BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read
M2 Technical Topics > Track / Autocross / Dragstrip > 18" vs 19" setup for track

Post Reply
 
Thread Tools Search this Thread
      11-21-2018, 06:34 AM   #1
GasBurnlife(landapanda)
Captain
573
Rep
683
Posts

Drives: BMW M2
Join Date: Aug 2012
Location: Ashburn, Virginia

iTrader: (0)

18" vs 19" setup for track

I wanted to post my thoughts on this topic that I have given a lot of thought recently and get everyone's input.

Assumptions:
- Camber plates, big brake kits, pads and fluids are out of scope of this discussion.
- I am focused on attaining an ideal track day setup, not a racing one as I wanted to keep compliance with club racing rules out of scope.
- Wheel budget is limited to $2,000 for a set of 4 wheels
- Tire budget is limited to to $1,200 for a set of 4 tires

I have couple of concerns/questions regarding the proper function of the electronic and mechanical systems. Then there are subsequent decisions driven mainly by cost, performance, practicality, weight and aesthetics in descending order:

1a. How much can tier diameter deviate from OEM setup before ability of electronic systems to function as designed is impacted - abs, traction control, stability control? Does this matter with DCS and ESC turned off?
1b. How much can tier diameter deviate from OEM setup before ability of mechanical systems to function as designed and their longevity is impacted - rear differential is the only one that comes to mind.

Cost:
2a - assuming comparison of same make/model or across manufacturers looking at similar material and build process, 18" wheels are cheaper. Same can be said for tires.
2b - 18" square setup will give you the ability to rotate tires front to back, saving you money. Arguably, this is true for a 19" setup.
2c - a square setup with the right tires will also allow you to flip those tires (run them backwards - counter to their intended rotation), giving you additional days of track time on the same tires, assuming there is usable rubber left.
2d - you can buy a set of takeoffs for ~$500-$600; you will usually have 2/3 of the heat cycles left in them. Similar tire setup will run at least $1,000-$1,200 new, but your selection will be limited to the offering of the reseller.

Performance
3. I think this one is a wash. Many competitive teams, including the Pirelli World Challenge M235iR cars run 18" square setup. Some may argue that 19" tires have a superior wall stiffness, resulting in less tire roll. There may be other arguments and I am interested in hearing those.

Practicality
4. If you invested in a big brake kit or are considering one, tour wheel choice may be impacted based on which BBK manufacturer you chose. However, most manufacturers kits are by design compatible with 18" wheels.

5. Weight - 18" vs 19" wheel/tire combo will generally save 2.5-5 pounds of rotational weight per wheel, 10-25 pounds total, which translates to roughly 20-50 pounds weight savings of sprung weight (assuming 1:2 ratio of sprung to unsprung weight for argument's sake - meaning a weight saving of one pound on a sprung component is an equivalent of saving two pounds on an unsprung component). Of course, one can buy expensive 19" wheels made of exotic materials that can be significantly lighter than 18" wheels, but I am assuming a budget of roughly $500/wheel, and not $2000/wheel or more. I created a spreadsheet to track a variety of tire 18" and 19" Bridgestone RE71R tire sizes and dimensions, including contact patch and weight, as well as sample wheel weight (I used APEX wheels as an example) - https://docs.google.com/spreadsheets...it?usp=sharing

6. Aesthetics - least, but somewhat important, as you will live with tour buying decision for months and years to come. 18" wheels are arguably still more popular for racing purposes, and there is a great, if not better, selection of competition wheels in this size that are pleasing to the eye.

Thanks for reading and I look forward to your input!

Last edited by GasBurnlife(landapanda); 11-21-2018 at 07:56 AM.. Reason: URL Added
Appreciate 0
      11-21-2018, 04:40 PM   #2
ZM2
Brigadier General
2785
Rep
3,681
Posts

Drives: 2017 LBB M2
Join Date: Mar 2017
Location: Baltimore

iTrader: (1)

I’ve run a lot of different 18” & 19” combos.

1. I’ve never noticed an impact to running different diameters with MDM on or DSC completely off. Altho, the general rule is you should not run a shorter diameter in the rear vs the front.

2. My 19” VMR V710FF’s were cheaper than my 18” Apex EX-7s. 19” tires are a little more expensive, but you’re usually buying more rubber and width to go with it. If you’re driving the car in a balanced manner (not plowing, using throttle to turn), I’ve found the front & rear tires on a 19” staggered setup wear quite evenly. I don’t find take offs worth it, as you’re spending time/paying for mount & balance more often.

3. Most any square setup on a car with decent hp, whether for DE or racing, is purely for cost savings. The speed of our cars is rear traction limited bc of all the torque we can generate. Larger rear width vs the front will always be faster. My 19” staggered setups on similar rubber were 1-2sec quicker on a track.

