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03-17-2018, 11:09 AM | #23 |
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Dogbone-
Thanks for the tire insight. I will be trying out the R1-S out next. My R7's lasted 4 days then got really slippery on the 5th day. They cycled out before they corded which seems the most common. Did you try lower pressure? Everyone I talked to runs them at much lower pressure than hoosier recommends, like 30 hot. I guess it doesn't really matter since it looks like you've moved on to Pirellis. |
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03-17-2018, 11:49 AM | #24 | |
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What that shows is that if you get a tire that's way too wide for a given rim (a 285 tire should have at least a 10-10.5 in rim), then yes, you are going to get vague steering feedback because the sidewalls are not being supported properly. It's too bad they didn't try a wider rim on the 285. |
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03-17-2018, 12:31 PM | #26 | |||
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In looking at the tirerack article you linked, I see what they are trying to say, but I'm a road course guy and I believe the overall demands to be different. I think it's safe to say that during a full 20 minute road course session with 6-8 hot laps that you will build up significantly more heat into the tires than a single autocross lap. So while the narrow tire communicates well and feels good for a single, let's assume, 1-minute autocross lap, I'd say that the narrow 245 tire would get crushed with heat from a road course session, and that the 285 in that article would have held up much better by comparison on a road course. Also, in general, road courses don't turn as sharply as autocross courses, so a slight loss in feedback on a wider road course isn't as much of a detriment. Let's look at it this way----the tirerack article was from 2009 and they used a Mustang GT. Let's assume it was a 2009 Mustang GT. That car weighed around 3500 lbs. If you put a 3500lbs car with 245 (most likely not slicks) square tires onto a road course track for 20 minutes and you are a competent driver that can take tires to their grip limit.....I don't think that's gonna go too well 6 laps in....and how are those 245's gonna look after 5 sessions of a typical HPDE day? I'm not sure I'd want to drive home on those.... |
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03-17-2018, 02:27 PM | #27 | |
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When possible, I do my best to find the proper way of running things from vendors. Usually I get pretty good advice. As I've said before, I don't come to motorsport with a deep well of knowledge, so I try to give myself the best chance for success by asking lots of questions from reputable places. |
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03-18-2018, 02:19 AM | #28 | |
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I don't know the answer for the tank tracks. I don't know how those things work. |
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03-18-2018, 03:37 AM | #29 | |
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For purchasing Michelins, there's an interesting dealer about 30 minutes south of Los Angeles called Subesports. They offer a 10% discount on all their products if you buy a $100 annual membership with them. They keep Michelin slicks in stock and getting 10% discount and not having to deal with shipping (if you're in LA) is pretty nice! |
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03-18-2018, 05:01 PM | #30 | |
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There's a place near Road America that sells slick take-offs -- typically used for a few laps to qualify and then removed. They're dirt cheap even if I count the gas it takes to drive there and back. The only downside is that the availability of various sizes/brands is all over the place, so you just have to keep checking and jump on the first set you find.
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03-29-2018, 03:57 AM | #31 | ||
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The TD/Z221 is still available here. We also have access to the Yokohama A050, which is a direct competitor to the TD/Z221, with almost identical lap times. According to the Yokohama website, the A050 is only available in Japan and Australia, although, a new A052 was recently released and available in the USA but it's a slower tyre than the A050 and probably equivalent to a Michelin PSC/PSC2. There is a relatively new Nankang AR-1 R-comp, which one might not think much of, given the brand and its predecessor, but it's surprisingly a great tyre, being only 0.27s slower on a 60s lap than a TD/Z221 C70 (Soft), while being less than half the price! Not to mention, they can take multiple consecutive hot laps and produce consistent times through the day, and day after day, although they can take some time to get up to temp, which means the first session or two can be wasted getting pressures right. This information is not entirely useful for you, given your progression to slicks, but hopefully somewhat useful for others starting out and looking for an inexpensive option. My next tyre was going to be the A7 (the P-car forums seem to love this tyre) but after reading your thoughts, it makes me hesitant. The BFG R1S seems to be a great all-round option and as good as it gets without going to a full slick. But those extra 2-3 seconds on the Pirelli !!! How many heat cycles do you get out of the Pirelli DH and how long are those sessions? What's the falloff in times once the Pirelli DH and R1S are no longer fresh, i.e. second track day and beyond? |
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03-29-2018, 03:40 PM | #32 |
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Dogbone - thanks for the awesome post.
Question - why have you not tried the hoosier R7? My understanding is the A7 is more of an autocross oriented tire that doesn't need to be warmed up. I would think the R7 would be more suitable for your use and would last longer.
