Different tire size question

C

coldfusion11

Forum Member
I had my tire blowout on me this morning. I have 17" mustang bullit wheels with 245/45-17 tires on my crown victoria and the driver side rear blew out. My spare was a 16" steel wheel with a 225/60-16 tire.

I had like 4 miles till work so I had to throw that tire on. Is it ok to drive a longer distance with the two rear tires different overal diameters? I have a traction lock in the rear end so the clutches should provide the slip I need for it to drive straight.

Thanks.
 
I wouldn't have done it, would wear the clutches prematurely. Could have put the spare on the front and taken a 245-45-17 from the front and put it on the rear.

--Joe
 
But lets say 40 miles home wouldn't be good?

I thought about doing the front tire swap but I didn't have alot of time to do this and I thought that would mess up the ABS system having them different sizes.
 
Fryguy302 said:
It's the same as driving a long way in a slight curve or driving in a big circle. 4 miles is no big deal.
Click to expand...

Come on Raj, there is quite a bit of difference. If you are fine with doing that it's your call. But the safest bet would be to just swap the front to back and put the spare up front.

I would post up all the math but it would put everyone to sleep........suffice it to say that there is a lot more slip involved in running those 2 separate sized rear tires.

--Joe
 
soap said:
Come on Raj, there is quite a bit of difference. If you are fine with doing that it's your call. But the safest bet would be to just swap the front to back and put the spare up front.

I would post up all the math but it would put everyone to sleep........suffice it to say that there is a lot more slip involved in running those 2 separate sized rear tires.

--Joe
Click to expand...

I'm with Joe, there's no way i would drive that way. Tire heidth vs roll out is a big deal, and will kill the clutches. Going around a curve is much more gradual than tire heigth difference.

Edit:http://gti-vr6.net/library/engine/Schrick_howto/wheeldiameters.htm
 
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I'm bored....

Using the following info.......
245-45-17 = 6.72' rollout
225-60-16 - 6.97' rollout

Assuming you were to drive in a 4 mile circle (no where is this possible) and the vehicle has a 65" track width, you end up with a 5 rotation difference after the 4 mile trip.

Inner tire = 21120' / 6.72' = 3142.86 rotations
Outer tire = 21154.5' / 6.72' = 3148 rotations
Difference = 5.13 rotations

Driving 4 miles in a perfectly straight line using the 2 different sized tires you end up with almost a 113 rotation difference after the 4 mile trip.

21120' / 6.97' = 3030.13 rotations
21120' / 6.72' = 3142.86 rotations
Difference = 112.7 rotations

That is quite a lot of extra slip IMO.

--Joe
 
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soap said:
Come on Raj, there is quite a bit of difference. If you are fine with doing that it's your call. But the safest bet would be to just swap the front to back and put the spare up front.

I would post up all the math but it would put everyone to sleep........suffice it to say that there is a lot more slip involved in running those 2 separate sized rear tires.

--Joe
Click to expand...

Billydroveit said:
I'm with Joe, there's no way i would drive that way. Tire heidth vs roll out is a big deal, and will kill the clutches. Going around a curve is much more gradual than tire heigth difference.

Edit:http://gti-vr6.net/library/engine/Schrick_howto/wheeldiameters.htm
Click to expand...


I really don't have time to do the math, but if we took the difference in tire height between the two tires (which might not even be much), then we took my statement of a "big circle" and defined it.....we could take the track width of the car and figure out the perimeter of both circles that each rear tire would make, then figure the difference. Then we could extrapolate that difference to equal 4 miles and see which one is worse.

I'm curious, just not curious enough to make time to do it.
 
It just occurred to me that there might be a greater difference if the circle was less than 4 miles. And I did just say "big circle". Do some more math at a 1 mile circle! :lol:
 
Fryguy302 said:
It just occurred to me that there might be a greater difference if the circle was less than 4 miles. And I did just say "big circle". Do some more math at a 1 mile circle! :lol:
Click to expand...

Of course there would be a smaller difference but that doesn't help your argument. Besides he said he has to drive 4 miles.

--Joe
 
soap said:
Of course there would be a smaller difference but that doesn't help your argument. Besides he said he has to drive 4 miles.

--Joe
Click to expand...


It seems like a tighter circle would actually be a greater difference between the two wheels.
 
Fryguy302 said:
It seems like a tighter circle would actually be a greater difference between the two wheels.
Click to expand...

Assuming you were to drive in a 1 mile circle and the vehicle has a 65" track width, you end up with a 5 rotation difference after the 1 mile trip.

Inner tire = 5280' / 6.72' = 785.7 rotations
Outer tire = 5314.6' / 6.72' = 790.9 rotations
Difference = 5.2 rotations

--Joe
 
Dude im so fucked up right now but this thread is epic! Nerds arguing, and I just said fuck it, and changed the front to the rear, so now my final answer is 0 Rotations so I fucking win :buds:
 
coldfusion11 said:
Dude im so fucked up right now but this thread is epic! Nerds arguing, and I just said fuck it, and changed the front to the rear, so now my final answer is 0 Rotations so I fucking win :buds:
Click to expand...

LOL! And you can thank Joe after you drive the next 40 miles to get home.
 
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