Rear tire size for 1150 with 4.5" GSXR wheel

[tyler1150]

Guys,

I finally conceded to the fact that a 5.5" is not worth the headache. Opted for a 4.5" wheel instead

Now its new tire time. I have been told that a 150 is fine for the 4.5" rim.

My question: will a 160 be to much?

[cbxchris]

I would be more concerned with a larger size if my chain is going to clear. The 1150 comes stock with a 130. They get real close with a 140 but have seen some sqeeze a 150 in there. Be careful that you don`t get into a clearance problem.

[RacingJake]

Hey Dean

I was running a 150/70x17 tire on my stock 2.50x17 rim and it worked fined. I think a 160 should'nt be a problem with a 4.5 rim. Maybe a 170 would work too?

Good luck
Jake

PS Your old slick is working out great. Just had to do alittle cutting and pounding with a hammer for clearance but boy does it look mean.

[Billy Ricks]

I run a 160 on mine. It's what the Gixxers ran with them.

[Anonymous]

is it possible to run a 150/70x17 tire on my stock 2.5 inch?
the bike is a 1983 gs750es, from what ive herd it couldnt be done?

[cbxchris]

Jake did you mean to say 3.50 instead of 2.50? The early 1150`s(84/85) had 3.00 rear wheels. The 86 had a 3.50. I have gotten a 3.50 for my 84 and may attempt a 150 later this summer. I have seen where several have fitted the 140 on a 3.50. When I get froggy I have a widened stock kosman wheel that I intend to use.

[Billy Ricks]

Pete, don't try to sueeze a 150 onto a 2.5" wheel. You'll have the sidewalls so squeezed down you'll end up with a smaller contact patch than you already have and it will be squirmy when leaned over. A 130 is the most you want to use on a 2.5", and no radials.

I've run a 140 radial on a 3.5" wheel before.

[Anonymous]

Why no radials? They are so nice with the tough sidewalls, I had a rear Dunlop K591 go flat doing 130 km/h and it didn't effect handling enough for me to stop until it started to wander a little.

Steve

[RacingJake]

It's a Michelin Radial on a 2.5 rim and work great going straight. Never been on the twistee's so I can't give you any feedback there. The sides are alittle sharper so i would think you have to be alittle careful taking hard corners and braking, it could cause you to low side the bike.

[Billy Ricks]

Why no radials?

It's safer to run an oversized bias ply tire on too small of a wheel than a radial. Radials already have so little sidewall that when you pinch them into too small of a rim you're changing everything about the tire. You have a poor bead seat because the tire is pinched too much. The profile of the tire ends up triangular. So you have a smaller contact patch than with the right size tire. It will also be hard to get the bike to initiate a turn. Once it does it will fall into the turn and be tough to hold a line. Too much torque and friction when leaned over might even break the bead. Yokohama used to make some narrow raidals but I don't think they do anymore. You are right about the strength of the sidewalls. I've rolled mine out of the garage with zero air in the tires and it looked like they were fully inflated.

[lhanscom]

What's the smallest rim you can safely put a radial on?

[Billy Ricks]

Most tire manufacturers will have recommended rim widths on their websites. A 120 front normally gets mounted on a 3.5" wheel. You can get by with a 3". A 110 might be okay on a 2.5" front. On the rear a 140 fits a 3.5" wheel fine and you might get by with it on a 3" wheel. 4.5" wheels normally use a 160. 180 on a 5.5" wheel. You can use these sizes normally on wheels that are +/- 1/2". Tire manufacturers build their tires for performance on certain size wheels.

[Billy Ricks]

Here's a guide for bias ply tires.

http://home.earthlink.net/~mildness/yo/frames/faqv2_17.html

[cbxchris]

Billy is correct on radials. Radials recommend wheel widths commonly 1/2 to 1 inch wider than bias for the same size tire. I do wonder how a 150 would do on a 3.50 wheel? I wouldn`t try it on a 3 but what does everyone think it will do with that extra half inch? I am using a bias ply tire. If I use a 150 on a 1150 I might have to go to a 530 chain to clear.

[Anonymous]

This makes sense. When I mounted a K491 100/90-18 on my front wheel I was almost sick to my stomach. It looked really bad until I pumped it up, but thankfully it took it's proper form. The spec is for a 3x18 so I figured 100 was close enough but man! The 491 is huge compared to a 3 inch street tire and it's even bigger than a 3.5 inch dual sport tire! It barely fits under the fender too, it's quite tall. My top speed dropped from 130 to 120 km/h too, as it's got the speedo messed up with it's size.

Steve