed at: European Info Link or North American Link but are listed at Oz (most states) Importer Link and I suspect they are also the GT501 series listed at Dunlop Australia Link
Sport touring bias tyre with modern technology for classic bikes.
Ideal for lightweight and classic bikes
Stylish design
State of the art performance
Innovative compounds with tailor-made silica optimise the balance between wet grip and mileage
Given the official variance availability must be questionable however they are available online at motorcycletyrewarehouse.com.au
Jul 2022
Avon AM26 RoadRider MkII
REAR: 130/80-18 66V or 140/70-18² 67V
Designed for motorcycles of all ages, the Roadrider MKII provides a step forward in performance and reliability over its predecessor.
The only tyre that I have found that comes in sizes to suit all versions of the bike.
Note: despite the international site reporting that this tyre isn’t available in Australia you can buy it online at motorcycletyrewarehouse.com.au.
Feb 2021
Second (A7-A10) & Third (A11- A16) Generation
Front: 17×3.00 – 120/70/17 Rear: 18×3.50 – 150/70/18
Note: although different generation bikes have different rims & tyres, the OD (outer diameter) of the tyres remains the same, hence the overall frame geometry is also *generally* unchanged.
+A7³ Dunlop RoadSmart (Z)
Oz (most states) Importer Link
Roadsmart features a new pattern with higher groove concentration in the central tread area to maximise wet performance . The “Triple Tread” rear construction places the traction compound in this area to enhance tyre life, whilst the ‘Flex Steel’ jointless belting system increases high speed stability by better absorbing shocks from road surface imperfections . The “grip” compound is is placed in the shoulder section to give high wet and dry grip performance in turns.New compounds have been developed for this latest sport touring tyre from Dunlop using ultra fine carbon enriched with silica.
So according to the international sites nothing fits – even though I have these on my A8 right now (Feb 2021). The Aussie Dunlop link lists both the 150/70/18 or 16/60/18 rear rim sizes BUT the Australian importer link shows nothing but 17″ rears.
Feb 2022 Update.
Again I can only reinforce how “hard” these tyres ride. I’ve played around with pressures and at 36psi at the rear gives wonderful feel, grip ()see below) & cornering stability, but also bucks like a bronco over bumps. If I were touring I’d simply have to drop the rear pressures to make riding in the saddle even remotely comfortable. Many owners talk about tightening up the front of 2nd gen bikes with heavier oil and stronger springs – but even with the front at just 28/29 psi I simply could not imagine doing this, as the negatives of mid-corner bump reaction would, IMHO, far outweigh any rebound improvement. I’ve simply accepted that the front forks are 30-40yo technology, and for minimising speeding tickets they are not a bad speed-limiter.
Perhaps the strangest issue with these tyres is wear. Every other brand/type I have owned has been replaced as a set because they both needed changing at the same time. With these the front wears much more than the rear so I didn’t actually need to change the rear last year. FYI the only geometry change was reducing the rear Hagon preload by two turns so I have no idea why there is unequal wear except perhaps that these tyres encourage more spirited riding, so I’m working the front harder.
Although not worn to anywhere near replacing I have recently noticed the rear slipping when tipped over and crossing painted lines – even in the dry. Whilst a good reminder *not to* cross the paint it’s still a bit nervy! The only anomoly I can see is that the rubber on the tyre shoulder is scuffed (image contrast adjusted for emphasis), whereas the centre and outermost portions (chicken strips are perfect of course!) seem smoother. Since I have a spare I’m going to put this on anyway so I’ll see what happens with the new one.
Feb 2021 Update.
My understanding is that Dunlop were making 18″ rears, even for the RS4, but have either discontinued production or are simply not bringing into Australia. Great. Last year my local tyre supplier told me there were just FIVE 18″ rears in Oz, 4x RS3 & 1xRS4, so I ordered a spare so at least I can refit these next time. No problems getting fronts. So I can’t imagine there are many locally, however ‘old’ stock still appears to be available from www.motorcycletyrewarehouse.com.au
Owner Review
At my last re-tyre a pleasant surprise with more tyre choices this time, Dunlop making/releasing an 18″ rear letting me use the OEM sizes of 120/70/17″ front and 150/70/18″ rear. Note I did use the RS2 on the front (rather then the RS3) for a couple of reasons. My tyre guy (small owner business) had one already there from an earlier cancelled order and offered it at a discount. So sure, I could have pushed for the newer one, but I like to help support my local small businesses and it saved a bit of coin.
