getting 2 tires put on.. will this cause problems?

[d1giPhux]

So, im getting a bit annoyed. I went to get my car registered.. and the inside of my 2 front tires are worn.. so.. looks like i need 2 new tires. I have the shop order the tires.. and then i go to have them put on, and the guy says that it can damage my car because they will be heavier then the rear ones, and cause damage. So.. they basically wont put them on unless i will buy another 2. I thought this was only true when changing 2 different types of tires onto the car.. anyways.. just need some advice.

The rear tires are a bit worn down.. but not TOO much, and the front one would be brand new. Should i worry about doing this.. or should i just bit the bullet and get all 4 done (dammit).

Thanks.

[shazapple]

It's not because the tires are heavier, it is because they have a slightly different diameter than tires that are worn down. The two different rolling speeds causes the center diff to heat up and wear more, maybe even completely fail depending on how large the difference is.

Check out the owners manual. I believe there is a section in there about tires and how much of a difference in tread depth you can have (assuming the new front and old rear are the same make). Show the shop this if you have to.

[Huffer]

Normally you want to run 4 tires the same... proper rotation of the tires should avoid any abnormal wear...

[d1giPhux]

yea. the wearing was definitely an alignment issue.. i should have taken care of that long ago.. but i didnt. Thanks for the info on the diameter as well.. they said something about weight and i was like.. huh? Makes more sense with diameter. I suppose i will just have to bite the bullet and get 4 new ones.. even tho im broke as hell =[

[ivwarrior]

Subaru says all 4 must be within 1/4 inch rolling circumference. That's very little difference in tread depth. Since even tires marked as being the same size vary in true size from one brand to the next, my advice would be to get the 4 new ones, and not have to worry about spending a lot more fixing damage down the road.

http://www.subaru.com/common/faq/tech_info.jsp#4

[LegacyRob]

And don't forget to get that alignment done :wink:

[d1giPhux]

yea.. the alignment definitely needs to be done.. i was stupid and lazy and didnt get it done last time.. and yea.. ate my tires up.. blah. Well, looks like im going to get all 4 new ones put on, then get it aligned.. so everything should be cool. damn.. sucks how rubber costs so much! :( LOL!

[JLav211]

Bumping this back from the dead.

I want to play devil's advocate for the heck of it. As far as the guidelines provided by Subaru, how much of this is genuine protocol for the well-being of the vehicle versus Subaru covering their ass against any defects in the differential?

For the record, I had to get a tire replaced recently. It's pretty close to the other tires on the car, so I'm really not worried about doing damage to the diffs. Subaru just did the differential service 1K miles ago, and I've had slightly uneven tire depth for the past few months - nothing wrong the diff. Granted, they are the exact same tire, but I've been thinking about this again given I just replaced a tire I blew out.

Thoughts?

[decke48]

i dont think you will have much of a problem with minor different tread depth only if the difference of front and rear revs per miles is way off. example is for front tires spin 810r'pm and the rears spin 825r'pm then you might be running into problem in the long run

[Perdue]

I'm thinking the rule of thumb is 3/32" maybe? It's pretty close. And yeah, you def risk burning up any differential when you treat it like that, no matter who made it.

[Kris]

might as well ask here than staring a new topic.
is it safe for 3 Tires used 2000KM/hwy and 1 new all the same type?
and if there's any difference should the new on front or rear?

[decke48]

are they all the same brand and type?
what the tread depth differance on the old tires vs the new one?