Tire wear at the track

PrimeBMW · 06-19-2019, 10:49 AM

Quote:

Originally Posted by dparm

Quote:

Originally Posted by rhyary

I have on the front PS91 275/30/19 and will be using them on the next rainy track day.

Otherwise, I am on RR slicks until I use up my stash from the winter.

Then I am going to try Hoosier A7 or R7 265/35/19. Fit would be potentially an issue so it will be a project playing with the JRZ coil overs for hight and other clearance issues

Never a dull moment

I thought the A7 was more of an autocross tire? I'd be hesitant to take that on the track unless you just need a tire for a quick qualifying lap or whatever. I would think it's going to overheat fast.

Historically I believe you are correct regarding the A7 being a "autocross" tire. But in the last few years (maybe they changed the compound) club racers have started using it for qualifying and race. It seems to be the fast and smart choice. The downside is that it heat cycles out quickly. So for HPDE I would choose the R7 as it seems to have some drop off but fairly consistent speed throughout its life.

dparm · 06-19-2019, 11:21 AM

Quote:

Originally Posted by PrimeBMW

Historically I believe you are correct regarding the A7 being a "autocross" tire. But in the last few years (maybe they changed the compound) club racers have started using it for qualifying and race. It seems to be the fast and smart choice. The downside is that it heat cycles out quickly. So for HPDE I would choose the R7 as it seems to have some drop off but fairly consistent speed throughout its life.

Thanks for clarifying.

I think the R7 is the smarter choice for HPDE, as it's not like shaving a few tenths off a lap time is going to make the difference between winning the trophy and taking second place.

rhyary · 06-24-2019, 10:10 AM

Quote:

Originally Posted by dparm

Quote:

Originally Posted by PrimeBMW

Historically I believe you are correct regarding the A7 being a "autocross" tire. But in the last few years (maybe they changed the compound) club racers have started using it for qualifying and race. It seems to be the fast and smart choice. The downside is that it heat cycles out quickly. So for HPDE I would choose the R7 as it seems to have some drop off but fairly consistent speed throughout its life.

Thanks for clarifying.

I think the R7 is the smarter choice for HPDE, as it's not like shaving a few tenths off a lap time is going to make the difference between winning the trophy and taking second place.

The Hoosier 265/35/19 works.
Just came back from a test drive
Hooray!

Now we need to see if the inner fenders will survive a track day.

rhyary · 06-24-2019, 10:11 AM

Good results with the following aligment:
-3.0 front
-2.0 rear
0 Toe

Tire wear is as good as it gets

rhyary · 06-30-2019, 11:36 AM

Quote:

Originally Posted by slicer

Quote:

Originally Posted by rhyary

Quote:

Originally Posted by slicer

Quote:

Originally Posted by rhyary

Quote:

Originally Posted by slicer

A spacer will not help fender liner clearance. It will make it worse. Think about the wheel position when the wheel is turned. Adding a spacer will push it closer to the fender liner.

That being said there are a couple of options. There is metal that can be cut to increase room on the back side of wheel well. In addition the windshield washer tank is located behind the liner on passenger side. That can be removed (saves 10 lbs with fluid). Lastly you can install steering rack limiters to prevent turning the wheel far enough to cause clearance issues.

Another thing to point out is that you can improve inner clearance with your JRZ by going to a shorter spring and or helper. Do you know if you are using a no-load helper? If not there may be some available stack height reduction by switching to a no-load helper. I was able to completely delete my helper but Ohlins uses an inverted design which allows me to pre-load the spring without a helper.

Here is my 275/30/19 and JRZ
Perhaps it will give you some insights into coming up with a solution.

That's a rated tender spring. Going to a no- load helper will push the perch up about 12mm because it has a 12mm shorter stack height.

You can possibly gain more by going to a shorter main spring if a shorter spring has enough travel for your suspension setup

I am not sure 12mm will solve the problem.
I am concerned that a shorter spring may not results in better laptime.