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03-29-2018, 05:24 PM | #33 | |
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I guess I'm just not a big Hoosier guy. The R6 was ok. It was elegant but not super fast and it wore out quickly and it's at the top end of price for a non-slick. My friend, who was very familiar with R6 also ran R7. It wasn't much faster and didn't last any longer. I ran A7 because I wanted the grippiest thing I could find and people spoke very highly of A7. Remember, I do time attack-style stuff. Two or three hot laps and get off the track, so A7 should fall right into that. For the criteria that matter to me, the R1S beats the R7 in every category. |
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03-29-2018, 06:52 PM | #34 | ||
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03-29-2018, 08:27 PM | #35 |
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In general, the R7 is faster than the R6 and more durable used properly. Tehy run wider than the sames size R6, in general, also. One does not simply bolt on any new tire and get to optimum, and R7 setup is a bit different than R6 (Some cars it needs more camber, R6 had a more rounded shoulder, they went more square on R7 for instance). You should try it too. The BFG's are very good no doubt. I'd agree they're the best "DOT slick" on the market right now on the speed/value quotient. They seem to wear really well for their speed. But, I think there are a lot of SCCA National Championships Runoffs results that tend to argue against the BFG being the fastest DOT tire on a ground pounder like ours. Hoosier contingency awards are way better, but the wheel to wheel racers do tend to converge on what is faster.
The 295 Hoosier has a wider section width and narrower tread width. And it's nearly half an inch taller, which means it's still a bigger tire overall than the 285 R1S. When you're talking about these two tires though, you really cannot go wrong.
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03-29-2018, 09:36 PM | #36 | |
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However, regarding tire widths, tirerack disagrees with you on tread width. The tread width of 285 R1S is wider than 295 A7. Here's what tirerack says: the tread width of the 285 R1S is 11.3" (I just went out to my garage and hand measured a scrub unmounted R1S at 11.4"), and they list Hoosier A7 at 10.8", and the R7 (which I have never seen in person) is 10.7". Tirerack says the section width is .2 wider on Hoosier, but I'm telling ya, when you have them side by side, you don't even need a ruler to see it. I have had 285/30/18 R1S sitting on the floor right next to Hoosier A7 295/30/18 in my garage. You can see it with the naked eye. I know it sounds crazy, but the R1S is just a fat, blocky, crazy-ass barely "DOT" fricking tire hahahaha I just hand measured the 285 R1S against a 305 Pirelli DH I have here too unmounted. Their tread widths are within 1/16" of each other......how crazy is that? |
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03-30-2018, 12:52 AM | #37 | |
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I found the first 5-6 short heat cycles on the new Pirellis to be awesome. After that, they were very nice, but not like new. The first hot lap on the new Pirelli was a special experience. It took two warm up laps to scrub the brand new Pirellis in. R1S feel really good for the first 10 heat cycles. From 11-16 they fall off but are still very fun to drive. I usually cord one by 16 heat cycles in. I'll toss that one and over time assemble scrub sets and get 5-6 more cycles out of them. They're not very fast, but they are fun. I believe the weight of the car affects these experiences to some extent. The Trinity Autosport E92 M3 is 400 lbs lighter than my car. Joe claims that he can get 23 heat cycles out of a set of R1S. Interesting. |
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03-30-2018, 08:40 AM | #38 | |
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But tire diameter matters a lot too. A "bigger" tire will give you more grip in more situations all things being equal, even if it's a bit narrower. So it's worth a test at least. Scuse me while I continue to try to spend your money for you It's also 1lb heavier according to TR! When you measure in lb of tire/dollar, the Hoosier almost breaks even! I'm always going to be a Hoosier (now, Continental, sorta) booster though. Their support for grassroots motorsport in this country is second to none, so, grain of salt and all that
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03-30-2018, 09:17 PM | #39 |
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Does tread width matter?
Thanks dogbone and Richbot.
How many HCs would a set of Pirelli DH scrubs have done? 10 or more? If so, it sounds like you could get 25 short 3-hot-lap HCs out of the Pirelli DH. Are you still able to run the same times on the new (now 10 HC old) Pirelli DH? Otherwise, how many seconds slower are they now? I'm guessing they're still faster than DH scrubs. And it looks like the R1S gets 20 HCs, i.e. 10 great HCs + 5 good HCs + 5 scrub HCs. Were the R1S HCs also 3-hot-lap sessions or were you running 20-30 min (10/15/20 lap?) sessions on them? Again, are you still able to run the same times on the R1S through its first 10 HCs? Otherwise, how many seconds slower do they get during this first 10 HCs and especially after in the next 5-10 HCs (since that's how you'd determine the value/speed proposition if them). Interesting - my unlightened 135i weighs about the same as your track-prepped SC'd M3. I haven't gone down the stripped, roll-caged and aero path yet. 2850 lbs (1295kg) would be achievable with my car but that would extremely expensive. A race-prepped 3000 lbs (1360kg) shouldn't be too difficult and bearably expensive. |
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03-30-2018, 10:40 PM | #40 |
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03-31-2018, 11:47 PM | #41 | ||||
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04-01-2018, 06:51 AM | #43 |
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Miatas are no picnic to make go fast around a racetrack reliably too. The wheelbase and pckaging constraints (tire, cooling frontal area, jellybean aero is horrendous)
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04-03-2018, 03:49 PM | #44 | |
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