Car Question - Tire size differences - Calgarypuck Forums - The Unofficial Calgary Flames Fan Community

photon · 03-26-2008, 08:52 PM

K I got a flat on the Murano, now I've put new tires on there that are slightly bigger than the old ones (265/60R18 vs original 235/65R18), they're less than 5% different for diameter.

But of course the spare is the original size (the bigger one doesn't even fit).

How bad is that for the rear differential (it's the rear left tire)? Obviously we'll get it fixed asap but the bolt that punctured the tire was pretty big, plus my wife drove on it for quite a bit. There's no visible damage, but it's possible the tire isn't repairable, in which case they'll probably have to order in a replacement.

So what does that <5% difference in tire size mean in terms of driving the car? Is it ok to drive for a few days? Should I leave it parked until the replacement tire comes in? Ok to drive but keep it to a minimum and/or under a certain speed?

burn_this_city · 03-26-2008, 09:18 PM

I wouldnt drive on it for long.. The aspect ratio difference is approximately 18%. If it was fwd and on the back it would be ok. But because the its going through a differential it will make the limited slip go continously. I dont suggest going for more than 50km..

265/60 = 4.42
235/65 = 3.62

4X4 · 03-26-2008, 09:25 PM

Plus it'll demolish your other tires. If it was a beater, I'd say run with it. Since it's not, I'd highly recommend at least matching your two front tires and your two rear tires. Having two different tires on your front or rear will cause your car to feel funny when driving at highway speed.

burn_this_city · 03-26-2008, 09:29 PM

^^ I wouldnt drive more than 80km/h, highway speeds would be dangerous.

photon · 03-26-2008, 09:42 PM

Ok thanks, we'll have to make arrangements then, I'll call the tire place to see if they have the right tire in stock (Yokohama Geolander, I'm not optimistic), then maybe take it in to see if they can repair it, but seriously it's a bolt, not a nail, so not sure if they can fix it or not. The tire place is maybe 12km away.

burn_this_city · 03-26-2008, 09:48 PM

Quote:

Originally Posted by photon

Ok thanks, we'll have to make arrangements then, I'll call the tire place to see if they have the right tire in stock (Yokohama Geolander, I'm not optimistic), then maybe take it in to see if they can repair it, but seriously it's a bolt, not a nail, so not sure if they can fix it or not. The tire place is maybe 12km away.

Aslong as the bolt didnt go in sideways it can be patched.. I used to fix tires for a couple of years and you'd be suprised what is repairable. Of course theres no guarantee unless I saw the tire, theres a few factors which could make the tire unrepairable. If you drove on it for a lil while it could be damaged inside. Or if the bolt went through the sidewall or on the edge. I'd say theres a good chance you wont need a new tire if none of these things happened.

photon · 03-26-2008, 09:49 PM

She drove on it for quite a while, so I'm not hopeful

CRXguy · 03-26-2008, 11:13 PM

It's AWD, right? Park it and have it towed. I would not risk driving it, even if it's only 12km. Doesn't take much for the centre diff to overheat and break down.

photon · 03-27-2008, 12:15 AM

It's not full time AWD though, I think it's front wheel unless it actually needs to drive the rear wheels.

Either way I'm probably gonna take the tire in myself in my car, so the only driving will be a few blocks if that.

4X4 · 03-27-2008, 12:45 AM

I misunderstood the original post... I thought you replaced the bunk tire with a different one. You're saying that you've slapped on the spare (that is a different size because you bought new tires aftermarket) and you want to get the other tire fixed? Definitely. Go ahead and drive on the spare for a week or two. No biggie. Just don't go replacing one tire with a totally different tire permanently. Get it fixed before you do a road trip or something.
And most punctures that came through the tread are fixable. Sidewall punctures, not so much.

Bill Bumface · 03-27-2008, 12:49 AM

Quote:

Originally Posted by burn_this_city

I wouldnt drive on it for long.. The aspect ratio difference is approximately 18%. If it was fwd and on the back it would be ok. But because the its going through a differential it will make the limited slip go continously. I dont suggest going for more than 50km..

265/60 = 4.42
235/65 = 3.62

265 * 0.60 = 159
235 * 0.65 = 152.75

If your original 3 tires are fairly worn and your spare is brand new you'd be running pretty damn close to even, so your diff would probably be alright.

Even if that is the case, running with one side a different width isn't the best. Uneven braking for sure will be an issue.

burn_this_city · 03-27-2008, 06:34 AM

Quote:

Originally Posted by hulkrogan

265 * 0.60 = 159
235 * 0.65 = 152.75

If your original 3 tires are fairly worn and your spare is brand new you'd be running pretty damn close to even, so your diff would probably be alright.

Even if that is the case, running with one side a different width isn't the best. Uneven braking for sure will be an issue.

He's correct.. Ignore my shabby advice, I wasnt quite with it when I came up with those numbers. I also misread the original post, its thats the spare from the factory it should be fine.

photon · 03-27-2008, 08:16 AM

The new ones aren't very worn, maybe a year old if that, but that makes me feel more comfortable with it.. I'm dropping the tire off this AM and they said if they can fix it great, if not they can have a replacement in by tomorrow, so the only driving will be around Chestermere if absolutely necessary, so it works out well.

I'd get another one to have a spare of the same size, but the newer tires are wide enough that the cover for the spare well doesn't close with the bigger tire in it!

Thanks guys, I appreciate all the help.