Tires.
12-03-2003, 11:34 PM
#1
Burning Brakes
Thread Starter
Tires.
Can someone please explain this to me, I am dumb.
Why does shaving the tire save wear ?
Notice:
The ECSTA V700 must be shaved to 3/32" - 4/32" tread depth for any autocross or track use in the dry.
Kumho advises that the ECSTA V700 DOT-legal competition radial must be shaved prior to use in dry conditions. If this tire is not shaved, excessive wear may occur causing the tire to wear to the cords prematurely in a localized area.
Tire heat cycling will not prevent the excessive localized wear of full tread depth tires but will continue to enhance the tire consistency and wear on shaved tires.
The ECSTA V700 should only be used at full tread depth (6/32") for wet track and wet autocross use.
Why does shaving the tire save wear ?
Notice:
The ECSTA V700 must be shaved to 3/32" - 4/32" tread depth for any autocross or track use in the dry.
Kumho advises that the ECSTA V700 DOT-legal competition radial must be shaved prior to use in dry conditions. If this tire is not shaved, excessive wear may occur causing the tire to wear to the cords prematurely in a localized area.
Tire heat cycling will not prevent the excessive localized wear of full tread depth tires but will continue to enhance the tire consistency and wear on shaved tires.
The ECSTA V700 should only be used at full tread depth (6/32") for wet track and wet autocross use.
12-03-2003, 11:40 PM
#2
Instructor
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I'm not sure if this is totally correct, but I think a street tire used on the track will overheat and tend to "chunk" apart unless it is shaved to a low tread depth. I'm sure some of the race guys will be able to elaborate on this.
12-03-2003, 11:52 PM
#3
Indeed, they do chunk at full tread depth.
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12-04-2003, 12:00 AM
#4
Race Car
That's pretty much what I've heard. I've also had it explained to me along these lines; at full tread depth the surface of the tire has more flex, this makes more heat which in turn allows the tire to wear faster. I don't know which of these answers is correct or maybe it's both, or neither.....
I have a set of Kuhmo Ecsta V700, 225/50-15 on cookie cutters, I bought them shaved. There was noticable wear after the first autocross (8 runs and 140 miles to and from) the 9 runs (1 1/2 events) after that didn't seem to make much of a difference but there was no highway use involved. DO NOT GET THEM WET, they SUCK in the rain. They are not that great on dry pavement either, not much better than my RE-730s, I'm getting Hoosiers next time (provided I'm employed, otherwise I might be running on my snow tires).
I have a set of Kuhmo Ecsta V700, 225/50-15 on cookie cutters, I bought them shaved. There was noticable wear after the first autocross (8 runs and 140 miles to and from) the 9 runs (1 1/2 events) after that didn't seem to make much of a difference but there was no highway use involved. DO NOT GET THEM WET, they SUCK in the rain. They are not that great on dry pavement either, not much better than my RE-730s, I'm getting Hoosiers next time (provided I'm employed, otherwise I might be running on my snow tires).
12-04-2003, 12:06 AM
#5
Snow tires have incredible traction when they are on the last 3/32nds!!
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12-04-2003, 10:50 AM
#7
Race Director
My thoughts on tire shaving: it's a little bit of snake oil. First off, IMHO, shaving street tires is a waste of $$. Shaving R-compound track tires may or may not help, and may or may not improve your tire wear.
If you are not yet at the point where you are going to get dedicated track tires for autocross and track driving, then just stick with your regular street tires. They may chunk, and wear, but shaving them will most likely not help much in both chunking and wearing! (My opinions)
The rest of my post here refers to R-compound track tires:
If you are racing and need the 0.01 seconds you gain by shaving will get you a podium finish, then go ahead and shave those tires.
And while the idea of heat transfer being greater at full tread depth has some logic to it, most of the other R-compound tires out there do not require shaving for track driving, or even for autocross.
Proper tire maintenance will make your tires go farther than shaving: for example: moderate heat cycling will help. If possible, rotating the tires front to rear, side to side regularly will also help extent tire life.
If you browse around the Michelin website, there's a power point presentation on their Pilot Sport Cup R-compound tire. Here's some information from there:
Note that the quotes above are specifically about the Michelin Pilot Sport cup. While they do say that heat cycling / shaving will help a little, they do make it clear that it's not that big a margin. IMHO, for DE track and non-national competition autocross, I do NOT recommend shaving, especially on a high quality tire like the Michelin PSC's.
Now the Kumho's are a different beast all together. I have no experience with them, but I have seen them wear significantly quicker on the track than the Michelin's, the Pirelli's (P-0C), and other 'brand name' tires. I am not a big fan of the Kumho R-compound tires. Sure, they are 1/2 price compared to the 'better' tires, but they wear twice as fast!
Just my $0.42,
-Z.
