New SEDiv SCCA Class - Spec Miata Toyo

Best tire for spec Miata would be a Dunlop direzza star spec. 80$ and last forever

I think they're really like $120 but I'm 100% on board 

Just to answer the question about regional shaving.  As far as I know no one shaves tires in Utah NASA SM for our normal seasonal racing (there is no "regional" distinction of course.)   People definitely shaved tires for Nationals in 2013 (out of state people coming in) when it ran here and I imagine will shave again for 2020 at Nats when it returns to Utah Motorsports Campus (yeah an early plug to get people out here.  We'll have the Outerloop in March and Aug (including the 6-hour enduro if you want to really learn the track before Nats in Sep.)

But I also think it is important to point out that the difference between a shaved RR and unshaved that is at the optimal heat cycle is tenths, whereas the RA-1 was seconds.  (At least at our track.)   I think this is a salient point for regional racing.   You had to shave the RA-1 if you wanted to be at the front.    For regional racing, I don't think that's really the case for the RR.   There are too many other factors.   Might not hold true for the larger and more competitive regions, but like people have been saying, it sort of defeats the purpose of the class and if that is what you want, stay on the Hoosiers and run HST etc.

Someone needs to ask the question. What weight is removed oz. or lb. and what is the diameter reduction?  Is it the reduced weight, the smaller diameter tire or the new surface from shaving the tire where the lap time gain comes from. Me   JD2, clear enough? 

Well guys, you should step up and get it started. No, I’m not kidding. Get a group together willing to do a series of regional races and document what you learn. Shave them to several different depths and collect data. As Jim C. and numerous others before him have demonstrated, stop complaining, stop asking, start doing. I’m not even racing currently but I’ll commit to a modest financial contribution and volunteer to set up and manage a fund from others willing to support a genuine effort to come up with a better alternative.

I've had a conversation with a few guys locally... could be a fun experiment. Already running NASA and Toyos i don't think people would be quite as in for experimenting (Most are quite happy with Toyo wear) but hell, I'd try it. I wouldn't mind one more excuse why I'm not at the pointy end of the field. 

 

But I also think it is important to point out that the difference between a shaved RR and unshaved that is at the optimal heat cycle is tenths, whereas the RA-1 was seconds.  

Yeah, I'd venture that most of the shave advantage for RA1 was because of squirm with treaded tire vs non treaded.... Can't imagine the RR shave advantage is as much except for those few freak tracks that love an old, thin tire... but even then still not as much.  

IIRC, at the TOYO national championships at Watkins Glen, (before the mandated non-shaved marked tires at COTA), I believe P1 and P2 were on shaved Toyo RR's. I was not. I was not too far off the pace, but I was definitely hanging on for 3rd and not a contender for the win. Not sure that you can infer anything from this N-of-1 data point, but it is worth noting. Not sure what was used at the 2019 NASA Champs at Mid Ohio, but my guess was the tires were really thin (shaved or not shaved). 

Are they prone to graining at any particular tracks or under particular conditions?

At full thick they grain at Mid-O

At full thick they grain at Mid-O

They will grain at half thickness at mid Ohio they will grain at 1/32 at mid Ohio if they are new rubber...

They can be shaved by shaving or driving them hard at another abrasive track hard. In the north take them to Putnam or gingerman for a day.

true, 
I destroyed new 1/32 shaves in one session. 
 
 
 

IIRC, at the TOYO national championships at Watkins Glen, (before the mandated non-shaved marked tires at COTA), I believe P1 and P2 were on shaved Toyo RR's. I was not. I was not too far off the pace, but I was definitely hanging on for 3rd and not a contender for the win. Not sure that you can infer anything from this N-of-1 data point, but it is worth noting. Not sure what was used at the 2019 NASA Champs at Mid Ohio, but my guess was the tires were really thin (shaved or not shaved).

 
 I used tires I got from Chris Haldeman that were shaved for Cota Champs in 18, had 3-4 sessions on them by the time I raced /qualified them

"One of the reasons radial racing slicks are so effective is they feature shallow tread depths, and their contact patch acts as a single unit. However, any tread design that breaks up the contact patch into smaller elements or adds additional tread depth (required to enhance wet traction) will increase tread block squirm and reduce dry performance. This means that tires typically provide their worst wet traction and their best dry performance just before they wear out. It's also important to remember that the heat generated every time a tire is driven activates bonding agents in the rubber. As this process is repeated continually throughout the tire's life, its rubber compounds gradually harden and lose flexibility, reducing the tire's grip. Therefore, a shaved new tire will provide more traction than a tire worn to the exact same tread depth after being driven for thousands of miles on the road.

Tire shaving is an effective means of permitting more of a tire's performance capability to be realized early in its life. And in many cases, shaved tires used in competition actually have a longer useful life than tires that enter competition at full tread depth.