4. Plenty of good BBK’s that fit both 18” & 19” wheels.

5. I find this completely overblown unless you’re a top tier driver in a sprint race. Few of us have the skill to maximize the performance of the car lap after lap to make up for the few tenths of a second any additional weight would add.

6. I like the way 19’s fill the wheel well more than 18’s. No wrong choice here, tho.
Appreciate 2
      11-21-2018, 06:09 PM   #3
ChrisM4
Captain
ChrisM4's Avatar
Canada
1525
Rep
954
Posts

Drives: 2024 M4 Comp X-Drive
Join Date: Nov 2018
Location: Canada

iTrader: (0)

Garage List
One thing to consider is if you end up trading your 2018 and earlier M2 on a 2019 comp (or the CS that's coming) a 18 inch wheel won't fit over the brakes.
__________________
2024 Dravit Grey M4 Competition X-Drive
Appreciate 0
      11-22-2018, 12:12 PM   #4
Old Geezer
Private First Class
204
Rep
189
Posts

Drives: 2019 M2C
Join Date: Oct 2016
Location: Houston, TX

iTrader: (0)

Quote:
Originally Posted by ChrisM2 View Post
One thing to consider is if you end up trading your 2018 and earlier M2 on a 2019 comp (or the CS that's coming) a 18 inch wheel won't fit over the brakes.
Wheel and tire selection is more limited in 19” (at least for now). If I had a choice, I’d go with 18”.
Appreciate 0
      11-22-2018, 01:48 PM   #5
Proctor750
Lieutenant
426
Rep
538
Posts

Drives: E30 M3
Join Date: Aug 2018
Location: Hattie B's

iTrader: (0)

Quote:
Originally Posted by ZM2 View Post
I’ve run a lot of different 18” & 19” combos.

1. I’ve never noticed an impact to running different diameters with MDM on or DSC completely off. Altho, the general rule is you should not run a shorter diameter in the rear vs the front.

2. My 19” VMR V710FF’s were cheaper than my 18” Apex EX-7s. 19” tires are a little more expensive, but you’re usually buying more rubber and width to go with it. If you’re driving the car in a balanced manner (not plowing, using throttle to turn), I’ve found the front & rear tires on a 19” staggered setup wear quite evenly. I don’t find take offs worth it, as you’re spending time/paying for mount & balance more often.
What different 19" have you tried, can you list a few for the m2c guys? Im struggling..
Offsets, wheel and tire specs and spacers used please.

I see from another thread you had 265/30/19 & 295/30/19 Trofeo R’s on the VMR V710FF, did you use spacers? what were the offsets

Last edited by Proctor750; 11-22-2018 at 01:54 PM..
Appreciate 0
      11-22-2018, 03:44 PM   #6
ZM2
Brigadier General
2785
Rep
3,681
Posts

Drives: 2017 LBB M2
Join Date: Mar 2017
Location: Baltimore

iTrader: (1)

Quote:
Originally Posted by Proctor750 View Post
What different 19" have you tried, can you list a few for the m2c guys? Im struggling..
Offsets, wheel and tire specs and spacers used please.

I see from another thread you had 265/30/19 & 295/30/19 Trofeo R’s on the VMR V710FF, did you use spacers? what were the offsets
The Max Rubber thread has all the specs. Check it out there so I don’t muddy the 18 vs 19” question by the OP.

As for 19” tires, Trofeo R, Hoosier R7, R888R, PSC2, RE-71R are all options. The best performance bang for the buck is 255/35/19 & 285/35/19 RE-71R on the stock rims. No one will have more grip unless they’re running R7’s.
Appreciate 0
      11-22-2018, 09:55 PM   #7
Proctor750
Lieutenant
426
Rep
538
Posts

Drives: E30 M3
Join Date: Aug 2018
Location: Hattie B's

iTrader: (0)

Quote:
Originally Posted by ZM2 View Post
The Max Rubber thread has all the specs. Check it out there so I don’t muddy the 18 vs 19” question by the OP.

As for 19” tires, Trofeo R, Hoosier R7, R888R, PSC2, RE-71R are all options. The best performance bang for the buck is 255/35/19 & 285/35/19 RE-71R on the stock rims. No one will have more grip unless they’re running R7’s.