Wow….different. I’ve read that the reason the GPz ride is hard at lower speeds is because the engineers designed it for +100mph stuff, and to be honest they were also probably thinking of the nice smooth highways of Japan (or the racetrack) rather than a typical Australian country road! And these tyres are firm and quite sensitive to tyre pressure!
The A8 has no front forks pre-load adjustment and they have just been serviced with new oil and seals, so it’s pretty close to spec. And yes, I have adjusted my rear shock to give some static sag!
I’ve adjusted the front to be 29psi – noticeably firmer than 28 (wriggly) but noticeably softer than 30. Yes, this sensitivity surprised me too. IMHO you can’t go higher – it’s just too much work. Higher PSI makes the bike more agile, but the front crashes and bashes through bumps so you end up having to work & concentrate hard to counteract road imperfections. Ultimately it isn’t all that enjoyable, and nd that’s for roads where I already know where the bumps are.
I normally simply set the rear at +4psi from the front, I suspect there is more ‘range’ at the rear-end as well. But make no mistake the ride is still firm – there’s several known bumps where if I’m not standing up off the seat it’s helium time. I had read some riders of bigger bikes (GPz is 222kg…) had front-end lift at speed with these tyres. Well there is nothing of that with my set-up. At within reason road speeds the bike is incredibly stable and secure – brilliant really. Grip is also astounding – wet or dry.
Update: had a chance to cruise a racetrack recently – at 220km/h on the straight there was zero front end lift, so I suspect this is more to do with the tyre on a particular bike setup rather than a trait of the tyre itself. And on the smooth surface of a racetrack, even at cruising speeds, these tyres felt absolutely fabulous and IMHO would be quite fine for a more competitive track day. You could definitely run higher psi.
Summary
IMHO these tyres match the design intent of the bike. Agile, grippy – it’s biased to performance and they significantly improve agility over the BT45/Avon combo. The best way to describe then is that they give you more range – ie you can be less precise with entry lines and speed because it’s really no drama to make mid-corner corrections if required. They really do make the bike feel lighter and increased agility improves city riding dynamics as well.
Are they better than the Contis?
Too long between drinks to really compare, but my memory (fading) says these are more precise – but definitely firmer.
Are they better than the BT45/Avon combo?
If I were mainly touring then I probably wouldn’t keep these – a softer ride, especially at the front, is simply more relaxing for long journeys. So it all depends on how you like to ride your GPz900r!
I’ve stuck with these because I do like the twisty stuff and these tyres are more fun to play with, but I would have been just as happy with the BT45/Avon combo as well. But the next set will be the Dunlops…if I can still get them
+A7: Dunlop GT601 (H)
Oz (most states) Importer Link
The Arrowmax GT601 line-up complements the StreetSmart range, to form a formidable line-up in highly performing sport-touring bias tyres.
Silica blend compound for stable grip in all conditions, with high abrasion resistance and great wet performance
Combining our popular Wide Parallel Grooves with the latest simulation technologies for tuning pattern rigidity
Responsive and smooth handling, with ample feedback even at high lean angles
Details on this H-rated tyre aren’t listed at the Australian Dunlop site. The international link doesn’t list the 120/70/17 front BUT it is listed on the OZ importer catalogue AND available at motorcycletyrewarehouse.com.au. Although only H-rated I suspect it’s a close thing, as several sizes are V-rated including a 130/80/18 rear – unfortunately no 16″ sizes though.
Feb 2021
A1-A6³ +A7³ Dunlop GT501 (H)
Australian (most states) Importer Link
- The Tasmanian importer is a link to the 2016/17 Dunlop Catalogue PDF – 99% sure many sizes are no longer available in Australia.
