17" wheels for 1982 GS1100GL

[Guest]

Hi All,

The last thing I'd like to do with my GS project is get it on 17s. It appears there's a 17" rear wheel option on similar year GSs with shaft drive, and the parts for the gears, brake rotor, etc are the same #s, so that generally means a direct swap. Is that the case here?

For the front, I don't see anything from that vintage in a 17". I understand there are newer options, and I would consider going all the way with a USD fork, but a more appropriate wheel would be preferred. It's in this front-end area that I'm really scratching my head, and I figure it's all been done before, so what say you?

-Ben
GS profile.jpg

[Steve]

A 17" rear is rather doable. I have gone the other way, from a 17" to a 16" on my 850G to get the tire that I wanted. I don't see why you couldn't go the other way around. One thing to note: the 17" tire is obviously a bit larger, and will change your drive ratio a bit. Your 1100 should handle it just fine, as the change is pretty close to matching the final drive ratio change that they did in '83.

What is the appeal of putting a smaller wheel on the front?

.

[HammyDownGS]

Hey Steve,

Thanks for the reply! The appeal is I'm a "sporty" rider, and I not only want to further change the original geometry of the bike by another inch or so, but I want open up my tire selection by a LOT!

[GregT]

Hey Steve,

Thanks for the reply! The appeal is I'm a "sporty" rider, and I not only want to further change the original geometry of the bike by another inch or so, but I want open up my tire selection by a LOT!

Yes, you can find and fit later 17in fronts which will give you a wider - literally - selection at that end. Your problem is that with a shaftie, the 17in rear you can fit is by modern standards a very narrow rim.
There is no easy way around this. Space is your problem.

[Steve]

The appeal is I'm a "sporty" rider, and I not only want to further change the original geometry of the bike by another inch or so, but I want open up my tire selection by a LOT!

Interesting that you claim to be "sporty", yet have a shaft-driven bike as your bike of choice. Then you want to intentionally upset ("change") the geometry by lowering the front of the bike, which will not only decrease the rake and the trail, it will decrease your cornering clearance. Add that to raising the rear half an inch with the larger tire, rake and trail will be decreased even more. Not exactly where instability will set in, but you would probably be getting close.

Now, let's define "sporty".
If you are simply meaning that you like to maintain elevated velocities while negotiating non-straight sections of road, we need to introduce you to bwringer. He has an 850G, and very few can keep up with him unless he dials it back a notch or two. And that is with the stock wheels and tire sizes on an 850, 100/90-19 up front and 130/90-17 on the rear. I believe his tire of choice is the Avon RoadRider.

As GregT menitoned, you might be able to change the front wheel, but you will have to also change the forks and triples to something that is wider. With the current setup, you will have a hard time fitting a 110 front tire, regardless of diameter. The rear is also hampered by wheel width. To complicate matters, unless you have a machine shop and a good welder, you will not be able to go any wider with wheel or tires. A wider wheel would have to have a custom rim adapted to the stock wheel, but a wider tire would hit on the swingarm, anyway.

If you need any more "sporty" than that, you simply have the wrong bike.

.

[HammyDownGS]

Interesting that you claim to be "sporty", yet have a shaft-driven bike as your bike of choice. Then you want to intentionally upset ("change") the geometry by lowering the front of the bike, which will not only decrease the rake and the trail,

Now, let's define "sporty".
If you are simply meaning that you like to maintain elevated velocities while negotiating non-straight sections of road, we need to introduce you to bwringer. He has an 850G, and very few can keep up with him unless he dials it back a notch or two. And that is with the stock wheels and tire sizes on an 850, 100/90-19 up front and 130/90-17 on the rear. I believe his tire of choice is the Avon RoadRider.

As GregT menitoned, you might be able to change the front wheel, but you will have to also change the forks and triples to something that is wider. With the current setup, you will have a hard time fitting a 110 front tire, regardless of diameter. The rear is also hampered by wheel width. To complicate matters, unless you have a machine shop and a good welder, you will not be able to go any wider with wheel or tires. A wider wheel would have to have a custom rim adapted to the stock wheel, but a wider tire would hit on the swingarm, anyway.

If you need any more "sporty" than that, you simply have the wrong bike.

.

