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[Stars1315]

I bought snows in late January. Went to a local guy in nj from out in nevada who generally knows his stuff. Never dealt with him before but heard good things. Did the staggered calc in front of me and everything looked fine. Got 225/40 and 245/40. The other day I felt the traction control freak out on dry road on a turn and decided to investigate. Sure enough the tires are 2.4% not sub 1% guess he just goofed somewhere in the calculation. Having 40/40 should've set off a red flag in my head but I didn't worry about it at the time.

My question is, will I damage anything like this? Idrive or something? It doesn't seem to be an issue unless accelerating on a turn, or going up around 80-90mph the traction blinks but doesnt cut throttle or anything. The tires do great in the snow i don't want to get rid of em. Shouldnt be pealing around turns and going 80+ in the winter anyway haha.

In the case that I will break something... if I just go to a square setup and put two more of the rear size tires on the front will I be okay?

[floydarogers]

The transfer case is being stressed and I would change out one set (probably going square). You're either heating the transfer case's fluid or wearing out the clutch pack, or both.

There is no center differential; it's a transfer case with clutch apportioning more/less torque to the front axle (rear axle is always driven, no matter what some things/people say.)

[Antetokounmpo]

2.4% is HUGE. I would have to assume you feel some vibration, no?

Get 255/35 or 225/40 in the back ASAP (even if rears are 8.5" you can still easily put a 225/40 on)

[Stars1315]

Nope feels fine. Hence why I didn't notice anything was wrong until the traction control flared.

[Antetokounmpo]

Originally Posted by mreto727

Nope feels fine. Hence why I didn't notice anything was wrong until the traction control flared.

One time I accidentally put a set with a 1.2% difference on and there was a noticeable vibration from the transfer case.

[Stars1315]

Originally Posted by Harambe

One time I accidentally put a set with a 1.2% difference on and there was a noticeable vibration from the transfer case.

Maybe because this car is fairly new to me I didn't notice. I only had my previous tires on it a week or so before I put the snows on.

If I drive another 200 miles on these, will I be okay? My tire guy is back in NJ and I am in MA for school currently. I'm assuming it takes more than a few hundred miles to actually screw it up.

[deeLow]

You have XI?

I'm on winters in a RWD car. Square setup. My traction control light constantly goes off if I hit the gas in a turn. Not because I'm actually at risk of spinning or anything, but because the tires are soft and have more "give" in them.

[Stars1315]

Originally Posted by deeLow

You have XI?

I'm on winters in a RWD car. Square setup. My traction control light constantly goes off if I hit the gas in a turn. Not because I'm actually at risk of spinning or anything, but because the tires are soft and have more "give" in them.

I'm on xi, yes. It's definitely the tire sizing. Tires are past break in period. Originally I thought it might be just that, but when it did it again the other day I decided to have a look at what was up, and sure enough, I saw 40/40 on 245/225. Ready to shoot myself right now for not catching that earlier. Should've asked for a square setup to begin with.

[n55jb4]

If you can't swap tires right away - you can in theory over-inflate fronts by 3-5psi more and keep rears at normal psi - that would even it out - diameter for fronts will change by 2-3% so there ya go

I have 328xi with staggered setup and I keep my fronts overinflated by default all the time - I have 18' rims and low profile tires so I need more pressure in my front tires to avoid breaking my front suspension on every pothole

[Stars1315]

Originally Posted by n55jb4

If you can't swap tires right away - you can in theory over-inflate fronts by 3-5psi more and keep rears at normal psi - that would even it out - diameter for fronts will change by 2-3% so there ya go

I have 328xi with staggered setup and I keep my fronts overinflated by default all the time - I have 18' rims and low profile tires so I need more pressure in my front tires to avoid breaking my front suspension on every pothole

I'll just do that and go get em swapped. Thanks for the tip.

On a side note though, how much does it take to wear the clutch or blow the box? At ~2.4% I'm assuming/hoping it's not immediate? It'll be 700 miles driven total once I've got the correct ones on.

[infinite_creations25]

Would you rather spend a bit more to get the proper size tires or would you rather risk spending much more if your transfer case ends up going in the future?

[Stars1315]

Originally Posted by infinite_creations25

Would you rather spend a bit more to get the proper size tires or would you rather risk spending much more if your transfer case ends up going in the future?

I'm going to get the new tires... I'm just curious how much it takes for the transfer case to blow in general... Trying to quantify if I've done any considerable damage to it with the ~500 miles I've gone before realizing the tires are wrong.

[n55jb4]

Originally Posted by mreto727

I'm going to get the new tires... I'm just curious how much it takes for the transfer case to blow in general... Trying to quantify if I've done any considerable damage to it with the ~500 miles I've gone before realizing the tires are wrong.

I don't think you've damaged anything yet, after all new rubber is very pliable and tiny differences like +1.4% over the limit (1.0%) are not going to damage your case instantly, otherwise we would have had broken transfer cases anytime rear/front tires have slightly different psi - happens all the time with many of us. However, the sooner you replace the better. I remember I had vibration - caused from circumference differences at some speeds during turning. If you don't have vibration - chances are you are ok for now, just change tires at your earliest convenience

[Stars1315]

Okay cool.

Still can't believe I heard the words "okay so 245/40 rear and 225/40 front" and just went yep that's fine. *facepalm*