GS cast wheel sizes

[TitanNeil]

O.k, here's one for the experts. In my quest for a rear wheel with a good spline set, I ended up with 3 rear wheels. My original 16" (splines taken out, not much left to them), one 16" with completely stripped splines, and a 17" with minty-fresh splines. I can transfer the spline set to the 16" original wheel, but what would a 17" wheel do for the gearing in my '83 GS1100GK? Would it enable higher speeds at less RPM, better gas milage, or would if totally screw up the rear suspension (bottoming out) and make the bike sit like a cat in heat with its tail in the air?

[Steve]

The difference will be negligible. I think it was Grandpa that had both wheels for his bike and alternated them with each tire change, so he would give the best answer for this.

.

[tkent02]

O.k, here's one for the experts. In my quest for a rear wheel with a good spline set, I ended up with 3 rear wheels. My original 16" (splines taken out, not much left to them), one 16" with completely stripped splines, and a 17" with minty-fresh splines. I can transfer the spline set to the 16" original wheel, but what would a 17" wheel do for the gearing in my '83 GS1100GK? Would it enable higher speeds at less RPM, better gas milage, or would if totally screw up the rear suspension (bottoming out) and make the bike sit like a cat in heat with its tail in the air?

If you use smaller width and profile tires to get the same diameter it would make no difference.
You can look up diameter on some of the internet tire places.
We ran the wheels interchangeably on a GK and on a G, 16", 17" both were fine.

[Grandpa]

The difference will be negligible. I think it was Grandpa that had both wheels for his bike and alternated them with each tire change, so he would give the best answer for this.

.

You're quite correct, Steve.

I had a GS1100GK for 9 riding seasons. The stock rear wheel is a 16, on which I installed a 130/90-16 rear wheel.

I also had a 17-inch rear wheel off a 1980 GS850G I used to own. That wheel worked well on the GK, and I alternated the 16 and the 17. The shimming had to be adjusted, but I fooled with it a bit and the problem was solved.

The main reason for alternating is not to change the gearing. It was to save time and trouble at tire-changing time.

I would buy a rear tire, install it on the idle wheel, and leave it set until the working rear tire was worn out. Then, with one session, off with the old wheel, on with the new.

Whenever I went from the 16 to the 17, I would notice the slight change in gearing. Pretty soon, the "new" feeling would dissipate and I wouldn't think about it any more. The change in gearing is negligible.

Do the math. The percent change from 16 to 17 is just 6.25%. No big deal. The circumference changes at the same rate as the diameter and radius, since all are linear units.

Keep in mind that the standard GS1100G comes stock with a 17 rear wheel. The frames and swingarms on both the standard and the GK models are practically identical. So, a 17 rear wheel on the GK is just fine. No clearance problems, nothing.

You should try to get a spline set for the idle wheel. Both my rear wheels had spline sets for early GS850's, the black ones. They last. Go on eBay for that. All spline sets are interchangeable on 850, 1000, and 1100 shafties, L models included, and the GK.

[TitanNeil]

Thanks Grandpa, for the detailed response. Its really nice to hear from someone who has DONE what you are considering, and can give real answers, not just an opinion or theory. GS Resources is aptly named!

I probably worried about this more than I should have, since the 17" tire that is on the rim was VERY tall and the wheel/tire combo looked enormous next to the 16". I'll stick with the 16" since it has a good tire, but keep the 17" wheel and keep an eye out for another spline set. My good friend has a bike wrecking yard with over 500 bikes - there are a few more GS rear wheels there that need investigating. He lets me take whatever I want, but I don't want to keep testing his goodwill!

[Grandpa]

You're welcome, TitanNeil. Glad to be of help.

Nick Diaz
Middletown, MD