[Track/S]

Originally Posted by medphysdave

I've made a step in the right direction.

[///MPhatic]

Originally Posted by medphysdave

The CSR runs a 41mm spacer iirc.

This has always amazed me. Tooling cost for that wheel can't be much for BMW, yet they chose a HUGE spacer. I get off the spacer train at 15mm, but I guess BMW knows something I don't. Probably a LOT of things I don't.

[medphysdave]

Originally Posted by ///MPhatic

This has always amazed me. Tooling cost for that wheel can't be much for BMW, yet they chose a HUGE spacer. I get off the spacer train at 15mm, but I guess BMW knows something I don't. Probably a LOT of things I don't.

I'm also quite surprised by the gigantic spacers. Couldn't they have built the offset into the wheel, or would that impact the load integrity? Maybe spacers allow more applications with the as designed offset? Or did they just decide it was cheaper to make only one wheel offset so a spacer that size is just required to make it work?

[///MPhatic]

Originally Posted by medphysdave

I'm also quite surprised by the gigantic spacers. Couldn't they have built the offset into the wheel, or would that impact the load integrity? Maybe spacers allow more applications with the as designed offset? Or did they just decide it was cheaper to make only one wheel offset so a spacer that size is just required to make it work?

They absolutely could have redesigned the wheel, but track certifications do take some time, so maybe that was a factor. Maybe in racing applications the larger spacers don't matter as much when you have other things supporting them, and they are off and on so frequently. Probably a combination of cheaper, faster, and passable for racing.

[RSXDC5]

Originally Posted by ///MPhatic

They absolutely could have redesigned the wheel, but track certifications do take some time, so maybe that was a factor. Maybe in racing applications the larger spacers don't matter as much when you have other things supporting them, and they are off and on so frequently. Probably a combination of cheaper, faster, and passable for racing.

You’ve hit the nail on the head.

Unless you absolutely need to be able to rotate tires, the squared offset isn’t most ideal as the massive front spacer is necessary. Ideally, fronts need their own width/offset package and so do the rears.

[feri130]

Originally Posted by ZM2

As an update, after running countless combo’s I’ve settled on 275/35/18 & 295/35/18. No spacers or fender work needed with the right wheel offsets (I’m on 18x10ET25 and 18x10.5ET40 Apex VS-5RS).

I much prefer the feel of 20mm F/R stagger for in-corner four wheel drift, and F/R wear is very similar if you’re driving the car in a balanced manner.

Currently running RE-71RS’s and looking forward to trying the Nankang CR-S v2 2023 updated tire when my preferred sizes are available later this year.

You will love nankang crs 2023 compound, as fast as ar1, in my local 2minute track it gave me a 3 second faster lap compared to cup2 connect. Wheels are volk te37 sl 18x9,5 et22, ohlins road and track, 2.4 front and 2degrees of negative camber at the rear, tyres 265/35/18. No spacers. I am ordering a set of 275/35-295/35 crs for next season, wheels will be 513m 10j wide rears at the front and 10.5j wide 513m cs racing at the back. Will need spacers for sure.

[jwr9152]

Will be interesting to see how the Nankangs wear also. I was paddocked next to Jackie Ding last weekend. He was in CRS and I was on RE71RS. His looked brand new and mine had a weekend on them. By the end of the weekend my tires were completely done and his were still in great condition. Different cars and he has a full spl setup where I was just camber plates up front and the rear was stock. Not apples to apples but I was very impressed with the condition of his tires by the end of the weekend. Going to try a set next myself.

[ThreeStripes]

Originally Posted by jwr9152

Will be interesting to see how the Nankangs wear also. I was paddocked next to Jackie Ding last weekend. He was in CRS and I was on RE71RS. His looked brand new and mine had a weekend on them. By the end of the weekend my tires were completely done and his were still in great condition. Different cars and he has a full spl setup where I was just camber plates up front and the rear was stock. Not apples to apples but I was very impressed with the condition of his tires by the end of the weekend. Going to try a set next myself.

When you say they had a weekend on the RE71RS do you mean a LONG weekend? Are you really only getting 4 total days out of RE71RS? I know I suck at driving and my pace is a world off yours but I’m hoping to stretch a set of fronts 4 weekends Lol.

