06 330i SP- Alternate rear tire size?

thecadman99 · 10-15-2012, 10:22 AM

I have conti DWS running factory size 255-35-18 in the rear, and 225 40 18 in the front.

I also have Eibach pro-kit springs = little lower than factory.

I'd like to get new rear tires without changing the front. I'm looking for a taller sidewall, and maybe a narrower rear for better snow traction.

Will increasing the rear diameter without increasing the front cause problems with DTC?

The difference between the factory front and rear diameter is only .24 %

Can I run 255-40-18 for a little more comfort? (2.4% difference)

Can I run 245-40-18 for better snow traction? (1.22% difference) Are they too narrow for the factory rims?

Thanks!

VTECaddict · 10-15-2012, 11:50 PM

For better snow traction, get dedicated snow tires instead of fudging with tire sizes. You're throwing things out of whack and you probably won't even gain any noticeable snow traction in the process.

Get some cheap wheels (like the 17x8 non-sport OEM wheels) and throw some 225 snow tires all around.

thecadman99 · 10-16-2012, 01:21 PM

Thanks for the reply,
I guess I'm really looking for a bit more comfort (taller sidewalls) and protection from the bad roads in my area.

If the 245 40 18 would fit ok as far as width, I would gain a little sidewall height.

I just wondered if anyone had run that width on the factory sport wheels.

biz77 · 10-16-2012, 03:46 PM

225 section width can be run at all four corners on the OEM staggered set up.

conrad325i · 10-17-2012, 09:52 AM

Just go to the tire size calculator at the top of this forum and put your shit in it and it will spit you back out all you need.

Mavus · 10-17-2012, 11:33 AM

Quote:

Originally Posted by thecadman99

I have conti DWS running factory size 255-35-18 in the rear, and 225 40 18 in the front.

I also have Eibach pro-kit springs = little lower than factory.

I'd like to get new rear tires without changing the front. I'm looking for a taller sidewall, and maybe a narrower rear for better snow traction.

Will increasing the rear diameter without increasing the front cause problems with DTC?

The difference between the factory front and rear diameter is only .24 %

Can I run 255-40-18 for a little more comfort? (2.4% difference)

Can I run 245-40-18 for better snow traction? (1.22% difference) Are they too narrow for the factory rims?

Thanks!

235/40 all around ... 245 is wide for 8" rim (assiming in front and 8.5" in rear)

You are mixing things up here. If you want snow traction you need 225/45 winter rubber as mentioned above.

Comfort on dry and wet are two different things. Maybe the best option for you is to get all season rubber but you will diminish handling on dry roads, if that matters at all. Tire compound properties change with temps and the comfort, handling and braking are then impacted accordingly.

GL

thecadman99 · 10-17-2012, 01:19 PM

Quote:

Originally Posted by conrad325i

Just go to the tire size calculator at the top of this forum and put your shit in it and it will spit you back out all you need.

Wow, classy

thecadman99 · 10-17-2012, 01:24 PM

Quote:

Originally Posted by NokTurNaL 330i

235/40 all around ... 245 is wide for 8" rim (assiming in front and 8.5" in rear)

You are mixing things up here. If you want snow traction you need 225/45 winter rubber as mentioned above.

Comfort on dry and wet are two different things. Maybe the best option for you is to get all season rubber but you will diminish handling on dry roads, if that matters at all. Tire compound properties change with temps and the comfort, handling and braking are then impacted accordingly.

GL

Thanks,
For now lets forget the snow traction and just say I want a taller sidewall without having to change the fronts from stock. I want to keep the stock front 225 40 18 and get the largest rear sidewalls I can without causing problems with the traction control.

From what I've read its good as long as I keep the size difference below 3%?

Mavus · 10-17-2012, 04:21 PM

Quote:

Originally Posted by thecadman99

Thanks,
For now lets forget the snow traction and just say I want a taller sidewall without having to change the fronts from stock. I want to keep the stock front 225 40 18 and get the largest rear sidewalls I can without causing problems with the traction control.

