traction fail after changing tire size !

[kh4l4f]

hello guys

i was running on the stock tire size which was

front : 255/35/19 5mm wheel spacer
rear : 275/35/19 10mm wheel spacer

and the the grip was great with bad traction from the Michelin cup2 series

so i decide to have the proxies 888r and i found only 295/30/19

so when i drive on the highway corner exist while on pretty good speed the traction control lamp flashing all the way until i finish the corner ! even when im getting slow ! on the old tire there is nothing wrong

so i decide to remove the spacer which i did with the same issue ! i really dont know whats wrong with the 888r !

note : tire psi : 35

any idea or thoughts ?

[MadZarBMR]

The smaller circumference of the 295/30/19 is what is making DSC kick in sooner than expected. 295/35/19 will solve this issue.

[kh4l4f]

Originally Posted by MadZarBMR

The smaller circumference of the 295/30/19 is what is making DSC kick in sooner than expected. 295/35/19 will solve this issue.

toyo 888r doesn't have 295/35/19

you can check tire sizes option here

https://www.toyotires.com/tire/patte...s-proxes-r888r

[Circuit Hunter]

Turn off DSC.

[Suds]

OP, what size fronts are you running with the Proxies?
My understanding is the traction control is comparing the wheel speed of the fronts to the rears, so the fronts need to have a slightly smaller rollout, "rolling diameter."

[MannyM5]

If you are on the stock 19in wheels your best choice in r888r is 265/35/19 front and 285/35/19 rear. This will maintain the proper F-R ratio to keep dsc happy. If you are keeping the 295/30's you can always get the r888r's in 265/30 for your front wheels. This will also fix your current complaint.

[wsccsw13]

DSC adapts to changes in tire size/stagger. The system needs a little time but it will detect and adapt so as to be no more intrusive. You did switch from a streetable track tire (sport cup 2) to a racing tire while drive on regular roads ie not clean, nor as smooth, and with not much heat in the tire compared to pushing it on a track....I think all of that would lead to your current problem.

[kh4l4f]

i will get a wider front tire maybe this will help the DSC to take control again

thank u guys

[Signature Wheel BMW]

Originally Posted by wsccsw13

DSC adapts to changes in tire size/stagger. The system needs a little time but it will detect and adapt so as to be no more intrusive. You did switch from a streetable track tire (sport cup 2) to a racing tire while drive on regular roads ie not clean, nor as smooth, and with not much heat in the tire compared to pushing it on a track....I think all of that would lead to your current problem.

False, DSC will not "adapt" your new tire size that significant. It does learn small differences due to tire pressure delta. But going from 2.2% taller rear OEM to 0% taller is a big difference. I found that coding Euro MDM does help if you like to run in MDM all the time like I did. We have lots of track guys running squared setup with Euro MDM coded, no issues.

OP, what you're experience is a ECU attempting to slow the rear wheels down because it thinks your rear wheels are slipping. This is the "hesitation" feeling people have at high speed with improper tire setup.

The proper 295 size combo is 265/35/19 front and 295 or 285/35/19 rear. RWD F8x platform likes the rear to be about 2.2-2.7% taller, give or take 0.8%. So when your setup are the same height front/rear, your rear wheels are spinning 2.2-2.6% faster than the front. You can also do 265/30/19 front with what you have now, but that increases wheel gaps.

[MannyM5]

Originally Posted by kh4l4f

i will get a wider front tire maybe this will help the DSC to take control again

thank u guys

Its not the width, its the overall diameter. You will want the lower profile 265/30 if you are keeping your 295/30 rears.

[M3SQRD]

Originally Posted by Signature Wheel BMW

False, DSC will not "adapt" your new tire size that significant. It does learn small differences due to tire pressure delta. But going from 2.2% taller rear OEM to 0% taller is a big difference. I found that coding Euro MDM does help if you like to run in MDM all the time like I did. We have lots of track guys running squared setup with Euro MDM coded, no issues.

OP, what you're experience is a ECU attempting to slow the rear wheels down because it thinks your rear wheels are slipping. This is the "hesitation" feeling people have at high speed with improper tire setup.

The proper 295 size combo is 265/35/19 front and 295 or 285/35/19 rear. RWD F8x platform likes the rear to be about 2.2-2.7% taller, give or take 0.8%. So when your setup are the same height front/rear, your rear wheels are spinning 2.2-2.6% faster than the front. You can also do 265/30/19 front with what you have now, but that increases wheel gaps.

So are you saying the DSC cannot deal with a worn rear tire + a newish front tire? The % difference is very similar to (if not worse than) new 265/35 and 295/30 tires.

I had zero DSC/MDM issues with PSC2 265/35 and 295/30 tires. Before someone says I don’t drive aggressively enough, I have almost 30 years of track experience.

[gatorfast]

Originally Posted by M3SQRD

So are you saying the DSC cannot deal with a worn rear tire + a newish front tire? The % difference is very similar to (if not worse than) new 265/35 and 295/30 tires.

I had zero DSC/MDM issues with PSC2 265/35 and 295/30 tires. Before someone says I don’t drive aggressively enough, I have almost 30 years of track experience.

The overall diameter difference between a 295/30/19 tire and a 295/35/19 tire is about 1.1 inches. This is a far bigger difference than tire wear which would only be about 7/32nd of an inch when brand new until completely worn.

[M3SQRD]

Originally Posted by gatorfast

The overall diameter difference between a 295/30/19 tire and a 295/35/19 tire is about 1.1 inches. This is a far bigger difference than tire wear which would only be about 7/32nd of an inch when brand new until completely worn.