- Tread looks identical to Dunlop Streetsmart but the listed available sizes slightly vary and they come up as different products below.
The fourth generation of the famous Arrowmax line incorporates all the lessons learned over 15 years of Arrowmax development . State of the art Aramid fibreglass belted designs give precise steering and handling as well as greater mileage by bracing and stiffening the tread area . Large range of ‘V’ &’H’ speed rated sizes to suit bikes from 250cc upwards. All sizes tubeless.More value and mileage than previous Arrowmax models by increased tread depth.
According to Dunlop all sizes are available for both generations of bikes, however this particular tyre IS NOT listed AT ALL at the Australian (most states) Importer Link – the closest they have is the 150/70/18 rear GT502, a V-rated tyre for Harleys. So although there are sizes to suit +A7 bikes listed as available at motorcycletyrewarehouse.com.au it’s likely that this is old stock.
Feb 2021
+A7¹³ Michelin Pilot Road 2/3 (W)
A combination of technologies for better grip on wet surfaces, for longer periods of time. Ride with total peace of mind in all types of weather!
160/60/18 Rear
Note this size is not available in the 4 or 5 range .
Feb 2021
Although theoretically available only some sizes from the Pilot 2 & 4 range are available online at motorcycletyrewarehouse.com.au with no 18″ rears. I’ve just included a 17″ rear to show an indicative price.
160/60/18 availability unconfirmed.
+A7¹ Pirelli Angel GT (Z)
160/60/18 Rear
THE HIGHEST MILEAGE SPORT TOURING TIRE: 100% ITALIAN GRAN TURISMO
- The ideal tyre for travellers using the bike for long road trips, with side bags and passenger, looking for safety on wet, stability and mileage
- The evolution of the Angel™ ST, stretching the concept of Sport Touring into Gran Turismo, bringing the sporty attitude to a wider range of usage conditions and for longer distances
- The new reference for mileage in Sport Touring tyres
- Excellency in wet performance and grip
- Top handling capabilities, typical of the Pirelli DNA
- Performance consistency until the end of the tyre’s life
- Bi-compound
- Personalisable through sidewall rubber labels
Another sports tyre you can use as a matched pair when using the 160/60/18 rear.
Apr 2021: An owner who purchased these reported that these are very stiff tyres and very difficult to get onto the rim, the front being the hardest. He runs 36/41psi.
Feb 2021
Superceded bythe GT II which of course drops the 18″ rear. The ‘old’ GT is still available online at motorcycletyrewarehouse.com.au
+A7¹³ Metzeler Roadtec Z8 Interact (V)
160/60/18 Rear
ROADTEC™ Z8 INTERACT™ ensures peace of mind in the hardest situations, in the cold or wet, providing ideal handling for true riding pleasure.
Riding easiness, comfort, predictability, easy turn in, progressivity in lean, are provided by the interaction of sport touring profiles with the Greek π tread pattern and the patented Interact™ technology.Interact™ is the multi tension technology allowing Metzeler tyres to offer the best performance in all conditions; the differentiated tensioning of the steel belt underneath the tread compound gives a tailored performance.High steel belts winding tension in the center reduces compound movement and increases stability of the footprint area which reduces wear and ensures high speed stability
Low steel belts winding tension creates more flexibility and energy absorption, the compound increases the temperature and becomes softer, offering more grip while leaning
The variable winding process of the 0° steel belt guarantees a progressive behavior at different lean angles without discontinuity of performance
Feb 2021
Another sports tyre you can use as a matched pair when using the 160/60/18 rear, however only the front is available online at motorcycletyrewarehouse.com.au, I’ve used a 17″ rear for a price comparison.
160/60/18 availability unconfirmed.
+A7² Metzeler ME888 Marathon (V/H)
Metzeler ME 888 MARATHON™ ULTRA is the best partner for long and safe travelling on cruiser, tourers and their custom versions.
To achieve this targets, Metzeler designers finely combined the specifications which determine the characteristics of tyres: profile, structure, tread pattern and compound.
