Heat cycle Falken Azenis RT-660 tires for max performance | Project Toyota MR2 Turbo

J.G.
Update by J.G. Pasterjak to the Toyota MR2 Turbo project car
Jun 16, 2022

Photography Credit: J.G. Pasterjak

Before we could test some tires on our Toyota MR2–we’re looking to maximize performance under some NASA TT regs–we had to do some prep work.

First, we rolled the fenders a tad so we could fit the largest tires possible inside the stock fenders. Read about that step here.

Once we got those 235/40R17 and 255/40R17 tires mounted on 8- and 9.5-inch wide König wheels front and rear, respectively, we headed to our official test track at the Florida International Rally and Motorsport Park to make sure we were rub-free.

We’d also scrub in the two sets of tires that we’d be comparing.


[Ultimate track tire guide | 200tw, 100tw, street-legal track and R-comps]

Both our Toyo Proxes RRs and Falken Azenis RT660s fit fine–one very superficial rubbing occurred on plastic fender liners and only in the most extreme situations–so we ran a couple sessions on each set to give them a proper heat cycle before coming back later for our actual testing.

Our tire tester extraordinaire, Andy Hollis, has been waving the flag of proper heat cycling forever, and we’re believers, but this exercise was a real slap-in-the-face lesson in proper tire treatment for best performance.

Notably, the Falken Azenis RT660s felt sluggish right out of the box. On our first few laps, we found ourselves thinking, “these don’t seem as sharp or grippy as other RT660s we’ve driven.” (Spoiler alert: The Falkens felt transformed during the follow-up testing: crisp, grippy and sharp with communicative transitions.)

So, yeah, heat cycling is a big deal and should be done on every set of new tires, although different models will benefit more or less from a true heat cycle.

[How to manage tire temperatures for improved on-track performance]

When we talk about a heat cycle, what me mean is bringing the entire tire up to operating temperature, then allowing it to cool back to ambient temperature at a slow, steady rate.

Like any material, the rubber in tires has a cellular structure that becomes excited under heat and force. A proper heat cycle can better align that cellular structure in a more uniform way, helping the tire better resist wear while also generating more grip.

But the key concepts there are thorough dynamic heating of the entire structure and controlled cooling. Heating just the tread surface, or static heating through the use of tire warmers, while better than simply doing nothing, doesn’t really provide the dynamic forces necessary to stretch, pull and knead the granular structure into better order.

And cooling too quickly could also cool different parts of the tire at different rates, meaning those cellular bonds within the rubber could become inconsistent. Best practice is to allow the tires to cool at ambient temperature for at least 24 hours, then consider them fully heat cycled.

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APEowner
APEowner GRM+ Memberand SuperDork
6/10/22 1:00 p.m.

I've never heat cycled tires before but with the higher cost of the 660s over the previous tire and their habit of delaminating when abused I'm going to start doing that. 

The challenge is that it's going to require more tire swaps and tire management than I've done in the past.  I've always just stuck a set on, run them till they were worn out and slapped the next set on. Now I'm going to have to either schedule tire scrubbing time at the track or scrub tires during one of the practice sessions on a race weekend.

I suppose I could scrub tires during worker rides.

JG Pasterjak
JG Pasterjak Production/Art Director
6/15/22 3:17 p.m.
APEowner said:

I've never heat cycled tires before but with the higher cost of the 660s over the previous tire and their habit of delaminating when abused I'm going to start doing that. 

The challenge is that it's going to require more tire swaps and tire management than I've done in the past.  I've always just stuck a set on, run them till they were worn out and slapped the next set on. Now I'm going to have to either schedule tire scrubbing time at the track or scrub tires during one of the practice sessions on a race weekend.

I suppose I could scrub tires during worker rides.

Admittedly I'm not always great about heat cycling, either. But Andy Hollis has been beating the RT660 heat cycle drum forever and we finally got a chance to put data on his pestering and darned if he wasn't right all along (no surprise there, I suppose). 

APEowner
APEowner GRM+ Memberand SuperDork
6/15/22 6:42 p.m.
JG Pasterjak said:
APEowner said:

I've never heat cycled tires before but with the higher cost of the 660s over the previous tire and their habit of delaminating when abused I'm going to start doing that. 

The challenge is that it's going to require more tire swaps and tire management than I've done in the past.  I've always just stuck a set on, run them till they were worn out and slapped the next set on. Now I'm going to have to either schedule tire scrubbing time at the track or scrub tires during one of the practice sessions on a race weekend.

I suppose I could scrub tires during worker rides.

Admittedly I'm not always great about heat cycling, either. But Andy Hollis has been beating the RT660 heat cycle drum forever and we finally got a chance to put data on his pestering and darned if he wasn't right all along (no surprise there, I suppose). 

