New Hoosier R7/A7

[hyboost]

We ran the R7 last week at Sebring for 1 session and immediately beat our personal best after just a couple laps. Previous times were always 2:22-2:23 and this time we saw 20s and 21s right out the gate.

The only variables were temperature (cool 50 degrees) and R7 was 245/35/18 vs R6 245/40/17. Side by side, 245 R7 is significantly wider than 245 R6...resulting in some rubbing so we had to take them off and run a very old set of NT01s.

Will report back how they hold up after a few heat cycles.

[CP Louie]

Hey folks, please just be aware that as you drop pressures, the load carrying ability of the tire goes down. Careful inspection of tires every session is important, but if you drop starting pressures and hot pressures down, most tread separation problems will occur on the insides of the rear, so check often when running lower pressures.

[herrubermensch]

I found the sweet spot for tire pressure with R7s on an E46 M3 at 2700-2800 lbs. to be 31 lbs. hot.

--Peter

[magnetic1]

R7s cost me a potential win at NASA East Champs. My mistake of gambling and going to a new tire for such a big event but I did not think they would fall off as they did. About 7-8 laps in I lost ALL grip. Hoosier blamed the humidity.

[ScotcH]

R7s cost me a potential win at NASA East Champs. My mistake of gambling and going to a new tire for such a big event but I did not think they would fall off as they did. About 7-8 laps in I lost ALL grip. Hoosier blamed the humidity.

They should blame their crappy inconsistent compound instead. These tires are awesome ... for 4 laps. Then if you're lucky they'll be "ok" for another 3 sessions.

[magnetic1]

They should blame their crappy inconsistent compound instead. These tires are awesome ... for 4 laps. Then if you're lucky they'll be "ok" for another 3 sessions.

pretty much what I experienced. Lost all grip. Understeer into a corner, oversteer out. There was NO managing it. Was like I was driving on slicks in the rain almost.

I wont be using them again. The A7s seemed to fare WAY better though and I wonder if those would have worked better.

[TXV007]

I've also struggled with consistency and longevity but I don't think I've worked out the pressures yet. I'm new to this so I was working off pressure advise based on the R6 which was hot in the low 40's psi for a 3,000lb GTS2 M3. At that pressure the tire does not have great grip and is wearing unevenly causing vibrations. However, I find around 35 psi the tire feels lazy and soft during turn in. I think there may be a pretty small sweat spot on pressures, 2-3 psi.

Sometimes it also seems like I can't get enough heat into them but maybe that's just me.

[herrubermensch]

Wow. I noticed a drop off after a few heat cycles, but I guess I am not a fast enough driver to notice how much. I have put 8-9 heat cycles on my current (second) set of R7s, running hot pressures ranging from 31 to 35, and in the last session at VIR Full Course hit my PR of 2:07.89 with the R7s at 31 lbs pressure hot (which I recognize is low for R7s in particular). I will continue working through my current set of R7s, but what is the better alternative (next to slicks)?

--Peter

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They should blame their crappy inconsistent compound instead. These tires are awesome ... for 4 laps. Then if you're lucky they'll be "ok" for another 3 sessions.

That's definitely not inconsistent with my experience. I guess I've just been lucky that the "OK" seemed pretty good to me as a newbie driver.

--Peter

[Spec3HOR]

I've also struggled with consistency and longevity but I don't think I've worked out the pressures yet. I'm new to this so I was working off pressure advise based on the R6 which was hot in the low 40's psi for a 3,000lb GTS2 M3. At that pressure the tire does not have great grip and is wearing unevenly causing vibrations. However, I find around 35 psi the tire feels lazy and soft during turn in. I think there may be a pretty small sweat spot on pressures, 2-3 psi.

Sometimes it also seems like I can't get enough heat into them but maybe that's just me.

Low 40s is WAYYYY too high. Aim for 38psi.

[hyboost]

Interesting feedback on the tires. I can't say that I've seen the same dramatic drop off. We were just out at Sebring and tires had 9 heat cycles on them prior to weekend. We ran 3 sessions, each with 10-12 laps, and was within 1 second of fast lap throughout. Ran 35-36psi hot, car is 2490lbs and it was a hot/humid 90 degree day.

What's a good alternative tire? We've been using NT01 as a beater tire (long life, inexpensive) and are consistently 2-3 seconds off the pace of R6/R7. Recently switched to R888 due to new wheel/suspension setup since NT01 doesn't offer size I need. Haven't tried them yet but don't expect anything more that NT01. Would be curious to hear about an option to the Hoosier though...

[ScotcH]

Low 40s is WAYYYY too high. Aim for 38psi.

34-35 we found on the Contis, but that's on a 2700# car.

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Interesting feedback on the tires. I can't say that I've seen the same dramatic drop off. We were just out at Sebring and tires had 9 heat cycles on them prior to weekend. We ran 3 sessions, each with 10-12 laps, and was within 1 second of fast lap throughout. Ran 35-36psi hot, car is 2490lbs and it was a hot/humid 90 degree day.