Also, both the 265/35 and 295/30 are taller.

A 295 perhaps would have too much hard issues to solve. Will 265/35 be easier to solve?

I hate engineering. There is always something in the way.

265 is definitely easier to solve. There's zero reason to make any adjustment to the suspension for a 265/35/19. It will fit easily - other than the diameter causing some rubbing on the fender liner (which would not likely be solved by a more conservative offset afforded by more inner clearance). The need for increased inner space is for fitting a wide 295 which needs all the room it can get (width-wise).

A shorter spring in the same spring rate would have zero impact on your lap time. The change will not be detectable As long as the spring has enough travel (you simply want to avoid a spring that will bottom out before the suspension does). The gain would come from the added grip of a wider 295 tire (afforded by the extra space provided by the shorter spring)

I will point out that all of this is easier with 18" wheels because of available tire sizes. For example 265/35/18 and 295/30/18 are far easier to fit due to their 1" smaller diameter (when compared to 19" tires of the same width and aspect ratio). I know you are committed to your current brake kit and would not consider changing it. However this point will benefit others considering what brake kit and wheel size to build around. For those of you who don't know - @rhyary has a Brembo 380 kit which is very limiting when it comes to wheel fitment. There are only a select few 18" wheels that can clear that kit, therefore @rhyary is focused on 19" wheel and tire fitments.

Here's a picture to illustrate the reduced stack height of a no -load helper. Note how thin the helper spring coils are.

Wheel fit by slicerM, on Flickr

"265 is definitely easier to solve. There's zero reason to make any adjustment to the suspension for a 265/35/19. It will fit easily"

@Slicer, thank you.
2 x 1 hour session and
2 x 30 minutes at LRP and no issues with the Hoosier 265/35/19 up front

slicer · 06-30-2019, 12:29 PM

Sweet! Glad to hear it!

ThunderMoose · 06-30-2019, 12:31 PM

Quote:

Originally Posted by rhyary

Quote:

Originally Posted by slicer

Quote:

Originally Posted by rhyary

Quote:

Originally Posted by slicer

Quote:

Originally Posted by rhyary

Quote:

Originally Posted by slicer

A spacer will not help fender liner clearance. It will make it worse. Think about the wheel position when the wheel is turned. Adding a spacer will push it closer to the fender liner.

That being said there are a couple of options. There is metal that can be cut to increase room on the back side of wheel well. In addition the windshield washer tank is located behind the liner on passenger side. That can be removed (saves 10 lbs with fluid). Lastly you can install steering rack limiters to prevent turning the wheel far enough to cause clearance issues.

Another thing to point out is that you can improve inner clearance with your JRZ by going to a shorter spring and or helper. Do you know if you are using a no-load helper? If not there may be some available stack height reduction by switching to a no-load helper. I was able to completely delete my helper but Ohlins uses an inverted design which allows me to pre-load the spring without a helper.

Here is my 275/30/19 and JRZ
Perhaps it will give you some insights into coming up with a solution.

That's a rated tender spring. Going to a no- load helper will push the perch up about 12mm because it has a 12mm shorter stack height.

You can possibly gain more by going to a shorter main spring if a shorter spring has enough travel for your suspension setup

I am not sure 12mm will solve the problem.
I am concerned that a shorter spring may not results in better laptime.

Also, both the 265/35 and 295/30 are taller.

A 295 perhaps would have too much hard issues to solve. Will 265/35 be easier to solve?

I hate engineering. There is always something in the way.

265 is definitely easier to solve. There's zero reason to make any adjustment to the suspension for a 265/35/19. It will fit easily - other than the diameter causing some rubbing on the fender liner (which would not likely be solved by a more conservative offset afforded by more inner clearance). The need for increased inner space is for fitting a wide 295 which needs all the room it can get (width-wise).

