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another wheel size question as it pertains to spare
anyone using a space saver spare? if so, off what...which also begs the question as to what the bolt circle is on these year cars...ours is a 1967 cutlass.
we have 15's on it now since I did the disc brake conversion up front. threw out the 14" spare since it will do us no good except on the back which also has 15's now. as long as we are replacing, thought I would go with a donut if one will fit. thanks for any insights....
I hate the donut spares, and have no reason to save space in the huge trunk. I would just pick up a 15" wheel and a used tire that's close in diameter of your current set.
I understand. guess I have gotten used to them and figure I can go to the boneyard and get one for almost nothing and use it. just would have to make sure it has the right bolt circle and would clear the front discs. hopefully, never use it. the one in my Cobra has never been on the ground since I have had the car (knocking on wood.....).
Why didn't you just keep the 14" spare? I swapped to 15" wheels as you did and the 14" spare is what I have in my car at the moment. 245-60-15 vs. 245-60-14 is only an inch difference in overall height, so 1/2" difference in ground clearance.
edit: I realized you had a 14x6 that would not clear the discs whereas I have 14x7 that will. Nevermind.
Last edited by Fun71; March 4th, 2016 at 04:26 PM.
Why didn't you just keep the 14" spare? I swapped to 15" wheels as you did and the 14" spare is what I have in my car at the moment. 245-60-15 vs. 245-60-14 is only an inch difference in overall height, so 1/2" difference in ground clearance.
edit: I realized you had a 14x6 that would not clear the discs whereas I have 14x7 that will. Nevermind.
edit: I realized you had a 14x6 that would not clear the discs whereas I have 14x7 that will. Nevermind.
And yet, Olds built disc brake cars in 1967-69 with 14x6 wheels.
Once again, the problem ISN'T the diameter or width, it is the contour on the backside of the rim that will or won't clear the caliper. Logic should tell you that a narrower rim should have MORE clearance.
This photo should be a sticky, since I have to keep posting it. LH is the disc brake rim. RH is drum only.
And here, the red line is the contour of the drum only rim:
And yet, Olds built disc brake cars in 1967-69 with 14x6 wheels.
Once again, the problem ISN'T the diameter or width, it is the contour on the backside of the rim that will or won't clear the caliper. Logic should tell you that a narrower rim should have MORE clearance.
This photo should be a sticky, since I have to keep posting it. LH is the disc brake rim. RH is drum only.
And here, the red line is the contour of the drum only rim:
Great info!!! Thanx for posting again!! you are right...should be a sticky.
Curious...can a disk brake rim be used on drum brakes? I picked up a 15 inch rim for a new spare it is clearly a disk break rim.
Considering that cars with front disk brakes use the same rims on the rear drum brakes, I'd say yeah.
The "disk brake" rims simply have additional clearance on the backside to clear the caliper. That has no affect when used on drum brakes - well, actually, it might allow additional airflow space for drum cooling.
gonna take some measurements as to height of the donuts when I go to the boneyard next time and see what I can find that will work. will be cheaper, if I can find one, than buying a 15" rim and a new tire.
gonna take some measurements as to height of the donuts when I go to the boneyard next time and see what I can find that will work. will be cheaper, if I can find one, than buying a 15" rim and a new tire.
None of them will be as tall as your stock tires. That's why they are "mini-spares". The higher pressure reduces sidewall deflection, but the rolling radius will still be smaller. This is why they are limited to 50 miles of use. To make it easy, just get the mini spare from a 1980-1990 B-body. These wheels came with both the 4.75" and the 5" bolt circles, and those cars came from the factory with tires that were 27"-28" in diameter. Plus, car weight will be comparable to yours, so the spare will be sized for that.
None of them will be as tall as your stock tires. That's why they are "mini-spares". The higher pressure reduces sidewall deflection, but the rolling radius will still be smaller. This is why they are limited to 50 miles of use. To make it easy, just get the mini spare from a 1980-1990 B-body. These wheels came with both the 4.75" and the 5" bolt circles, and those cars came from the factory with tires that were 27"-28" in diameter. Plus, car weight will be comparable to yours, so the spare will be sized for that.
March 4th, 2016, 01:00 PM
