Wheel change (17") on an 1982 GS1100GL

[Charmed]

Hey ya'll,

This is one of those questions that kind of requires some direct experience, BUT, I wanted to ask the BARFS to see what tribal knowledge is out there. I inherited an old cruiser from my Uncle, and not being my style I decided to turn it into something I wanted to ride every freaking day. After shedding parts and making a bunch of changes, the final thing I'd like to do with my GS project is get it on 17s for rubber choice, sharper handling geometry and cosmetics. 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. There's a bit of room before I hit the swingarm, so I think it could handle a 140.

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 front end al la GSXR, 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? I'm looking for possible/creativity.

 

[budman]

Dude. The bike looks awesome.

Hope you find your path. :ride.

 

[scootergmc]

That things is sweet. I would leave it as is. Yeah, handling, tires, grip, and cornering sucks comparatively, but a good looking bike it is.

 

[Charmed]

Dude. The bike looks awesome.

Hope you find your path. :ride.

Thanks, Bud!!

That things is sweet. I would leave it as is. Yeah, handling, tires, grip, and cornering sucks comparatively, but a good looking bike it is.

I really do appreciate it, but I'm not real good at leaving things be:laughing The fact is I have my mind set on leveling this bike out and making it more/different than it is to ME. Trust me, I dig it right now, but I've changed bars, suspension, dropped triples, tuned it, had a custom seat made on the original pan, beefed up brakes, and more...but I need 17s for my own satisfaction on this build :thumbup

 

[motomania2007]

The wheels of that time are not designed for radial tires of modern design and they're too narrow even for a 140 that you might have space for so you really don't want to do that. It's better to stick with bias ply tires that that bike was designed for.
The alternative and I've seen many examples of this is where someone has swapped out the entire front clip forks triple clamps brakes and front wheel with a modern suspension bike such as a GSXR 1000.
Some of those mods have also included a similar mod to the rear where they figure out a way to bolt up a rear suspension off of a more modern motorcycle that's wide enough to accommodate modern radial tires yet still align properly with the counter shaft.

It's an interesting project not so easy to do when you start digging into the details.

By the way I attempted to put a radial tire on a similar vintage 17-in wheel and it didn't work very well at all It didn't want to seat properly in the wheel and once I did finally get it to seat it didn't last very long because the tire was pinched because the rim was too narrow for it and handling stunk.

 

[Charmed]

The wheels of that time are not designed for radial tires of modern design and they're too narrow even for a 140 that you might have space for so you really don't want to do that. It's better to stick with bias ply tires that that bike was designed for.
The alternative and I've seen many examples of this is where someone has swapped out the entire front clip forks triple clamps brakes and front wheel with a modern suspension bike such as a GSXR 1000.
Some of those mods have also included a similar mod to the rear where they figure out a way to bolt up a rear suspension off of a more modern motorcycle that's wide enough to accommodate modern radial tires yet still align properly with the counter shaft.

It's an interesting project not so easy to do when you start digging into the details.

By the way I attempted to put a radial tire on a similar vintage 17-in wheel and it didn't work very well at all It didn't want to seat properly in the wheel and once I did finally get it to seat it didn't last very long because the tire was pinched because the rim was too narrow for it and handling stunk.

Hmmm...interesting stuff. I can tell you that I have radials on it, and it's built for them. The earlier GS models have the bias ply rims. The current tire is a Pirelli Sport Demon 130/90/16. I have about 3/4" on both sides and loads of room up top, so I think I could put a 140/70/17 on there no problem.

 

[scootergmc]

Thanks, Bud!!


I really do appreciate it, but I'm not real good at leaving things be:laughing The fact is I have my mind set on leveling this bike out and making it more/different than it is to ME. Trust me, I dig it right now, but I've changed bars, suspension, dropped triples, tuned it, had a custom seat made on the original pan, beefed up brakes, and more...but I need 17s for my own satisfaction on this build :thumbup

I get it, for sure. Perhaps the answer is already yes, but have you checked the oldschoolsuzuki website? I've seen front end/wheel conversions on there but I've never paid close enough attention.

 

[Charmed]

I get it, for sure. Perhaps the answer is already yes, but have you checked the oldschoolsuzuki website? I've seen front end/wheel conversions on there but I've never paid close enough attention.

You could say that I've been to the holy land for this bike...the GS Resources forum:cool

I got the "Wrong bike for this, Bro" answer, so here I am. For anyone that follows riding/motorcycles, that's a ludicrous response. As riders we MAKE the bikes we want.

 

[scootergmc]

Well I just went down a not so quick rabbit hole. I don't know all the subtle differences between all the early 80s zooks because there were a ton, but if the Katana is anywhere close, there's this: https://www.bcsportbikes.com/threads/vintage-efi-katana-build-1983.131610/


I found it interesting to say the max? Or least?

 

[Jalopyshoppe]

Being someone else who likes doing the wrong thing, I encourage your experimentation. I would advise you to look at the wheel width as your tire size guide. I wouldn't put anything over a 130 on a 3.5" wide rear rim. I know Harley guys that do it, and the peaked tire profile is counterproductive all the way around. I found a 17x4.5" for my project, and run a 150/70/17 out back. Good profile, fits in the swingarm. If you have a similar width, do it!
Up front, You might think about sticking with the 19" rim. There are good options in 19" front tires, especially in the 110/80/19 size. Changing to a 17" will seriously change the look of the bike, and unless you do a lot of math, you'll find the bike twitchy on turn in and less stable at high speeds. My FXR actually started to weave at 90mph when I ran an 18" front. I needed the 19" rim gyro and height to stabilize it at high speeds.
The problem with using a sport bike fork is that they're usually shorter, so you'll exacerbate the shortened trail. Adding tire diameter out back will lift the rear and change the rake angle, albeit slightly, but it'll add fuel to a fire.
Being shaft driven, you can't alter the wheelbase easily to try to counteract any of the effects of steepening the chassis.
Cool bike, and I wish you the best of luck in whatever way you build it!

