To R-Compound or not?
07-08-2004, 10:13 PM
#1
Instructor
Thread Starter
Join Date: Dec 2002
Location: New Jersey
Posts: 228
Likes: 0
Received 0 Likes
on
0 Posts
To R-Compound or not?
I am trying to decide between Pilot Sports 2 and Sports Cup for my 996TT for track use only.
I've been to 7 track weekends on P-zeros. The general wisdom is that you learn more by starting with street tires. My question is am I ready to upgrade to Sports Cup or should I stay pure street for another year or so.
Asked another way, what would be the indicators that one has learned enough on the street tires and could move to R-Compound?
Advice much appreciated.
I've been to 7 track weekends on P-zeros. The general wisdom is that you learn more by starting with street tires. My question is am I ready to upgrade to Sports Cup or should I stay pure street for another year or so.
Asked another way, what would be the indicators that one has learned enough on the street tires and could move to R-Compound?
Advice much appreciated.
07-08-2004, 10:58 PM
#2
Advanced
Join Date: Nov 2001
Location: Boston, MA
Posts: 88
Likes: 0
Received 0 Likes
on
0 Posts
Hi Shan,
I'm biased, so consider your self warned.
It all depends on how good a driver you are. If you started 'fresh' on DE events with a 996TT then the bet is that the car have potentially saved you on one or more occasions, maybe without you knowing. If you had driven an older model 7x-89 then there would have been a better learning curve. I'm not saying that 7 events is not enough before going to sticky's, its more that the older cars gives you different feedback and they don't save you if you make a mistake.
That said. A R-compound tire will give a much stiffer side wall, be more sticky and thereby allow you to go faster. It will also be less forgiving than a street tire.
I once talked with Rick Bye, a well know racer in the Porsche world, and his take was; If you can produce consistent lap times then upgrading makes sense.
It's your call in the end. You'll need extra wheels. If you're close to the track you can potentially drive there, if not then you may need to trailer them some how. Cost wise, good street tires are expensive so I'm not sure if there is anything to save.
Hope I didn't discurage you from getting some new tires, I only tried to put some different info on the table.
Michael
I'm biased, so consider your self warned.
It all depends on how good a driver you are. If you started 'fresh' on DE events with a 996TT then the bet is that the car have potentially saved you on one or more occasions, maybe without you knowing. If you had driven an older model 7x-89 then there would have been a better learning curve. I'm not saying that 7 events is not enough before going to sticky's, its more that the older cars gives you different feedback and they don't save you if you make a mistake.
That said. A R-compound tire will give a much stiffer side wall, be more sticky and thereby allow you to go faster. It will also be less forgiving than a street tire.
I once talked with Rick Bye, a well know racer in the Porsche world, and his take was; If you can produce consistent lap times then upgrading makes sense.
It's your call in the end. You'll need extra wheels. If you're close to the track you can potentially drive there, if not then you may need to trailer them some how. Cost wise, good street tires are expensive so I'm not sure if there is anything to save.
Hope I didn't discurage you from getting some new tires, I only tried to put some different info on the table.
Michael
07-08-2004, 11:29 PM
#3
Addict
Rennlist Member
Rennlist Member
Hey Shan;
Quite good advice from Michael.
The modern cars do confound in a lot of ways because the traditional indicators are not possible. I would have said if you are able to be consistent, fast, and smooth, but simply fry the street tires in no time, THEN you are ready for Rs. Trouble is, The electronics keep this from happening to a large extent.
Rs will not teach you anything free. You have to have your chops to learn from them. Streets will teach you car control at lower speeds with a softer edge and a greater chance of recovery. when you have the ingrained responses, you're ready.
Here's a modern solution, perhaps. If you are able to drive really swiftly WITHOUT activating PSM, then you are ready. How's that? It can be done, and the PSM can be used as a barometer of smoothness.
Stick with the streets for now and give the PSM Test a try, eh?
Quite good advice from Michael.
The modern cars do confound in a lot of ways because the traditional indicators are not possible. I would have said if you are able to be consistent, fast, and smooth, but simply fry the street tires in no time, THEN you are ready for Rs. Trouble is, The electronics keep this from happening to a large extent.
Rs will not teach you anything free. You have to have your chops to learn from them. Streets will teach you car control at lower speeds with a softer edge and a greater chance of recovery. when you have the ingrained responses, you're ready.
Here's a modern solution, perhaps. If you are able to drive really swiftly WITHOUT activating PSM, then you are ready. How's that? It can be done, and the PSM can be used as a barometer of smoothness.
Stick with the streets for now and give the PSM Test a try, eh?
07-09-2004, 12:09 AM
#4
Instructor
Thread Starter
Join Date: Dec 2002
Location: New Jersey
Posts: 228
Likes: 0
Received 0 Likes
on
0 Posts
Besides the track days, I also did about 12 autocrosses and 2 car control clinics in the past 1.5 years. Together, I wore out two sets of P-Zeros.
I've been keeping the PSM on for most events and used it as exactly the learning tool. I found that I produced the fastest time if I can just stay under PSM. i.e. keep the slip angle below 7-8 degrees.
