follow ft86club on our blog, twitter or facebook.
FT86CLUB
Ft86Club
Speed By Design
Register Garage Members List Calendar Search Today's Posts Mark Forums Read

Go Back   Scion FR-S Forum | Subaru BRZ Forum | Toyota 86 GT 86 Forum | AS1 Forum - FT86CLUB > Technical Topics > Tracking / Autocross / HPDE / Drifting

Tracking / Autocross / HPDE / Drifting What these cars were built for!


User Tag List

Reply
 
Thread Tools Search this Thread
Old 11-23-2016, 12:56 AM   #15
zdr93523
Senior Member
 
zdr93523's Avatar
 
Join Date: Apr 2013
Drives: 2013 BRZ Limited
Location: Utah
Posts: 631
Thanks: 447
Thanked 341 Times in 166 Posts
Mentioned: 5 Post(s)
Tagged: 2 Thread(s)
Garage
Quote:
Originally Posted by wparsons View Post
To really set pressures and camber you need a pyrometer, good lap timer, and consistent driving/weather. Just because a car starts to understeer more with 0.5psi higher pressure doesn't mean it's slower, it might be generating more grip and have higher cornering speeds, it just shifted the grip balance rearward a bit.
While a pyrometer is a useful tool, tire wear is actually the only thing you should use to determine a final camber setting... Unless you're doing time attack, then who cares about wear?

I didn't go back and check but I believe this thread started with someone who doesn't have sufficient adjustability for any of this conversation to be relevant and hence why the pressures are going to be way more important than a pyrometer. I'm not even sure why a pyrometer was brought up in the first place. Because of this lack of adjustability, wear and heat will be both excessive on the outside edge no matter what so pressures are the only real thing that will make a difference. Spending money and time (including this conversation) with things that don't have an affect or solution is a waste.
__________________
Instagram: @zdr_93523
Youtube: https://www.youtube.com/user/zdr93523
Pink Ribbon Racing 2013 BRZ Limited NASA ST2 and TT2 race car
www.makesmodels.com
www.camautomag.com
zdr93523 is offline   Reply With Quote
The Following 2 Users Say Thank You to zdr93523 For This Useful Post:
OND (11-23-2016), wparsons (11-23-2016)
Old 11-23-2016, 07:39 PM   #16
OND
Senior Member
 
OND's Avatar
 
Join Date: May 2016
Drives: '15 BRZ
Location: Austin, TX
Posts: 189
Thanks: 118
Thanked 194 Times in 82 Posts
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quote:
Originally Posted by zdr93523 View Post
While a pyrometer is a useful tool, tire wear is actually the only thing you should use to determine a final camber setting... Unless you're doing time attack, then who cares about wear?

I didn't go back and check but I believe this thread started with someone who doesn't have sufficient adjustability for any of this conversation to be relevant and hence why the pressures are going to be way more important than a pyrometer. I'm not even sure why a pyrometer was brought up in the first place. Because of this lack of adjustability, wear and heat will be both excessive on the outside edge no matter what so pressures are the only real thing that will make a difference. Spending money and time (including this conversation) with things that don't have an affect or solution is a waste.
Makes sense, I will start with monitoring tire pressures closer and adding a second set of camber bolts to begin with. Pyrometer readings etc might come at a later stage if/when I upgrade some suspension components to gain more adjustability.

I am actually starting to think my higher cold pressures might be causing a vicious cycle where my front tires slide too much, which heats up the tires, which in turn increases the pressure and causes even more understeer.
OND is offline   Reply With Quote
Old 11-24-2016, 03:31 PM   #17
zdr93523
Senior Member
 
zdr93523's Avatar
 
Join Date: Apr 2013
Drives: 2013 BRZ Limited
Location: Utah
Posts: 631
Thanks: 447
Thanked 341 Times in 166 Posts
Mentioned: 5 Post(s)
Tagged: 2 Thread(s)
Garage
Quote:
Originally Posted by OND View Post
Makes sense, I will start with monitoring tire pressures closer and adding a second set of camber bolts to begin with. Pyrometer readings etc might come at a later stage if/when I upgrade some suspension components to gain more adjustability.

I am actually starting to think my higher cold pressures might be causing a vicious cycle where my front tires slide too much, which heats up the tires, which in turn increases the pressure and causes even more understeer.
Could be. Once you reduce pressure to your target after the first session, you should only have to drop each tire a few pounds at most following each subsequent session.

I would caution the second set of camber bolts. You're likely very close to contacting the spring perch with the tire as it is now.