The structure shape features a flat and wide geometry that conveys and dissipates toward the sidewall the stress generated under the footprint, reducing the fatigue and the wear process.
To increase wear regularity, the transversal grooves of the tread pattern are discontinued by ‘compound bridges’, resulting in a more solid and stiffer tread design that reduces the stress transmitted to the belts and carcass plies.
Also the edges of grooves are critical areas for wear regularity. ME 888 groove walls have different inclination to ensure the best operating angle in every position.
The polymers of the compound are abrasion resistant, providing higher resistance to wear and hence high mileage.
A ultra-high milage cruiser tyre and although the official Metzeler site doesn’t included sizes (duh!) other international online stores suggest the OEM +A7 tyre sizes are available, V-rated front & H-rated rear.
Feb 2021
Both tyres available at motorcycletyrewarehouse.com.au.
+A7¹ Bridgestone Battlax T31 (Z)
160/60/18 Rear
A significant improvements in wet performance leads to a feeling of safety. The ideal sports touring radial, able to cope with a wide variety of riding conditions.
Feb 2021 Update
+A7¹²³ Bridgestone Adventure A41 (Z)
160/60/18
An Adventure Type tire that has evolved in all aspects to offer outstanding straight-line stability and performance in the wet, in addition to satisfactory wear life.
Feb 2021
The 2020 importer catalogue lists all the sizes including the 160/60/18 – however as it is not currently available on motorcycletyrewarehouse.com.au I have added a 17″ rear for a price comparison.
160/60/18 availability unconfirmed.
+A7²³ Metzeler Tourance Next (V)
The Enduro Street tyre that dares you to challenge any weather condition and any road
Feb 2021
Although listed on the Oz Metzeler site the 18″ rear is not available at motorcycletyrewarehouse.com.au, I’ve just included a 17″ rear to show an indicative price.
150/70/18 availability unconfirmed.
+A7¹ Avon Spirit ST (Z)
160/60/18 Rear
Avon’s latest hypersport touring tyre with exceptional wet grip performance and mileage. Manufactured in the UK.
Note: despite the international site reporting that this tyre isn’t available in Australia you can buy it online!
Feb 2021
+A7³ IRC Road Winner RX-01 (H)
A sport-bias tire with well-balanced abrasion resistance and grip.
A mix of narrow and wide grooves provide a flexible tread surface for superior road grip and traction on wet roads.
Stronger casing construction provides improved straight-line stability.
Feb 2021
The manufacturer site lists 120/70/17 & 150/70/18, curiously they specify a MT4.0 rim for the rear tyre. However apart from some used sizes available on eBay.com.au I haven’t found a local Aussie supplier. Looks like readily available in the US (inc Amazon) & also available online at japan.webike.net
Availability unconfirmed.
+A7³ IRC Road Winner RX-02 (H)
The RX-02 is an updated, all-around, sport, bias-ply tire based on the rider-favorite RX-01. We made a number of technical upgrades that boost performance on wet roads by 10 percent and reducing tire wear by 20 percent when compared to the RX-01, yet maintain the “easy handling” of the tire.
We added the latest compound technology to many of our new tires to improve grip on wet roads and reduce tire wear on advanced sport and touring bikes.
A new tread pattern is arranged linearly from center to shoulder, making neutral handling possible and improving grip performance in dry and wet conditions while maintaining balanced wear performance.
Front tire design was focused on neutral handling while design of the rear was focused on stability.
Feb 2021
The manufacturer site lists 120/70/17 & 150/70/18, curiously they specify a MT4.0 rim for the rear tyre. However the only local supplier I have found is at wrp.net.au however they only list a single rear size 150/70/70 for $159.94. Looks like readily available in the US (inc Amazon) & also available online at japan.webike.net
Availability unconfirmed.
For +2nd gen bikes the growth of the adventure bike market has been a godsend. Our rear tyre choice was always very limited, but many modern adventure bikes now use the 150/70/18 rear. Designed for heavy & fast bikes that are mainly used on bitumen I suspect these will be excellent on the GPz900r.