I love the RE71 although they can't take the abuse like the rs4 on the e30.
I guess ill end up staggered which I hoped to avoid but the torque just won't allow square setup. No shot at stock wheels, the width and weight isn't going to work.
Appreciate 1
ZM22785.00
      11-23-2018, 06:32 AM   #8
GasBurnlife(landapanda)
Captain
573
Rep
683
Posts

Drives: BMW M2
Join Date: Aug 2012
Location: Ashburn, Virginia

iTrader: (0)

Look at my spreadsheet at the top of the thread. You can get to the wider tires with stock OEMs rims, but you will sacrifice little bit of thread width this way. Ideally you are going to 9.5 and 10.5(or 11) rim width, but don't have to if you don't want to buy another set of rims.
Appreciate 2
ZM22785.00
      11-23-2018, 12:02 PM   #9
ZM2
Brigadier General
2785
Rep
3,681
Posts

Drives: 2017 LBB M2
Join Date: Mar 2017
Location: Baltimore

iTrader: (1)

Quote:
Originally Posted by Proctor750 View Post
I love the RE71 although they can't take the abuse like the rs4 on the e30.
I guess ill end up staggered which I hoped to avoid but the torque just won't allow square setup. No shot at stock wheels, the width and weight isn't going to work.
Yeah, RE-71R doesn’t last as long as the RS4, but the grip!

I’m going to try 265/35 & 305/30 RE-71R as my next round of tires on my VMR’s. We’ll see if the rear fits and how to car handles. I don’t think you need that much tire in the rear with stock power, but I’m now running the DINAN Stage 4 setup, so more helps.
Appreciate 1
      11-23-2018, 01:56 PM   #10
GasBurnlife(landapanda)
Captain
573
Rep
683
Posts

Drives: BMW M2
Join Date: Aug 2012
Location: Ashburn, Virginia

iTrader: (0)

Quote:
Originally Posted by ZM2 View Post
Quote:
Originally Posted by Proctor750 View Post
I love the RE71 although they can't take the abuse like the rs4 on the e30.
I guess ill end up staggered which I hoped to avoid but the torque just won't allow square setup. No shot at stock wheels, the width and weight isn't going to work.
Yeah, RE-71R doesn’t last as long as the RS4, but the grip!

I’m going to try 265/35 & 305/30 RE-71R as my next round of tires on my VMR’s. We’ll see if the rear fits and how to car handles. I don’t think you need that much tire in the rear with stock power, but I’m now running the DINAN Stage 4 setup, so more helps.
Would love to hear how that setup works. RE71Rs don't come in 295/35/19, so next step down is 285/35.
Appreciate 1
ZM22785.00
      12-06-2018, 06:30 PM   #11
dubzz24
Private First Class
dubzz24's Avatar
Canada
117
Rep
147
Posts

Drives: 2022 M3 Comp xDrive
Join Date: Mar 2012
Location: Vancouver, BC

iTrader: (0)

Have you considered OEM base F80/82 style 513m wheels? Same width and offset as the OEM M2 19's, but in a lighter (and more attractive IMO) 18" forged wheel.

If you wanted to run a square setup you could probably pick up 2 sets and run all 4 rear wheels with a bunch of camber in the front, and sell the remaining 4 front wheels to someone with a narrow body 3 or 2 series.

Last edited by dubzz24; 05-29-2019 at 01:08 PM..
Appreciate 0
      12-07-2018, 07:20 PM   #12
GasBurnlife(landapanda)
Captain
573
Rep
683
Posts

Drives: BMW M2
Join Date: Aug 2012
Location: Ashburn, Virginia

iTrader: (0)

Quote:
Originally Posted by dubzz24 View Post
Have you considered OEM base F80/82 style 513m wheels? Same width and offset as the OEM M2 19's, but in a lighter (and more attractive IMO) 18" forged wheel. I bought my set used on the F8x forum for $1500 shipped with good tread MPSS.

If you wanted to run a square setup you could probably pick up 2 sets and run all 4 rear wheels with a bunch of camber in the front, and sell the remaining 4 front wheels to someone with a narrow body 3 or 2 series.
Appreciate the post. Will take a look at those wheels.
Appreciate 0
      12-19-2018, 06:57 AM   #13
M Fifty
Banned
844
Rep
1,962
Posts

Drives: M2 & 330CI
Join Date: May 2018
Location: The Interweb

iTrader: (0)

The M4 GT4 runs 11x18" ET30 with 390mm front discs.
Appreciate 0
      12-19-2018, 11:08 AM   #14
CosmosMpower
Brigadier General
CosmosMpower's Avatar
2049
Rep
3,714
Posts

Drives: F87c, GT3, MK7 GTI
Join Date: Apr 2011
Location: Frisco, TX

iTrader: (1)

If you can run 18's run 18's if you have to run 19's run 19's. I prefer 10" square all 4 corners with 275 or 285 square tire setup.
Appreciate 0
      12-21-2018, 02:05 PM   #15
z3papa
Captain
United_States
190
Rep
969
Posts

Drives: 11 E92 M3 ZCP, 07 335i
Join Date: Oct 2009
Location: Bloomington IL

iTrader: (2)

Quote:
Originally Posted by landapanda View Post
I wanted to post my thoughts on this topic that I have given a lot of thought recently and get everyone's input.