Hmmm...well I appreciate the feedback. A couple bits are useful and food for thought. Definitely lots of assumptions in your reply, but that's to be expected online! I don't "claim" to be sporty...I actually am. This bike, which I created a post for a while back, was stated as a gift from an older uncle of mine. She was ugly as sin, and not my style, so I decided I would rebuild it in my image I actually have understanding of frame flex, suspension, and *gasp* rake and trail and their characteristics. I thought we were in a mods/customization sub forum. If you look at my sig you'll see I have a handful of machines, and these are only the ones I own right now. I have 30 years of riding dirt, street and track under my belt, and I'm not the worst welder! I don't put bikes together with "no", but thanks again for your input. I'm looking for alternatives. Stories of creativity, fabrication and possibility...not "you ain't got the right bike."

[GregT]

Hmmm...well I appreciate the feedback. A couple bits are useful and food for thought. Definitely lots of assumptions in your reply, but that's to be expected online! I don't "claim" to be sporty...I actually am. This bike, which I created a post for a while back, was stated as a gift from an older uncle of mine. She was ugly as sin, and not my style, so I decided I would rebuild it in my image I actually have understanding of frame flex, suspension, and *gasp* rake and trail and their characteristics. I thought we were in a mods/customization sub forum. If you look at my sig you'll see I have a handful of machines, and these are only the ones I own right now. I have 30 years of riding dirt, street and track under my belt, and I'm not the worst welder! I don't put bikes together with "no", but thanks again for your input. I'm looking for alternatives. Stories of creativity, fabrication and possibility...not "you ain't got the right bike."

All fair comment. But yes, IMO you have got the wrong bike. I've built a fair few GS into what we call Post Classic - and you lot call Vintage - race bikes.
Characteristically, they use modernish rim widths - 3.5in front and around 5in rear - and are jacked up at the rear to achieve better ground clearance. A frequent result of this is the quick/too quick steering compromise. I'm sure you've struck this previously.
But a shaftie does not lend itself to this approach at all. The U-joints do not like being run at extreme angles for a start. With a chain drive you can change the driveline offset readily.
A shaft is much,much harder to move over. Tyre width is compromised. Take a look at a late Guzzi compared to an earlier one. The engine is moved over to gain room for wider rims.
It's a lot of work for very little gain.

[bwringer]

Howdy! Fellow slobbering red-eyed nail-biting GS850G-abusing lean angle addict here.

The only non-anecdotal evidence I have, really... sorry about the mismatched clearance rain gear.



Properly sorted out and tastefully updated, GS shafties handle remarkably well. Suzuki really got the geometry right on these.

Yes, they're heavy (and the 850 is the heaviest of all) and they're not insanely powerful. But a well-running GS850 has one of the more entertaining engines you'll find, with a giggle-inducing rush and howl from 6,000 rpm to redline. The 1000G and 1100G have more power and torque, but I much prefer the 850. And there's an old saying that it's a lot more fun to ride a slow bike fast than the other way around.


Anyway, yes, there are various projects that have grafted a more modern front end onto a shaftie, complete with 17" front wheel. The most common difficulty is that most of the available choices are quite a bit shorter than the original, so the front end is lower and thus cornering clearance is badly compromised. There are ways to deal with this, of course; choosing longer donor forks from naked or dual-sport bikes or crafting fork extensions, etc.

Out back, the limitations are a fair bit more severe, because there's simply not room in the swingarm to go much wider. I can't recall any successful projects along these lines, although there have been many inquiries hereabouts over the years. I do know the VX800 used a 150/70-17 rear, which was technically a little too wide for the wheel, and that the VX800 wheel will mate up to the 850 final drive. However, the 150 tire contacts the GS swingarm.

If you are able to fabricate or modify the swingarm and frame to address this, then you are operating at a level well beyond anything we've seen here and you don't need our input. We do respectfully request lots of pictures...


The handling limits of the GS850G are set by frame flex, not the tires. As Steve noted, there are some excellent choices for very sticky rubber in the appropriate sizes. The Avon RoadRider is well-regarded, and the Pirelli Sport Demon is probably the very stickiest of all, although short-lived. The Michelin Pilot Activ is a relative newcomer and may even dethrone the Pirelli. However, I don't recall any reports yet from out on the ragged edge... we're an, uh, frugal group, and the Michelins are very spendy.

Personally, I've been running the Shinko 230 for quite a while. They're sticky, neutral-handling, and cheap, but short-lived. The GS only gets about 3,000 miles a year these days, and they last about 2,500 3,000 miles under my abuse. They behave flawlessly down to the wear bars, and I like having fresh tires more often.


There have been a few projects that experimented with frame and swingarm bracing on a shaftie with satisfactory results.

I've also wondered whether replacing the stock 37mm forks with the much stiffer 41mm forks from a GS1100GK (and thus the slightly wider wheel and the 110/90-19 front tire) would be worth the weight penalty. There may be other stiffer front ends with sufficient length. Still, my opinion is that out on that ragged edge, it's the frame flex that's far more of an issue than the fork. Tire grip is a distant 14th or so on the list of things holding you back.

