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Old 04-01-2012, 01:52 AM   #16
dble Trouble
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Without proper experience or instruction first, I would not recommend R compounds. Depends on your driving resume.
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Old 04-01-2012, 07:49 AM   #17
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^^^ Why is that ? I drove on R-comps pretty much right away 2nd time out I think.
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Old 04-01-2012, 01:04 PM   #18
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because the limit is much higher with those tires, with inexperience they could be very unforgiving. Gradually increasing the compound (starting with high performance street tire) is the best way to go.
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Old 04-01-2012, 02:15 PM   #19
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^^^ Why is that ? I drove on R-comps pretty much right away 2nd time out I think.

It's a typical rookie thing to do. I was going to say mistake, but it all depends on the way you look at it. From an instructor, and safety point of view, it is a mistake. As Dave mentioned, the limits are much higher, but most R comps don't squeal at the limit they just give away, if you're not experienced controlling or regaining control may be difficult or not possible. Also, there is less feedback from the tires as you approach the limit. Another reason is, when learning, you should be able to drive the wheels off of the car with street tires before you move to 'r' comps. By doing this you learn at a more modest speed and learn more car control skills.

If your sole objective is to go fast and forget learning well then use 'r's right away and chance it. But you won't learn nearly as well or as quick than if you had good street tires.
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Old 04-02-2012, 02:31 AM   #20
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Originally Posted by dcramer View Post
Choice 1: S54
Choice 2: rebuild S52 and put some goodies on it like cam/hfm/software
Choice 3: use the money for track days
I say definitely NUMBER 1


....... just because I dare you to pull it of for $4500!
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Old 04-02-2012, 12:12 PM   #21
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Originally Posted by dble Trouble View Post
Without proper experience or instruction first, I would not recommend R compounds. Depends on your driving resume.
So what would constitute "proper instruction" ? I've been to the trillium ADS a few times and was not given any specific instructions related to this at all.
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Old 04-02-2012, 03:13 PM   #22
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I think he just meant instruction to the point that you're comfortable with the limits of your street tires-- knowing when traction will be lost, how it feels and what to do so that when it happens faster on the r-comps, it won't be a surprise
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Old 04-02-2012, 04:10 PM   #23
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I'm curious about "happens faster" ? I would think that because you can go faster that it would happen at a higher speed. My experience suggests that when R-comps do let go they are much more controllable and recoverable.

One thing that I was surprised about was on a the cool down lap they do some very strange things over the cement at mosport due to the difference in grip between cement and pavement.

None of my instructors mentioned this before it happened.
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Old 04-02-2012, 11:16 PM   #24
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I'm curious about "happens faster" ? I would think that because you can go faster that it would happen at a higher speed. My experience suggests that when R-comps do let go they are much more controllable and recoverable.

One thing that I was surprised about was on a the cool down lap they do some very strange things over the cement at mosport due to the difference in grip between cement and pavement.

None of my instructors mentioned this before it happened.

The reason you didn't hear anything from the instructors is that it is not part of the curriculum to discuss the differences modifications make for C and B students. Of course if you ask your instructor they will answer you. There are just too many other things to cover at that level. However in the A curriculum there are some discussions about some modifications from benefits to set ups etc.

R comps do not recover quicker. Once you've reached the liimit of adhesion with an R comp, they completely let go until you slow down enough that they regain their composure or you hit a wall! (lol) But seriously, it has happened. The only time in my driving career that I ever spun out was on R comps. Luckily for me all 4 tires stayed on the asphalt. It's like once you reach the limit your grip falls off a cliff hence the suddeness. Street tires are constantly howling at the track, but as you push harder, they scream louder and your senses ie your hearing tells you that you're reaching the limits amongst other things. Your car will also be less responsive at this point but still controllable until you push a little harder and then start to slide at which point its up to you to control what's happening.

Now once you're in a slide it's up to you to bring it back but since 1.) you are going slower with streets you can recover quicker, but also the nature of the rubber will start to regain composure more quickly 2.) R's will not give you the same type of warnings so to the amateur/rookie/intermediate driver you may not see the warning signs coming.....

