Veloce Raptor

The 888's and the NT01's really seem to like 2-3 lbs less pressure than the RA1's did.

Ritter v4.0

Could be you- not the tires. Do a blind test. Have someone change the tire pressures and not tell you the settings- go and run and see what is quickest.

boss351

Can you explain to a noob about heat cycling effecting the wear? I have seen it offered (with shaving) from places like tirerack and wonderred about it.

todinlaw

That is a controversial as I cannot find anywhere that Toyo recommends that the tire be heat cycled. Some people say it is unnecessary. Others, applying what is recommended for the R6 say that if you do, it would increase the tire life, but rubber compounds are unique to each other, and so far, I cannot find anything that supports it one way or the other on the 888. Just my 8 cents.

boss351

Sorry this thread is getting minorly hijacked but is the intention of the heat cyle to harden the soft compound up? Thats the only answer that seems to make sense to me in getting better wear out of a tyre but then wouldn't you be giving up grip at the same time?

TRAKCAR

I did a lot of trying with the R888's last weekend.

I started out with real 24PSI all around, 20-21PSI on the display, the tires got good as soon as the display hits about 26-27PSI in the second lap, so I assume that my real pressure is about 30PSI at that point.

Than the tires stayed good untill the display started to show 31PSI so again assuming I hit real 35PSI in the rear while the fronts stayed feeling good as they stopped going up at at about 29PSI( Again on the display, so +/- 33PSI ) As soon as the rears hit 32PSI on the display the grip goes away fast.

I hit up to 34PSI on the display in the rear, after a cool down lap they still showed 33PSI and the actual PSI was 38-39.

During the day I let out 2 PSI twice! Once leaving at real 22PSI and they took one lap longer to get there, but than the rears never went over real 34PSI and they stayed grippy till the session ended after 25mins, about 11 laps.

Unlike the RA1's as soon as they are slicks all grip is gine and they will cord in 2-3 sessions.

Bull

Here is the thought behind heat cycling tires, as described by Tire Rack (who also sells the service). I do not endorse nor deny the ideas presented here, I am just reporting it:

From Tire Rack's website:

"The first time a competition tire is used is the most important. During that run, its tread compound is stretched, some of the weaker bonds between the rubber molecules will be broken (which generates some of the heat). If the tires are initially run too hard or too long, some of the stronger bonds will also be broken which will reduces the tire's grip and wear qualities. Running new tires through an easy heat cycle first, and allowing them to relax allows the rubber bonds to relink in a more uniform manner than they were originally manufactured. It actually makes them more consistent in strength and more resistant to losing their strength the next time they are used. An important heat cycling step is that after being brought up to temperature, the tires require a minimum of 24 to 48 hours to relax and reform the bonds between their rubber molecules.

Looking at the heat cycling system, it positions a mounted and inflated tire between rollers which apply pressure while the tire is rolled up to speed. It is very important to note that this allows heat to be generated as a result of deflecting (stretching) the tire within its normal operating range. There is no "artificial" heat added (no oven, no forced air, etc). Then they receive the stamp showing they are Tire Rack heat cycled.

Measuring the tread temperatures with a tire pyrometer we confirmed that in our controlled environment we were able to achieve appropriate and more consistent temperatures across the tire's tread without causing treadwear. All of these are significant improvements over heat cycling tires on our test track. And the 24 to 48 hour waiting period efficiently occurs while the tires are in transit to you. That means the tires are ready to use when they arrive!

The cost of heat cycling is $15 per tire. Avon, Hoosier, Kumho and Yokohama all recommend that their competition tires be "heat cycled" before being run in competition".

boss351

Thanks, no mention of Toyo in there.. Interesting.

todinlaw

Exactly, now to the next question, can it hurt? No, I heat cycle mine, but for those who have told me they don't recommend it. I can't argue. A few weeks ago someone posted a link to a toyo web cite that had tons of information about competition tires. this was part of it:


Getting More out of Competition Tires
When developing your vehicle's handling, maximize your:
Wheels - Always use the widest wheel allowed on your car's class, that fits your car
and/or is recommended by the tire manufacturer for your tire size.
Alignment-Springs and Sway Bars - Keep our tires perpendicular in corners, try to
achieve neutral steer (With power oversteer for rear wheel drive cars)
Shock Absorbers - Can help tune transitional handling
Inflation Pressures - Always use the lowest pressure possible, while higher inflation
pressures may enhance responsiveness, they sacrifice traction. If uneven wear begins
while at low pressures, increase them.
Tire Tips
Between races, never store tires exposed to the elements on your race car trailer's tire rack
or outside your shop, store them in a cool, dry place away from electric motors.
Immediately after every track session, remove debris and inspect your tires for damage
and wear. If possible, let them cool while they are off the ground
Your tire's tread temperatures as read by a pyrometer will "never" be even across your
tire's tread (Unless you have just completed a successful tuning session on a skid pad.)
Tire pressure increases 1 psi for every 10 degrees in ambient temperature
Shade pairs of tires from direct sunlight between sessions as much as possible. The sun's
heat will raise your tire's pressure.
Autocross inflation pressures should be adjusted warm, road racing inflation pressures
should be adjusted hot.
For racing or track events, your rain tire's starting inflation pressure should be higher than
your dry tires.
Tires are part of your suspension, using lower profile tires is like using shorter, stiffer
springs.

Dr911

In searching for guidelines to correctly break in R888s, I found this old thread.
I missed the chance to get heat cycling at the time of purchase.

Driving an old stock g series 911, DE only, and from reading this thread here's what I've surmised so far:

1. take it for a long drive (200+miles) and build up tire temp gradually
2. use road/tire feel or a pyrometer to get temp up over 180F
3. let tires cool 24+hours
4. they are ready and "cured" for track
5. get alignment checked, adj camber/casters

Is there anything I'm missing from the procedure?

sbelles

Did you get them shaved? If not they will be a little squirrely and slower the first session or two no matter how many street miles you put on.

Dr911

Did not get them shaved...Thank you for the heads up.
Otherwise, I'll proceed per my 4 step list below.
Thx!
A.