[lens]

Hey guys,

So I'm looking to get a bit more traction by going up in tire sizes, I'm lowered on Dinan springs currently, and have 19x8.5 ET35 Front, 19x9.5 ET42 Rear.

What's the recommended setup or max tire size I could run that won't mess with the xDrive?

Thanks.

[BMW335i_]

Originally Posted by chaungo

Hey guys,

So I'm looking to get a bit more traction by going up in tire sizes, I'm lowered on Dinan springs currently, and have 19x8.5 ET35 Front, 19x9.5 ET42 Rear.

What's the recommended setup or max tire size I could run that won't mess with the xDrive?

Thanks.

235/35/19 and 265/30/19

[BASELINE]

I would think the best performance minded option would be to find the right wheel offset that would allow you to squeeze 255 all around. I'm of the mindset that the xdrive cars will "rotate" better with a square setup. When you factor in that a bigger rear tire isn't needed for traction due to AWD, and the added weight upfront just exacerbates the understeer...keep it square unless aesthetics are your main concern.

[lens]

Originally Posted by BASELINE

I would think the best performance minded option would be to find the right wheel offset that would allow you to squeeze 255 all around. I'm of the mindset that the xdrive cars will "rotate" better with a square setup. When you factor in that a bigger rear tire isn't needed for traction due to AWD, and the added weight upfront just exacerbates the understeer...keep it square unless aesthetics are your main concern.

Well I would do that if the xDrive system was actually 50/50 split....except it isn't. My rears wear out ridiculously faster than my fronts (doesn't help that I'm FBO minus IC.) My fronts are at 80% while my rears are around 30-40%

[JC35i]

Originally Posted by chaungo

Hey guys,

So I'm looking to get a bit more traction by going up in tire sizes, I'm lowered on Dinan springs currently, and have 19x8.5 ET35 Front, 19x9.5 ET42 Rear.

What's the recommended setup or max tire size I could run that won't mess with the xDrive?

Thanks.

Chaungo,

In similar situation and have now responded to a few threads trying to completely narrow it down as I also do not want to mess up my xdrive with DHP...
So far the consensus seems to be 245/35/19 and 275/30/19 (looking into purchasing Conti DWS06 from Discount Tire as they offered best price thus far).
I have also stumbled upon a few member running the same wheel set up on stock OEM 225/40 and 255/35?

[5hift]

for the 19's the exact combination would be

235/35/19 on an 8.5" wide front wheel
275/30/19 on a 9.5" wide rear wheel

this in turn will result at an overall tire diameter of 25.5" which is .5" lower than stock and will produce an equal 815 revolutions per mile. this is the safest set-up you will have for a 19" staggered set-up.
i based these specs on what was posted on TireRack as per the specs of Continental DWS06. at times different tire manufacturers have slightly different specs for the same tire size for different brands. i would advise you to do also your own research if you are choosing a different tire manufacturer.
some people say that the transfer case of the xdrive system would allow a slight difference between front and rear overall diameter, im not an engineer, but in a way i would believe that, but after several thousand miles how does this wear and tear affect the mechanical parts due to stress. i just had my transfer case changed at 54,000 miles, it was a $6500 repair cost. im currently is using a square set-up as per the advise of the service manager at my local BMW. hth.

[.BMW.]

Another option would be 235/40-19 front and 265/35-19 rear, which has almost identical diameters.

[Handyman2007]

Well I am running 245/35R19 front and 285/30R19 rear which is the same +0.4% differential between front and rear of the stock 225/40R19 front and 255/35R19 rear and everything was fine for the first 2 summer but this last summer it sounded like the traction control or transfer case was jurking the car a lot more on hard acceleration. My current diameter when new was 25.7/25.8 vs stock 26/26.1 and the revs 784 vs 775 stock... I believe that I have to get even closer to 775 revs!!! I put my winter on and they are square setup at 225/40R19 and the jurking went away.... Any other people with similar problem out there

[ouengineer]

Originally Posted by chaungo

Well I would do that if the xDrive system was actually 50/50 split....except it isn't. My rears wear out ridiculously faster than my fronts (doesn't help that I'm FBO minus IC.) My fronts are at 80% while my rears are around 30-40%

I doubt the rear tires wearing faster has much to do with the 40:60 torque split of the x-drive system. Could just be the wider tires in the rear wear out faster (or maybe you launch the car from a stop a lot and all that weight transfer on the rear wheels is causing premature wear?)

A square setup would give you much better wear and handling characteristics without any loss of straight line traction, but it would be best with a square wheel setup as you'd have to stretch the rear tires a little on a 9.5" wide rim which would likely yield a slightly different tire diameter.

If you need more traction with awd, you just need new tires, not a wider staggered setup. I would be very surprised if a good 245/40 UHP all-season couldn't hold the power you're at for straight line grip.

[rhdh1049]

I have a 13 328i xDrive sedan with sport package 18x8 397's
I ordered new VMR 705's 19 x 8.5 +35 (square set up) tire rack shows 225/40/19 tires
seems too narrow, for 8.5" wide wheels... what should i buy?

[.BMW.]

Originally Posted by rhdh1049

I ordered new VMR 705's 19 x 8.5 +35 (square set up) tire rack shows 225/40/19 tires
seems too narrow, for 8.5" wide wheels... what should i buy?

I would recommend 245/40-19 square!

[rhdh1049]

Originally Posted by .BMW.

I would recommend 245/40-19 square!

They will be too tall for a F30 3/4" taller overall diameter.

[.BMW.]

Originally Posted by rhdh1049

They will be too tall for a F30 3/4" taller overall diameter.

Yes, about 2% taller than OEM.

But that's a good thing, corrects the optimistic speedo and fills the wheel wells a bit better.

[rhdh1049]

Originally Posted by .BMW.

Yes, about 2% taller than OEM.

But that's a good thing, corrects the optimistic speedo and fills the wheel wells a bit better.

I thought maybe 245/35/19

[.BMW.]

Originally Posted by rhdh1049

I thought maybe 245/35/19

Will fit as well, slightly shorter than OEM sizes.

[rhdh1049]

Originally Posted by .BMW.

Will fit as well, slightly shorter than OEM sizes.

235/40/19 ?

[chicagoshark]

Originally Posted by .BMW.

Yes, about 2% taller than OEM.

But that's a good thing, corrects the optimistic speedo and fills the wheel wells a bit better.

From my limited understanding, stock size matching with the speedometer, still results in the car giving a speed of 2-3 miles per hour HIGHER then actual speed? Thus, a slightly smaller tire, will further this inaccuracy, perhaps to 3-4 MPH off of actual speed? Or do I have this reversed?

I think I am a good 4 MPH off of accurate speedometer reading. I'm cruising at 80, and people are passing me by...

[.BMW.]

Here is a list with possible tire sizes for 8.5x19" ET35 wheels:
225/40-19, OEM size
235/40-19, 1% taller
245/40-19, 2% taller
235/35-19, 2% shorter
245/35-19, 1% shorter
255/35-19, OEM size

[.BMW.]

Originally Posted by chicagoshark

From my limited understanding, stock size matching with the speedometer, still results in the car giving a speed of 2-3 miles per hour HIGHER then actual speed? Thus, a slightly smaller tire, will further this inaccuracy, perhaps to 3-4 MPH off of actual speed? Or do I have this reversed?

I agree.

With OEM tire sizes the speedo show a few percent higher speed than actual. But we discussed a tire that is 2% taller than OEM, with that tire size the speedo will be spot on.

Shorter tires than OEM will make the speedo error even worse.

[963mw]

Anyone know if on stock X-Drive suspension, will 19x9.5 & 19x10.5 wheels cause any issue? Going to order Vorsteiner wheels in the next couple of days.

[rhdh1049]

Originally Posted by .BMW.

Here is a list with possible tire sizes for 8.5x19" ET35 wheels:
225/40-19, OEM size
235/40-19, 1% taller
245/40-19, 2% taller
235/35-19, 2% shorter
245/35-19, 1% shorter
255/35-19, OEM size

This will help a lot, thank you!

[BASELINE]

I'm thinking either a Square 255/35-19 setup.

Or

255/35-19 (F) / 275/30-19 (F) which is the F80 oem sizing and only 2% rotation different front:back should work.

Anyone try either?