Spare Causes Front Diff Failure?
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Spare Causes Front Diff Failure?
After suffering a right front flat tire this afternoon (225-40-18 Yokohama AVS Sports on 18x7.5 Prodrive P1s) I installed the spare. Everything was working fine until then. After a jaunt back on the freeway at 70 mph, about 30 miles, something happened as soon as I pulled off the freeway. Upon trying to commence motion on a green light the car was hard to launch and the transmission, though it shifted well, was making some serious grinding noises seemingly corresponding with every few revolutions of the tires.
Has anybody else experienced anything similar that may or may not have been caused by mounting a spare? Could it have anything to do with a different outer diameter between left Yokohama and stock spare tire? OR did something else happen that just coincidentally coincided with my spare tire/freeway venture? It was factory spare, inflated to proper 60 psi as per sidewall and manual.
Thanks in advance!
--BA
Has anybody else experienced anything similar that may or may not have been caused by mounting a spare? Could it have anything to do with a different outer diameter between left Yokohama and stock spare tire? OR did something else happen that just coincidentally coincided with my spare tire/freeway venture? It was factory spare, inflated to proper 60 psi as per sidewall and manual.
Thanks in advance!
--BA
Registered User
Joined: Jul 2003
Posts: 66
From: Sacramento, CA
Car Info: 03 WRX Wagon
quote "Could it have anything to do with a different outer diameter between left Yokohama and stock spare tire? "
-yes-
you have 3 tires of similar or same circumference and one that is different on an AWD vehicle, then you drove on the freeway for 30 miles at 70 mph. You may have cooked the front diff and/or the center diff. That's why in the owners manual they tell you to flatbed the car (and my salesman when I bought mine went into great detail on why not to do this) if you don't have the same size spare. Even the warranty roadside assistance will flatbed your car (if it is still under warranty) if you get a flat
I hope for your sake I am wrong
-yes-
you have 3 tires of similar or same circumference and one that is different on an AWD vehicle, then you drove on the freeway for 30 miles at 70 mph. You may have cooked the front diff and/or the center diff. That's why in the owners manual they tell you to flatbed the car (and my salesman when I bought mine went into great detail on why not to do this) if you don't have the same size spare. Even the warranty roadside assistance will flatbed your car (if it is still under warranty) if you get a flat
I hope for your sake I am wrong
VIP Member
Joined: Mar 2003
Posts: 2,023
From: Phoenix, AZ
Car Info: Subaru Impreza WRX 2002
I think it is pretty common knowledge that regardless of whether your car is 2WD or AWD, you don't drive more than 50 MPH and longer than 5-10 miles on a donut spare, period. Driving 70 was essentially drivetrain suicide, though this doesn't do much good as hindsight.
Let's hope they warranty your repair. With aftermarket wheels and tires, you may be out of luck.
Let's hope they warranty your repair. With aftermarket wheels and tires, you may be out of luck.
VIP Member
Joined: Mar 2003
Posts: 2,023
From: Phoenix, AZ
Car Info: Subaru Impreza WRX 2002
<insert sound of Nelson from the Simpsons>
Ha-Ha!
I'm typically not one to laugh at anyone's misfortune, but I just checked my spare and it does say right on the tire to stay under 50 and get off the donut spare ASAP. Live and learn!
Ha-Ha!
I'm typically not one to laugh at anyone's misfortune, but I just checked my spare and it does say right on the tire to stay under 50 and get off the donut spare ASAP. Live and learn!
Registered User
Joined: Dec 2003
Posts: 372
From: Encinitas CA
Car Info: Black 03 WRX
even though it is open, the different diameter wheels will cause the differential to act as if it is turning and if you go over 50 for an extended period of time it will heat the thing up really well and it will fry it. It would be even worse in the rear though. If you get a rear flat, put a front tire on the back and the doughnut if the front and GO SLOW.
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I heard that all the tires have to be the same all around and i'm sure your prodrives vs. the spare are not the same. well anyways it will definatley kill your awd. That is because the spare being a different size is going to spin faster than your prodrive which the drivetrain doesn't like. I killed my llegacy drivetrain by doing that. It now RIPs in a subaru recycler.
225/40/18 is 637mm diameter
205/55/16 is 631.9mm diameter
it's less than 1% difference in diameter though.
I doubt its enough to cause trouble.
but true, shouldnt have gone more than 50mph and shouldn't have driven 30miles
your symptoms seems similar to mine, I broke transmission by running low on oil (didnt notice the leak from transmission).
Maybe you should check transmission fluid.
205/55/16 is 631.9mm diameter
it's less than 1% difference in diameter though.
I doubt its enough to cause trouble.
but true, shouldnt have gone more than 50mph and shouldn't have driven 30miles
your symptoms seems similar to mine, I broke transmission by running low on oil (didnt notice the leak from transmission).
Maybe you should check transmission fluid.
Guest
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Strange brew
So the dealer looked at the car and said nothing was wrong. I couldn;t believe it -- went down, went for a drive and there was no noise, no drag, no nothing. Like there never was a problem. Strange! So they drained the fluids and looked for metal pieces, burnt oil, etc., and there was nothing out of the ordinary. So the car's behaving normally now and, well, this all just doesn't make sense to me...
Many thanks to all for all of your insight and input!
--BA
Many thanks to all for all of your insight and input!
--BA
Guest
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my thoughts on this....
Based on what you posted I would say that for one you really need to read the manual from cover to cover. Two, you messed up by driving on the spare for 30 miles at 70MPH. Three, you were VERY lucky and most likely did not do any permanent damage.
By having the tire's diameter different sizes you made the differential work some major overtime and heated up the fluid to a very unhappy level which caused the diff to malfunction. Once the fluid cooled down to normal operating temperature everything went back to working normal (although still not in perfect condition).
I would recommend being more careful in the future, and don't be surprised if your diff has a premature failure sometime in the future.
Good luck.....I hope you learned something...
-Steve
By having the tire's diameter different sizes you made the differential work some major overtime and heated up the fluid to a very unhappy level which caused the diff to malfunction. Once the fluid cooled down to normal operating temperature everything went back to working normal (although still not in perfect condition).
I would recommend being more careful in the future, and don't be surprised if your diff has a premature failure sometime in the future.
Good luck.....I hope you learned something...
-Steve
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Car Info: 98 Impreza Outback Sport
[QUOTE]Originally posted by go go go
[B]225/40/18 is 637mm diameter
205/55/16 is 631.9mm diameter
it's less than 1% difference in diameter though.
I doubt its enough to cause trouble.
It seems to me that the circumference is what we're lookin at... so it's probably closer to 3% difference. Not tryin to split hairs, but 3% is quite a bit more substantial
[B]225/40/18 is 637mm diameter
205/55/16 is 631.9mm diameter
it's less than 1% difference in diameter though.
I doubt its enough to cause trouble.
It seems to me that the circumference is what we're lookin at... so it's probably closer to 3% difference. Not tryin to split hairs, but 3% is quite a bit more substantial