The car has a tendency to understeer. So I try to enter most turns with a lot of safety margin but power out aggressively (throttle steer). If I apply too much power, PSM will cut the power and I can see the yellow light flashing. Since the car has a lot of tourque (about 450), I found that even if I was too conservative in entering a turn, I still would not lose much time.
I have 3 sets of rims so it's not a limiting factor.
I can see that staying with street tires will help me optimize the entry part of a corner. The squeeling gives me more feedback and the tires are more forgiving.
I've been keeping the PSM on for most events and used it as exactly the learning tool. I found that I produced the fastest time if I can just stay under PSM. i.e. keep the slip angle below 7-8 degrees.
The car has a tendency to understeer. So I try to enter most turns with a lot of safety margin but power out aggressively (throttle steer). If I apply too much power, PSM will cut the power and I can see the yellow light flashing. Since the car has a lot of tourque (about 450), I found that even if I was too conservative in entering a turn, I still would not lose much time.
I have 3 sets of rims so it's not a limiting factor.
I can see that staying with street tires will help me optimize the entry part of a corner. The squeeling gives me more feedback and the tires are more forgiving.
07-09-2004, 05:37 AM
#5
I've heard a couple good rules on this.
1) You should be able to run down most (if not all) of the entire white run group on street tires. I know I was able to do this in a 200 HP tiptronic boxster. Along with that, you should probably be able to run down most of the black run group as well.
2) You'll know when it's time to switch and you won't have to ask the question. For a long time, I thought this was a bit elitist, and I was also quite unsure of how I'd really know. So... I switched midway through a season and drove on R-compounds for about 10 DE days. At one event I corded those tires and I was forced to use my street tires again. Through the course of that event, I quickly learned how to get the most out of my street tires and there was absolutely no doubt in my mind of whether or not I was near the limits of those tires. At that point, I understood why people said that "you'll just know when it's time to switch."
With the above being said, if you have an extra set of rims, I can see why you might be a bit anxious to switch. And, you won't be alone if you switch too early.
Keep this in mind...
1) Street tires squeal a lot when you are approaching the limits and you are about to spin
2) Track tires squeal a lot when you have exceeded the limits and you are in a spin
3) With track tires you are definitely going to be driving faster
4) Track tires are much more progressive - this means that they ramp up to the limit quicker and they tail off quicker
All of the above means that you should have a VERY GOOD sense of what your car is doing as you won't have audio clues of when you are reaching the limit, and you do reach that limit, you have to react quicker and smoother. If you have those skills, great! Perhaps this is why some people suggest that you will just know when it's time to switch?
FYI: I switched to R-compounds after 29 DE days. I felt that I was at the limits of my street tires after 45 DE days. I also feel that I'm a bit of a slow learner, so it's quite possible that you are picking it up quicker. I've seen some guys with about 20 DE days driving amazingly well.
1) You should be able to run down most (if not all) of the entire white run group on street tires. I know I was able to do this in a 200 HP tiptronic boxster. Along with that, you should probably be able to run down most of the black run group as well.
2) You'll know when it's time to switch and you won't have to ask the question. For a long time, I thought this was a bit elitist, and I was also quite unsure of how I'd really know. So... I switched midway through a season and drove on R-compounds for about 10 DE days. At one event I corded those tires and I was forced to use my street tires again. Through the course of that event, I quickly learned how to get the most out of my street tires and there was absolutely no doubt in my mind of whether or not I was near the limits of those tires. At that point, I understood why people said that "you'll just know when it's time to switch."
With the above being said, if you have an extra set of rims, I can see why you might be a bit anxious to switch. And, you won't be alone if you switch too early.
Keep this in mind...
1) Street tires squeal a lot when you are approaching the limits and you are about to spin
2) Track tires squeal a lot when you have exceeded the limits and you are in a spin
3) With track tires you are definitely going to be driving faster
4) Track tires are much more progressive - this means that they ramp up to the limit quicker and they tail off quicker
All of the above means that you should have a VERY GOOD sense of what your car is doing as you won't have audio clues of when you are reaching the limit, and you do reach that limit, you have to react quicker and smoother. If you have those skills, great! Perhaps this is why some people suggest that you will just know when it's time to switch?
FYI: I switched to R-compounds after 29 DE days. I felt that I was at the limits of my street tires after 45 DE days. I also feel that I'm a bit of a slow learner, so it's quite possible that you are picking it up quicker. I've seen some guys with about 20 DE days driving amazingly well.
07-09-2004, 12:26 PM
#6
Race Director
If you are still getting faster on the street tires then you should stay with them. What I mean is that if you lap times are dropping more and more with streets you are still learning something.
If you are not getting any faster and are making all the speed in the corners you can and you have legitimaly played with different lines, turn and braking points and are smooth then you have maxed the streets.
If are running PSM on try running PSM off for a while. Can you consistant run as fast or faster without PSM? To me PSM are like training wheels. Nice to start, but at some point to you need to take it way to get the very most from the car and driver.
In my case. I have a 944 race car and 944 stock street tire autocrosser.