From what I've read its good as long as I keep the size difference below 3%?

rft or non-rft? if you have rft just replace them with non-rft and problem solved.

what tires do you have now? performance tires have stiffer sidewalls and maybe you need to change the tire type.

need details ... tire type, rim sizes, rft or non-rft etc.

If the rear rim size is 8.5" the tire width will be limited but you can play with tire type. Most likely you can go with 235/40 but tire compound/type will impact comfort more than size change in your case.

10-15-2012, 10:22 AM	#1
thecadman99 Lieutenant 53 Rep 450 Posts Drives: e90 330i 6mt spt bk/bk Join Date: Jun 2012 Location: Virginia iTrader: (0)	06 330i SP- Alternate rear tire size? I have conti DWS running factory size 255-35-18 in the rear, and 225 40 18 in the front. I also have Eibach pro-kit springs = little lower than factory. I'd like to get new rear tires without changing the front. I'm looking for a taller sidewall, and maybe a narrower rear for better snow traction. Will increasing the rear diameter without increasing the front cause problems with DTC? The difference between the factory front and rear diameter is only .24 % Can I run 255-40-18 for a little more comfort? (2.4% difference) Can I run 245-40-18 for better snow traction? (1.22% difference) Are they too narrow for the factory rims? Thanks! __________________ 06 330i 6mt Spt- Eibach Springs, BMW Perf Susp, Supersprint Exhaust, BSW Audio RIP-94 325i 5mt 4d- M3 springs/susp, Z3 wheels, Chipped, Intake, Exhaust= FUN!
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10-15-2012, 11:50 PM	#2
VTECaddict Where'd my VTEC go? 481 Rep 6,067 Posts Drives: 06 330i 6MT Join Date: Mar 2009 Location: Seattle, WA iTrader: (4)	For better snow traction, get dedicated snow tires instead of fudging with tire sizes. You're throwing things out of whack and you probably won't even gain any noticeable snow traction in the process. Get some cheap wheels (like the 17x8 non-sport OEM wheels) and throw some 225 snow tires all around. __________________ AW/Terra \| ZSP \| ZPP \| ZCW \| iDrive \| CA Mods: BC BR coilovers \| Blacklines \| M-tech rear \| dual exhaust \| M3 steering wheel \| BMW SSK \| ZHP shift knob \| High-kick CF spoiler \| NBT Retrofit M3 front control arms \| M3 rear guide rods \| Manzo rear toe and camber links \| Monroe rear shock mounts \| Varrstoen ES1 19x9.5+20 Front, 19x11+25 rear
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10-16-2012, 01:21 PM	#3
thecadman99 Lieutenant 53 Rep 450 Posts Drives: e90 330i 6mt spt bk/bk Join Date: Jun 2012 Location: Virginia iTrader: (0)	Thanks for the reply, I guess I'm really looking for a bit more comfort (taller sidewalls) and protection from the bad roads in my area. If the 245 40 18 would fit ok as far as width, I would gain a little sidewall height. I just wondered if anyone had run that width on the factory sport wheels. __________________ 06 330i 6mt Spt- Eibach Springs, BMW Perf Susp, Supersprint Exhaust, BSW Audio RIP-94 325i 5mt 4d- M3 springs/susp, Z3 wheels, Chipped, Intake, Exhaust= FUN!
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10-16-2012, 03:46 PM	#4
biz77 Captain 174 Rep 614 Posts Drives: 2021 X3 M40i Join Date: Aug 2010 Location: Spokane, WA iTrader: (4)	225 section width can be run at all four corners on the OEM staggered set up.
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10-17-2012, 09:52 AM	#5
conrad325i Private First Class 12 Rep 162 Posts Drives: 2008 335i Join Date: Aug 2011 Location: Knoxville, TN iTrader: (0)	Just go to the tire size calculator at the top of this forum and put your shit in it and it will spit you back out all you need. __________________ \| H&R Coilovers \|ApexArc-8s\| M3 ControlArms \| RogueTransMounts \| AFEDualCone \| ERChargePipe \| TialBOV \| ETSIntercooler \| 335isClutch \| BMSCatchCan \| UUC EVO3 SSK \| MichelinPSS \| CobbAP \| JB4 \|
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