I've suspected that they'd benefit from it and I guess it's good to have the data to confirm it but I still don't like it. Reality has a way of being reality whether I like it or not.

hunter47
hunter47 Reader
6/15/22 7:38 p.m.

I've "heat cycled" my RT660s by just driving on them from home to event. 

I can't do that nowadays since I don't have space to swap tires at the apartment, but it's something that was recommended to me. 

V2U_03
V2U_03 GRM+ Memberand New Reader
6/15/22 8:53 p.m.

Heat em up...let 'em cool for 24hrs! Got it! Wait...I paid $375 for this track day. What am I supposed to do for the rest of the sessions? Maybe I'll just run my old set because I always buy new track tires when I already have a perfectly good set.

Ha! This is obviously intended for a more sophisticated, better funded track rat than I! Goals!

JG Pasterjak
JG Pasterjak Production/Art Director
6/15/22 10:44 p.m.
V2U_03 said:

Heat em up...let 'em cool for 24hrs! Got it! Wait...I paid $375 for this track day. What am I supposed to do for the rest of the sessions? Maybe I'll just run my old set because I always buy new track tires when I already have a perfectly good set.

Ha! This is obviously intended for a more sophisticated, better funded track rat than I! Goals!

Yeah, the struggle is real. Even while we may admittedly have access to some resources that some folks don't, this can even be a complex proposition for us at times. I actually have an email into Falken addressing some of these exact complications, namely, just how hard do you have to stress the tire to produce an adequate heat cycle. 

Like, bedding in brake pads is fairly doable on a lightly traveled public road or abandoned parking lot without attracting too much attention or doing anything blatantly illegal. But can the same be said for tire heat cycling? I'd love a real answer to that because even though track time is more accessible and affordable than ever, it's still not exactly easy for some folks driving their tires to the track to just run them for a single break in session then swap to somethign else for the day.

So, yeah. We feel you on this and we're working on answers to improve everyone's expeience.

mhaskins
mhaskins
6/16/22 1:14 a.m.

Trying out my first set of rt660s currently and tried to heat cycle them on some roads near me before my first track day on them. Don't think I was able to get enough heat through them beforehand and lost an impressive amount of tread the first day with some minor delamination occurring when they got hot and started throwing pieces everywhere. Backed it down to about 60%, swapped front to rear, and things improved. If I get another set in the future I'll definitely be heat cycling. 

slowTA
slowTA New Reader
6/16/22 11:43 a.m.

How many questions is the Tire Rack going to get about heat cycling RT660s?

 

The answer is, yes.  

hunter47
hunter47 Reader
6/16/22 11:50 a.m.

In reply to mhaskins :

That's interesting, I haven't actually properly heat cycled my RT660s but they've held up just fine. When they were new, I drove them straight to an event, ran them, and drove home, and didn't see anything excessive. Do you have pictures of this minor delamination? 

Andy Hollis
Andy Hollis
6/17/22 10:10 p.m.

Guess what I did yesterday?  Went to the track and heat cycled a set of RT660's for an upcoming tire test comparo.  :)

 

Andy Hollis
Andy Hollis
6/17/22 10:13 p.m.

In reply to hunter47 :

This is typical of hammering on RT660's w/o a heat cycle...

No photo description available.

 

Andy Hollis
Andy Hollis
6/17/22 10:16 p.m.

In reply to slowTA :

Tire Rack will merely refer folks to this tech bulletin on their site: https://www.tirerack.com/tires/tiretech/techpage.jsp?techid=66

te72
te72 Reader
6/21/22 12:33 a.m.

I had Tire Rack heat cycle the last set of R888R's I bought, I'll have them heat cycle the RT660's I have my eye on for the next Exocet tire. I'm one of those people without access to anything resembling a facility to do this sort of thing myself. Even bedding in brake pads is difficult around here, legally.

dps214
dps214 Dork
6/21/22 8:48 a.m.

So far it looks like our heat cycle by aggressive street driving has worked out. Our first set was heat cycled by just taking them straight to autocross events, but in early season cold weather such that I think we did the first three events without ever getting them fully hot. Something we've noticed that might support shaving as well is that the tire seems to behave a bit different at full tread. Our 200 run old tires have definitely lost a bit of peak grip and pace, but the limit of grip seems to be a bit less harsh and the "over the limit" grip seems to be about the same as the new tires. Which all results in the older tires being a bit easier and more forgiving to drive. Not sure if that's something about the extra tread squirm from the extra depth, or something about the compound breaking in. But those 200 run probably just about heat cycled out tires are still above the wear bars, so new ones could probably have 2/32" shaved off of them and still run out of heat cycles before they cord.

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