If you are not yet at the point where you are going to get dedicated track tires for autocross and track driving, then just stick with your regular street tires. They may chunk, and wear, but shaving them will most likely not help much in both chunking and wearing! (My opinions)
The rest of my post here refers to R-compound track tires:
If you are racing and need the 0.01 seconds you gain by shaving will get you a podium finish, then go ahead and shave those tires.
And while the idea of heat transfer being greater at full tread depth has some logic to it, most of the other R-compound tires out there do not require shaving for track driving, or even for autocross.
Proper tire maintenance will make your tires go farther than shaving: for example: moderate heat cycling will help. If possible, rotating the tires front to rear, side to side regularly will also help extent tire life.
If you browse around the Michelin website, there's a power point presentation on their Pilot Sport Cup R-compound tire. Here's some information from there:
Regarding Heat Cycling:
Heat cycled tires may come up to operating temperature slightly quicker than non-heat cycled tires, and on some cars we have noted a marginal improvement in lap times (maybe .1-.2 sec in a 38-40 sec autocross environment) and in tire wear. The improvement is not always obvious.
Heat cycled tires may come up to operating temperature slightly quicker than non-heat cycled tires, and on some cars we have noted a marginal improvement in lap times (maybe .1-.2 sec in a 38-40 sec autocross environment) and in tire wear. The improvement is not always obvious.
Regarding shaving:
Pilot Sport Cup starts life at 6/32nd of an inch (center tread depth)
Michelin testing shows that a shaved tire at 3.5/32nds of an inch offers slightly more grip from the start of the competition life of the tire.
Time differential between shaved/heat cycled @ and full tread depth/heat cycled is 0.5-0.6 seconds on a typical 35-38 sec autocross course. These are statistically-sound results; your results may vary.
Pilot Sport Cup starts life at 6/32nd of an inch (center tread depth)
Michelin testing shows that a shaved tire at 3.5/32nds of an inch offers slightly more grip from the start of the competition life of the tire.
Time differential between shaved/heat cycled @ and full tread depth/heat cycled is 0.5-0.6 seconds on a typical 35-38 sec autocross course. These are statistically-sound results; your results may vary.
Summary thoughts on heat cycling / shaving
The consumer must decide if he/she is willing to give up 2.5/32nds of tread life and the cost of shaving in exchange for a potential 0.6 seconds – it depends on how serious you are about your time spent at the track.
All things considered, the absolute quickest time will likely be achieved by shaving and heat cycling the Pilot Sport CUP.
The consumer must decide if he/she is willing to give up 2.5/32nds of tread life and the cost of shaving in exchange for a potential 0.6 seconds – it depends on how serious you are about your time spent at the track.
All things considered, the absolute quickest time will likely be achieved by shaving and heat cycling the Pilot Sport CUP.
Now the Kumho's are a different beast all together. I have no experience with them, but I have seen them wear significantly quicker on the track than the Michelin's, the Pirelli's (P-0C), and other 'brand name' tires. I am not a big fan of the Kumho R-compound tires. Sure, they are 1/2 price compared to the 'better' tires, but they wear twice as fast!
Just my $0.42,
-Z.
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12-04-2003, 11:19 AM
#8
Race Car
Originally posted by Z-man
Time differential between shaved/heat cycled @ and full tread depth/heat cycled is 0.5-0.6 seconds on a typical 35-38 sec autocross course. These are statistically-sound results; your results may vary.
Time differential between shaved/heat cycled @ and full tread depth/heat cycled is 0.5-0.6 seconds on a typical 35-38 sec autocross course. These are statistically-sound results; your results may vary.
Now the Kumho's are a different beast all together. I have no experience with them, but I have seen them wear significantly quicker on the track than the Michelin's, the Pirelli's (P-0C), and other 'brand name' tires. I am not a big fan of the Kumho R-compound tires. Sure, they are 1/2 price compared to the 'better' tires, but they wear twice as fast!
Z, E-mail me?
12-04-2003, 11:38 AM
#9
Race Director
Originally posted by Dave
I would not consider 0.6 seconds an insignificant change, I know a guy who lost an event by 0.006 seconds. I bet shaved tires would have made a big difference to him!
I would not consider 0.6 seconds an insignificant change, I know a guy who lost an event by 0.006 seconds. I bet shaved tires would have made a big difference to him!
Posted by Dave:
When/if I go to Hoosiers...
When/if I go to Hoosiers...
Dave:
Z, E-mail me?
Z, E-mail me?
-Z-man.
12-04-2003, 12:37 PM
#11
Race Director
Originally posted by Dave
I would not consider 0.6 seconds an insignificant change, I know a guy who lost an event by 0.006 seconds. I bet shaved tires would have made a big difference to him!
I would not consider 0.6 seconds an insignificant change, I know a guy who lost an event by 0.006 seconds. I bet shaved tires would have made a big difference to him!
But he's been a no-show this whole season! Where are you Phil!?!? -Z.