Tire Sizes
01-10-2010, 04:47 PM
#1
Tire Sizes
Hello All, I don't get around here much, so I apologize for not contributing much and just asking questions and runnin off to somewhere else, but sometimes I do need the help. Anyway,
From my records i see that the original tire size on my C3 was F-70-15. Can anyone tell me what the equivalent size would be in todays numbering system? I have been running a General XP-2000 in size P235/60/R-15 for about the last ten years. But I believe this tire is alittle smaller in diameter than original because my speedo is off about 4 miles per hour higher at 60 MPH. I need new tires now and want to get to the original size if I can. Also I want to get as close to the original tread width as possible because the wider footprint makes the steering alittle heavy.
Thanks for the help.
From my records i see that the original tire size on my C3 was F-70-15. Can anyone tell me what the equivalent size would be in todays numbering system? I have been running a General XP-2000 in size P235/60/R-15 for about the last ten years. But I believe this tire is alittle smaller in diameter than original because my speedo is off about 4 miles per hour higher at 60 MPH. I need new tires now and want to get to the original size if I can. Also I want to get as close to the original tread width as possible because the wider footprint makes the steering alittle heavy.
Thanks for the help.
01-10-2010, 06:05 PM
#4
6th Gear
Member Since: Jul 2005
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If you want to keep close to the original tire size the 215/70/R15 works well. It will give you a 26.85 in. tire that is within 1% of the F70/15 diameter, and you have the 70 profile. The tread width should also be close to the original.
01-10-2010, 06:11 PM
#5
Race Director
255/60/15 is 27" in diameter and what most here change to 
If you want a skinnier tire ( I don't like the look personally ) you could go to 215/70/15's they are 26.9" in diameter
If you want a skinnier tire ( I don't like the look personally ) you could go to 215/70/15's they are 26.9" in diameter
Last edited by MotorHead; 01-10-2010 at 06:14 PM.
01-10-2010, 08:27 PM
#7
Racer
In the early '70's the F in F70 meant 225 mm. Likewise the G in G60 meant 235 mm. A replacement for the F70-15 would be 225/70/15 and the G60 Pace Car tire would be 235/60/15. As previously posted many go with the 255/60/15.
01-10-2010, 08:37 PM
#8
Racer
Member Since: Nov 2009
Location: Franksville Wisconsin
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Or for my '81 255 60 15 is optional or 225 70 15 was standard. I'm putting new tires on and it came with the 255 but I'm going to 225 70 15s due to 1.cost 2.with the wider tires it tends to follow ruts and tar strips in road. 3. I like the slightly narrower tire look.
01-12-2010, 03:48 PM
#9
I really appreciate the input. I think I am leaning towards the 225/70/15s. I agree that the larger meatier tire looks good, but I have been living with that wide foot print for years. Since I am now an old man, I'm more interested in some lighter steering. In my plans for the next refreshening, I may go to completely stock and original specification. I've owned this car for more than 25 years, it has been in alot of different configuations, but nothing that can't be put back. I have all the original parts.
Thanks again.
Thanks again.
01-12-2010, 07:08 PM
#10
Burning Brakes
Member Since: Jan 2009
Location: Clarksville Indiana
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2556015 is about the only size I've ever put on my customers C-3's for many years. They can rub on some different spots on different years but that can usually be adressed or its not bad enough to worry about. I put them on mine last year and had to push my e-brake cables closer to the control arm because they were squeaking the inner sidewalls a touch.
01-12-2010, 07:41 PM
#11
Safety Car
I ran P235/70 R15 Goodyear RSA Plus tires up until recently and I was very happy with the look and the performance in a reasonably priced tire, and they wore well. They were original equipment on the Ford Crown Vic police cruisers here in California. I recently switched to a 255/60 R15 BFGoodrich radial on the rear and a 235 T/A on the front.
Great price from the Tire Rack folks, and a good ride, but if I had to do it over I'd either get a wider rim or a narrower tire for the rear. I found that after I changed over the car tends to "fall off" the sidewall in the rear on hard cornering, like a freeway onramp or on a track sweeper. It's a weird feeling that basically starts out OK and as I increase the cornering G's it does a quick sidestep and then re-settles, never breaking traction. I re-installed the goodyears just to satisfy myself that it was the tires and not some coincidental mechanical issue. I then installed just the 235 T/A's on the rear and it was fine, so I attribute it to the overly "square" profile with the 8" rim and the 255's.
Your experience may vary, but for out and out performance I preferred the RS-A's. I'm still trying to decide if I like the look of the much wider T/A on the rear compared to the old "correct" Goodyear size.
Hans
Great price from the Tire Rack folks, and a good ride, but if I had to do it over I'd either get a wider rim or a narrower tire for the rear. I found that after I changed over the car tends to "fall off" the sidewall in the rear on hard cornering, like a freeway onramp or on a track sweeper. It's a weird feeling that basically starts out OK and as I increase the cornering G's it does a quick sidestep and then re-settles, never breaking traction. I re-installed the goodyears just to satisfy myself that it was the tires and not some coincidental mechanical issue. I then installed just the 235 T/A's on the rear and it was fine, so I attribute it to the overly "square" profile with the 8" rim and the 255's.
Your experience may vary, but for out and out performance I preferred the RS-A's. I'm still trying to decide if I like the look of the much wider T/A on the rear compared to the old "correct" Goodyear size.
Hans
