I would like to go with Minilites for the front and rear of my 914-6 GT project. I am considering the Mag style with 7X15 fronts and 8X15 rears. I would like to pair these with the Michelin TB15 tires. The sizes would be 18/60R15 (215/55-15) front and 23/62R15 (270/45-15) rears.

Anyone have experience with this combination on a GT clone? Will I require spacers on either the front or rear?

270/45-15 tires are going to be way too short for street use. Unless you change the ratios in the gearbox, you are going to be spinning the engine really fast on the highway.

The spacing is hard to say definitively. I have 8s and 9s on 15 inch rims (the 9s are minilties) and am okay but wont work for everyone. The 7s and 8s are normally just fine for flared cars and are quite common.

I only run track so not sure on your tire size choices. 45 seems like a really low profile to me for.street use....

So on the question of spacers, part of the answer - fairly obviously - depends on the offset of the wheels you choose. In general, most wide body cars end up running large spacers on the front (25mm and wider) to both fill out the flares and and stop the tires rubbing on the inner fender.

On the rear, there are variables like 5-lug conversion that can make minor changes, but the need for spacers for 8x15 rims is either none or small (a few mm) for most Fuch rims (for example). Note the various "wider flare" options all look similar, but can vary dimensionally depending on the supplier and how they are fitted.

And in terms of tire diameter / gearing, as a data point: I run 215/60R15 rear tires with a 914-4 901 transmission; this translates to around 73mph at 3000rpm on my car. FYI, hope this helps,

- Tony

The car came with 185/65-15's. This gives a tire diameter of 24.47". The 270/45-15 tires are 24.57" in diameter. What am I missing?

I've currently got a set of the Michelin TB5s on 8x15 Fuchs, with spacers, and it's a great setup - however I have Tangerine Racing flares not GT...

The Hoosiers I've been using for track are actually about 23" diameter and it's never been a problem (for track) even though I have short gears as well. The car tops out around 135mph-ish which is not even achievable at some of the venues.

I'm running 205-50-15 fronts and 225-50-15 rears on Maxilite. fronts only have 1/2 spacers. Works and looks great.Click to view attachment

Getting back to tire diameter...The stock 914 used 165/80-15 tires which had a diameter of 25.4" The Michelin TB's I am considering would have a diameter of 24.5. That would lead to a 3-4% error in Speedo reading. Doesn't seem like much to me.

Who looks at the speedo anyway?

You are missing the part where Clay doesn't know that the 2nd number is a ratio, not an absolute.

It’s not just the speedo, but the shorter the tire, the higher the revs at a given speed, which can be annoying on the freeway and wasted gas. However 3-4% error will be negligible anyway for all the above. I’m also a fan of GPS speedometers. No bouncy speedo and always accurate.