Can anybody tell me the benefits of changing from 14" to 15" wheels besides the fact that they fill the well more or the car travels farther for one rotation of the bigger wheel. What is the effect on handling and why?

 

If you go to a heavier 15" wheel your brakes will have to work marginally harder to stop the forward momentum of your wheels. This is more of a concern if you go to 22" wheels.

 

I was thinking about goin to 15s on my 69 for the simple fact that thay make a conversion kit for rear disc brakes. This wont work with 14s.

Im all about the SSll wheels though, hard to find in 15s

 

Unless you are running on the bare wheel with no tires, the diameter of the WHEEL has absolutely no bearing on how far the car travels per rev. It's the diameter of the TIRE that matters.

As an example, a 215/70-14 tire and a 215/60-15 tire are both nearly the same diameter. In fact, the 15" tire is about 1/2" SMALLER in diameter than the 14" tire. The big difference is the 15" tire in this example is a lower profile 60 series, which will improve handling due to the shorter sidewall.

 

So the shorter the sidewall the stiffer the tire or the more tire surface contacts the pavement?

 

The shorter sidewall flexes less, so you get more precise handling.

 

Will the 15" SS wheels fit rear discs? If so, what company/brand kit is it? There was another thread recently dealing with 15" SS's and rear disc fitment problems. I would like them on my Vista if it wouldn't be too much of a project and I could use stock wheels. Even with standard front discs it's an adventure when you pull back on the reigns sometimes.

https://classicoldsmobile.com/forums...2-cutlass.html

 

I may have been the most recent post dealing with the fitment problems. I haven't been on for a while to update the status....

I did a 4-wheel disk conversion on my 72" Cutlass and encountered two problems.

First; the rear GM rotors were about 1/32" too small for the outer diamater of the hub. To correct this I had to do some sanding and grinding on the hub, but it eventally slipped on like a glove. (By the way; if you have to do this be sure to have the hub spinning so that you can sand evenly. You may also consider just taking the rotors to a machine shop and having them shave the rotors.)

Second; once I got the rotors and calipers on and mounted the rims, I found that the calipers rubbed on the wheel even though it was 15". Aparently the center of the 15" SSIII is the exact same center as the 14" SSIIs. The outer part of the wheel is just larger. To correct this I had to buy new, longer (2 1/8" long) set of wheel studs and a set of 1/2" wheel spacers.

I drove out the old wheel studs with a hammer and used a washer with a nut and my impact gun to pull the new studs through the hub. I then put the calipers back on, slid on the spacers, and mounted the wheel. The spacers set the wheels out enough to give me about 1/4" clearance from the caliper.

I haven't had a chance to corner with it yet so I don't know if they will end up rubbing, but if they do I will may have to try and go out to 3/4" spacers. (Hopefully, not.)

Anyway, hope this helps. Oh yeah, I got the brake kit through a reseller of MBM brakes. I was a bit disappointed in the fitment and the fact that they sent me two different lengths of E-brake cables. But then again modifying a car away from stock sometimes does require a bit of sawing, grinding, and banging on to get into place.

Other than that the set seems pretty solid so far.

 

Looked today. Year One has the 15" SSII. Good luck and let me know what you find....
Later

 

With 15 inch tires you will have a better selection of sizes to fit almost any need/application especially with B F Goodrich radial TA's