Christophe2m6

Hi Guys!

The question is for a 1969 Supreme 350ci!
Tried to search the answer on the forum first, then in the manuals.

And I found that my car had 7.75-14 tires!

Would like to find the nowadays size, and found 2 sizes:
205/75-14
215/70-14

And my car has actually a mix of both sizes: 215/75-14!

So which size should be the "correct" one?

Thanks a lot!!

oldcutlass

The following are the dimensions of the tires:

7.75-14 7.65" section width, 27.02 diameter

205-70-14 8.07" section width, 25.30 diameter
215-70-14 8.46" section width, 25.85 diameter
215-75-14 8.46" section width, 26.70 diameter
225-70-14 8.86" section width, 26.40 diameter

Your still going to come up shorter than the stock size by going to a radial. If you go to a 235-75-14 then your into the light truck or expensive vintage tires.

rcorrigan5

The tire my '68 4-4-2 originally came with was also a 7.75-14 and I went with a 215/70R14. On original steel wheels, they work nicely. On original SSI rims, the front tires rub slightly against the front part of the frame when steering is hard over to the right or left. It all has to do with backspacing, of which the SSI wheel has a deeper backspacing than the steel wheel. I'm planning to put on 215/70R14s on my '69 4-4-2 as well. The '69 has the SSI wheel for disc brakes and the backspacing is about the same as it is for the steel wheel.


Randy C.

joe_padavano

Personally I'd go with the 225/70-14s. These will fill the wheelwell nicely. Redlines would look awesome.

chip-powell

I must be the odd one around here. I have 235/70R 15's on mine. I just felt like I was going to bottom out with the 14's.

oldsmobiledave

235 70 15s are 28" tall. That is a very tall tire. What are your rear end gears? Your speedo must be way off (you are travelling way faster than you think you are).

chip-powell

Actually, it's not that tall at all (It is very wide though on those 15x7 cragars). With these tires, the bottom of my cutlass is sitting just under 5 inches from the ground. My speedo is a little off though. I'm actually traveling 5 mph slower than what my speedometer is reading. Go figure.

joe_padavano

The OP specifically asked about 14" tires. I have 15s on all my cars (except the 62).