Posted 12/12/2016 9:44 PM (#91715) Subject: Car Tire on mule for sidecar....
I was wondering if anyone has been able to put a car tire on a Yamaha Vstar 1100? I'm running a sidecar rig and having a square tire on the rear of the bike would be nice. Early thanks for any help. John
Posted 12/15/2016 1:01 AM (#91735 - in reply to #91715) Subject: RE: Car Tire on mule for sidecar....
Location: Pago Pago, American Samoa
You have a classic, no?
From everything I've read, a 15" c/t isn't a good match to a 15" m/c wheel (unlike other sizes) because of geometry problems with the bead, and with the bead retaining (sorry, very tired, brain isn't working well to remember the right words).
With a tubeless rim, I've heard of people turning down the bead portion of the wheel (doesn't take much), and the . I don't think this can be done on a spoked wheek.
I did ask around about mounting a 15" from a British motor car, $$$$$$$$ wow! I can replace a whole lot of tyres for the price of the job.
Posted 12/15/2016 12:55 PM (#91741 - in reply to #91715) Subject: Re: Car Tire on mule for sidecar....
Location: Tacoma, WA, USA
I agree with Michaelh. The diameter of your 15" rim is about 1/10" too big to fit a 15" car tire. If you wanted to try it, you can buy a used rim on eBay for about $200. Take that to a machine shop and have them take down the outer rim by 5/100" so that you can get a car tire on there without splitting the tire bead, then have them also take 5/100th's off the bead seat as well so that the tire will seat. They could also cut down the bead hump to make the seat a little wider. Once you do that, there are a variety of tires available in 195/65-R15 that should work fine and won't change your ride height much. Search that size on the Tire Rack website to see what they've got.
Posted 12/15/2016 6:11 PM (#91744 - in reply to #91741) Subject: Re: Car Tire on mule for sidecar....
Veteran, thanks for the detailed explanation/diagram of the car versus motorcycle rims. I'm curious if there is a company who specializes in modified rims as you suggest? I'll do some more research and see what I can discover and report back on this forum. John
Posted 12/16/2016 5:18 PM (#91750 - in reply to #91744) Subject: Re: Car Tire on mule for sidecar....
Veteran, I assume the rim/tire in the upper right of your diagram is the CT fitted to a 15" bike rim. In this diagram the left side shows the CT fit to the bike rim before being machined. The right side shows the fit after machining. Is this correct? I'd like to run a CT on my sidecar rig, but I'm afraid to buy a tire and not have it seat properly; this could be disastrous! Early thanks, John
Posted 12/17/2016 2:57 PM (#91756 - in reply to #91715) Subject: Re: Car Tire on mule for sidecar....
Location: Tacoma, WA, USA
The top two diagrams are the moto rim, the bottom two are the car rim. The upper right shows how a moto tire bead fits into the rim perfectly (right side), while a car tire doesn't (left side) because the bead is a little too wide to sit down properly in the bead seat. All dimensions are in millimeters. What the diagram doesn't show is the fact that the tire bead is NOT made from concrete. It will deform and conform to some extent to the bead seat. That's why car tires work OK on moto rims most of the time. The exception is for 15" tires. Only for 15-inchers is the car rim and the moto rim a different diameter when measured from the bead seat. Specifically, as stated above, the 15" moto rim is 10/100" larger. All that needs to be done is to spin the wheel on a lather and remove 5/100" from the bead seat. You don't really have to machine down the bead hump too (because of the deform/conform comment made above) but since the wheel is mounted on the lathe and spinning it would only take a machinist perhaps 60 more seconds to widen the bead seat by 5mm.
The bottom right diagram shows how a car tire bead fits perfectly in a car tire rim (right side) while a moto tire is a poor fit in a car rim (left side.)
Posted 12/17/2016 5:15 PM (#91757 - in reply to #91756) Subject: Re: Car Tire on mule for sidecar....
Thanks Drone, I believe I understand. What the machinist will remove is in the curve of the bead seat the amount you suggested. The bead hump can also be milled down. If the rim is on a lathe, removing the correct amount of metal on a convex curved surface must be difficult? Can you explain how this is done? Is there a name for the type lathe that would be used? My only knowledge of a lathe is a wood lathe, obviously a metal lathe is much different. Early thanks, John