I want an 18" rear tire for 850G

[Guest]

So I am building this sidecar bike and have a 1980 850G with a 17" wheel on it. If I could put an 18" wheel on it I could use these block style tires that are better suited for this. Just wondering if this a possibility?? Anyone know if it can be done?

[John Park]

Because it splines into the final drive gearbox, the stock wheel is the only thing that would fit. I'm not convinced that a squarer sidecar type tire would last much longer anyway; I'd just buy budget Shinkos and replace as necessary. An 18" would be considerably narrower than the stock 130 - 4" vs 5" - and that's why they went that way to handle the weight.

I can sympathize with what you are trying to do and an 850 seems like a good choice as a sidecar rig.

[3Wheeler]

I have a sidecar attached to my 79 GS850 but went for a 16" wheel on the rear. Primarily to give me a better choice of tyre but also to reduce the gearing. I used it for about 6 years with the 17" before slotting in a 16" from a GS850L model. Its a different spoke pattern, but also its 2.75 wide rather than the 17" which is 2.50. I had to make up a thinner spacer between the caliper carrier and the swinging arm as the hub seems slightly wider. Also needed to make up a different clamp for the rear brake pipe where it attaches to the swinging arm. Otherwise its a straight fit. I now fit Conti Milestone tyres as these are available as reinforced. My thinking was that it might help with the increased weight. I never had any problems with the 17" on normal motorcycle tyres and still use it depending on what gearing I want. The 16" gave an easier ride when touring the Swiss Alps last year.
A lot of the tyre width is unused as, from recollection, only about 3" makes contact with the road.
Have fun with your outfit

[gsrick]

I went the other way, 17"-16" to have the tune fork wheels on my 1000G, but I don't know of an 18" shaft drive wheel that Suzuki made. Intruders and Madura's are somewhat interchangeable, but I don't think either ever had an 18" rear. More like 15" and 16".

[Grimly]

There's the 15" wheel from the Cavalcade for those chair-ists who are searching for a lower overall gearing, or simply the ability to run car rubber on the rear - 135r15 tyres are available here. I will shortly be trial-fitting one to the dead GS to see what the problems are. I expect the spline spacing to need a slight adjustment, and two new wheel bearings to account for the original GS axle and the larger outer bearing diameter in the hub, and of course, different spacers made up. The brake disc for these is like hen's teeth, but a local engineering shop can make a plains SS one for 60 Euros, so that's not too bad. Then whatever needs to be done to mount the caliper - but I have the Cavalcade caliper mount and a choice of rear calipers, so not to bothered about that. If I find the overall gearing is too low, I can change the front bevel or rear bevel drive to suit it better.