If you every find your pressures extremely hard to control, you likely have moisture in the tires from the air compressor. If this happens, or you think it may help, pull the shrader valve on the valve stem, let the air drain, fill the tire without reinstalling the valve, repeat about 4 times. This will help to remove any moisture from the tire.
__________________
Instagram: @zdr_93523
Youtube: https://www.youtube.com/user/zdr93523
Pink Ribbon Racing 2013 BRZ Limited NASA ST2 and TT2 race car
www.makesmodels.com
www.camautomag.com
zdr93523 is offline   Reply With Quote
The Following User Says Thank You to zdr93523 For This Useful Post:
OND (11-29-2016)
Old 11-29-2016, 04:26 PM   #18
zdr93523
Senior Member
 
zdr93523's Avatar
 
Join Date: Apr 2013
Drives: 2013 BRZ Limited
Location: Utah
Posts: 631
Thanks: 447
Thanked 341 Times in 166 Posts
Mentioned: 5 Post(s)
Tagged: 2 Thread(s)
Garage
@OND or anyone else...

I'll add to my moisture comment. This usually occurs when an inexperienced person mounts your track tires. If they introduce lube into the tire vs. carefully lubricating the outer edge of the bead, you will have moisture in the tires. A lot of tire shops will slap lube all over the bead of your tires because it is easier for them and it doesn't matter with street tires. I try to mount my track tires with little to no lubrication to avoid this headache. If I do lube the bead, I only do it once the tire is mounted and I'm ready to seat the bead. That way no lube can get inside the tire.

and that's way too much talk about lube for one day haha.
__________________
Instagram: @zdr_93523
Youtube: https://www.youtube.com/user/zdr93523
Pink Ribbon Racing 2013 BRZ Limited NASA ST2 and TT2 race car
www.makesmodels.com
www.camautomag.com
zdr93523 is offline   Reply With Quote
Old 11-29-2016, 05:27 PM   #19
JDM4E
Senior Member
 
Join Date: Dec 2014
Drives: Honda Accord Euro
Location: Europe
Posts: 200
Thanks: 246
Thanked 50 Times in 37 Posts
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Wait a minute... Are you saing, that with stock car, driving PROPERLY, the tires will inevitably chunk like on the photo?
I have destroyed a tire exactly like OP on my Accord Euro during 5 laps, but that was because I drove like maniac too hot. There were other cars and during 20min session no one did that to the tires.
JDM4E is offline   Reply With Quote
Old 11-29-2016, 05:51 PM   #20
OND
Senior Member
 
OND's Avatar
 
Join Date: May 2016
Drives: '15 BRZ
Location: Austin, TX
Posts: 189
Thanks: 118
Thanked 194 Times in 82 Posts
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quote:
Originally Posted by JDM4E View Post
Wait a minute... Are you saing, that with stock car, driving PROPERLY, the tires will inevitably chunk like on the photo?
I have destroyed a tire exactly like OP on my Accord Euro during 5 laps, but that was because I drove like maniac too hot. There were other cars and during 20min session no one did that to the tires.
The wear pictured is after 5 trackdays (open lapping days, probably 1.5-2 hours of driving per day)
OND is offline   Reply With Quote
The Following User Says Thank You to OND For This Useful Post:
JDM4E (11-29-2016)
Old 11-29-2016, 05:59 PM   #21
JDM4E
Senior Member
 
Join Date: Dec 2014
Drives: Honda Accord Euro
Location: Europe
Posts: 200
Thanks: 246
Thanked 50 Times in 37 Posts
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quote:
Originally Posted by OND View Post
The wear pictured is after 5 trackdays (open lapping days, probably 1.5-2 hours of driving per day)
Oh, than I think all is normal!
JDM4E is offline   Reply With Quote
Old 06-05-2017, 06:25 PM   #22
OND
Senior Member
 
OND's Avatar
 
Join Date: May 2016
Drives: '15 BRZ
Location: Austin, TX
Posts: 189
Thanks: 118
Thanked 194 Times in 82 Posts
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quick update

Thanks again for all the advice. Here are the front Firestone Firehawk Indy 500's after 6 months (rotated twice) using -2.3 front camber and 30-32psi cold pressures:



- There is no chunking on front tires and very mild chunking on rear tires, so these tires are definitely a softer compound than Primacies that can take the heat better (despite the stated 340tw)

- As suggested by @zdr93523, the outer shoulders still take the most of the beating and are pretty worn out, even though the rest of the tire has loads of life left


Sooo here is another question for you guys. I might need to replace these tires within a couple months and I am in between these two options:

- Keep using similar Max Perf Summer tires (maybe directional tires like ventus v12, so I can remount them right to left to use the opposite shoulder). I am hoping this will limit max grip and body roll, keeping the tire shoulder wear at an acceptable level. These should also be better for wet track days, daily driving and overall playfulness of the car.

