Benefit of 17" rear wheel over 18"?

[glenlloyd]

I've been checking out the specs of the 81 GS1100E vs. the GS750E from 81/82. I noticed that they used a 17" rear wheel on the 1100E vs the 18" rear wheel on the 750E. What would be the benefit of using a smaller rear wheel?

Also, does anyone know what other differences existed between these two models? I assumed (wrongly) that aside from the engine size they were pretty much identical.

thanks
steve a

[80GS1000]

A smaller diameter wheel will turn in faster and has less unsprung weight.

[groundshock]

But if the tire diameters are different to make up for the circumference?

[Steve]

I have not done the math, but I suspect that a 130/90-17 and a 130/80-18 or a 120/90-18 will have pretty much the same circumference.

Differences? Quite a few, I'm sure, if they follow the pattern set by other models. In the GS line, there seems to be a change in all the models from '81 to '82. In the 850s and 1100s, for example, the tanks are shaped differently and mount differently. Because the tank mounts are different, there has to be a difference in the frame, too. Other changes happen from year to year, but things like front running lights and sidestand down indicators came about in '82. I am sure there are many other little details, and have no doubt that similar things happened with other models.

Yes, the 750E and 1100E were almost identical, but you have to compare similar years, too, and especially don't cross that '81/'82 threshold.

.

[SqDancerLynn1]

Better tire selection in 17" size

[glenlloyd]

Thanks for the info, I was basically comparing the 80-81 1100E with the 80-82 750E, which share tank, plastics, but based on parts numbers do not share frames. I also found that the swingarm bolt isn't the same either so apparently there are a lot of small differences between the two because of the engine displacement.

At any length, the 1100E used the 17x2.50 wheel while the 750E used the 18x2.15 wheel so next time I need a tire I'll probably swap in the wider wheel given that it fits the swingarm properly.

thanks again
steve a

[TheCafeKid]

I have not done the math, but I suspect that a 130/90-17 and a 130/80-18 or a 120/90-18 will have pretty much the same circumference.

Differences? Quite a few, I'm sure, if they follow the pattern set by other models. In the GS line, there seems to be a change in all the models from '81 to '82. In the 850s and 1100s, for example, the tanks are shaped differently and mount differently. Because the tank mounts are different, there has to be a difference in the frame, too. Other changes happen from year to year, but things like front running lights and sidestand down indicators came about in '82. I am sure there are many other little details, and have no doubt that similar things happened with other models.

Yes, the 750E and 1100E were almost identical, but you have to compare similar years, too, and especially don't cross that '81/'82 threshold.

.

AFAIK The 80/81 750 and the 81 1100 were identical with exception to motor size obviously the fork diameter, and the rear wheel. The 80/81 750 from what I am told, was the only one that used the "lunchbox" headlight, and they changed back to the round one from there i guess. I may be wrong, but I was told this by a couple of 80/81 750/1100 owners, figured they'd know better than i. Otherwise, the tank, seat, body panels are interchangeable, and the forks could be swapped from an 1100 to a 750 with little effort, mostly in bearing changes i believe. Smaller rear wheel is less rotational mass, allowing the motor to work less at any given RPM. Also, the better tire selection is true. I suspect Steve is correct in his assumption about the end wheel/tire diameter, but I have not done the math either. if they ARENT the same, they'd be damn close, otherwise significant ride hight would be lost (could be made up in shock hight, but if I read correctly, the shocks on the 1100E were actually shorter than that of the 750?? (anyone verify that?) )

[TheCafeKid]

Thanks for the info, I was basically comparing the 80-81 1100E with the 80-82 750E, which share tank, plastics, but based on parts numbers do not share frames. I also found that the swingarm bolt isn't the same either so apparently there are a lot of small differences between the two because of the engine displacement.

At any length, the 1100E used the 17x2.50 wheel while the 750E used the 18x2.15 wheel so next time I need a tire I'll probably swap in the wider wheel given that it fits the swingarm properly.

thanks again
steve a

Oh! yes forgot that. The swinger pivot for the 750 i believe is 12mm, and the 1100E is 16mm. Also, the swingers themselves are different lengths. about 2 inches in difference actually.