1980 GS1000G Tire Question

[Guest]

Just wondering, what is the widest tires I can put on this bike? I'm not a tire guy and don't know how to translate the different tire numbers.

If I can go wider at least in the back it would be nice to know.

From the manual Frt tire is 3.50 v 19 4pr and the rear is 4.50 v 17 4pr

I had them changed a few years back at a Honda dealership and currently have 100/90-19 on the front and 130/90-17 on the rear.

Any help is appreciated.

[bwringer]

Can we make this an FAQ or sticky or something?

This question gets asked a LOT. I don't know why. Maybe all the chopper shows infesting the airwaves have led the citizenry to believe that every motorcycle needs a phat 300 series beach ball for a rear tire.

On your bike, 130/90-17 is correct for the rear (this is actually a touch wider than the original, but is well-known to work great and is easily available). Up front, use 100/90-19.

You should not install a wider tire on the stock rims. Unlike low-tech four-wheeled appliances, motorcycles must lean to turn. This means that a rounded tire profile with a consistent radius is crucial to proper handling and maximum grip.

If you install a wider tire, the profile of the tire gets pinched into a cross-section shape more like a hamburger bun and the handling suffers greatly. Not to mention a wider tire will contact the swingarm.


And just to get out ahead of the inevitable follow-up question: no, there are no known wider wheels that you can install on a GS shaftie. There's been lots of talk about adapting a wider rim to work with a spoked Intruder hub, or widening the stock rim, or adapting a VX800 or GSX1100G rim, but AFAIK, no one has ever actually accomplished this. Even with a wider wheel, a wider tire is going to contact the swingarm (look how close the 130 tire is already), so then you're either offsetting the rear tire to the right or re-engineering the whole rear end... Sure, with enough explosives and money anything is possible, but this is just not a worthwhile battle.

If you really must have that phat rubba look on a GS, get a chain drive model, make friends with someone who works in a machine shop, and swap in some modern parts.


But here's the secret: with sticky rubber in the proper sizes, good shocks, fork springs, getting the brakes up to snuff, and a bit of work on your riding skills, your bike will handle superbly. Suzuki got the geometry exactly right on these bikes, and the shafties will rail corners with frankly astonishing agility. And all-day comfort.

[Dogma]

Edit: Brian beat me with a more comprehensive answer.

[Wingsconsin]

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But here's the secret: with sticky rubber in the proper sizes, good shocks, fork springs, getting the brakes up to snuff, and a bit of work on your riding skills, your bike will handle superbly. Suzuki got the geometry exactly right on these bikes, and the shafties will rail corners with frankly astonishing agility. And all-day comfort.

This I know to be true..
Last night I was out riding around - just de-stressing from a long work day
I found a fabulous set of long high speed sweepers and was just ripping along at an unknown speed.
But through several corners of rights and lefts I was just tickled when I felt the suspension settle, and the rear tire swing around as I leaned the bike through a corner -- When you can feel the bike set itself for the corner - and feel the G forces working that rear end - and the centrifugal force transfers down into the road surface rather than toward the outside of the corner... wow....

[njload]

Thanks for the responses, good info.

[landshark]

or widening the stock rim,

I completely agree with everything you said, but i do know a member here widened his rear to run with a side car set up.

[Steve]

... i do know a member here widened his rear to run with a side car set up.

Last time I checked, the setup for a sidecar was ever so slightly different.

For the most part, they don't have to worry about silly things like leaning in curves.

.

[landshark]

Last time I checked, the setup for a sidecar was ever so slightly different.

For the most part, they don't have to worry about silly things like leaning in curves.

.

I realise this, just stating its possible to fit between the swingarm.

[Steve]

But did you click the link?

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[landshark]

But did you click the link?

.

You got me there!

[bwringer]

I realise this, just stating its possible to fit between the swingarm.

You still wouldn't be able to mount a wider tire on a GS shaftie without offsetting the tire to the right (go out in the garage and look -- a 130 is very close to the swingarm). This wouldn't make much difference on a sidecar setup (might even help handling by a hair) but it's probably not advisable on a motorcycle that still has two wheels.

[landshark]

You still wouldn't be able to mount a wider tire on a GS shaftie without offsetting the tire to the right (go out in the garage and look -- a 130 is very close to the swingarm). This wouldn't make much difference on a sidecar setup (might even help handling by a hair) but it's probably not advisable on a motorcycle that still has two wheels.

John might chime in at some stage and tell you what size car wheel was welded onto the shaft drive hub, i think he did it more for height than width