- Go to an Extreme Perf Summer tire (RT615k looks pretty affordable) and hope that their softer compound and better heat tolerance help them wear more evenly on track. Does it even work that way? Or will those tires increase body roll and wear even more on the outer shoulders?

Which option would you go with?
OND is offline   Reply With Quote
Old 06-05-2017, 08:47 PM   #23
Icecreamtruk
Senior Member
 
Join Date: Dec 2015
Drives: Track preped NA FRS
Location: Montreal, Canada
Posts: 606
Thanks: 545
Thanked 385 Times in 236 Posts
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quote:
Originally Posted by OND View Post
Thanks again for all the advice. Here are the front Firestone Firehawk Indy 500's after 6 months (rotated twice) using -2.3 front camber and 30-32psi cold pressures:



- There is no chunking on front tires and very mild chunking on rear tires, so these tires are definitely a softer compound than Primacies that can take the heat better (despite the stated 340tw)

- As suggested by @zdr93523, the outer shoulders still take the most of the beating and are pretty worn out, even though the rest of the tire has loads of life left


Sooo here is another question for you guys. I might need to replace these tires within a couple months and I am in between these two options:

- Keep using similar Max Perf Summer tires (maybe directional tires like ventus v12, so I can remount them right to left to use the opposite shoulder). I am hoping this will limit max grip and body roll, keeping the tire shoulder wear at an acceptable level. These should also be better for wet track days, daily driving and overall playfulness of the car.

- Go to an Extreme Perf Summer tire (RT615k looks pretty affordable) and hope that their softer compound and better heat tolerance help them wear more evenly on track. Does it even work that way? Or will those tires increase body roll and wear even more on the outer shoulders?

Which option would you go with?
You are lacking camber, that is all. Regardless what tire you put there. If you use a more sticky tire, the car will roll more and it will eat up the shoulder even more.
Icecreamtruk is offline   Reply With Quote
The Following 2 Users Say Thank You to Icecreamtruk For This Useful Post:
OND (06-05-2017), strat61caster (06-05-2017)
Old 06-05-2017, 09:50 PM   #24
OND
Senior Member
 
OND's Avatar
 
Join Date: May 2016
Drives: '15 BRZ
Location: Austin, TX
Posts: 189
Thanks: 118
Thanked 194 Times in 82 Posts
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quote:
Originally Posted by Icecreamtruk View Post
You are lacking camber, that is all. Regardless what tire you put there. If you use a more sticky tire, the car will roll more and it will eat up the shoulder even more.
Yeah, that's for sure, but I don't have the budget to add any more camber up front right now, so I am trying to find the tires that would last the longest for my use case. I considered stiffer front and rear sways, but not so sure about those either, since our local track is pretty bumpy.
OND is offline   Reply With Quote
Old 06-06-2017, 12:10 AM   #25
Icecreamtruk
Senior Member
 
Join Date: Dec 2015
Drives: Track preped NA FRS
Location: Montreal, Canada
Posts: 606
Thanks: 545
Thanked 385 Times in 236 Posts
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quote:
Originally Posted by OND View Post
Yeah, that's for sure, but I don't have the budget to add any more camber up front right now, so I am trying to find the tires that would last the longest for my use case. I considered stiffer front and rear sways, but not so sure about those either, since our local track is pretty bumpy.
Sway bars will aid for sure. They will reduce body roll a lot, which is why you loose negative camber during cornering. Stiffer springs will also help, as will tires with stiffer sidewall. The more budget friendly solution is to get tires with a very stiff sidewall, and very little grip. You wont be going fast, but they will last you a lot and wear better.
Icecreamtruk is offline   Reply With Quote
 
Reply

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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
FS: Stock Tires (some chunking) bottle Canada Classifieds 4 07-28-2015 01:16 PM
Dunlop Z2's Chunking, Defective? kanundrum Tracking / Autocross / HPDE / Drifting 19 03-30-2014 09:49 PM
Toyota/ Scion is Taking GOOD Care of me. Tanuki Scion FR-S / Toyota 86 GT86 General Forum 23 08-30-2012 02:34 AM


All times are GMT -4. The time now is 12:45 PM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Garage vBulletin Plugins by Drive Thru Online, Inc.