Yokohama AO32R grip

[greg schroeder]

Does anyone have experience with the tires. I just put on a set of new 17s and Yokohama AO32R soft compound tires on my Cobra. Do they get more grip once they get hot? I'm concerned they won't have enough traction for acceleration at a club track day coming up. My rear tires are 315/35s

[JCoop]

Greg,
Like any soft compound racing tire, you'll have to heat cycle them, not only for traction but for longevity. An often-made mistake is to heat up the tires but not allowing them enough time to "relax". This must be done for a minimum of 24 hrs after the initial scrubbing or heat cycling of the set. Many folks will waste a good set and be unhappy with subsequent performance because they didn't want to waste the track time. A way around this of course is to scrub the tires, take them off, put on another set. Usually with new tires, you really waste the first day heat cycling your tires. It's worth it though, better than having squirelly tires for the rest of the season.

A summary and easy on-street alternative: (direct quote from tirecradle.com)

Heat Cycling (breaking in) New Tires
New tires are expensive and new performance tires are very expensive. As such, we thought that we would mention the correct way to ‘heat cycle’ your tires for both longer life and, more importantly, better traction over the lifetime of your tires.

When you buy new tires you should heat cycle them to insure long life and optimum traction. Heat cycling is quite simple and is imperative for performance tires but few have heard of this process yet alone know how to do it.

To heat cycle your tires you should do the following: Drive your car at about 55 to 65 mph for about 10 miles. Then drive the car slowly to let the tires cool for about 2 or 3 miles. At this point the car should be parked and the tires should be allowed to fully cool uniformly. Uniform cooling will require you to either jack the car up off of the ground or to use Tirecradles. If you cannot jack the car up off of the ground and if you do not have Tirecradles, then try to park the car on grass. The thing that you do not want to do is to park the car on concrete as this may cause a ‘cold set’ to occur at the site of the contact patch. This will result in a spot that will always be a little harder than the rest of the tire. All tires have a certain number of ‘heat cycles’ in their life; that is, before they become hard. Correctly heat cycling your tires the first time will greatly extend the useful life of your tires.

Having said this there is one caveat; heat cycling can only be effectively done in non-winter months in order for the tires to build the necessary heat. As such, try to avoid buying new tires in the winter.

Here's a good read: http://www.porschenet.com/bfgtires.html

Note they all say you MUST let the tires relax off the car. Like any workout regimen, the most important part of the strength-building process is the rest period...

[Igofastr]

Might I add that some companies (Tire Rack, for example) will heat cycle your tires for you at the time of purchase. I think TR charges an additional $15 each, but don't hold me to that.

[Chilibit]

I am guessing that the heat cycling has ONLY to do with heat and not any other scrubbing action. Can it be done with warmers or an oven? How does Tirerack do this? They must just heat them. How hot? Tub of 150 degree water? Why are they not shipped from the manufacturer heat cycled?

Ciao,

Chilibit

[JCoop]

Originally Posted by Chilibit

I am guessing that the heat cycling has ONLY to do with heat and not any other scrubbing action. Can it be done with warmers or an oven? How does Tirerack do this? They must just heat them. How hot? Tub of 150 degree water? Why are they not shipped from the manufacturer heat cycled?

Ciao,

Chilibit

Nope, there is a specific pattern of fitting tires to wheels and then wheels to car (different for FWD and RWD), see:
http://rogerkrausracing.com/fit.html
...and scrubbing is loosely used to actually mean the same thing as heat cycling. The heat cycling breaks the bonds of unevenly aligned and weaker molecules of rubber and the secret of heat cycling is actually the rest period or relaxing, because the molecules rebuild and realign, but in a more uniform pattern that could be unique to the car's weight and suspension geometry (don't quote me on that one) But theoretically, a counterclockwise track with a lot of LH sweepers will break the molecules more on the outside of the rf and rr tires, and on th insides of the lf and lr tires. In effect, after relaxing, the properly heat-cycled tires will have stronger sidewalls where you need them. The heat cycling that tirerack or discount tire does really isn't good enough IMHO. I believe they do it on a balancing machine that has another roller that applies force and pressure on the treads of the tire as they spin it for 15 mins., not enough time and lacking in diagonal and stop/go forces like in a couple of laps around the track.
Manufacturers don't heat-cycle the tires because of the time it involves. That would jack up the prices of the tires to unmarketable levels.

[Chilibit]

Much more to it than I appreciated. Thanks for the insights.

Chilibit

[MistressMotorsports]

The above being said, virtually no one (in fact actually no one) that I know takes their tires off the rims to relax them. At most, we heat cycle them once, then let them sit on the rims for 24 hours or more when possible. For 99 percent of weekend track junkies, this is just fine. You may even find that A032's, being really "tweener" tires (not as sticky as most R compounds, but stickier than regular street tires) are fine without heat cycling.

To answer your orginal question, the A032's will be better than a regular street tire once they have some heat in them. They will not be as good as some of the really trick R compounds. For a weekend club event, many people find them a good compromise. You can drive them to the track (you can't really do that with a Hoosier) and still have decent traction.

Mike

[greg schroeder]

The tires were driven to the track. When I arrived they were about 80F. I took them out on the track and got them up to about 110F, given the temp gun use after cruising in a ways to the pit area. I don't have one of the poker type temp testers.

I let the car sit about an hour and tires went down to about 60F. I used them one more time. They're stickier hot for certain. I didn't have enough balls to hit the corners any harder than I was given the walls, piles of hay bails and big rocks outside of just about every corner.

I did have fun in the 5/8 mile straight. Top of 4th gear was about 140 mph about half way down that, then I coasted as I didn't see the point of hitting 5th and having the car blow off the road.