72 replies to this topic

[John Costello]

I think despite the fact that we all complain( myself included), none of like the costs involved. I think this Spec class got it pretty close to right and gets better every year. Sure things could be different, but not sure different is better either? The tighter we make the rules and the competition, the more small and expensive gains will show up.

I think Jim is on the money here! SM does have it right. That is what attracted me to SM. I have raced successfully in another SCCA class and spent 10x more money in that class on both the car and development of the car. I am very skepticle if shaving this tire will really make a difference(not that I know anything). Racing is not cheap on any level, but SM seems to have the costs contained the best of any class.

[Doug007]

Doug, if you could run wheels that were 1 lb plus lighter legally, would you? Well a 1 lb lighter tire is better than that The more testing done, the faster shaved Hoosiers will be IMO.. Especially at Road America when a few tenths separates most over 4 miles.

I understand what you're saying about unsprung weight, I'm just not convinced that shaved tires will be faster than unshaved stickers. In other racing series in which I have friends that race R6s, the consensus over many years of racing is that stickers are the fastest and I never heard of people shaving them. SMers maybe a bit crazier than the PCA club racers I know but seems like folks would do it if it really yielded a significant improvement.

Hoosiers performance seems to be very heat cycle driven and from what I've heard, the first is the best. Dave's testing seems to be consistent with what I've seen/heard. Maybe the heat put into the tire during shaving (locally at the tread level) puts an equivalent heat cycle in them? Only testing will tell.

That said, running sticker Hoosiers all the time will be a LOT more expensive than the cost of shaving. People running 3-4 heat cycles and dumping the tires will be the $$$ driver IMO.

I'd be interested to see the results of more testing on SMs...

[guest driver]

I wouldn't know what questions to ask, so any more detailed info Hoosier can provide is welcome.

That stated, some things I have been wondering about are as follows:

• Most people that I have spoken with regarding curing say that they have not noticed a difference in performance or longevity with cured vs. non-cured tires. Why is that?
• Those same people state that there is a big (1-2 seconds) drop off in performance after the first few heat cycles. What are the realities in performance drop off over heat cycles?
• What changes to driving style are we expected to make going from RA1 to SM6?
• What are the breakaway characteristics like? Most slicks are rather abrupt.
• How does ambient and track temps affect pressures?
• What are the desired cross carcass hot temps?
  
  http://www.hoosierti...m/specmiata.htm
• From Hoosier's web site, what does the "Spring Rate Information" diagram mean with regards to "Vertical Spring Rate vs. Load" at different temps?
• Does 0 toe refer to front AND rear?

Thanks.

back to the original subject;
after the 2 Florida Double National events with at least 100 sets utilized (multiple heat cylcles each), some shaved, most not, it would be very helpful to most everyone if someone qualified would objectively answer the above questions.
Seems illogical SCCA has not required the new spec tire company, nor Hoosier has not provided an experienced tire engineer on this spec miata board to answer the above questions as well as any others.
Was there a Hoosier tire engineer present at Sebring or Homestead? helping take and interpret tire temps and set ups?
This would provide a great service to the 90% of SM racers through out the land that are not familiar with this new tire manufacturer brand and specific race tire .
just sayin ...

[James York]

back to the original subject;
after the 2 Florida Double National events with at least 100 sets utilized (multiple heat cylcles each), some shaved, most not, it would be very helpful to most everyone if someone qualified would objectively answer the above questions.
Seems illogical SCCA has not required the new spec tire company, nor Hoosier has not provided an experienced tire engineer on this spec miata board to answer the above questions as well as any others.
Was there a Hoosier tire engineer present at Sebring or Homestead? helping take and interpret tire temps and set ups?
This would provide a great service to the 90% of SM racers through out the land that are not familiar with this new tire manufacturer brand and specific race tire .
just sayin ...

I am just happy we will have a truck/vendor supplying Hoosiers trackside compared to what TOYO did for us. Plus the R-888 fiasco.

[granracing]

Seems illogical SCCA has not required the new spec tire company, nor Hoosier has not provided an experienced tire engineer on this spec miata board to answer the above questions as well as any others.

This is a big part of the reason why I posted this thread. Not having the above posted questions answered yet is my fault. I wanted to see what other questions may come up. I'll post their answers shortly.

I've been running Hoosiers for several years now and can say they are a fantastic tire company to deal with. I tried Hankooks which honestly, were good tires and had a nice contingency program at the time. As Phil will tell you, the supply issues became too much to deal with. "Tires are on a boat but we're not sure exactly when they'll arrive."

While I'm trying to put together a "FAQ and Questions" section, people should feel like they can call Hoosier directly with any questions. It's awesome to call the headquarters phone number, ask to speak with a tech guy, and have them be happy that you're calling. I never received that when I ran Toyos.

[Bench Racer]

A simple rule addition requiring anyone that wants a points position finish SHALL start the race on stickers that have been checked at grid with no grid tire changes allowed.

Want to spend money, knock yourself out, ya all brought it on yourselves with your Hoosier tire shaving.

There is another process except that it would burden every driver at every race.

[granracing]

I'm still not sure if stickers are the way to go for a longer sprint race (30 plus minutes) versus properly heat cycled tires.

[Rob Burgoon]

Maybe the next 'spec' class can get it right.

It's a cycle. Class starts out fun and casual, then it gets popular, and then is suddenly all too serious.

Here's a rant I posted on a another forum about a new local miata time trial series when someone said how fun and casual it was being new:

"That's simply because it's not a competitive series yet. The same thing has probably happened with every wildly successful SCCA class. That's how SM used to be, e30 still is, and probably how showroom stock was a long time ago. I think I was just reading about Trans-Am being that way years ago.