+A7 Pirelli Scorpion Trail II (W+V)
A NEW PATH FOR ADVENTURE
- Aggressive off road look
- Sport touring and Enduro performance blended into one product
- Bi-Compound
- Increased mileage
- Top level handling throughout the entire life
- Improved wet performance
In December 2021 I dropped into my local tyre supplier for a new front, and he told me about these Pirelli’s. Getting the rear has always been challenging for 2nd gen owners, but with so many adventure bikes coming onto the market there has been a resurgence of decent rubber.
Designed for fast & heavy modern adventure bikes many of these tyres are highly oriented towards bitumen, so these should be pretty good on the bike. I have a Dunlop rear yet to fit but if I didn;t have this already as a spare these Pirellis would be on the bike.
Reviews
+A7 Conti Trail Attack 3 (Z)
Our most agile On- / Off Road Tire, 100% trust from start for modern and powerful Adventure Tourers
100% TRUST: super short warm-up time – reaches his optimal temperature range within the first 1.500 meters*
BENCHMARK IN WEAR: the tire has after 3.500 km still more tread depth then a new benchmark tire and gives you better handling abilities**
PERFORMANCE OVER TIME: Built to ensure highest constant level of performance even after thousands of kilometers due to a mix of MultiGrip, carcass construction and pattern design
WET GRIP: Best wet grip achieved by compound & pattern design
AGILITY: Most agile All-rounder for easy, accurate and predictable handling
COMFORT & STABILITY: high level of comfort, absorption and stability even on challenging road conditions
OK – designed for adventure tourers rather than a sports bike BUT they are designed as 80% on-road AND have a speed rating of 168mph! Just goes to show how much faster all types of bikes are these days, and the tread pattern shows plenty of rubber on the road. Given their speed rating I’m wondering if these would be similar (or better?) in performance to bias tyres.
Feb 2021 Update
I have confirmed with the Australian importer (Ron Angel Wholesalers) that they are bringing in the 120/70/17 58W as well, even though motorcycletyrewarehouse.com.au only shows the rear in the older Trail Attack 2.
Review – N.L (UK)
The Conti trail attack 150x 18″ rear, don’t be put off thinking this is a trail bike tyre. Although not used on a gpz i’ve gone through about 10 of these on my KTM 990, all road use and it is a stonkingly good all round tyre that will outperform most riders – gives lots of confidence feedback, i’ve had a few minor – under power slides – typical corner exit and its fun – you get lots of warning and it happens progressively – the confidence side continues when on wet roads – – I suspect a potential advantage for the GPZ could be this tyre may help reduce harshness in the rear suspension – at least you have a range of sidewall stiffness to choose
+A7¹ Conti Road Attack 3 (Z)
160/60/18 Rear
The Allround tire with the highest standards in the sport touring segment.
Performance oriented pattern design for better drainage in wet conditions.
More improved wet grip due to an optimized compound.
The EasyHandling technology bestows the tire with linear handling even if stabilizing gyroscopic forces are nominal (e.g. when turning). Simultaneously, accuracy and groundingfeeling are improved at benchmark level – applies to all riding situations in this segment.
Comfortable and easy for all demands, whether on long rides or winding roads.
Balanced characteristics from the first to the last mile.
TractionSkin, a revolutionary new micro-rough tread surface, virtually puts an end to tire break-in. This is possible due to a new mold coating technology which eliminates the need for tire-release agents.
MultiGrip makes it possible to use a homogenous grip grading with a single compound thanks to temperature controlled curing of the tire during the production process.
The Road Attack 2 Classic Race was available in a 150/65/18 – which was a nice alternative option for the rear. Unfortunately NA unless you buy old stock from eBay, in Feb 2021 some (9) were still available with a manufacturing date of late 2012. Some folks say the max storage life is 6 years, others say 6-10, so either way these are old stock. Not much cheaper that other newer tyres either.
Feb 2021 Update
According to Continental a matched pair using the 160/60/18 is still available in the new generation RA3 and I have confirmed with the Australian importer Ron Angel Wholesalers that they are bringing the RA3 sizes in, though they didn’t currently have the rear in stock. Note motorcycletyrewarehouse.com.au is only showing the RA2 range.