A shorter spring in the same spring rate would have zero impact on your lap time. The change will not be detectable As long as the spring has enough travel (you simply want to avoid a spring that will bottom out before the suspension does). The gain would come from the added grip of a wider 295 tire (afforded by the extra space provided by the shorter spring)

I will point out that all of this is easier with 18" wheels because of available tire sizes. For example 265/35/18 and 295/30/18 are far easier to fit due to their 1" smaller diameter (when compared to 19" tires of the same width and aspect ratio). I know you are committed to your current brake kit and would not consider changing it. However this point will benefit others considering what brake kit and wheel size to build around. For those of you who don't know - @rhyary has a Brembo 380 kit which is very limiting when it comes to wheel fitment. There are only a select few 18" wheels that can clear that kit, therefore @rhyary is focused on 19" wheel and tire fitments.

Here's a picture to illustrate the reduced stack height of a no -load helper. Note how thin the helper spring coils are.

Wheel fit by slicerM, on Flickr

"265 is definitely easier to solve. There's zero reason to make any adjustment to the suspension for a 265/35/19. It will fit easily"

@Slicer, thank you.
2 x 1 hour session and
2 x 30 minutes at LRP and no issues with the Hoosier 265/35/19 up front

What did you think of Hoosiers?

rhyary · 06-30-2019, 06:55 PM

Quote:

Originally Posted by ThunderMoose

Quote:

Originally Posted by rhyary

Quote:

Originally Posted by slicer

Quote:

Originally Posted by rhyary

Quote:

Originally Posted by slicer

Quote:

Originally Posted by rhyary

Quote:

Originally Posted by slicer

A spacer will not help fender liner clearance. It will make it worse. Think about the wheel position when the wheel is turned. Adding a spacer will push it closer to the fender liner.

That being said there are a couple of options. There is metal that can be cut to increase room on the back side of wheel well. In addition the windshield washer tank is located behind the liner on passenger side. That can be removed (saves 10 lbs with fluid). Lastly you can install steering rack limiters to prevent turning the wheel far enough to cause clearance issues.

Another thing to point out is that you can improve inner clearance with your JRZ by going to a shorter spring and or helper. Do you know if you are using a no-load helper? If not there may be some available stack height reduction by switching to a no-load helper. I was able to completely delete my helper but Ohlins uses an inverted design which allows me to pre-load the spring without a helper.

Here is my 275/30/19 and JRZ
Perhaps it will give you some insights into coming up with a solution.

That's a rated tender spring. Going to a no- load helper will push the perch up about 12mm because it has a 12mm shorter stack height.

You can possibly gain more by going to a shorter main spring if a shorter spring has enough travel for your suspension setup

I am not sure 12mm will solve the problem.
I am concerned that a shorter spring may not results in better laptime.

Also, both the 265/35 and 295/30 are taller.

A 295 perhaps would have too much hard issues to solve. Will 265/35 be easier to solve?

I hate engineering. There is always something in the way.

265 is definitely easier to solve. There's zero reason to make any adjustment to the suspension for a 265/35/19. It will fit easily - other than the diameter causing some rubbing on the fender liner (which would not likely be solved by a more conservative offset afforded by more inner clearance). The need for increased inner space is for fitting a wide 295 which needs all the room it can get (width-wise).

A shorter spring in the same spring rate would have zero impact on your lap time. The change will not be detectable As long as the spring has enough travel (you simply want to avoid a spring that will bottom out before the suspension does). The gain would come from the added grip of a wider 295 tire (afforded by the extra space provided by the shorter spring)

I will point out that all of this is easier with 18" wheels because of available tire sizes. For example 265/35/18 and 295/30/18 are far easier to fit due to their 1" smaller diameter (when compared to 19" tires of the same width and aspect ratio). I know you are committed to your current brake kit and would not consider changing it. However this point will benefit others considering what brake kit and wheel size to build around. For those of you who don't know - @rhyary has a Brembo 380 kit which is very limiting when it comes to wheel fitment. There are only a select few 18" wheels that can clear that kit, therefore @rhyary is focused on 19" wheel and tire fitments.