And like any bike, the more you spend on suspension and brakes (and spend the time to set things up correctly), the more you'll like it. I'm using Sonic springs up front and Progressive shocks out back, which is kinda the cheapest option.

As far as shocks, sky's the limit; you could install $2K Ohlins, but most of us slap on a set of sub-$300 Hagon or Progressive shocks (there's also YSS, Ikon, and many others). You can also install emulators in the fork, which I haven't done.

I've experimented with a fork brace, but strangely I didn't like it. I think my brain got used to using the information provided by the flex from the forks. But YMMV, of course...

If you want to raise the rear a bit, you're limited by acceptable driveshaft angles. About 1/2" taller seems to work well. I haven't done this.

Stock brakes with braided lines, fresh innards, fresh sticky name-brand pads (I'm using EBC Red) are shockingly good compared to what many are riding around with. Still, the "twinpot" brake upgrade has been reported to have excellent results. It's also important to make sure the front end is up to snuff; the biggest immediate everyday benefit to proper straight-rate fork springs is drastically reduced brake dive.

[bwringer]

To more directly answer a few of your questions, explicit and implied:

- People like to poo on the GLs around here, so before that nonsense starts I'll just make it clear that the GL models handle identically well. The riding position is a little lower and different, maybe even better for handling. And the stock handlebars are crap either way, but everyone changes them anyway.

- It should definitely be possible to get a 17" rear from a G model to work. I don't know the details; I do recall a gent who had to space the brake rotor out a bit or something like that. A bit of experimentation should sort that out. Still, you're pretty much stuck with the 130/90 tire. Even a 130/80 affects the handling negatively. Similarly, many have tried a 110/90-90 up front and it is well-known to turn the handling piggish.

- I don't have the foggiest idea whether moving to a 17" up front (all else being equal) could improve handling over the 19". Probably not, and unless you take countermeasures, it will lower the front end by at least an inch and probably more, which I would consider entirely unacceptable for cornering clearance. Getting the brakes, spacers, etc. to match up is a bit of a mystery. All the projects I'm aware of changed the whole front end.

I do know the GS500 used a 17" front with a 110 tire. I'm not sure whether that would be a productive line of investigation at all; it or the tire may be too wide to fit the forks, or adapting the brakes might be too difficult. FWIW, you can stuff a 110/90-19 in there on a stock bike, but it's a very tight fit.

[kingofvenus]

Back in the eighties i rode with a guy who at that time raced a fz750 in ama superbike for a couple years. He was fast as heck on a backroad or two on some bikes with totally worn out junk tires. Watched him scrape parts on a cavalcade. Todays tires are WAY better than they were then. I'd bet you could find a front in a 19 that is up to the task, and then some.

[GregT]

Back in the eighties i rode with a guy who at that time raced a fz750 in ama superbike for a couple years. He was fast as heck on a backroad or two on some bikes with totally worn out junk tires. Watched him scrape parts on a cavalcade. Todays tires are WAY better than they were then. I'd bet you could find a front in a 19 that is up to the task, and then some.

I wouldn't disagree with that. Bridgestone BT39 are very sticky and suit heavy bikes well for track use.
The modern race compound 19's for Classic race bikes like Manx Nortons are too soft carcase construction for heavy bikes.

[Buffalo Bill]

Well, here's some ideas for the rear swingarm and wheel.
It may be possible to cut a notch in the shaft housing to accommodate a wider tire, because it is dry inside.
We had a member mount a 17" wheel from the later (91-94) GSX1100G, into his GS1100G, successfully and without modifications.
You may be able to get a 150/70-17 or 160/70-17 radial in there.
If the shaft housing and swingarm can be notched successfully, I recommend welding on a brace:

[bwringer]

Excellent info, Bill. I hadn't seen that before.

I do know that when we discussed a VX800 or GSX1100G wheel swap in the past (thanks to Suzuki's strong parts bin mindset, these use the same driven spline part and mate right up to the GS final drive, although the spacers and how they stack up would need to be checked and probably modified or fabricated), one potential issue was that the centerline of the wider wheel would end up offset to the right a bit.

The amount of offset and the effect this might have on handling are a little unknown. As long as everything is straight, a little offset doesn't seem to have much effect; there are bikes known to have some amount of offset from the factory.

[Buffalo Bill]

I considered doing this last year or so with my G, but I had to ask myself: why and for what result?
A G will never be equal to an E in performance.