Transition to SM7 feedback
#1
Posted 02-12-2014 11:56 AM
I have heard...
The SM6 is faster ( what we saw at test by about .2-3 on average)
The Sm7 is faster
The SM7 is more consistent and easier to drive
The SM7 slip angle is such that it breaks away with little warning
The SM7 is easier to drive and more consistent
The SM7 doesn't go away the entire race like the SM6 does
The Sm6 doesn't go away during the race like the SM7 does
The Sm7 gets better after a few cycles
Anyone with actual experience on the tires want to comment, I think this should be a good thread for all.
Any set up changes? More pressure? Less pressure?
East Street Auto Parts
Jim@Eaststreet.com
800 700 9080
#2
Posted 02-12-2014 12:02 PM
We don't even start racing until April....I keep waiting for the rest of you to figure it out
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#3
Posted 02-12-2014 12:21 PM
2 HC SM6 same story. Warned tire up slowly and it still grained.
10 HC Toyo RR no issues with graining just wailed on them on practice day.
SM7 2 lap warm up, no graining, stickers through 3 HC
SM7 definitely less grip cold. First turn out lap on stickers I put it off track as the tire had less grip than I found in the rain.
#4
Posted 02-12-2014 12:21 PM
What does Mr T. Craig Berry have to say ????
My Nola experience:
Same psi as SM6
Not good first session
Needs to cool off after initial session. Only sat for a couple hours. But, it was cold and windy.
Brown and Voytek raced on 3 session tires in Sunday SM race
Voytek ran 5 session old tires in Sunday STL race. He has never been on 5 session old tires, EVER!!!!
Most sessions had the fastest laps at end of session.
May be a tad slower than SM6, but we had no data to back that up, only seat of the pants feeling.
I got a warm fuzzy feeling that these will be an improvement. BUT, my only experience is at a track that nobody had any previous experience.
Dave
Dave Wheeler
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Building Championship winning cars since 1995
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#5
Posted 02-12-2014 12:29 PM
In my testing they are still plenty fast at cycle 5-6 and can do long runs. 15-20 lap runs with good laps at the beginning and of you need to you can put a flyer together at the end. Stickers are still good to me. A little edgy but the last bit you need is there hiding somewhere in lap 3-4.
A lot of lap records will get touched up on out here in the West I think.
I like the fact you can run just about any amount of camber with these tires and still get away. They will cord the outside edge after a lot of driving 8-10+ long cycles for what I'm doing but it's fast for a sprint race....
#6
Posted 02-12-2014 01:41 PM
We don't even start racing until April....I keep waiting for the rest of you to figure it out
The SM7 snow tires are pretty good in Ohio. I studded mine.
Frank
TnT Racing
SCCA Ohio Valley Region
#7
Posted 02-12-2014 02:08 PM
I think the only conclusion that can be made with my personal data, watching Alex and Lamb in Florida, and Voytek, Brown at NOLA, is that the 7 is a tire that will be the same or maybe even better for several sessions. I think this will be a better tire for our series.
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#8
Posted 02-12-2014 02:58 PM
Thanks for sharing guys. I ran them SM6's and SM7's at Sebring and at PBIR.
I want to exclude PBIR from this comparison as I believe that like Mid Ohio, this track likes older harder tires, as they grain really easily. I did not run NOLA but it sounds as though it is similar there.
- At some tracks the SM6 will be much better, it appears to be a grippier softer tire than the SM7, and is amazing in the early stages, but can fall off rapidly at the end of a race.
- It appears as if the SM7 is slightly harder compound and might be more durable, and might provide more usable heat cycles, but I can't say that with any certainty just yet.
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Danny
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#9
Posted 02-12-2014 03:46 PM
Jim
East Street Auto Parts
Jim@Eaststreet.com
800 700 9080
#10
Posted 02-12-2014 05:10 PM
I have only run the SM7 at NOLA, but it was definitely the better tire at that track. Regardless of which tire is faster, as that wont be an issue much longer, I REALLY like the SM7 so far. The tire stays very consistent if not improves for the first several heat cycles. Gone are the days where a set of stickers has a couple of tenths advantage. I have high hope that this tire will be very good for the class.