[jwr9152]

Originally Posted by ThreeStripes

When you say they had a weekend on the RE71RS do you mean a LONG weekend? Are you really only getting 4 total days out of RE71RS? I know I suck at driving and my pace is a world off yours but I’m hoping to stretch a set of fronts 4 weekends Lol.

Well I did the 1 weekend with you at Barber. I ran all sessions on Saturday and did 1 fast lap Sunday morning and called it a day. Then TTN I did 3 20 minute sessions Thursday and TT Friday which was roughly 6 laps on Friday. Track sprint Saturday, which was 4 sprints or roughly 1/2 the track per sprint. Sunday I did 4 laps total. Tires felt done by end of the day Thursday. So I would say I'm not making a full two weekends. They weren't corded, just felt heat cycled out.
They were fast for a lap though. Haha.

[swampfox94]

Anyone run a chunkier+wider set up? I’m fully stuck but haven’t loved the way the fronts have felt on track. Gonna add some camber as well up, probably just an extra deg nothing crazy.

I’m thinking about going from stock sizes to:

Front - 255/40/19
Rear -275/40/19

[M2guru]

Originally Posted by ThreeStripes

When you say they had a weekend on the RE71RS do you mean a LONG weekend? Are you really only getting 4 total days out of RE71RS? I know I suck at driving and my pace is a world off yours but I’m hoping to stretch a set of fronts 4 weekends Lol.

I got four days out of my RE71RS.

[Brokenbones]

Originally Posted by M2guru

I got four days out of my RE71RS.

Re71rs lasted 4 days 5x20 min sessions on 100-110 degree days without camber plates. Corded outside shoulder on penultimate run. Started loosing grip last run or 2. Inside shoulder was pristine.

New 71rs at 3 degree camber over 1.5 days, wear is mostly on outside edge of lateral 1/3 rib, not the shoulder. May need to air down more… running pressures 38-40 hot similar to without camber plates. Lot of hard corners, short straights maxing out at 128ish. Tends to give me 5-8 minutes of max pace before heating up and getting greasy.

Considering cr-s, all the fast guy are running it and they tires never look that worn. Or I’m a ham fisted monkey at the wheel which is probably the answer

[jwr9152]

Originally Posted by Brokenbones

Or I’m a ham fisted monkey at the wheel which is probably the answer

My problem too. I have no patience at all. Also going to try CRS next.

[jwr9152]

Originally Posted by swampfox94

Anyone run a chunkier+wider set up? I’m fully stuck but haven’t loved the way the fronts have felt on track. Gonna add some camber as well up, probably just an extra deg nothing crazy.

I’m thinking about going from stock sizes to:

Front - 255/40/19
Rear -275/40/19

A lot of people are running wider, not a lot seem to be running chunkier due to lack of clearance. 275/30/19 on the front and 295/30/19 rears seem to be very popular for 19" wheels.

[swampfox94]

Originally Posted by jwr9152

A lot of people are running wider, not a lot seem to be running chunkier due to lack of clearance. 275/30/19 on the front and 295/30/19 rears seem to be very popular for 19" wheels.

30 feels like it would be uncomfortably thin, no?

[CSBM5]

Originally Posted by swampfox94

Anyone run a chunkier+wider set up? I’m fully stuck but haven’t loved the way the fronts have felt on track. Gonna add some camber as well up, probably just an extra deg nothing crazy.

I’m thinking about going from stock sizes to:

Front - 255/40/19
Rear -275/40/19

The diameters of those sizes are too large. You'll have major rubbing/contact issues up front for sure.

[M2guru]

Originally Posted by Brokenbones

May need to air down more… running pressures 38-40 hot similar to without camber plates. Lot of hard corners, short straights maxing out at 128ish. Tends to give me 5-8 minutes of max pace before heating up and getting greasy.

For reference, I keep mine at 31-32 hot (well...as hot as I can keep them going from track to paddock then checking right away - no TPMS). I can feel a difference of 2-3 psi...definitely have less traction the higher it gets. I start low to mid 20s cold.

[jwr9152]

Originally Posted by swampfox94

30 feels like it would be uncomfortably thin, no?

