spare tire offset worry

[danieltrusty]

i blew a tire (RR) today and had to drive on the highway on the donut. I had to drive for over an hour and by the time i got home my differential was smoking and stinking and was obviously doing something bad. this was with my stock bd9 snowflakes with 205/55/r16 tires. i know i prolly shouldnt have been on the highway that long on the donut, but was it normal that it overheated like that? im going to change the fluid in the morning, but this has me worried now. i picked up a set of american racing ar606 16x7 +40 with almost new 205/55/r16 tires for $100 on CL, now i'm even more worried about this. WTF should i do about a spare, is it going to be an even bigger issue with these other wheels?

[danieltrusty]

hmmm no response. am i being unreasonable worrying about this? sorry, i have bad anxiety sometimes!

[ctbrighton]

yea you're worrying too much. i drove on a donut for well over 3 highway hours with no issues on my 98 bk, so you might have some underlying issues, to say the least.

[Wiscon_Mark]

I believe the recommendation is not more than 60 miles on the donut.

Which diff was having problems, the rear one? Manual or automatic?

If you have an auto, you can swap the donut to the rear and put it in FWD mode and help save some stress on the diffs. As it is, the rear diff is the easiest, cheapest to replace.

[danieltrusty]

this was the rear diff on a 5MT car. I drove from Appleton to Van Dyne and back, and when I pulled off of the ramp onto College Ave, there was a horrible smell and smoke coming out. Two things to note: Itwas pretty hot out thatday, and Ihad my A/C on

[Wiscon_Mark]

Well, if it doesn't give out, don't worry about it, maybe just look around for a spare junkyard diff the replace it when the time comes, if it does.

As for offset, that has nothing to do with tire circumference. It's really about having the same tire circumference that makes a difference. You're not even supposed to have 2 different amounts of wear with the exact same type & size tires on an AWD car, so I wouldn't get anything dramatically different for a spare, and definitely replace entire sets of tires for you daily driving tires.

If you do want to do a full size spare I'd recommend going stock size, or for something more equivalent than the donut, here's a great tool: http://www.miata.net/garage/tirecalc.html

Just plug your stock size in, then the size of the donut spare. Notice the percentage it is off, and aim for something lower than that. Obviously 205-55-16 is the ideal size.

[danieltrusty]

I'm sort of bringing this back up, but it is the total tire circumfrence that must be even at all four corners? I keep reading discussion about tire circumfrence/radius/diameter and different offsets etc being bad. what is it exactly that is imperative to keep in mind on an awd car? How particular doI really have to be? For instance my back tires are of the same size but of a different brand and different amount of wear than on the front. They are not dramatically different, but a little bit. So, then what is the issue with offsets? I was thinking of putting 10mm rear spacers and 5mm front spacers on 16x7 +40 wheels to flush them up to the fenders a little, is this bad? Why do people keep saying that staggered wheels can't be run on an awd, as long as the overall tire diameter is the same?

[Wiscon_Mark]

Circumference is what matters. When you get two different circumferences on the tires, they're spinning at different rates when you're moving. The creates wear on the differentials.

You should have the same tire, size, and amount of wear all the way around. Your center diff is probably suffering with your current setup. I would definitely recommend getting a new set of tires before you fry your center diff.

As for the offset, why do you want to do it? Is it for functionality or just looks? I would say that putting spacers would put undue wear on your hubs/wheel bearings, but shouldn't affect the diffs.

[danieltrusty]

spacers are really just for looks, im not going for hellaflush but my rears seems to sit much deeper in the fenders and it just sorta bugs me. i know spacers can stress the hubs, but im not going for crazy amounts so i don't think it will be a huge concern.

I got the set of tires and wheels for $100 on CL, all four tires are close to new. I wasn't sure about the wheels as they are chrome american racing wheels, but theyve grown on me and I think with a different finish, maybe graphite or just silver, they will be cool and a little different. New tires are in the works when I have the money living where we do im looking at nokians or continental dws

https://sl-i.net/FORUM/ (http://s434.photobucket.com/user/rotharpunc/media/Stuff/20130826_172110_zps9c8773cb.jpg.html)

this is the car with these wheels

[Wiscon_Mark]

I like my Continental DWSs. New tires are cheaper than a new center diff.

[danieltrusty]

looking at wheels, there are several package deals i can find with wheels and tires for around $600...starting a new job so just gotta save up