When did I compare it to a 295/35? I was comparing a WORN stock 275/35 to a new 295/30. The stock 275/35 has a diameter of 26.6” and a tread depth of 10/32” (let’s use a 2 mm wear bar so 8/32) so a worn stock tire has a diameter of 26.6 - 2x8/32 (remember comparing diameter so tread wear at top AND bottom needs to be accounted for) = 26.1” (25.98” at 10/32”) - 26.1” worn stock vs. 26.0” new 295/30. Based on the previous post, I guess that means BMW didn’t design the DSC system to be able to handle a new stock front tire and a worn stock rear tire?

Also, the % change in new diameter between the stock rear and a 295/35 is +1.9% vs. -2.2% for a 295/30 so DSC can handle a 1.9% increase but can’t handle a 2.2% decrease?

Tire pressure also needs to be factored in because the actual tire diameter is directly influenced by tire pressure. I doubt BMW neglected to account for potential changes in tire diameter due to tire pressure when developing their closed-loop feedback DSC system.

[wsccsw13]

Originally Posted by Signature Wheel BMW

False, DSC will not "adapt" your new tire size that significant. It does learn small differences due to tire pressure delta. But going from 2.2% taller rear OEM to 0% taller is a big difference. I found that coding Euro MDM does help if you like to run in MDM all the time like I did. We have lots of track guys running squared setup with Euro MDM coded, no issues.

OP, what you're experience is a ECU attempting to slow the rear wheels down because it thinks your rear wheels are slipping. This is the "hesitation" feeling people have at high speed with improper tire setup.

The proper 295 size combo is 265/35/19 front and 295 or 285/35/19 rear. RWD F8x platform likes the rear to be about 2.2-2.7% taller, give or take 0.8%. So when your setup are the same height front/rear, your rear wheels are spinning 2.2-2.6% faster than the front. You can also do 265/30/19 front with what you have now, but that increases wheel gaps.

Actually, no, not false. This came up in another thread related to square vs staggered diameter setups. BMW sells the M3/4 with a staggered setup for summer and square for winter. So I contacted Bosch who makes the system and developed it with BMW. This was their response:

Dear Mr. ____,

Thank you for your question and interest in our mobility solutions.

The dynamic stability control is very robust, which means that it can cope with all approved tire combinations. Any measurable differences in the tire circumference are detected and compensated by the system. The angular speed of the wheel is corrected without any changes in the application parameter.
Mit freundlichen Grüßen / Best regards


So the system detects differences and adapts.

[wsccsw13]

And Signature, lets not be so argumentative. I run a square setup on your SV503 track series wheels (19x10 gunmetal with MSC2s). Really like them, thanks for a great product.

[kh4l4f]

Originally Posted by MannyM5

Its not the width, its the overall diameter. You will want the lower profile 265/30 if you are keeping your 295/30 rears.

I just had these tire size with a new front set and its work great without issue

thnaks again guys

[kh4l4f]

Originally Posted by M3SQRD

So are you saying the DSC cannot deal with a worn rear tire + a newish front tire? The % difference is very similar to (if not worse than) new 265/35 and 295/30 tires.

I had zero DSC/MDM issues with PSC2 265/35 and 295/30 tires. Before someone says I don’t drive aggressively enough, I have almost 30 years of track experience.

thats right and strange at the same time ! cuz i ask some of my friends with the same sizes and setup some say they have problem with it like me and some says they work great ?! so maybe its all about the programing or something with the DCS SYSTEM ,,

[manosmiles]

Originally Posted by Signature Wheel BMW

False, DSC will not "adapt" your new tire size that significant. It does learn small differences due to tire pressure delta. But going from 2.2% taller rear OEM to 0% taller is a big difference. I found that coding Euro MDM does help if you like to run in MDM all the time like I did. We have lots of track guys running squared setup with Euro MDM coded, no issues.

OP, what you're experience is a ECU attempting to slow the rear wheels down because it thinks your rear wheels are slipping. This is the "hesitation" feeling people have at high speed with improper tire setup.

The proper 295 size combo is 265/35/19 front and 295 or 285/35/19 rear. RWD F8x platform likes the rear to be about 2.2-2.7% taller, give or take 0.8%. So when your setup are the same height front/rear, your rear wheels are spinning 2.2-2.6% faster than the front. You can also do 265/30/19 front with what you have now, but that increases wheel gaps.

hi,
is there a chance that having ceramic brakes makes any kind of difference?
i am having 265-35-29 and 285-35-19 and i am having brake dust in the back wheels and the bumper!!!!!
no error codes, no dsc lamp at any time. i am also having this with dsc off..

[LOW4LYF]

Originally Posted by wsccsw13

Actually, no, not false. This came up in another thread related to square vs staggered diameter setups. BMW sells the M3/4 with a staggered setup for summer and square for winter. So I contacted Bosch who makes the system and developed it with BMW. This was their response:

Dear Mr. ____,

Thank you for your question and interest in our mobility solutions.

The dynamic stability control is very robust, which means that it can cope with all approved tire combinations. Any measurable differences in the tire circumference are detected and compensated by the system. The angular speed of the wheel is corrected without any changes in the application parameter.
Mit freundlichen Grüßen / Best regards






So the system detects differences and adapts.

That's absolutely correct!

I run 255/35 20 & 305/30 with zero issues. Tons of people running square setups without any issues.

[manosmiles]

i run 265-35-19 & 285-35-19 and i am having problems!!!!!
why you think is that????