I have just picked up a 1969 Skylark Custom Convertible. The tires on it are 215/75/14. on all corners. I am wanting to stagger the size from back to front. What is the biggest size in the rear that will fit with out any cutting or mods to the car. I am going to run a 205/70 in the front and am looking to run a wider and taller tire in the rear. I was thinking abot 225/70 but would like to go bigger if possible....My car is now 2 hours away getting certified so I do not have it here with me at the moment....Here are the rims that are on it now.... Thanx in advance for any advice and knowledge...
I had 235/60R14's on my 69 convertible with stock rallys. They looked ok and fit without adjustments. I had new springs/shocks though.
Your tire choices are very limited with 14" wheels. You would be way better off going to a 15" Chrome Buick Wheel. They are reproduced, but are expensive. You might be able to buy some originals in "Parts Wanted" The P225/70R-14 is the closest to the G70-14 that the car could have been ordered with. I think they would fit all around with no problem. You want to stay as close to 26.4-26.6" tall for any wheel/tire height. Going away from that in the rear affects speedometer accuracy as well as final drive ratio.
The P235/60R-14 is only 25.10" tall. Not only would that compromise your speedometer accuracy and rear gear, but I think it probably didn't fill the wheel well sufficiently. The stock tire height was 26.4- 26,6".
Thanx everyone...some great info. Would 205/70/14 be a bad choice for the fronts if I were to go 225/70/14 on the rear...or would you suggest 225/70 on all four corners?
I have 225/70/14 all corners on mine now and am happy with them; 205s would be kinda small on the front. (If//when I switch to 15s I’ll probably go 245/60/15.) Patrick
225/70-14 on all corners is fine. The 205/70-14 is only 25.3" tall. It will look small in the wheel well IMO.
Used 225-70 R 14 on my '64 Skylark. No problems and look right. 205 will probably look too small in my opinion.
I want to thank everyone for the input...I went with 225/70/14 on all four corners and my mechanic says the fit really well....I haven't seen it yet...soon soon...lol I bought the Cooper Cobra GT Cheers
Good choice all around. Those tires will fill the wheel well and the Cooper Cobra is a nice riding/handling tire. Don't be afraid to run more air pressure in them. They have a maximum inflation pressure of 44 psi. I run 37 psi in mine.
I put p245/60R15 on my 69 and they fit nicely. Now I’m even going faster, Doah! I haven’t started workIng on this issue yet, but it’s going 55mph when I’m doing 40 mph. I’m assuming this issue has arisen before but... It’s got a PB turbo 400 in it 6548232 which I think complicates things further?
You need a different DRIVEN gear in the speedometer gear sleeve. To figure out which one, you need three numbers, 1) the rear tire height. P245/60R-15 is 26.6" tall 2) rear gear ratio? 3) the number of teeth on the speedometer DRIVE gear. That gear is on the transmission output shaft. You can see it when you pull the DRIVEN gear sleeve. When you pull the sleeve, you'll lose some fluid, be prepared for that. If you get the back of the car off the ground, and pull the sleeve, put the transmission in neutral and turn the drive shaft while carefully counting the teeth. The gear is helical so it is more difficult, but not impossible. Mark one tooth to make it easier. When you have all 3 numbers, plug them into this calculator, https://www.tciauto.com/speedometer-gear-calculator Depending on what DRIVEN gear you need, you may need a different sleeve. One sleeve takes gears from 34-39, the other, from 40-44.
I never did post a picture with the new tires.... It rides great and the tires fit the wells really well.
Looks great.. I just bought my 69' last weekend - and I was thinking the 205/70/14 were too small.. I think I'll do the 225/70/14 as well.. possibly the Coopers... Perfect timing on your post.. Thank you