The process removes tread rubber and reduces tire weight by several pounds. A shaved tire's tread profile will usually result in a slight increase in the width of the tire's contact patch, putting a little more rubber on the road. The resulting shallower tread depths reduce the tire's slip angle, increasing its responsiveness and cornering power by minimizing tread block squirm.

Minimizing tread block squirm also reduces heat buildup and the risk of making the tire go "off" by overheating its tread compound. Depending on the severity of overheating, the overworked areas of the tread compound may turn blue, tear, blister or chunk.

So with all of these benefits, the next important questions are: "Which tires need to be shaved?" and "How far should they be shaved?"

Me believes there's more ^ than diameter and weight.

Come on guys, how about some facts to go with the shaving hype. Not saying shaves not faster times, but without facts, it's leaves a lingering question.

Diameter pre shave?

Diameter post shave?

Weight pre shave?

Weight post shave?

"One of the reasons radial racing slicks are so effective is they feature shallow tread depths, and their contact patch acts as a single unit. However, any tread design that breaks up the contact patch into smaller elements or adds additional tread depth (required to enhance wet traction) will increase tread block squirm and reduce dry performance. This means that tires typically provide their worst wet traction and their best dry performance just before they wear out. It's also important to remember that the heat generated every time a tire is driven activates bonding agents in the rubber. As this process is repeated continually throughout the tire's life, its rubber compounds gradually harden and lose flexibility, reducing the tire's grip. Therefore, a shaved new tire will provide more traction than a tire worn to the exact same tread depth after being driven for thousands of miles on the road.

 

Tire shaving is an effective means of permitting more of a tire's performance capability to be realized early in its life. And in many cases, shaved tires used in competition actually have a longer useful life than tires that enter competition at full tread depth.

 

The process removes tread rubber and reduces tire weight by several pounds. A shaved tire's tread profile will usually result in a slight increase in the width of the tire's contact patch, putting a little more rubber on the road. The resulting shallower tread depths reduce the tire's slip angle, increasing its responsiveness and cornering power by minimizing tread block squirm.

 

Minimizing tread block squirm also reduces heat buildup and the risk of making the tire go "off" by overheating its tread compound. Depending on the severity of overheating, the overworked areas of the tread compound may turn blue, tear, blister or chunk.

So with all of these benefits, the next important questions are: "Which tires need to be shaved?" and "How far should they be shaved?"

 

Me believes there's more ^ than diameter and weight.

 

Come on guys, how about some facts to go with the shaving hype. Not saying shaves not faster times, but without facts, it's leaves a lingering question.

 

Diameter pre shave?

Diameter post shave?

Weight pre shave?

Weight post shave?

To be clear, hopefully everyone knows that the RR has two grooves in it... not a full tread like RA1. The context of the above passage sounds like it was written about a fully treaded tire. Correct me if I'm wrong but the RR and it's two minor grooves doesn't suffer from much "Squirm" at full depth... hence a much smaller advantage with shaving than back in the RA1 times. 

To be clear, hopefully everyone knows that the RR has two grooves in it... not a full tread like RA1. The context of the above passage sounds like it was written about a fully treaded tire. Correct me if I'm wrong but the RR and it's two minor grooves doesn't suffer from much "Squirm" at full depth... hence a much smaller advantage with shaving than back in the RA1 times. 

Jim, not saying you, but a truth of sentencing people should provide some weight and diameter facts. BUT, those in the know ain't talking facts. There's more to the story.

To be clear, hopefully everyone knows that the RR has two grooves in it... not a full tread like RA1. The context of the above passage sounds like it was written about a fully treaded tire. Correct me if I'm wrong but the RR and it's two minor grooves doesn't suffer from much "Squirm" at full depth... hence a much smaller advantage with shaving than back in the RA1 times. 

in general i agree with this statement, but at mid ohio the tread squirm is what causes the graining IMO.  this happens it seems no matter shaved or not till the rubber is hardened a bit from a few heat cycles.  I am no tire engineer but it sure feels from the seat that the tire is squirming when new at mid ohio, have not felt that other places like i do there.

Jim, not saying you, but a truth of sentencing people should provide some weight and diameter facts. BUT, those in the know ain't talking facts. There's more to the story.

I have not weighed tires in years.. nor do I care to. From memory it was about 2 lbs.  Same goes for diameter and circumference don't really care..

I shave to 2/32 for a big race, that allows me to get them as light as possible and still have 5-6 sessions of life out of them. What it saves really doesn't matter to me as that is a level I am comfortable shaving to for a race tire.  Most I shave to 3/32.   A 1/32 is not worth it to "me" as after shaving the tire it generally takes a session to true them on track.  1/32 would be a 1 session tire IMO. 

What are "sentencing people"?

Is that the same as a jury of my peers?

What are "sentencing people"?

 

Is that the same as a jury of my peers?

I assumed that was me.. When in doubt, it is either me, you or Scheifller