[jed52994]

HELP! I tried to look for this topic in the forums but I didn't find anything that addresses my current issue. So here I am. I recently replaced my RFT's on my F34 xdrive to regular tires in hopes of a quieter ride. I got a really good deal on a set of staggered replacement 405M wheels that are 19x8.5 et34 and 19x9.5 et40. According to my research as long as I stay within a 1% rolling diameter difference, it should be ok. I bought Yokohama Apex 235/40r19 and 265/35r19's at Discount Tires and they look like a great fit. This setup gives a difference of .4% which is well within the 1% acceptable difference. However, I feel slight jerkiness upon accelaration. Can this be resolve with tire pressure? If so what tire pressure should I set them? The door panel says 32 in front and 35 in back, but I assume that that's for the OEM 2258/50r18 tires? I can exchange the tires for 235/35r19 and 275/30r19 which will bring the difference to 0%, but it will lower the height down to 25.5". Will that still be ok? Your input are great appreciated.

[alohasurftoad]

regardless of wheel diameter, on F34 the standard OEM tire diameter is 27". 235/40/19, 265/35/19 is fine for x-drive but increases speedo/odometer error and wheel gap. 235/35/19, 275/30/19 is also fine for x-drive but will exacerbate the speedo/odometer error and wheel gap further.

imo the tire sizes you should be using are 245/40/19(26.7") & 275/35/19(26.6") or 225/45/19(27") & 255/40/19(27") or 235/45/19"(27.3"), 265/40/19(27.3"), not much selection in the last size combo, though.

btw, 19" 405M OEM wheel specs are 19x7.5 ET45, 19x8 ET52 for 2-series. you have replicas of some sort.
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[jed52994]

Originally Posted by alohasurftoad

regardless of wheel diameter, on F34 the standard OEM tire diameter is 27". 235/40/19, 265/35/19 is fine for x-drive but increases speedo/odometer error and wheel gap. 235/35/19, 275/30/19 is also fine for x-drive but will exacerbate the speedo/odometer error and wheel gap further.

imo the tire sizes you should be using are 245/40/19(26.7") & 275/35/19(26.6") or 225/45/19(27") & 255/40/19(27") or 235/45/19"(27.3"), 265/40/19(27.3"), not much selection in the last size combo, though.

btw, 19" 405M OEM wheel specs are 19x7.5 ET45, 19x8 ET52 for 2-series. you have replicas of some sort.
.

Yes they call replica "replacement wheels" at the store where I bought them. They were $1199 clearanced down to $699 so I couldn't resist. Thank you for the tire suggestions, however, the 245/40/19(26.7") & 275/35/19 will still give me a 0.4% rotation difference which is what I have now with the Yokohamas. I can try the 235/45/19"(27.3"), 265/40/19(27.3"). At 27.3" this is taller than the OEM square tires, which I'm ok with. That's actually what I like about the GT's, their slightly higher stance. I'm tired of hitting the curbs with my old 525i . I found a set of MICHELIN PILOT SPORT ALL SEASON 4 at Discount Tires. I've had Michelin Tires before so I know they are the best, I just wanted to save a bit of money and get summer tires like the Apex since I live in AZ. They're definitely more than the Yokohama Apex tires, but if this will solve the jerking problems long term I can certainly try it.

Update: Today I adjusted the tire pressure to 34 in front and 37 in rear and it seemed to help with the jerking. It's still there once in a while, but not as pronounced as before. I'm a middle age woman who is learning so much about wheels and tires, and I'm kinda enjoying it. Thank you for all your help.

[jed52994]

Does anyone have 235/45r19" front, 265/40r19 rears in their 3 series GT? Can you post pictures here please? I have 235/40r19 and 265/35r19's Yokohama Apex on mine and they look good, but there's a little bit of jerking so I'm debating if I want to keep adjusting the tire pressure until I find the setting where the jerking disappears, or do I just want to replace them with the 235/45/19"(27.3"), and 265/40/19(27.3") that Alohasurftoad suggested?