GS650G rear tire and wheel size

[hank2]

Newbie here to GS forums. In a couple of days, I'll be buying a '81 GS650G. Yes, I don't even have it yet, but trying to do some planning already around multiple other projects.

The seller had mounted a rear Shinko in 130/90/17 size. From what little I rode this bike, it seemed to feel strange ( to me ) on turn in with this size rear. It looks grossly too large for the wheel width. From what I've found online and the factory owners and shop manuals, this bike was supposed to use a rear in 4.25 x 17. I believe that converts most closely to a 110/90/17. Maybe a 120/ 80 or 90 /17 would be fine? Strange, but I can't find the 650G wheel width listed in the manuals. When I get the bike, it's likely stamped on the wheel. The 110 or 120 availability in a 17 in. tire seems to be very limited but I did see a couple on a big tire vendor like Rocky ATV. Most were listed as front tire models I'll also need to replace the front tire as it's very old. ( easy-peasy 100/90/19). I know I'm not going to find front and rear matching brand/model.

What works well for size on the 650G rear?

If I can beg one more ?, I believe I may have to deal with worn wheel drive splines. I know Suzuki still lists an OEM spline. Some here said they robbed them off of used Boulevard 800 model rear wheels. As a possible other option, GS850G wheels seem to be common used. Does the GS850G rear wheel interchange entirely with 650G wheel by chance? I've read on these forums that the pre '81 wheel splines were more durable. Thanks for any insights and info.

[Steve]

Yes, a 130 is too large for that wheel. A 110 might be "perfect", but a 120 is easier to find and is perfectly acceptable.

As I mentioned in your other thread, your slipping problem is likely clutch related, not splines. If you had bad splines, you would not be complaining of slipping, you would be complaining that you were stranded on the side of the road somewhere. They seem to hold the power ... until they don't, and you simply don't go ANYWHERE. Bad splines did not show up until the '82 model. And, if it <is> splines, you only need to change the spines, not the entire wheel, although the 850 wheel is identical, assuming the same year. There was a difference between '81 and '82 wheels for all the shafties, but they can be adapted merely with the use of spacers on the axle.

The early splines ('79-'81) were black and worked great. In '82, they went to a softer metal, it had a gold tint to it. In '83 they corrected that mistake, the splines are silver. That same silver spline is available today on the smaller Boulevards.

.

[Gorminrider]

tires to fit GS650G from my notes:
as PAIRS, Canadian dollars...
Bridgestone BT45 about $270
Avon Roadriders about $240
Duro HF261about $140 (!)
there are others of course..you can mix and match but it's nice to start with a pair on a bike new-2-U.... Shinko is one to look at. I've had these on other bikes....Metzler? "(Metronic") ? Michelin? dunno, offhand..

I've had the Avons, good riding tires but construction was poor...

now I have the BT45 which I like better.

It's not uncommon to run a front on the rear. AVON does this. Tread direction is merely REVERSED but other "sets" have differing tread patterns for front and rear and this shouldn't be done except in an emergency-I wouldn't use a BT45 front on the rear

[hank2]

Yes, a 130 is too large for that wheel. A 110 might be "perfect", but a 120 is easier to find and is perfectly acceptable.

As I mentioned in your other thread, your slipping problem is likely clutch related, not splines. If you had bad splines, you would not be complaining of slipping, you would be complaining that you were stranded on the side of the road somewhere. They seem to hold the power ... until they don't, and you simply don't go ANYWHERE. Bad splines did not show up until the '82 model. And, if it <is> splines, you only need to change the spines, not the entire wheel, although the 850 wheel is identical, assuming the same year. There was a difference between '81 and '82 wheels for all the shafties, but they can be adapted merely with the use of spacers on the axle.

The early splines ('79-'81) were black and worked great. In '82, they went to a softer metal, it had a gold tint to it. In '83 they corrected that mistake, the splines are silver. That same silver spline is available today on the smaller Boulevards.

.

Thanks for the info on the splines/model years and tire size. The 'splines work until they don't' makes perfect sense.

[hank2]

tires to fit GS650G from my notes:
as PAIRS, Canadian dollars...
Bridgestone BT45 about $270
Avon Roadriders about $240
Duro HF261about $140 (!)
there are others of course..you can mix and match but it's nice to start with a pair on a bike new-2-U.... Shinko is one to look at. I've had these on other bikes....Metzler? "(Metronic") ? Michelin? dunno, offhand..

I've had the Avons, good riding tires but construction was poor...

now I have the BT45 which I like better.

It's not uncommon to run a front on the rear. AVON does this. Tread direction is merely REVERSED but other "sets" have differing tread patterns for front and rear and this shouldn't be done except in an emergency-I wouldn't use a BT45 front on the rear

Good information, thanks! Upon further looking around, it looks like I could get a matched set of BS BT45's, if I go with a 120 rear. I had used them in the past on an old airhead. I have used several sets of the BS S11 Spitfires as well, which I preferred, but wouldn't find a rear in my size. As I recall, the front BT45 had a much more "pointy" front profile than the S11 front. I can see why it would be bad choice to use as a rear. I'm leaning towards an rear 120/80/17 vs. a 120/90/17, depending on availability.