My new Corvette came with 3 different size tires. 215 60R 15 on the front, the rear had 255 60R 15 and 215 70R 15. All treads are about worn out. So I thought I would swap the wheels out with those on my first project. They were 255 70R 15 all around. Well, I tried to back out of the garage and the front tire rub. It didn't dawn on me because I could push the old car around no problem. But there is no motor in it so it had clearance. DUH! So I am just going to buy a good set now. I would like to have all 4 the same size.

So, what size were the original tires? F70-15. What does that translate into?

What is the biggest tire that will fit on the front? Recommendations welcome.

 

I am about to do the same thing. From what I gather here on the Forum, 255/60-15 will fit all away around with no problems, and it is very close to the original tire diameter, so the speedometer will be pretty close to being correct.

 

I think you will find that F70 translates to 215 or 225-70R/15.

 

The original tire on your 74 was a GR70x15 radial. A GR70x15 tire converts to 225/70R15, in the modern metric sizes. 1972 was the last year that F70x15's bais ply tires were used.

You should be able to easily fit a 225/70x15 on the front. About the largest tire to fit the front is a 255/60x15, though these can rub on some cars. The 245/60x15 is a better choice for a trouble free wider front tire.

 

I have 245/60/15 on my 74 and they are fine all the way around.

 

OK guys I got the sweet deal on Firestone Firehawk INDY 500 series. Go to WWW.tirebuyer.com and look at these in a 255/R6015, delivered to your door, a set of 4 for around $360 bucks. Ordering mine tommorrow.

 

...and they fill in the wheel well very nicely.

 

I guess I will look at either 225 or 245 60R-15 tires. I put the 255 60R-15 tires on it and it took a small chunk out of the inner fender lip on one fender. The good news is that is the fender that has 2 cracks perpendicular to the wheel opening and one developing at the bonding strip. I think somone backed into it.

 

You may have a hard time finding the 245 tires but 235-60 will work as well. After all is said and done have your speedo checked for accuracy. You may have to change the transmission plastic gear.

 

On my car I have 255/50/16 fronts - 255/50/17 rear, fits perfectly.

 

This will happen on some pre 80 Corvettes. In 78, when Chevrolet started offering the 255/60x15's as an option, they trimmed the front wheel lip, to gain more clearence for the 60's. When the 80 front fenders were redesigned to include the spoiler, it eliminated the problem.

 

Steve and Paul, I like your 74s. No offense to the other great cars here.

For now, I think the 225 60R15s are teh way to go. I don't have to fool with the speedometer. Someday I hope to buy TT II wheels. I think they look really good on the C3s.

 

235R60-15's will fit nicely and their O.D. is just slightly smaller than the G70-15's. Anything wider may have interferrence with the wheelwell openings.

 

Thanks, I just re-read the thread. I didn't realize the original tires were 70 series. Unthinkable today for a sports car. Even the 255R60-15 is a smaller diameter, but they are 30 mm wider than the original.

It seems like it would be safer to go with 235R60-15 than 245. I can go measure how much interference I have with the 255R60-15 tires on it, but I have to worry about what happens when hitting bumps in a turn.

Does anybody still use the 225R70-15's. There are not a lot of choices and the B F Goodrich Radial T/A seems to be available in most of the above sizes.

 

Thank you.

 

T/A Radials are a good way to go...if you can get them. Good looking white letter tires, decent wear and performance, reasonable cost. Sam's Club used to sell them (they still might), but sizes started at 235 for R60-15's. That's what I put on my '71 and have had no problem at all. Wherever you have them installed, remove the trim rings and hubs if you have Ralley wheels. Also, pre-mark the locations of the trim ring clips (for original configuration rings) so the installer can know where NOT to put any balance weights. You don't want some 'rookie' installer to ruin your rings with a rubber mallet [or worse]!

 

Ok, Nothing is easy. I bought this car because I was tired of not having one to drive. I know that I am supposed to buy the best car I can afford. Well, my collection includes a 1951 Chevy half ton, a 1957 BelAir, and 2 1974 Corvettes. I managed to pay in the range of $5,000-6,000 for each of them. It just seems that when I get that much saved up I find something I have to have. I knew that a car in this range would have some issues. There had been a lot of work done on this car, so I was putting a little faith in the previous owner. Actually it was 2 owners ago. Anyhow, if someone else had put as much work into this I figured they wanted to drive it just like I do, and they probably did.

Wheels. The car is not legal for inspection and the tires it came with were 3 sizes. The car wobbled going down the road. So I wanted to buy tires that fit. The safest thing to do is to buy the factory size. (Not pictured below. I will tke pictures later.) I am happy with them. I installed them and my front driver tire rubbed just as did the 255 60-15. UGH! I had it on the lift and it struck me that the tire was not centered in the wheel opening. Loh and behold the other side is centered.

Drivers side.



Passenger side



On my parts car there is about a 2 inch hole in the frame and if I look at the inner fender, it crosses about halfway across the hole. On this car you can see almost the whole thing. (I know I need pictures of that too.)

Now the picture begins to set in that the front end has been off the car. The driver's door needs adjusted. It binds when latching. It seeems like the top rear corner is about flush but the gap is tight. I think the striker pin is hitting in the bottom of the latch slot. That means the front of the door needs rotated down. There is no room. The gap has no slop. Also I tried to adjust the hood. It rubs on the passenger side when lowered. I tried to unbolt the passeenger side then tighten while lifiting that side and the to push down on the driver side hinge. But if the whole front end is pulled farther back on the driver side this might explain the hood problem as well.





I need to start another thread about body mounts. There are no bolts in the forward 2.

You may notice the chewed up fender. I know it is heresy, but I took out a grinder and evened up the damage. I figured I need to replace the fender one day, but I am determined to motor this thing around this summer, pretty or not.