In my opinion no. My last set of rears were 295/30/18 and they felt fine. Probably the exact right tire for a track like Barber because of gearing. Allowed me to stay in 3rd and 4th the entire tack and had good acceleration and never came close to the rev limiter. But for a track like NCM a 295/35/18 would have been perfect. Was hitting the rev limiter sooner than I wanted at NCM, but too close to the end of the straight to make shifting gears worth it.

[Brokenbones]

Originally Posted by M2guru

For reference, I keep mine at 31-32 hot (well...as hot as I can keep them going from track to paddock then checking right away - no TPMS). I can feel a difference of 2-3 psi...definitely have less traction the higher it gets. I start low to mid 20s cold.

Thanks for advice. I agree temps and grip drop off quickly with higher pressures. with the camber plates I’m dropping my hot pressures slowly while keeping an eye on shoulder wear. I’ll see if I can get down to the low 30s. Without camber plates 34-35 hot caused high wear on shoulder tread of 71rs while setting my fastest time, 3.28 on 5 mile thunderhill.

[E90convert]

Hi all - I'm looking for tire advice on the upcoming track season.

EC-7 19x9.5 and 19x10.5 with 255/275/35 RE-71RS or AD09

EC-7 19x9.5 and 19x10.5 with 265/275/35 Nankang CRS V2

VS-5RS 18x10 ET40 with a front spacer. 275/35 square. I would have to buy these wheels. Is it worth the $5k for the wheels, tires, spacers, and sensors to run square setup?

My focus is consistently lapping with HPDE. It does not have to be the fastest tire (all thought that helps ); I want more consistency than melting my PS4S tires within 3 laps.

Car is stock suspension with 3 degrees front camber. I would consider a larger front sway bar as well.

[ZM2]

I'll give you two other options that I would choose between:

EC-7 19x9.5 and 19x10.5 with 255/285/35 RE-71RS
EC-7 19x9.5 and 19x10.5 with 265/295/30 CR-S v2

You'll get more grip with those setups, vs a 275 square setup. The whole idea of a square setup as beneficial is overblown. If you're driving the car in a balanced manner and not self-inducing plowing or oversteer, the fronts & rears in staggered setup wear very similarly. And, as you alluded to, if you do want to run a neutral square setup on our cars, you have to modify the suspension.

Plus, driving staggered setups on our cars is a lot of fun. It really teaches you how to be more aggressive with the throttle to help rotate the car, improving your car control.

As for 71RS vs CR-S v2: 71RS has better wet/cold grip, ready to go after 2-laps, has a bit better feel. CR-S has more longevity but costs more so probably not real $/lap savings, and has better high temp tolerance which you may not have to worry about as much in OH. Lap time difference b/n the two tires are close enough that the driver in the box will make the difference!

[E90convert]

Originally Posted by ZM2

I'll give you two other options that I would choose between:

EC-7 19x9.5 and 19x10.5 with 255/285/35 RE-71RS
EC-7 19x9.5 and 19x10.5 with 265/295/30 CR-S v2

You'll get more grip with those setups, vs a 275 square setup. The whole idea of a square setup as beneficial is overblown. If you're driving the car in a balanced manner and not self-inducing plowing or oversteer, the fronts & rears in staggered setup wears very similarly. And, as you alluded to, if you do want to run a neutral square setup on our cars, you have to modify the suspension.

Plus, driving staggered setups on our cars is a lot of fun. It really teaches you how to be more aggressive with the throttle to help rotate the car, improving your car control.

As for 71RS vs CR-S v2: 71RS has better wet/cold grip, ready to go after 2-laps, has a bit better feel. CR-S has more longevity but costs more so probably not real $/lap savings, and has better high temp tolerance which you may not have to worry about as much in OH. Lap time difference b/n the two tires are close enough that the driver in the box will make the difference!

Thanks for your insight! I did enjoy the stagger feel for the 255/275 PS4S I ran over the summer, the car felt balanced overall. I had a good rear grip, except when the tires started overheating (stock power). The rears would lose grip more toward the end of a session; this problem will probably go away with a better compound. So, at this point, I do not feel the need to increase the width of the rear tire. The car would certainly default to understeer quickly as the 255 section overheated. A better compound and slightly wider may benefit.

Would the 30mm stagger be too much and result in a lot of understeering at the limit?