Reviews
A few years ago I ran Road Attack 2 tyres with a 150/65/18 and really liked using them. I was getting back into bikes and these were grippy and the smaller rear tyre meant the bike felt very planted & secure whilst I was figuring out how to ride again. I don’t think they are designed for longevity! The only gripe was a very fine buzz through the perfectly balanced front tyre – which was kinda odd when you look at the consider the blockier tread pattern of the BT45 that replaced it. Unfortunately Continental had discontinued importing this size in the RS2 range which was the only reason why I changed.
Despite conventional wisdom regarding matching front & rears, *sometimes* local supply means there are no matched pairs for our rim sizes so here are individual tyres for interest.
150/70/18²³ Avon Cobra AV72
The Avon Cobra Chrome is our newest offering aimed at the power cruiser/touring/custom market featuring premium performance, a stylish Cobra themed design and a wide range of sizes.
Note that the AV72 has been superceded with the Cobra Chrome.
This tyre was run in combination with a BT45 front, as neither tyre comes in a matched pair. The tyre choice (suggestedby my fitter) followed on from Conti Road Attack 2’s which were no longer available in the 150/65/18 rear. The intent at this change was for a longer-lasting tyre rather than performance, I had recently made the pilgrimage to Philip Island and the Contis wear horribly in a straight line.
Review
Firstly I really liked the design, much more than the new Cobra Chromes actually.
Of course these are not performance tyres, and they handle at least two levels below the Dunlop Road Smarts that replaced them. But they weren’t bad at normal road speeds and were still very secure & predictable when cornering. It is only when really riding with spirit that you notice a difference, faster more precise tipping in and much quicker & easier changes of direction.
Ultimately the most the greatest difference was comfort – the bias-tyres are much, much friendlier. I had to drop the rear shock pre-load by two complete turns with the Dunlop otherwise hitting road bumps was like riding a bucking bronco.
IMHO the GPz ride can never be described as comfortable, so if touring or highway riding is your riding priority I would take this Avon over the Dunlop every day.
Never had any dramas in the dry or wet, however the only really quirky issue I had with the Avon was that it would ‘shimmy’ (as opposed to slide) over surface transitions. Initially very disconcerting but ultimately it also very predictable, so just became something that you got used to.
GPz900R (ZX900) Database
Number of owner contacted & confirmed bikes.
A1
A2
A3
A4
A5
A5A
A6
A7
A8
A9
A10
A11
A12
A13
A14
A15
A16
Top Gun
About the Site
My family loves older vehicles, the newest one we own is 2003! But I am acutely aware of the ownership complexities especially:
- they often need more 'hands-on' mechanical work &;
- there often isn't any local expertise from the service centres;
- there is often no new parts available from the manufacturer;
- parts often have to be sourced 2nd-hand or from overseas.
So we often end up doing a lot of the research & work ourselves and this information gets stored either locally with the bike or online forums - although finding the useful parts in these forums isn't always simple.
The original goal of the site was simply somewhere for me to record service work & contacts on my GPz900r so that my kids (the one that likes bikes anyway!) could easily access it - it doesn't concern me if it was publicly available.
I then realised that with this online structure in place I could also offer it to other owners, and the site could potentially expand to record other owners experiences and expertise , meaning we can learn from others but also pass on this knowledge to subsequent owners of these wonderful motorcycles.
At least Covid-19 has given me plenty of spare time to pursue my passion for the motorcycle!
Location
Adelaide
South Australia
gpz900r@motoshoot.com.au
Timeline
1983 - Honda XR200
1984 - wanted a GPz
1985-2013 - cars+family
2014 - finally got one!
Disclaimer
The information provided on this site (or links) is personal experiences from non-professional home-mechanics, so neither it's accuracy nor it's validity can be confirmed. If you need professional advise please visit your local Kawasaki dealership or a qualified industry professional.
Like riding any motorcycle, at the end of the day the only opinion that really counts is your own!