Here's a picture to illustrate the reduced stack height of a no -load helper. Note how thin the helper spring coils are.

[img]https://live.staticflickr.com/65535/...079144fc_b.jpg[/img]Wheel fit by slicerM, on Flickr

"265 is definitely easier to solve. There's zero reason to make any adjustment to the suspension for a 265/35/19. It will fit easily"

@Slicer, thank you.
2 x 1 hour session and
2 x 30 minutes at LRP and no issues with the Hoosier 265/35/19 up front

What did you think of Hoosiers?

They felt good, but not drastically better than the RR 235.

Anecdotally, they felt "meatier" like there is more tire between me and the road (thickness) but my times were not better than the RR.

In the context of cost, the Hoosier is $430 and the RR is $230.

Since I tried them for the first time at LRP, I don't have enough laps there to really know.

I will have a better idea tomorrow at NYST.

Tire wear is excellent! This is the front driver side, the one that works hard at LRP.

Tomorrow at NYST, the front passenger gets to work hard.
.

Dreamer99 · 07-16-2019, 10:39 PM

Here is the same tire from the original picture in this post. I did two track days on them then had them swapped on the rims and they now have 4.5 track days total. What do you think?

My front alignment is -2.75 with zero toe. Will a bit more camber help with less inside wear?

Is there another track day left in them? Maybe run them backwards?

Bartledoo · 07-17-2019, 12:48 AM

Quote:

Originally Posted by Dreamer99

Here is the same tire from the original picture in this post. I did two track days on them then had them swapped on the rims and they now have 4.5 track days total. What do you think?

My front alignment is -2.75 with zero toe. Will a bit more camber help with less inside wear?

Is there another track day left in them? Maybe run them backwards?

The color is throwing me off.

Dreamer99 · 07-17-2019, 09:11 AM

Here is a better picture

rhyary · 07-17-2019, 05:44 PM

Quote:

Originally Posted by Dreamer99

Here is a better picture

Which side is the outside?

Dreamer99 · 07-17-2019, 08:01 PM

Quote:

Originally Posted by rhyary

Quote:

Originally Posted by Dreamer99

Here is a better picture

Which side is the outside?

The side with more tread. It's the inside edge wear that has me confused.

06-24-2019, 10:11 AM	#180
rhyary Colonel 1563 Rep 2,869 Posts Drives: 2013 M3 Join Date: May 2015 Location: Albany, NY iTrader: (0)	Good results with the following aligment: -3.0 front -2.0 rear 0 Toe Tire wear is as good as it gets Attached Images
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06-30-2019, 12:29 PM	#182
slicer Major General 2736 Rep 6,734 Posts Drives: 'E46 M3 Race Car, '23 X7 Join Date: Jan 2009 Location: Wisconsin - Instagram - @slicer_m iTrader: (39)	Sweet! Glad to hear it! __________________ '23 X7 '04 M3 - Fall Line Motorsports Built Race Car - S65 swap, Dry Sump, Bosch Stand-Alone ECU, Drenth Sequential Trans, MCS 3-Way, Flossmann Wide Body, Brembo Motorsports Brakes, Drexler LSD, BBS E88 Etc. INSTAGRAM - @Slicer_M
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07-16-2019, 10:39 PM	#185
Dreamer99 First Lieutenant 87 Rep 397 Posts Drives: E92M3 Join Date: Feb 2015 Location: British Columbia iTrader: (1)	Here is the same tire from the original picture in this post. I did two track days on them then had them swapped on the rims and they now have 4.5 track days total. What do you think? My front alignment is -2.75 with zero toe. Will a bit more camber help with less inside wear? Is there another track day left in them? Maybe run them backwards? Attached Images
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07-17-2019, 09:11 AM	#187
Dreamer99 First Lieutenant 87 Rep 397 Posts Drives: E92M3 Join Date: Feb 2015 Location: British Columbia iTrader: (1)	Here is a better picture Attached Images
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