Driving on a temp spare?

[Frank Lee]

If anything, all indicators point to car tires being better used on bikes than bike tires and temp spares to be used on cars.

[CapriRacer]

Originally Posted by todayican

......On to this rim size mismatch thing, with it being a couple of hundredths off, are we talking "be a little more careful mounting it" or "are you #$@&%ing crazy??"......

We're talking "#$@&%ing crazy"!!

First, the pressure inside a tire has a tremendous amount of explosive energy. In order to keep this energy level down to a reasonable level, the rule is not to use more than 40 psi to seat the beads. People have been killed when the beads broke during the bead seating process.

In the case of car tires on motorcycle rims, there have been reports of using very high pressures to seat the beads - and there have been reports of beads breaking – and there have been reports of injuries. Unfortunately, the folks who are doing this are so fixated on doing this, they are ignoring the risks involved. I just hope this will pass before a fatality occurs.

Originally Posted by todayican

........Any ways to make the process easier / safer? putting the tire in ice water to contract it a touch?........

Well.... first you are going the wrong direction. You want the rim small and the tire large.

But, no, I am not aware of any way to make this work - at least to the point where it becomes the same risk normally faced when mounting tires.

Originally Posted by todayican

........I found "proper car tires" over at Coker tire 125/70R15 so I’m liking that........

I hope you realize that the tires at Coker Tire are reproductions for the purpose of having authentic looking, but usable tires for vintage cars. They were not made with rolling resistance. So other than the aerodynamics of narrow tires, there is no real advantage to using a small tire from Coker. You would be further ahead using a current technology passenger car tire in a bigger size on proper car rims – or a motorcycle tire on that M/C rim.

[todayican]

Capri, I appreciate the help, what of that Last question about other mc rims being mis matched as well, 16" 17"?

Reason im so determined to make a MC rim work (safely) is Id really like a flat profile on a reasonably thin rim and not have to fab sprocket mounts on a car wheel.

Thanks again!
Tom

[Frank Lee]

There are some really skinny 15"ers made for the classic Beetles, and some if not most of them appear to me to be nice low r.r. radial designs.