As soon as you get enough people with motivation and egos to show up, the run what you brung fun will change into something much more serious.

If the series shot the moon, add every single spec miata "enhancement" to that list, including pro engines.

Will this happen? No. You can measure any class on a scale from fun to hardcore. This event is parked solidly at the bottom with MC a few notches more serious (maybe another notch for unlimited).

Lemons was an attempt to lock the scale on fun at the bottom, but even that failed. People that want to win just keep showing up...

Is this a problem? No, not really. If you're having fun, that's usually all that matters.

However, I'll still make snarky remarks about the ruleset since it's pretty imbalanced."

[Cy Peake]

My understanding is that the Hoosier R6 is a different tire than the SM6 so I can't validate comparisons between the two of them. And then there's the @$55 difference in price...

[granracing]

It's the same tire. The pricing difference was related to the spec tire deal made with SCCA and other oganizations. There's been a SM tire available at a discounted rate for at least a few years.

[granracing]

Here's information from Jeff over at Hoosier:

• Most people that I have spoken with regarding curing say that they have not noticed a difference in performance or longevity with cured vs. non-cured tires. Why is that?

Because the SM6 has a reduced tread depth and high traction tread compound, heat cycling the tire will extend the life (tire wear) and performance of the tire. I would believe with a lightweight / low horsepower vehicle there may be no difference in time between the first session of a new tire and the second session of a heat cycled tires, but not bedding in or heat cycling a tire will shorten the life of the tire on the back end.

My note: I’ve seen a fairly substantial difference in longevity between properly heat cycled tires (the properly aspect is important) versus running sticker tires. I did a crude experiment with running sticker tires and comparing it to ones heat cycled. http://www.goaheadta...saving-process/

• Those same people state that there is a big (1-2 seconds) drop off in performance after the first few heat cycles. What are the realities in performance drop off over heat cycles?

Honestly, I think there is something else going on or the drivers who see this drop off may have not heat cycled the SM6. A heat cycled SM6 will offer consistency of lap times over a period of track sessions compared to running on a new set of SM6’s. As we started the 2012 season in Florida, we had several SM weekend winners win on multiple track session tires.

• What changes to driving style are we expected to make going from RA1 to SM6?

I feel the SM6 could accept or handle aggressive driving styles like sliding, high steering input, heavy braking, however you will find a less aggressive driving input will results in faster lap times. Running higher air pressures, rotating the tires around the car and eventually flipping the tires on the rim(non-directional) will result in faster lap times and extended tire life.

My note: When I transitioned from Toyos to Hoosiers, my biggest challenge was getting used to the extra grip and trusting it would be there. I didn’t feel that a different driving style was necessary.

• What are the breakaway characteristics like? Most slicks are rather abrupt.

The SM6 internal design is much different than our current GT slick tire which should allow a bigger window of forgiveness when the tire is overdriven. The SM6 tire gives the driver several indications before actually losing total grip.

My note: I think one aspect some might need to get accustomed to is not relying on the tire noise for feedback. One thing is that the Hoosiers are a bit more prone to flat spotting compared to the Toyos were.

• How does ambient and track temps affect pressures?

I feel a good HOT pressure for the SM6 is 38 – 42 psi. This HOT pressure should be utilized in any level of ambient air temperature. The key is the COLD / STARTING pressure to get to the HOT air pressure setting. If you have cold air temperatures, start your pressure higher. If you have hot air temperatures, start your pressure a little lower, however the goal is the 38 – 42 psi HOT.

• What are the desired cross carcass hot temps?

Most SM drivers should see tire temperatures, using a needle pyrometer, between 140 – 180 degrees F. Once again, the tread temperature will fluctuate based on air temperature. The more important information is to have your tread temperature difference from shoulder to shoulder show only 20 degrees difference. If a driver sees this temperature difference higher, then camber needs to be adjusted.

http://www.hoosierti...m/specmiata.htm

• From Hoosier's web site, what does the "Spring Rate Information" diagram mean with regards to "Vertical Spring Rate vs. Load" at different (pressures)? Changed to pressures.

A spring rate of a tire will change with different air pressure. The higher the air pressure the higher the spring rate.

• Does 0 toe refer to front AND rear?

Yes, there is no need to have any toe setting front to rear. Most race cars do have a little bit in the front if care to – maybe 1/8” out.

[FTodaro]

back to the original subject;
after the 2 Florida Double National events with at least 100 sets utilized (multiple heat cylcles each), some shaved, most not, it would be very helpful to most everyone if someone qualified would objectively answer the above questions.
Seems illogical SCCA has not required the new spec tire company, nor Hoosier has not provided an experienced tire engineer on this spec miata board to answer the above questions as well as any others.
Was there a Hoosier tire engineer present at Sebring or Homestead? helping take and interpret tire temps and set ups?
This would provide a great service to the 90% of SM racers through out the land that are not familiar with this new tire manufacturer brand and specific race tire .
just sayin ...

I think you should direct your question to one of the Hoosier engienners who service us at the track. While we all have opinions and anticdotal information, they may be able to bring some science to the table. I too have opinions based upon my limited experience at limited tracks but that may not help you.

My understanding is that the Hoosier R6 is a different tire than the SM6 so I can't validate comparisons between the two of them. And then there's the @$55 difference in price...

I was told by a Hoosier engineer this is the same tire, just given a new name and price for us.

Edit: my post was to late.

[LarryKing]

What are the breakaway characteristics like? Most slicks are rather abrupt.

My experience is that Ho Hos give less 'warning' than Toyos. Where the Toyo will slide, the Hoosier breaks traction.

I ran a set of sticker SM6s with no curing once - I got maybe 8 heat cycles before they were junk.