[RMachuca3d]

Originally Posted by ctbear

Yea, that is true...but why do people tend to track with 18" rims instead of 19" rims, even for aftermarkets?

What's a good bang for the buck brand aftermarket 18" square setup that would be lighter? Those Apex seem awesome but $$....

18's have several benefits, meatier sidewall, generally the wheels are lighter and cheaper tires, not to mention the wheels themselves will be cheaper.

Popular brands for tracking are enkei's, apex and the like.

[brigade24]

Originally Posted by ctbear

Yea, that is true...but why do people tend to track with 18" rims instead of 19" rims, even for aftermarkets?

What's a good bang for the buck brand aftermarket 18" square setup that would be lighter? Those Apex seem awesome but $$....

check out RF03RR or RF05RR superspeed. New company. they make nice light weight wheels at a reasonable price in 18"...

[ctbear]

Originally Posted by RMachuca3d

18's have several benefits, meatier sidewall, generally the wheels are lighter and cheaper tires, not to mention the wheels themselves will be cheaper.

Popular brands for tracking are enkei's, apex and the like.

Originally Posted by brigade24

check out RF03RR or RF05RR superspeed. New company. they make nice light weight wheels at a reasonable price in 18"...

Thanks for the suggestions guys. I'm tired of getting beat up on my 19" 403m's with m-sport suspension and run flat tires. Teeth clenching impacts on over the slightest road imperfection actually makes me drive slower than traffic sometimes...

[reyoasian]

400M 18x8 square
595RS-RR 245/40R18

[ctbear]

Originally Posted by Polo08816

You probably have more experience than me.

I've settled on 18x8.5 square with 255/40/18 MPSS tires. I figure the most I would do is run RE-71R on the track in that size and if that's not enough, I just need better skills and/or better car.

Is 18x8.5 ET38 square setup with 255/40/18 tires the widest I'd be able to run without using spacers? 2015 F30 335i m-sport.

OP's post says that tire size is ideally paired with 9" wide wheels?

[alohasurftoad]

for a reasonably priced 18" street/occasional track set up, consider sportline 8s. 18x8.5, +32, 20.2lbs, 18x9.5(deep), +45, 19.8lbs on 245/40/18(23lbs), 265/40/18(26lbs), continental extremecontact sport tires. $1160 wheels, $780 tires, not including shipping, mount/balance, install.

your 403 wheels/tires weigh about 54lbs/57lbs. the sportline 8s with contis weigh 44lbs/46lbs. removing 10lbs at each wheel is a big deal.

EDIT...another wheel is the TSW Bathurst. they are lighter than the sportlines and can be found for $1260 shipped on amazon in slightly different sizes. i've even found and bought tires shipped from amazon.

with either wheel choice you could also consider consider square setups with 255/40/18 if you want tire rotation.

[ctbear]

Originally Posted by alohasurftoad

for a reasonably priced 18" street/occasional track set up, consider sportline 8s. 18x8.5, +32, 20.2lbs, 18x9.5(deep), +45, 19.8lbs on 245/40/18(23lbs), 265/40/18(26lbs), continental extremecontact sport tires. $1160 wheels, $780 tires, not including shipping, mount/balance, install.

your 403 wheels/tires weigh about 54lbs/57lbs. the sportline 8s with contis weigh 44lbs/46lbs. removing 10lbs at each wheel is a big deal.

EDIT...another wheel is the TSW Bathurst. they are lighter than the sportlines and can be found for $1260 shipped on amazon in slightly different sizes. i've even found and bought tires shipped from amazon.

with either wheel choice you could also consider consider square setups with 255/40/18 if you want tire rotation.

Thanks for the detailed post
For the optimum 255/40/18 square setup, the ideal wheel size all around would be 18x8.5 ET38 correct?

For the wheels you mentioned, wouldn't I be better off just going for even lighter weight Apex ARC-8s? Pricing seems about the same.