Assumptions:
- Camber plates, big brake kits, pads and fluids are out of scope of this discussion.
- I am focused on attaining an ideal track day setup, not a racing one as I wanted to keep compliance with club racing rules out of scope.
- Wheel budget is limited to $2,000 for a set of 4 wheels
- Tire budget is limited to to $1,200 for a set of 4 tires

I have couple of concerns/questions regarding the proper function of the electronic and mechanical systems. Then there are subsequent decisions driven mainly by cost, performance, practicality, weight and aesthetics in descending order:

1a. How much can tier diameter deviate from OEM setup before ability of electronic systems to function as designed is impacted - abs, traction control, stability control? Does this matter with DCS and ESC turned off?

This is a non-issue. Dropping down 1" in diameter in wheel which will likely result in shorter tires will not be an issue.

1b. How much can tier diameter deviate from OEM setup before ability of mechanical systems to function as designed and their longevity is impacted - rear differential is the only one that comes to mind.

Saame response as above. Smaller diameter wheels/shorter tires don't adversely impact the differential

Cost:
2a - assuming comparison of same make/model or across manufacturers looking at similar material and build process, 18" wheels are cheaper. Same can be said for tires.

Yes to both. Wearables are cheaper which would be the #1 reason to do this provided you can access tires in the sizes you want

2b - 18" square setup will give you the ability to rotate tires front to back, saving you money. Arguably, this is true for a 19" setup.

Square setups such as the 18x10 to the extent they fit into your wheel well are ideal for rotation and more even wear. The car will also be easier to make it more neutral provided you're fine with that setup

2c - a square setup with the right tires will also allow you to flip those tires (run them backwards - counter to their intended rotation), giving you additional days of track time on the same tires, assuming there is usable rubber left.

If you get uneven wear, say shoulder wear from insufficient front camber or inside wear in the rear due to toe in, my suggestion is to not flip them and run them backwards but flip them on axel so the driver's front is now the passenger front and vis versa

2d - you can buy a set of takeoffs for ~$500-$600; you will usually have 2/3 of the heat cycles left in them. Similar tire setup will run at least $1,000-$1,200 new, but your selection will be limited to the offering of the reseller.

Take offs have their trade offs. You need to factor in the cost of mount/balances versus what you are saving. Some people, especially toward the end of the summer, sell low run take offs either because they've won tires on contingency, and don't want to store them over the winter or want them cleared out.

Performance
3. I think this one is a wash. Many competitive teams, including the Pirelli World Challenge M235iR cars run 18" square setup. Some may argue that 19" tires have a superior wall stiffness, resulting in less tire roll. There may be other arguments and I am interested in hearing those.

Most of the really good tires have pretty damn stiff sidewalls. IMO -- going to the lower aspect of 19" tires really compromises suspension compliance which arises from the sidewall. Here -- I'd say 18" wheels/tires is better.

Practicality
4. If you invested in a big brake kit or are considering one, tour wheel choice may be impacted based on which BBK manufacturer you chose. However, most manufacturers kits are by design compatible with 18" wheels.

No opinion as I have not run BBK which could not fit with 18" wheels

5. Weight - 18" vs 19" wheel/tire combo will generally save 2.5-5 pounds of rotational weight per wheel, 10-25 pounds total, which translates to roughly 20-50 pounds weight savings of sprung weight (assuming 1:2 ratio of sprung to unsprung weight for argument's sake - meaning a weight saving of one pound on a sprung component is an equivalent of saving two pounds on an unsprung component). Of course, one can buy expensive 19" wheels made of exotic materials that can be significantly lighter than 18" wheels, but I am assuming a budget of roughly $500/wheel, and not $2000/wheel or more. I created a spreadsheet to track a variety of tire 18" and 19" Bridgestone RE71R tire sizes and dimensions, including contact patch and weight, as well as sample wheel weight (I used APEX wheels as an example) - https://docs.google.com/spreadsheets...it?usp=sharing

Weight can be felt and = time

6. Aesthetics - least, but somewhat important, as you will live with tour buying decision for months and years to come. 18" wheels are arguably still more popular for racing purposes, and there is a great, if not better, selection of competition wheels in this size that are pleasing to the eye.

Thanks for reading and I look forward to your input!
See bolds for my responses. YMMV
__________________
Sold 2011.5 E92 M3 ZCP.
Appreciate 1
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 04:06 PM.




m2
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST