sonphan13

I have a 2006 525Xi No Sport Package. About 3 weeks ago I had to put 2 used Front tires on my car. I just need to throw some tires on so the two used tires I had laying around were 225/55/17. After the tires were installed on the Front, I noticed I was feeling some torque steer. I thought there were something wrong with the tires so I then rotated the tires to the Rear. After the tires were moved to the rear, everytime I accelerate my DSC would activate. This all happened during my 3 hour trip. Finally when I arrived at my destination I started hearing some noise from the engine bay. I got out and saw a puddle of oil below the car. To make it short I had my car towed to a BMW dealership and they told me that I have a hole in my transfercase. Luckily it was covered under my CPO warranty. I ended up having to replace my Transfercase. After performing the installation the Tech took the car out for a test drive, the DSC still activates under acceleration. They suggested that I get two new tires that are the same size as the others.

My main question is, is this normal? Are you not supposed to have different size tires (Front and Rear)? This worries me because I have a set of M6 19" wheels I'm planning on putting on my car this spring. With the stagger set up I'm planning on putting 245/35/19 on the Front and 275/30/19 on the Rear. Am I going to see the same issue with the different tire size? Has anyone else encountered this problem? Thanks.

AchtungE60

Your issue is not related to tires in my opinion and 245/35/19 on the Front and 275/30/19 on the Rear is the BMW recommendation for 19's. It's on your doorjam sticker and what most of us, including myself, run currently.


just curious, the 225/55/17 you were running.....what brand? Curious to know the overall diameter.

advancedlogic

I'm no expert in this area - there are numerous much more knowledgeable folks here. However, I will attempt to answer.


First, a staggered setup should be fine. My 545i came stock with a staggered setup. I think your DSC issue is more related to tire width and height - 225/55. A 225 width offers significantly less "bite"/traction than the 245 stock size. Coupled with a 55 percent aspect ratio on a 17 inch rim, there is a 3.33% diameter difference - a bit much and over the recommended maximum thresholds of no more than 3%. The computer may be misinterpreting this as some kind of slippage. Stock diameter is 225/50/17. The 245 and 275 are 0.39% and 1.4% respectively and should be fine.

sonphan13

The 225/55/17 were used Yokohomas, they were kinda old.

The tech told me he replaced my two 225/55/17 with 2 other BMW 225/50/17 to match all my tires and the problem went away and no DSC.

sonphan13

"ADVANCEDLOGIC" - BMW told me the reason for the DSC trigger was due to the tires with the 55% ratio spinning slower than the tires with the 50% ratio. Therefore that goes along with what you said.

I guess I'll have to becareful with which tires I put on my car next time.

advancedlogic

With a 55% ratio, the speedo is actually 3.445% too slow. At 60mph, the speedometer would indicate 58mph. So, while the sensors with the 50% ratio would indicate 60mph, the 55% would send 58mph to the computer. The difference, even at slower speeds, were enough to fool the system into thinking the difference between front and rear was attributable to wheel slippage.

AchtungE60

Sounds right. If you have a difference in overall diameter it will throw off sensors which will in turn most likely be a problem. Damage though? I highly doubt that. So you already have a new tire setup but still had them replace the stock wheel with a stock tire? Why didn't you just put the staggered set on?

luigi524td

If the offset is not appropriate for your all wheel drive BMW it will most certainly be a problem. Wheel offset is a thoroughly covered topic in the forum ... search please.

AchtungE60

Good point. I would have assumed OPdid research first. OP - are they OEM or replicas? Did you buy a set of wheels without checking fitment?

sonphan13

The reason I did not just put my 19" staggered set on because of Winter. I'm waiting until spring to put them on, which is why I figured I threw on some used tires for the winter.It is still strange that my differential was damaged from this then. I think either a gear or bearing exploded and blew through the differential casing.

Yes, I did do my research on the Forum before I purchased the new wheels with the recomended off-set. I bought M6 19" from ModBargains 19x8.5 ET35 and 19x9.5 ET43. The only reason I asked was because of the different size issue I was having, which didn't have to do with Off-set. Which AdvanceLogic answered. Thanks.