As far as NOLA is concerned, I switched over to the SM7 on Saturday qual and ran quite a bit faster than Friday afternoon. Some of that time I do attribute to the faster tire, but it was also a new track so I was getting faster each session. I ran the SM7 Saturday qual, Saturday race and Sunday race. Each time the tires felt great. I ran them particularly hard on the Saturday race and I was sure there was going to be graining when I came in. Much to my surprise they looked great. They seem to be able to take a high level of abuse without destroying themselves.
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#12
Posted 02-12-2014 08:48 PM
Frank
TnT Racing
SCCA Ohio Valley Region
#13
Posted 02-12-2014 09:03 PM
Maybe I have missed it but are sticker SM7s any faster, is it going to eliminate the need to sticker up?
In my limited experience, I would say stickers are actually slower. Or at least at NOLA it seemed to be no advantage.
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James York
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#03
#14
Posted 02-13-2014 12:40 AM
So that just means we'll get back to people complaining about predictability of when tires "come in"
I miss those days!!!
And they were predictable if you did your homework.
I have an opinion so I must be right
#15
Posted 02-13-2014 08:10 AM
Racing in January and February. What a luxury!
--because someone commented that we should all post our names, and not be anonymous. I agree.
#16
Posted 02-13-2014 08:10 AM
I think at certain tracks you MAY be able to use them all weekend.Rotate your new set in on the practice day or in qualifying if the track likes them. If they work for 5 HC EVERY time and if most tracks like a one HC tire ---we will be golden.
The whole goal of using less tires comes down to 4 laps as I see it. SM6 tires are ALMOST always faster for the first few laps---thus the need to always sticker up. Get rid of that and it will help everyone's tire budget may times over. It sounds promising that this tire is closer to that.
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#17
Posted 02-13-2014 09:17 AM
My car felt the same throughout the weekend but developed a push on the left handlers in the closing laps of a 30 minute SARRC race. Car stayed neutral in the right handlers all weekend.
With my limited experience, it looks like the SM6 fell off in the closing laps and the SM7 held on for the duration.
- RussMcB likes this
#18
Posted 02-13-2014 10:20 AM
I still haven't looked closely at my data. I did a pressure sweep high to low with them at Sebring (regional) and the 7's were much more forgiving at high pressures than the the 6's are.
One thing that did happen and that I had never experienced. We were running after the big bore GT1 etc. cars. When we took the track it was like driving on ice. The first few turns I really had to be careful not to crash. By driving off line and aggressively warming up the tires it got better. I think most did have better grip and times later in the race. It just seemed like the 7's were less compatible with other tire compounds. This may be track specific, I don't know. The corners that seemed worse were concrete.
#19
Posted 02-13-2014 10:50 AM
<snip> I placed it on the left front and went racing...
Now, THAT's the right way to do real tire comparison testing! :-)
Pretty interesting, Jeff. Thanks for sharing.
#20
Posted 02-13-2014 11:55 AM
Since the cat is out of the bag, here is what we ran at NOLA
LF; SM6, 2 heat cycles, higher pressure with decrease in negative camber
RF; SM7 stickers, lower pressure, normal camber
LR; SM7, 3 cycles, high pressure, normal camber but additional toe out
RR; SM6, stickers, normal pressure, more negative camber with toe in
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Dave Wheeler
Advanced Autosports, the nations most complete Spec Miata shop
Author, Spec Miata Constructors Guide, version 1 and 2.0
Building Championship winning cars since 1995
4 time Central Division Spec Miata Champion car builder 2012-2013-2014-2017
Back to Back June Sprints Spec Miata 1-2 finishes 2016 and 2017
5 time June Sprints winner in Mazda's
6 Time Northern Conference Champion Car Builder
2014 SCCA Majors National point Champion car builder
2014 SCCA Runoffs winner, T4 (Bender)
2014 Central Division Champion, ITS (Wheeler)
2013 Thunderhill 25 hour winning crew chief
2007 June Sprints winner, (GT1, Mohrhauser)
Over 200 race wins and counting.
www.advanced-autosports.com
dave@advanced-autosports.com
608-313-1230
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