What's a good alternative tire? We've been using NT01 as a beater tire (long life, inexpensive) and are consistently 2-3 seconds off the pace of R6/R7. Recently switched to R888 due to new wheel/suspension setup since NT01 doesn't offer size I need. Haven't tried them yet but don't expect anything more that NT01. Would be curious to hear about an option to the Hoosier though...

To me, 1 sec is totally dropped off, lol ... if I ran 1 sec different between sessions, I'd be looking for problems Also, you didn't experience them from new. You probably would have been 2 seconds faster!

[Fair]

I've used both the A6 and R6 and the A7 and R7 on different vehicles this year, but don't have enough data to draw any major conclusions. Just some trends.



We were quicker on the same tracks that we ran in 2014 on the new A7 vs the A6 last year on our TT3 Mustang. They also seemed to work better in autocrossing conditions, where the same car set Top PAX on the A7s (running at 3802 pounds with a pretty poor SM class PAX factor).



I've used the R7 on our TTC Corvette to decent success, and have used the same set on 3 different weekends so far. We haven't run the R6 on this car, and likely won't because the size we need is gone. They worked well for us right away, usually setting the best laps on on lap 1 or 2. Felt great to me...



These R7s still look great, wear great, but these aren't used in long on-track stints. Many folks here seem to be referring to sprint races/longer stints on track. I don't have any data for these tires in those conditions.

So... I dunno, for what that's worth?

[TXBDan]

What's the current consensus on R7s? I'm looking for a new TT tire and it would be a good fit in terms of points/classing, speed, and durability i think.

How many competitive heat cycles should i expect and how many before they totally fall off? 225/45/17 on a 17x9" wheel. E36 at 3150lb race weight.

Thanks!

[DocWyte]

I'd go with a 245-40-17 on a 17x9. Hard to say how many competitive heat cycles you can get, depends on your driving style and the tracks you run. I was surprised at how durable they were but they definitely fell off the last half of use...

[alwaysinboost]

If you're selective with when you use your good tires, you can make them last a very long time. For TT I always bring two sets of tires to the track, one to compete on and another set to play on. The competition set was only used for 1 session per day, which was usually the very first session in the AM when the track is in the best condition. The other set was used for playing around for the rest of the weekend as to not waste valuable heat cycles.

why are you going with a 45 series 225 instead of a 40 series? The 40 series will be a little smaller profile, giving you a slight gearing advantage over the 45 series, and also a slightly larger contract patch to boot.

[TXBDan]

Indeed, that's my plan. Practice on NT01s and do the TT on the R7s. Our club runs a TT format in which there are only three times laps for score. So its a session consisting of a warm up lap, three timed laps for score, and a cool down. So not a lot of wear, although its still a heat cycle.

How many "fast" heat cycles do you see typically and how many "decent" heat cycles before they die? I've heard around 8-10 fast cycles followed by 10-15 usable cycles.

Good call on the 225/40, i didn't even consider it. I need to stick to a 225 width for points/classing reasons, but they run quite wide. I'm not even sure a 245 R7 would fit.

[Emre]

I've found the Hankook Z214 has just about the same level of grip as the R7 but is less sensitive to camber and lasts much longer before falling off. I'm a huge fan. The Hoosiers are too much of a PITA to deal with.

Then again, I'm racing for fun. If the Hoosier is a few tenths faster for 2-3 heat cycles (then falls off a cliff) I don't consider it "better" for my use. Consistency over a reasonable number of heat cycles is worth more to me. If someone else were paying for my tires and I could show up with multiple sets mounted up and ready to go, maybe I'd change my tune.

[alwaysinboost]

Indeed, that's my plan. Practice on NT01s and do the TT on the R7s. Our club runs a TT format in which there are only three times laps for score. So its a session consisting of a warm up lap, three timed laps for score, and a cool down. So not a lot of wear, although its still a heat cycle.

How many "fast" heat cycles do you see typically and how many "decent" heat cycles before they die? I've heard around 8-10 fast cycles followed by 10-15 usable cycles.

Good call on the 225/40, i didn't even consider it. I need to stick to a 225 width for points/classing reasons, but they run quite wide. I'm not even sure a 245 R7 would fit.

what region are you in? How you listed the format is how i've found MA and sometimes NE does it. NE is more inconsistent than MA with regard to TT sessions, but that is a whole different story.

Fast heat cycles depend on how you treat your tires. For stickers, I always follow hoosiers guidelines by bringing them up to temp slowly for their first HC. Gradually build heat in them but don't overheat them so they get greasy or "shock" them by hitting ABS. Then, once MAX grip was reached, usually within 2-3 laps depending on the size of the track, I'd pit-in, jack the car up, remove the tires and let them sit at least a week. This is why you will need at least 2 sets if you want them to last, I've been known to bring 3 sets of tires to the track if its going to be a busy weekend.

