Something I forgot to account for when upgrading brakes

IIGood

Founding Member
Aug 1, 1998
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Churchton, MD
About 2 years ago I upgraded the stock front brakes on my GT to Mach 1 brakes. 13" rotors and associated calipers, naturally.

The other night, the front passenger side tire blew out. I get over to the shoulder, break out the jack and spare, and go to town on starting to get it changed. I swapped it all over and once I got the donut on, it wouldn't turn.

Initially I thought I torqued the lugs down too tight so I backed them off a bit. Still wouldn't turn. WTF??

Then it hit me. The stock donut must've been scraping up against the caliper, preventing it from turning. Crap. I had to get it towed. So I guess I'll have to look for a Mach or Cobra spare now. Boo.
 
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the issue with running a spare donut on the rear axle is you can easily wear out your LSD if you don't get a new tire on right away. I had to wait a week before I could get a matching tire, and in that week my rear diff got so bad it needed to be rebuilt.
 
Well that's a problem if you have after market brakes or not, if you pop a rear tire you need to put the spare on - it's really just to get home. Not for driving around for a week even if it was on the front. When I popped a tire, I drove it with the spare to my tire place and they patched it in half hour.
Of course is it's a sidewall tear or blow out this isnt a choice.
 
Well that's a problem if you have after market brakes or not, if you pop a rear tire you need to put the spare on - it's really just to get home. Not for driving around for a week even if it was on the front. When I popped a tire, I drove it with the spare to my tire place and they patched it in half hour.
Of course is it's a sidewall tear or blow out this isnt a choice.

Yeah, my point was that simply putting the spare on the rear isn't a good idea for more than a few miles. My car is my daily driver, and I just didn't think it would be an issue for a few days. I don't want someone else to make the same mistake.
 
i'll have to check that next time i have my front rims off.

my 15x3's are spaced out 1" and they dont scrub. maybe the backwards spare would work just to get you home. i wouldnt trust it much over 40 mph but it is better than being stranded
 
the issue with running a spare donut on the rear axle is you can easily wear out your LSD if you don't get a new tire on right away. I had to wait a week before I could get a matching tire, and in that week my rear diff got so bad it needed to be rebuilt.

EXACT same thing happened to me. I had the spare on the rear for a week while waiting for new tires to come in. My diff is totally shot, and I need a rebuild. It's very expensive too, costing about $700 w/labour and a 8.8" re-build kit from FRPP.
 
I beleive the 05+ Mustangs come with a 17" spare tire and a 185/60/17 tire on them.

That tire size is EXACTLY the same od as the 245/45/17 on the sn95's. Both are 25.7" in diameter.

In retrospec, the 16" spare on the 99-04 GT's is a 145/80/16 tire and is 25.1" in diamter...and slightly shorter. So it may wear an LSD if you drive for a long time on the rear.

I have not bolted up a 05+ spare though...so unsure how well it clears the 13" brakes. I am in the same boat myself. 13" cobra brakes up front and no spare tire in the well.
 
We do have a 17" spare (even though my car has 18s) and I can take some pictures with measurements in the morning if it'll help any of you guys out any. It's nothing fancy but sure will beat being stranded :)