tire size for KMS car

[jim rosenthal]

I have been trying to figure out how to solve a tire and wheel size problem with my KMS car (#486). Maybe someone can offer some suggestions here.

My car has the coil-over chassis with the 289 slab-side style body. The tires rub the edges of the fenders, even with the ride height set rather far up. The car was shipped with 7" Halibrand-style Trigo wheels, and Yokohama 215/70-15 tires (A4s) The tires seem fine; I'm not driving it very aggressively (yet) partly because whenever I go over a serious bump, the left rear tire rubs the rolled edge of the fender for an instant.

Not very many KMS "hybrid" cars have been built, according to them, and not many are on the road, let alone in frequent use like mine, so we're still working out what to do about this.

KMS have offered to mill the insides of the wheels at no charge to me (they are great guys and a pleasure to deal with; their support of their cars is phenomenal) but we don't know how much to mill off. In addition, I have been wondering whether changing to a smaller tire would help. The car has a 3.73 ring and pinion in it, and changing to a smaller diameter tire would effectively raise the numerical axle ratio, which would be fine with me. The engine is a 302, and the transmission is a Tremec TKO600.

But performance tires for 15" rims are not easy to find, particularly in the taller aspect ratios which would be correct for a 1960s style car. Does anyone have any suggestions for particular tires, and sources for same? I welcome any help I can get. The car is not driven on the track- just road driving, but I would like to be able to set the ride height where it ought to be and not have the tires rub the fender edges as they now do.

Thanks, in advance, for any help given.

[Ronbo]

Won't necessarily change your ratio, the big factor is tire height. This can vary quite a bit between mfg's for the same size tire.

Depending on how much clearance you need, shaving the wheel face would be the fastest route (the hub face can also be shaved a little).

Rims with a little more backspacing would be ideal (if available). The wire spoke rims are actually the correct rims for the slabside I believe.

These are the FIA (289) and 427 rims...

http://www.trigowheels.com/original.html

Not sure who sells the wire rims, but I think they're still available.

[bbrown]

Jim,
Had similar problem with my car, KMPS007, a leaf spring car. My solution was to take a 1/4 inch from the hub mounting surface, which increased the back spacing.

I would suggest that you jack up your car, take off the shock and spring, remount the wheel and then cycle the wheel up and down on the suspension (while the car is jacked up) so you can view the total suspension movement and measure clearances. I suspect you have a bunch of room on the inside fender and things get real close on the outer fender. Estimate the distance you need to move the wheel/tire in and then double check the clearance from the brake caliper and the inner face of the spokes. You don't want to take off so much material from the hub that now you rub the inside of the spokes on the caliper.

All in all, it is a simple deal. Take up the brothers offer and do some measuring. Once it's done you'll never look back. Oh, and if you are going to use a spare in the trunk, double check that a modified wheel will work at the front also.

Bert Brown

[open roads]

I'm looking at getting a slab side and want as much rubber as possible while retaining an elegant looking wheel well.

I'll let everyone know what happens.

Your suggestion is strait forward and should work well.

[rustyBob]

...here's something to think about....they didnt have 70 series tires when the Slab Side Cobras where built...my book shows they useed a 6.50/6.70-15 tire which would be rather tall but not near as wide as a 70 series tire of today...