R 6 question
11-04-2011, 11:22 AM
#1
Pro
Thread Starter
R 6 question
Just finished my first few session on the Hoosier R6's after running only on street tires and have a question. I did cord the tires around the outside edge which I have been told is from not enough negative camber. My questions is what would cause a large amount of track rubber build up around the middle of the tire? Too much air or not enough? 3 out of the 4 tires have a large bead of old rubber down the middle of the tire all the way around.
11-04-2011, 11:31 AM
#2
I will be running R6's for the first time next weekend. I plan on using 22 to 26 psi in front and 18 to 24 psi in the rear. I am getting my car's alignment change to -2.5 to -3 in front and -1.5 or -2 in the rear. How does your setup compare.
11-04-2011, 11:34 AM
#3
Tech Contributor
That's simply how soft compound tires cool sometimes. That excess rubber will sluff off as soon as they are run next time, provided they were not corded.
Typically, one can determine if the inflation pressure was correct by watching the scrub across the surface of the "tread": scrub complete to outside and inside = not over-inflated. Unfortunately, since your camber was off, this read will not be very reliable.
The best way to determine optimum pressure is with a probe pyrometer, and a search here will give you much info on the topic. However, that work will be useless until you get negative camber in the correct range.
Ed LoPresti
Typically, one can determine if the inflation pressure was correct by watching the scrub across the surface of the "tread": scrub complete to outside and inside = not over-inflated. Unfortunately, since your camber was off, this read will not be very reliable.
The best way to determine optimum pressure is with a probe pyrometer, and a search here will give you much info on the topic. However, that work will be useless until you get negative camber in the correct range.
Ed LoPresti
Last edited by RacePro Engineering; 11-04-2011 at 11:37 AM.
11-04-2011, 11:44 AM
#4
Le Mans Master
Just finished my first few session on the Hoosier R6's after running only on street tires and have a question. I did cord the tires around the outside edge which I have been told is from not enough negative camber. My questions is what would cause a large amount of track rubber build up around the middle of the tire? Too much air or not enough? 3 out of the 4 tires have a large bead of old rubber down the middle of the tire all the way around.
11-04-2011, 02:30 PM
#5
Instructor
Member Since: Dec 2009
Location: Marion In
Posts: 165
Likes: 0
Received 0 Likes
on
0 Posts
I am running similar camber on front and rear and run28-30 in front and 26-28 rear and shooting for the 33-34 range when hot. Without a pyrometer and many checks , we are only guessing what is best. I think 22 front and 18 rear is too low, just guessing. I run thru about 3 sets of R6's a season--I change before they cord--usually when they are greasy.
11-04-2011, 02:35 PM
#6
Pro
Thread Starter
I started with the cold tire pressure I got from Hoosier. I am looking to go with -3 front and about -2.5 rear for next year.
11-04-2011, 03:56 PM
#7
Le Mans Master
11-04-2011, 04:20 PM
#8
Team Owner
Member Since: Sep 2003
Location: Raleigh / Rolesville NC
Posts: 43,084
Likes: 0
Received 25 Likes
on
25 Posts
I am running similar camber on front and rear and run28-30 in front and 26-28 rear and shooting for the 33-34 range when hot. Without a pyrometer and many checks , we are only guessing what is best. I think 22 front and 18 rear is too low, just guessing. I run thru about 3 sets of R6's a season--I change before they cord--usually when they are greasy.
20-22 front COLD 28 HOT 30 becomes too greasy and slippery
18-20 rear COLD 28 HOT
depending on how you run, but still shoot for the ~28 HOT
as they age even lower
11-05-2011, 08:07 AM
#11
Probably should have said I will run as much negative camber as the car will give me.
Last edited by beerkat; 11-05-2011 at 08:10 AM.
11-05-2011, 11:10 AM
#14
Pro
Thread Starter
Not yet everything is still stock as it came from factory. I am planning on doing the Pfadt heavyweight front and rear sway bars as well as the pillow blocks. Do you suggest I go with the poly bushings also ? Have sent Danny a few e-mails w/o any response. I am looking at doing the light weight clutch this winter, will most likely hold off on the cage until 2013 ( need more experience before I step up to the big league)
11-05-2011, 01:34 PM
#15
Supporting Vendor
Good advice from everybody. You will need poly bushings for the negative camber to work properly. With stock stuff once you turn in your camber doesn't hold.
That would be about three sets for me, especially the fronts.
11-05-2011, 08:45 PM
#17
Le Mans Master
11-06-2011, 07:30 AM
#18
11-06-2011, 09:22 AM
#19
Team Owner
Just finished my first few session on the Hoosier R6's after running only on street tires and have a question. I did cord the tires around the outside edge which I have been told is from not enough negative camber. My questions is what would cause a large amount of track rubber build up around the middle of the tire? Too much air or not enough? 3 out of the 4 tires have a large bead of old rubber down the middle of the tire all the way around.
That usually happens at track speeds under 50 MPH.
Step it up next time and that won't happen
11-06-2011, 09:30 AM
#20
Drifting
Well, that would be one set of rears. I'm new to race tires. Last time out it was all I could do to get them around T1 at VIR. I found a couple of good coaches that helped me adjust air pressures but each session just got worse after a couple of laps. At the end of session 4 on day 2, the rears were corded. I should also add that the negative camber was not correct.
So how many heat cycles can an R6 take before performance goes away?
Some one indicated 32/3 -10? Maybe I should b asking what a heat cycle is - one hpde session? If so, that's a new set of R6's for every HPDE
That's not in my budget.
Jim
I'm new to race tires. Last time out it was all I could do to get them around T1 at VIR. I found a couple of good coaches that helped me adjust air pressures but each session just got worse after a couple of laps. At the end of session 4 on day 2, the rears were corded. I should also add that the negative camber was not correct.So how many heat cycles can an R6 take before performance goes away?
Some one indicated 32/3 -10? Maybe I should b asking what a heat cycle is - one hpde session? If so, that's a new set of R6's for every HPDE
That's not in my budget.Jim
Last edited by jlutherva; 11-06-2011 at 09:31 AM. Reason: spelling and content