Doing it this way seems to keep their peak grip longer... I've gone 5-6 weekend events, meaning 10-12 HC's until they start to drop off and even then its not a fall off a cliff.. its more of a gradual reduction.

[TXBDan]

I'm running with a club called COMSCC in the new England area. We run at NHMS, Thompson, Palmer, Watkins Glen, Canaan, and I think the new Tamworth, NH track this year. NASA NE doesn't run much up here, only the Glen and recently Palmer since it opened a couple years ago. I might try to get a TT license with NASA but I'm not sure it'll be worth the hoops I'll have to jump through.

Good tips on the care and feeding, thanks. I might be able to a single heat cycle on them at a preseason test and tune if the weather is good. I working through different logistics options, but a tire trailer might be in my future so I can have three sets: streets for travel/rain/backup, practice tires, and TT tires.

[alwaysinboost]

oh yeah, a tire trailer is a must if you are doing arrive and drive (no trailer).

This is how i got all my tires to and from events.





Harbor freight special with some garage engineering.

[TXBDan]

Ha! That's an impressive collection on a trailer. I used to run a tire trailer with my old E30 and did the typical one set plus a toolbox on the HF 40x48". I'll definitely need to carry two sets with the current plan and so i guess it's possible set up how you did. I can throw tools in the trunk.

I made a spreadsheet to help figure out how to cycle tires. I figure with two sets of R7s, i can almost cover three seasons if i use street tires for the first two sessions of the weekend. I'd run my current NT01s as practice tires initially. I attached it.
tires.PNG

I'm debating if i want a simple 40x48" trailer or maybe somethign bigget like 4x6 or 4x8 that i could also use to haul sheet stock and other stuff with. I do a lot of home improvement stuff and don't have a truck.

Need to figure out wheels. Right now i have (4) 17x9 ARC-8s and (6) 17x8.5" K1s. Buying two more K1s is the cheaper options, but a set of 17x9s would be better.

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alwaysinboost, also, what trailer hitch did you use on the M3? The Curt one?

[Pat533i]

oh yeah, a tire trailer is a must if you are doing arrive and drive (no trailer).

This is how i got all my tires to and from events.

Planning to run tt4 this year?

Im hoping to be competitive on the 225's since I don't want to mess with my fenders.

[alwaysinboost]

Ha! That's an impressive collection on a trailer. I used to run a tire trailer with my old E30 and did the typical one set plus a toolbox on the HF 40x48". I'll definitely need to carry two sets with the current plan and so i guess it's possible set up how you did. I can throw tools in the trunk.

I made a spreadsheet to help figure out how to cycle tires. I figure with two sets of R7s, i can almost cover three seasons if i use street tires for the first two sessions of the weekend. I'd run my current NT01s as practice tires initially. I attached it.
tires.PNG

I'm debating if i want a simple 40x48" trailer or maybe somethign bigget like 4x6 or 4x8 that i could also use to haul sheet stock and other stuff with. I do a lot of home improvement stuff and don't have a truck.

Need to figure out wheels. Right now i have (4) 17x9 ARC-8s and (6) 17x8.5" K1s. Buying two more K1s is the cheaper options, but a set of 17x9s would be better.

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alwaysinboost, also, what trailer hitch did you use on the M3? The Curt one?

I used a da'lan hitch from etrailer.com.

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Planning to run tt4 this year?

Im hoping to be competitive on the 225's since I don't want to mess with my fenders.

225's should be fine... they run wide as fu(k

[Fair]

Just a follow up after another season on R7s... running TTD for 2016 in NASA Texas



We ran all season with a 245/40/17 R7 on a 17x10" on this 2001 BMW 330Ci. Pressures worked well at 32-33 psi hot, for us.



At several events we ran longer than normal sessions (for Time Trial) and even had one weekend where we double-stinted the car with two drivers, me in TT and another in HPDE. Never saw the sudden "grip drop off" on these, so your results may vary?



We ran all season on two sets of tires, and we only noted a drop off in lap times only on the 7th weekend on the same set of tires...



...but they were corded AF by the point. I guess I pushed that set a little too far, hehe.



All said I'm very happy with the R7 and it worked well enough to take the regional TTD championship for us, and we had a 100% bone stock drivetrain all season (down 50 whp from the class limit). Running this car again in 2017 with added power and maxing out the points for the class.

Cheers,

[TXBDan]

Thanks for the input. It's encouraging to hear you can be competitive with an R7 build over a R1S build. I'm choosing the R7 for durability and for the lower classing points cost and hope i don't regret it.

What are you thoughts on using a 8.5" vs 9" wide wheel with a 225/40/17 R7? I need another set of wheels and already have two extra 8.5" K1s kicking around. It'd be nice to only have to buy two K1s instead of a whole set of 9" ARC-8s.

Thanks!