R compounds are faster, and more durable at the track so yes I do recommend everyone to aspire to them, just don't start with them. One more thing I'd like to add, R compounds are very susceptible to tire temperatures. For example your 1st lap out on cold r compounds the will have LESS grip than any street tire. As they warm up the tire pressures alter drastically with air and moderately with nitrogen. Don't listen to anyone that tells you Nitrogen doesn't change tire pressures with temperature...IT DOES! Just not nearly as much as with air. As the rubber compound warms up it starts to give more grip altering the feel and approach to cornering including slip angles, speed, positioning etc. Also with the tire pressure get greater with the heat, that also affects the feel and approach to driving. There are so many more things that I can talk about in regards to this one topic but my fingers are getting tired from typing!!! I think you get the idea. Keep the questions coming though if you want more......
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Old 04-02-2012, 11:27 PM   #25
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If you were surprised by anything that happened with r-comps on your car you were not ready

Instructors teach technic, not car set up.
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Old 04-03-2012, 06:58 AM   #26
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If you were surprised by anything that happened with r-comps on your car you were not ready

Instructors teach technic, not car set up.
How would you "prepare" yourself for the first time you experience a sudden change of grip across the cement patches at Mosport? It doesn't happen with street tires. The only way you can understand it is to experience it. It is also only becomes really noticeable when you are going slow.

As far as what the instructor teaches; the instructors have all asked me what tires I have, I would think if I were riding in a car with someone on r-comps I might mention it.
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Old 04-03-2012, 07:18 AM   #27
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The reason you didn't hear anything from the instructors is that it is not part of the curriculum to discuss the differences modifications make for C and B students. Of course if you ask your instructor they will answer you. There are just too many other things to cover at that level. However in the A curriculum there are some discussions about some modifications from benefits to set ups etc.
I've never heard it at the A level either.

Quote:
R comps do not recover quicker. Once you've reached the liimit of adhesion with an R comp, they completely let go until you slow down enough that they regain their composure or you hit a wall! (lol) But seriously, it has happened. The only time in my driving career that I ever spun out was on R comps. Luckily for me all 4 tires stayed on the asphalt. It's like once you reach the limit your grip falls off a cliff hence the suddeness. Street tires are constantly howling at the track, but as you push harder, they scream louder and your senses ie your hearing tells you that you're reaching the limits amongst other things. Your car will also be less responsive at this point but still controllable until you push a little harder and then start to slide at which point its up to you to control what's happening.
Apologies in advance for my need for evidence.

This would suggest that the difference between the static friction and kinetic friction of R-comps is greater than the difference for street tires. While this is likely do you have any real evidence other than subjective ?

Quote:
Now once you're in a slide it's up to you to bring it back but since 1.) you are going slower with streets you can recover quicker, but also the nature of the rubber will start to regain composure more quickly
nature of the rubber ???? Can you point me to any links which explain this ?


Quote:
R compounds are faster, and more durable at the track so yes I do recommend everyone to aspire to them, just don't start with them. One more thing I'd like to add, R compounds are very susceptible to tire temperatures. For example your 1st lap out on cold r compounds the will have LESS grip than any street tire.
This is fairly obvious.


Quote:
As they warm up the tire pressures alter drastically with air and moderately with nitrogen.
Don't listen to anyone that tells you Nitrogen doesn't change tire pressures with temperature...IT DOES! Just not nearly as much as with air.

Well nitrogen is a gas, and actually 78% of air by volume. As a gas nitrogen has to obey the Ideal gas law PV=nR http://en.wikipedia.org/wiki/Ideal_gas_law

If you remove moisture out of the equation (which nitrogen attempts to do ) there should be 0 difference between nitrogen and air.

Keep the answers coming!!!
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Old 04-03-2012, 11:00 AM   #28
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I doubt he will sell you it to you for $250.
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Old 04-03-2012, 12:25 PM   #29
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You won't do a S54 swap for $4500.

Make your car better. You don't drive on a track every weekend, and it's not a race car.
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Old 04-03-2012, 01:22 PM   #30
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There's enough variation in "street tires" and "R-compounds" that you shouldn't make generalizations between the two.
A V710 has plenty of stick when at ambient temp on a warm day, for example.
RA1's behave like very sticky, responsive "street tires" in my experience.

I'd recommend learning on RA1's, for example, rather than crappy all seasons...but a good/great street tire like a Direzza Star Spec or RS2, RS3, NT01, or... would be very good for learning. Just my .02.
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