[alohasurftoad]

Originally Posted by ctbear

Thanks for the detailed post
For the optimum 255/40/18 square setup, the ideal wheel size all around would be 18x8.5 ET38 correct? For the wheels you mentioned, wouldn't I be better off just going for even lighter weight Apex ARC-8s? Pricing seems about the same.

To me, the best size for 255/40/18 is 18x9 +35ish. Apex is fine, I'd rock them. I was just giving you some other choices. 255 /40/18 on 8.5 is a faintly oversized, nothing wrong with that and I prefer it to stretch for curbs. on 9" the 255 sidewall is square and will have optimum contact patch. It's unlikely you'd be able to tell the difference between 255 on 8 or 9, though.

[ctbear]

Originally Posted by alohasurftoad

To me, the best size for 255/40/18 is 18x9 +35ish. Apex is fine, I'd rock them. I was just giving you some other choices. 255 /40/18 on 8.5 is a faintly oversized, nothing wrong with that and I prefer it to stretch for curbs. on 9" the 255 sidewall is square and will have optimum contact patch. It's unlikely you'd be able to tell the difference between 255 on 8 or 9, though.

Will 18x9 +35ish square fit all around without rubbing? Or does it require spacers? I'm leaning towards options that won't require spacers.

[alohasurftoad]

Originally Posted by ctbear

Will 18x9 +35ish square fit all around without rubbing? Or does it require spacers? I'm leaning towards options that won't require spacers.

18x9 +35 w/255/40/18 will fit without rubbing and does not need spacers. the position of the 255/40/18 is the same place on 18x8.5 +35, but the tire has an insignificant (6mm) bulge on 8.5" compared to a 9'.

https://f30.bimmerpost.com/forums/sh...%2F4018+square

EDIT...if i were to go arc-8 square i'd run 18x9.5 +35 with 255/40/18 square, turn-in sharpness is better since the tread width is narrower than the rim width, due to a mild stretch and you'd compromise just 0.4lbs for profile 3 concavity. it would still fit without rubbing or spacer.

the links below have cars on 19x9.5 +35 square with 255, for visual reference. 18's would have a more sidewall but the tire and rim position would be the same.

https://f30.bimmerpost.com/forums/sh...=18x9.5+square

https://f30.bimmerpost.com/forums/sh...+square&page=2

[ctbear]

Originally Posted by alohasurftoad

18x9 +35 w/255/40/18 will fit without rubbing and does not need spacers. the position of the 255/40/18 is the same place on 18x8.5 +35, but the tire has an insignificant (6mm) bulge on 8.5" compared to a 9'.

https://f30.bimmerpost.com/forums/sh...%2F4018+square

EDIT...if i were to go arc-8 square i'd run 18x9.5 +35 with 255/40/18 square, turn-in sharpness is better since the tread width is narrower than the rim width, due to a mild stretch and you'd compromise just 0.4lbs for profile 3 concavity. it would still fit without rubbing or spacer.

the links below have cars on 19x9.5 +35 square with 255, for visual reference. 18's would have a more sidewall but the tire and rim position would be the same.

https://f30.bimmerpost.com/forums/sh...=18x9.5+square

https://f30.bimmerpost.com/forums/sh...+square&page=2

Wow thanks a lot! Incredibly helpful links. I can see the bulge you are mentioning on the narrower wheel, which makes it look more "normal" when compared to those sexy straight vertical tire walls. Though the slight bulge does offer some protection...hmmm choices to contemplate over

I don't think I like the stretch look on 9.5 wheels. Makes me feel vulnerable with the wheels sticking out like that! lol

EDIT: I heard using XL rated non run flat tires also help with duplicating the responsiveness that were present on the original Run Flat tires (?). Or just increasing PSI

EDIT 2: I was watching this video on the new m340i:

and I noticed that it looks like their wheel and tire set up looks similar to the stretch look on 9.5 wheels...hmmm has me thinking

[alohasurftoad]

https://f30.bimmerpost.com/forums/sh...+squared+setup

here's 18x8.5 +35 SM-10 on 245/40/18 square.

there's a lot of wheel/tire combos

[ctbear]

Originally Posted by alohasurftoad

https://f30.bimmerpost.com/forums/sh...+squared+setup

here's 18x8.5 +35 SM-10 on 245/40/18 square.

there's a lot of wheel/tire combos

That seems like a great daily set up for average drivers who don't track. Do you know what the OEM 18" square setup for a 335i/340i is 225?

