GPX750r tyres

[Thehunted]

Hi all, 

Wonder if I can pick people's brains from some advice. I'm doing up and old Kawasaki GPX750R and at the final stages after it being off the road since 2011. I need two new tyres. The original specs are 110/90/16 and 140/80/18. The tyres currently on are 120/80/16 and 150/70/18. What size do you think I should go for. 

 

Thanks 

[Simon Davey]

14 minutes ago, Thehunted said:

Hi all, 

Wonder if I can pick people's brains from some advice. I'm doing up and old Kawasaki GPX750R and at the final stages after it being off the road since 2011. I need two new tyres. The original specs are 110/90/16 and 140/80/18. The tyres currently on are 120/80/16 and 150/70/18. What size do you think I should go for. 

 

Thanks 

 

I would go for the originals.

There's been a "thing" for changing to wider tyres, I'm assuming to keep traction on a heavy lean(?).

But I'm of the school of thought that, those tyre sizes, and that bike, were designed that way for a good reason.

[Thehunted]

Thanks Simon, I was leaning towards the original myself. Being a 16" front wheel, I'm limited for choice. I can get the original sizes in a Bridgestone Battalax BT46 and Pirelli sport demon. I can can the larger size in the BT46 only. Has anyone used the above tyres and can recommend. 

 

Thank you

[RideWithStyles]

get the original sizes!
unless for what ever reason they dont make them anymore.

all the “over size” twice (front a rear) will make the bike quite noticeably slower to tip in and turn also the pressure may need upping atouch from the book’s recommended. But at least it would be crudely similar both front and rear.

[RideWithStyles]

Personally I not a fan of BS myself, but some do like them.

What was on them before and did you like them? If yes stick to that brand if not then change.

Dont bother with any OEM tyres they are garbage and cost more.
if you ride only summer time the Pirelli will do you good, they are on the royal Enfield range and a few others as std, good tyres but avoid the oem specs.

bt45 were oem on jap bikes of that era but bs have slightly updated them from first release century ago.

[Thehunted]

The OEM are no longer available, neither are the tyres that are on it at the moment. Michelin and Continental but obviously older models which they no longer produce. I've never ridden the bike so no idea how it handles. I think I'll get the Pirellis. 

 

Thanks  

[RideWithStyles]

Depending on what you want out of tyres as they are very dynamic, they can make or break a bikes handling or feel.

 

Michelins are a soft in feel but quite hard wearing tyre compound, soft construction which give a soft smoother ride but requires higher pressures and has some may say less feel of what they are doing but they great all rounder (winter is ok with them) if you dont need shouting at to trust them with few negatives.

pirellis are sportier, slightly firmer and slightly warmer climate biased but still good. Which I’d say is inbetween to two others.

bridgestones are harder carcass and rubber which is slightly oldschool, they will let you know what they are doing but they can have a quite hard plastic feeling to them (especially in cool and wet weather) if your that type of person that want them to shout at you. You might feel to drop the pressures slightly if you want a smoother ride but all that does is make the tyre rebound more (flex and spring back) which leads to strange wear and feel off or hard work.

but again it depends on what you want out of them and you need for yourself.
 

[Thehunted]

Thanks for the info. To be honest I haven't got alot of experience, being self employed I thought it would he better for my legs to be one piece whilst building up the business so it's been years since I've ridden. Now I'm older and slower I just want something I can plod around onwitb the wife on the back occasionally. Not really interested with high speed etc, and as it's an older bike I assume the handling is going to be a bit ropey. Just looking for something safe and predictable.

[RideWithStyles]

Ropey is only if it’s not maintained and condition is not correct.

Make sure fork and shock is serviced - stripped, cleaned and replaced oil (probably with a slightly thicker oil if there is no adjustment) and gas or as with the case with the shock probly wont be serviceable so that may need changing if the damping has gone.

 

[Thehunted]

Everything has been replaced or serviced. Forks have been rechromed and new oil installed. I've read they wasn't the best and quite twitchy on corners due to the 16" front wheel. I've ordered the pirelli tyres and get them fitted next week. Hopefully they are ok. Thanks for the advice 

[Simon Davey]

Good luck with it, I'm sure it'll be a very satisfying bike to ride, especially after all the effort. 

[Thehunted]

Thanks Simon, and thanks for the advice.

[JRH]

On 14/07/2024 at 22:26, RideWithStyles said:

Ropey is only if it’s not maintained and condition is not correct.

Make sure fork and shock is serviced - stripped, cleaned and replaced oil (probably with a slightly thicker oil if there is no adjustment) and gas or as with the case with the shock probly wont be serviceable so that may need changing if the damping has gone.

 

Ropey! The GPX were not the best handling bikes from new. I had one for many many years and the handling was skittish to nervous. This was mainly due to the 16” front wheel. It was also very sensitive to the rear tyre pressure. I tended to run a few PSI higher than book.

[JRH]

On 14/07/2024 at 19:11, Thehunted said:

The OEM are no longer available, neither are the tyres that are on it at the moment. Michelin and Continental but obviously older models which they no longer produce. I've never ridden the bike so no idea how it handles. I think I'll get the Pirellis. 

 

Thanks  

I ran Bridgestone on mine. Can’t remember the designation, but at the time BS were the only manufacturers doing that size in matched front and rear. Handling can be skittish with the front tipping in. Mine was also sensitive to the tyre pressures. I tended to run the rear several PSI above book. The original rear shocks were never the best and by the time I traded mine in the rear shock was struggling to hold air pressure. 

[Thehunted]

Thanks, I have read about the handling and doesn't really fill me with much confidence. 

 

The shock is original and amazingly still holds air. I cleaned it all down. Replaced the air tube valve because mice had nibbled it where it had been stored, but once pumped up it's still the same pressure 6 months later give or take a couple of psi. 

 

To be honest its not going to be ridden much and it's definitely not going to be ridden fast so hopefully handling won't be much of problem. 

[JRH]

14 hours ago, Thehunted said:

Thanks, I have read about the handling and doesn't really fill me with much confidence. 

 

The shock is original and amazingly still holds air. I cleaned it all down. Replaced the air tube valve because mice had nibbled it where it had been stored, but once pumped up it's still the same pressure 6 months later give or take a couple of psi. 

 

To be honest its not going to be ridden much and it's definitely not going to be ridden fast so hopefully handling won't be much of problem. 

I went from a kwak GT750 to the GPX so the handling then was an improvement for me. I rode it pretty quick and so got used to the quick steering and the “flexibility “ that was sometimes encountered mid corner.

 

its only when you get onto a “modern” bike that you realise how much the bikes have improved.