 

[Demoni]

What are the current tire sizes on the bike? How wide are the rims?

 

[Charmed]

Well I just went down a not so quick rabbit hole. I don't know all the subtle differences between all the early 80s zooks because there were a ton, but if the Katana is anywhere close, there's this: https://www.bcsportbikes.com/threads/vintage-efi-katana-build-1983.131610/


I found it interesting to say the max? Or least?

Ok...:laughing It was hard to get past the "I'm doing a turbo project on this beat ass frame", BUT, that was a damn cool bike:thumbup Unfortunately nothing really relevant to this build. You're awesome for even looking anything uparty

Being someone else who likes doing the wrong thing, I encourage your experimentation. I would advise you to look at the wheel width as your tire size guide. I wouldn't put anything over a 130 on a 3.5" wide rear rim. I know Harley guys that do it, and the peaked tire profile is counterproductive all the way around. I found a 17x4.5" for my project, and run a 150/70/17 out back. Good profile, fits in the swingarm. If you have a similar width, do it!
Up front, You might think about sticking with the 19" rim. There are good options in 19" front tires, especially in the 110/80/19 size. Changing to a 17" will seriously change the look of the bike, and unless you do a lot of math, you'll find the bike twitchy on turn in and less stable at high speeds. My FXR actually started to weave at 90mph when I ran an 18" front. I needed the 19" rim gyro and height to stabilize it at high speeds.
The problem with using a sport bike fork is that they're usually shorter, so you'll exacerbate the shortened trail. Adding tire diameter out back will lift the rear and change the rake angle, albeit slightly, but it'll add fuel to a fire.
Being shaft driven, you can't alter the wheelbase easily to try to counteract any of the effects of steepening the chassis.
Cool bike, and I wish you the best of luck in whatever way you build it!

Cool answer! It looks like a 4 or 4.25" rim, so it would be good to go with a 140 tire. I don't need Rossi, I just want more choices for quality rubber. As far as geo, I pretty much grew up on short rake "twitchy" bikes, so that's what I like. When I dropped the triples down 1.5 inches on this bike it started to feel more comfortable, so I'd like more. As far as overall measurements, I have done the (approx) math. 19 up front, 16 at the rear, and since the forks are built up a good inch for cruiser style, I go up 1" in the back, and down 2" in front, and I'm sitting at pretty even money. I can always go back up on the forks with the triples if it's funky. I want 17s, dammit!!

 

[budman]

17’s dammit!! :laughing

:thumbup

 

[Charmed]

17’s dammit!! :laughing

:thumbup

BOOM:laughing

 

[auntiebling]

ben ben ben
ben
ben ben ben ben ben...

you have my number man. jeez.

anyway, step 1 is get a rear wheel. you'll want the front to match so since your selection of rears is so limited that's your "long pole in the tent" so to speak

you could probably adapt a matching front, once you find one that matches the rear close enough, 17 to the existing forks but the diameter reduction and comparatively loooooooog forks will make it look really weird in, addition to the geometry problems jaloppyshoppe mentioned

if you pursue a front end swap to get the sprotbile forks that match the 17, my personal opinion is that USD forks look out of place on these 70s pigs (don't care that yours is made in 80s, it's a 70s design ) though a thicker fork tube does help functionally and aesthetically.
other fork options i explored a long time ago...


All Balls has adapter bearings listed for fork swaps. it does not check stem length or any of the other hurdles (steering stops, speedometer cable presence and on and on)

stem length is usually longer on these bikes than sport bikes but that can be overcome several ways.

years after starting the search, and now witout a bike to even put it on, i've assembled enough parts to start the front end i'm putting on a goldwing... someday! i plan to keep the 19" front on mine though for geometry reasons and i don't like the "17 front look on 70s pigs as mentioned. it'll have silly huge brakes though, that probably feel wooden but they'll look cool if i ever get it finished

 

[spdt509]

heres' my solution,man....

1) sell the bike

2) use the money towards that crazy $$$ double kick drum kit you were gonna buy 'someday'. practice after 7PM.

3) the neighbors that don't like you will move (see number 2)

4)ignore steps 1 through 3 and do the gsxr swap and call it a day

 

[scootergmc]

I'll take #1 for $800, Alex.

 

[Maddevill]

It can be done but some major changes are needed. First, I wouldn't bother with just changing wheels. I put a GSXR1100 front end and rear wheel on a 86 VFR750. Required a custom stem for the front. The rear wheel was actually easy. Had to have a FOX shock with ride height because the bike sat much lower. These changes allowed me to use modern radial tires. On your bike you are looking at fitting a completely different swingarm on there. Then modern wheels etc. There is a whole cottage industry in Japan updating these old bikes, but if yours is a shaft drive it will really complicate things. May need custom fabrication, ( Hello Curt Winter)

Mad

 

[SFMCjohn]

they don’t make beautiful engines like that, anymore ... :thumbup

link to the turbo’d Katana build was awesome, too ...

:ride

 

[Jalopyshoppe]

17’s dammit!! :laughing

:thumbup

Fair enough.
A quick way to get there is find an interchangeable spoked wheel for those forks (I'm sure it exists), and just have Chris Quinn lace an appropriate hoop. Probably be $400 into the package, but it will be the shortest path with the least fabrication.
Mags in back spokes in front is cool, by the way.