[alohasurftoad]

Originally Posted by ctbear

That seems like a great daily set up for average drivers who don't track. Do you know what the OEM 18" square setup for a 335i/340i is 225?

yes. oem square is 18x8 +34 225/45/18. i believe one or both of those guys track occasionally, but i could be wrong. i'd have to go dig through threads.

[ctbear]

Originally Posted by alohasurftoad

yes. oem square is 18x8 +34 225/45/18. i believe one or both of those guys track occasionally, but i could be wrong. i'd have to go dig through threads.

Useful article I found:
https://support.apexraceparts.com/hc...-Fitment-Guide

Hmm guess oem square 225 tires offer sufficient traction for stock N55 power...
Debating if I should stick to oem specs so as not to throw off the original balance of the vehicle tuned from the factory.
My m-sport package is 19" staggered so I could just swap it to oem 18" square setup.

[alohasurftoad]

Originally Posted by ctbear

Useful article I found:
https://support.apexraceparts.com/hc...-Fitment-Guide

Hmm guess oem square 225 tires offer sufficient traction for stock N55 power...
Debating if I should stick to oem specs so as not to throw off the original balance of the vehicle tuned from the factory.
My m-sport package is 19" staggered so I could just swap it to oem 18" square setup.

to me, 225/45/18 is too narrow for F3/4-series on the track. at minimum i'd go 18x8.5 square with 245/40/18. if you use staggered oem 18"(400M or 441M), i'd go 245/40/18 on the 18x8 front and keep oem size 255/40/18 on the 18x8.5" rear. if you want to stay with your 403M, run 245/35/19 front, 255/35/19 rear.

here are pics of 442M, front tires size changed from 225/40/19 to 245/35/19 on the 19x8 +34. rear size remained oem 255/35/19(max on 8.5"). michelin pilot sport 4s. you need to increase front grip to reduce understeer on the track. staying with stock offset is good because the front track width is wider than the rear, which is better for handling as well.

i'd try this tire change 1st. you might be satisfied with the performance and ride with go-flat max performance tires, such as michelin pilot sport 4s or continental extremecontact sport, assuming you still want street tires.

[ctbear]

Originally Posted by alohasurftoad

to me, 225/45/18 is too narrow for F3/4-series on the track. at minimum i'd go 18x8.5 square with 245/40/18. if you use staggered oem 18"(400M or 441M), i'd go 245/40/18 on the 18x8 front and keep oem size 255/40/18 on the 18x8.5" rear. if you want to stay with your 403M, run 245/35/19 front, 255/35/19 rear.

here are pics of 442M, front tires size changed from 225/40/19 to 245/35/19 on the 19x8 +34. rear size remained oem 255/35/19(max on 8.5"). michelin pilot sport 4s. you need to increase front grip to reduce understeer on the track. staying with stock offset is good because the front track width is wider than the rear, which is better for handling as well.

i'd try this tire change 1st. you might be satisfied with the performance and ride with go-flat max performance tires, such as michelin pilot sport 4s or continental extremecontact sport, assuming you still want street tires.

You know, I think that is the root of my dissatisfaction with the oem staggered 19" setup (besides the terrible ride quality of the runflats). That slower and heavier turn in feel compared to the quick agility and lighter front end of the 330i loaner vehicle I had with a square setup. If a wider front tire on my current 403m can help alleviate that, I would be pleased. Thanks for that suggestion!

