I am thinking of switching back to the original wheels for my cutlass after I get them media blasted and painted. When I bought the car I switched them out and put 15x7 Cragars on because of how low the car was sitting (I kept bottoming out on speed bumps). I know that original equipment is 215/75-14. However, all the BF Goodrich tires that I am finding are 215/70-14.

My question is this...how big a difference is there is a aspect ratio of 70 instead of the original 75? Will I be hugging the ground again? I'm not a tire guru so I really have no idea.

 

Aspect Ratio is sidewall height as a % of width. width is stated in millimeters Comparing a 215/75 to a 215/70 the 70 will be a little less than an inch short.
225/70's are available and fit a little better

 

75 to 70 is not very noticeable. 60 is noticeable from a 70.

 

Go 225/70R14. My 70S has a ridiculous amount ground clearance, especially on the front, 205/70R14 and 225/70R14 BFG TA's. My 88 has low ground clearance as well. I have 205/75R14 front and 215/75R14's on the back on the 88. It has helped compared to the 235/60R14 that were on it. Remember one size wider in a 70 series will be close to a 75 series in height. Here is a good calculator.http://tech.oldsgmail.com/axle_RPM.php

 

Thanks for the info. Two more questions.

I have the bezel rings, but do not have the center caps. I don't mind buying repros, but everything that I am finding does not have the mounting hardware included. What does the mounting hardware look like and are the SSII and SSIII center caps the same?

 

If the rims are original to your car they'll have bolt on caps so all you need are a handful of bolts/screws that thread in. SS1's you a retainer.
SS2 & SS3 are the same except for the paint

 

That tire size didn't exist when your car was new. Original equipment was F78x14 (G78x14 for cars with A/C due to the extra weight). G70x14 was optionally available.

What matters is overall tire diameter. F78x14 tires were 26.5" diameter. G78x14 were 27.02". G70x14 were 26.82".

225/70-14 tires are 26.4" diameter. 215/75-14 are 26.7" diameter. Keep in mind that radial tires have more flexible sidewalls than do the original bias ply tires. The actual ground clearance will be slightly less than the theoretical diameter would suggest because of that.

 

There is press on and bolt on. I believe your wheels are bolt on, I am sure our resident expert will chime in on hardware.

 

You need to do the math. 225/75-14 (if you can find them) is 27.3" OD. 225/70-14 is 26.4" OD. 225/60-14 is 26.05" OD. The difference between 75 and 70 is 0.9". The difference from 70 to 60 is 0.35".

 

If they are factory 1970 wheels, they are bolt-on centers. Supercars and others sell the special screws.

 

Thanks guys. They are the original rims. They came with the cutlass when I bought it. I just never mounted them because they were all scraped up and I figured that I would wait until I had put back enough money to paint the car and then get the rims done at the same time.

 

Just for grins, why don't you post a photo of one of the wheels so we all know for sure if they are bolt-in or snap-in. I suspect that most early cars now have snap-in SSII/III wheels.

 

Here are a few pictures. It appears that at one time the previous owner painted them black. No idea why, but he made a mess of it. About half of the bezels that I removed from the rims have paint on them. Easy fix though.


So much for the pics...for some reason I am unable to upload them. I'll keep trying.

 

 

And as suspected, those are NOT original 1970 wheels, they are 1975-up SSII/III that take the snap-in centers. This is why I suggested posting photos.

 

The 225/60R14's are 24.6" tall. Myself and few others have found the BFG's shorter than they advertise but it gives an idea.

 

 

You are correct. The secret to doing math is that you have to type the correct numbers. For example, say you type 255 instead of 225, you get a much larger diameter (like 26" instead of 24.6")... Sorry about that.

 

FYI, it's fairly easy to refinish wheels. I redid both the 14x7 original wheels that came on my car and a set of 15x7 wheels that I bought locally.
The 14x7s I stripped with oven cleaner; the 15x7s I had media blasted at a local welding shop.
I primered both with rattle can etching primer, sprayed the backsides with rattle can black paint, then sprayed the fronts with a Preval sprayer and body color paint.




Below are finished results of the two different wheels.
One is a 14x7 bolt in center cap, the other is a 15x7 snap in center cap, both with with 245-60 tires.

 

And you need to not presume I was talking about height.

 

D@mn. Well that's disappointing. How could you tell the difference?

 

The raised center circular portion of the wheel has five notches where the center cap snaps in.

The bolt-in style doesn't have that raised center part and there are five bolt holes, one on the end of each of the "points" between the lug nut holes.

Picture of bolt-on center cap wheel that I found in an old post:
https://classicoldsmobile.com/forums...ray-shade.html




I wouldn't really worry about it - can you tell the difference in the two wheels I posted above? The average person would have no idea they are different unless they saw them side-by-side, and maybe not even then.

 

Just my $.02 but I wouldn't put the $$ and time into restoring 14" rims with snap on caps. Get some 15's so you have more availability with tire selection.