[alohasurftoad]

Originally Posted by ctbear

You know, I think that is the root of my dissatisfaction with the oem staggered 19" setup (besides the terrible ride quality of the runflats). That slower and heavier turn in feel compared to the quick agility and lighter front end of the 330i loaner vehicle I had with a square setup. If a wider front tire on my current 403m can help alleviate that, I would be pleased. Thanks for that suggestion!

honestly the turn in may feel about the same, however you will be able to carry much more speed through corners, especially high speed ones. after you are really comfortable with your car, then go next step to lighter 18's. you'll have a better idea on what width, offsets, tire sizes and tires you want to run,for more serious track intentions.

[f22_shayan]

I run Nitto NT01's and i love them on track, even on the street they are great, they dont take too long to heat up and deal with the heat very very well.

[DVC]

Been a while since I've checked in on this thread, so I've got a couple updates to share.

First, with the Apex ARC-8s in 18x9.5 et35 and RE-71Rs in 265/35-18 that I got back in 2017 were a perfect fit with no spacers. Of course, I do run about -3.0° camber in the front, so if you're running much less than that, then fender clearance will be an issue. This tire size was a perfect fit on 9.5" wheels; I think 275 would have been a bit squishy. (On my previous set of wheels, 18x9 Apex ARC-8s, I had run both 245s and 255s, and both felt very good.)

Fast forward to earlier this month, and I've just successfully squeezed in a set of BimmerWorld TE-AL TA16 wheels in 18x10 et33 with RE-71Rs in 275-/35-18. It needed a mild fender roll/pull both front and rear, and a 5mm front spacer to make everything clear, but after a 2-day track event this past weekend with zero rubbing, I can say that it was absolutely worth the effort... the car had tons of grip, felt nimble and responsive, and balance was as good as ever. I think this size tire is the sweet spot for a car of this size/weight; for the first time, I felt like the grip and traction overshadowed the power.

So to circle back to the original question I posed in this thread, as a general rule, from what I've learned, for best grip and feel on track, I think that max/extreme performance summer tires match up best to wheel sizes where the section width of the tire within ~1" inch wider than the wheel... so this breaks down roughly as follows:

8.0" -- 225
8.5" -- 235
9.0" -- 245/255
9.5" -- 265
10.0" -- 275
10.5" -- 285

(It's worth noting that Dunlop Direzzas run a bit narrow, and Hankook R-S4s run a bit wide, so it may make sense to adjust accordingly to keep the tire section width within ~1" of wheel width)

[FaRKle!]

I'll add a data point with some alignment dependency.

I have Apex SM-10 18x8.5 ET35 up front with NT01 245/40r18 tires. My negative camber has been around -1.6 to -1.8deg and I asked for caster set at 8deg (one wheel was 8, the other was 7.6deg).

This hasn't been an issue at Thunderhill or Sonoma, but last time at Laguna Seca I found out that track gives me more front compression than the others. At some of the heavy compression sections (like the dip just before the crest and drop of the T8 corkscrew) I was getting rubbing on the wheel liner at the 10 o-clock position (driver side, 2 o-clock passenger side). This only happened to the wheel at 8deg caster, the wheel at 7.6deg caster didn't see rubbing anywhere.

[DVC]

Originally Posted by FaRKle!

I'll add a data point with some alignment dependency.

I have Apex SM-10 18x8.5 ET35 up front with NT01 245/40r18 tires. My negative camber has been around -1.6 to -1.8deg and I asked for caster set at 8deg (one wheel was 8, the other was 7.6deg).

This hasn't been an issue at Thunderhill or Sonoma, but last time at Laguna Seca I found out that track gives me more front compression than the others. At some of the heavy compression sections (like the dip just before the crest and drop of the T8 corkscrew) I was getting rubbing on the wheel liner at the 10 o-clock position (driver side, 2 o-clock passenger side). This only happened to the wheel at 8deg caster, the wheel at 7.6deg caster didn't see rubbing anywhere.

Interesting.... I haven't seen that happen, even with bigger tires, similar caster, and crushing the brakes with race pads into a compression brake zone. Are you significantly lowered?