Reason for the street tires is to teach my wife to autocross. Anyway I can tell that in a autocross the street tires are holding me back. I quickly reach the limit of the street tires and then proceded to balance the car right at the max limit of adhesion often giving corrections and adjustment many many times even short autocross corners. Invaribly the tires sing through each corner at their very limit. Even when I exceed their limit I can immedialy feel that and back it down before control is lost. It is hard to explain, but I feel like can use those tires and abuse the tires and never feel out of control. Althought the grip level I have is much less than R-tires I seem to feel like I can carry speed through drifts and quick car rotations to make-up for the less grip. I also feel like I can make up speed vs compeitor by running much closer to the edge than most R- compound guys. This is often reflected in my autocross times that are often one of the best times for any street tired car. This is from stock 125 whp 944 with stock suspension and cheap shocks.
I also too my stock 944 Turbo out to the track and the streets were super controlable even when the stepped out. All that was needed was simple correction with no drama involved. Again to be fast I slipped and slided the car around the track keeping the car smoothly balanced through many minor input corrections in each corner.
The biggest issue with R-tires is that they have much higher threashold and give you fewer warnings on impending loss of traction. Untill you can fully master street tires the R-tires either will not be used to their full potential, could cause a snap spin due to their breakaway charateristics, and will save you when you make a mistake and never tell you thus limiting you future learnings.
If you are not getting any faster and are making all the speed in the corners you can and you have legitimaly played with different lines, turn and braking points and are smooth then you have maxed the streets.
If are running PSM on try running PSM off for a while. Can you consistant run as fast or faster without PSM? To me PSM are like training wheels. Nice to start, but at some point to you need to take it way to get the very most from the car and driver.
In my case. I have a 944 race car and 944 stock street tire autocrosser.
Reason for the street tires is to teach my wife to autocross. Anyway I can tell that in a autocross the street tires are holding me back. I quickly reach the limit of the street tires and then proceded to balance the car right at the max limit of adhesion often giving corrections and adjustment many many times even short autocross corners. Invaribly the tires sing through each corner at their very limit. Even when I exceed their limit I can immedialy feel that and back it down before control is lost. It is hard to explain, but I feel like can use those tires and abuse the tires and never feel out of control. Althought the grip level I have is much less than R-tires I seem to feel like I can carry speed through drifts and quick car rotations to make-up for the less grip. I also feel like I can make up speed vs compeitor by running much closer to the edge than most R- compound guys. This is often reflected in my autocross times that are often one of the best times for any street tired car. This is from stock 125 whp 944 with stock suspension and cheap shocks.
I also too my stock 944 Turbo out to the track and the streets were super controlable even when the stepped out. All that was needed was simple correction with no drama involved. Again to be fast I slipped and slided the car around the track keeping the car smoothly balanced through many minor input corrections in each corner.
The biggest issue with R-tires is that they have much higher threashold and give you fewer warnings on impending loss of traction. Untill you can fully master street tires the R-tires either will not be used to their full potential, could cause a snap spin due to their breakaway charateristics, and will save you when you make a mistake and never tell you thus limiting you future learnings.
07-09-2004, 02:25 PM
#7
Addict
Rennlist Member
Rennlist Member
Hey;
I also forgot to mention that in most cases R compound tires need a substantial bit more negative camber to stay healthy and work properly.
And thus the slope "begins to lack grip!"
I also forgot to mention that in most cases R compound tires need a substantial bit more negative camber to stay healthy and work properly.
And thus the slope "begins to lack grip!"
Trending Topics
07-09-2004, 02:46 PM
#8
There are a multitude of good reasons listed above to stay with street tires. Your key to satisfaction with this advice is to never ride or drive a car with a set of stickers on it. Once you do, you won't be satisfied with street tires. Although Redline man is certainly correct that R compounds will do better with more camber, even at stock allignment they are a lot stickier than street tires. I've tracked a 996tt with MPSC's. If you do go to MPSC (or other R compounds), the stock brake pads are lacking and will fail rapidly under the extra work. A pad switch is easy to do at the time you switch from your street to track wheels.
Last edited by prg; 07-09-2004 at 09:22 PM.
07-09-2004, 03:03 PM
#9
Still plays with cars.
Lifetime Rennlist
Member
YPSHAN - It sounds to me like you're ready for an R compound tire. The understeer you mentioned will be greatly reduced by the sticky tire. I am assuming that the understeer is NOT caused by acceleration before the apex - a common beginner error so forgive me for mentioning it.
It sounds like you've progressed to the level of consistency and you pass Redline's test (a very good one!). If you are going quickly you should have already experienced premature wear on the outside shoulder of your tires. If not, you're not carrying enough speed in the corners yet.
The R compound tire will also wear at the shoulder unless you dial in more negative camber. As PRG mentions, an R compound tire like the Michelin Cup, Toyo RA1, Pirelli Corsa or Dunlop SS Race will work well with street camber but you'll wear out the shoulder. Performance and tire life on track will improve with more negative camber. Pirelli and Michelin claim their tires will work well with only 1.5 deg negative but that best performance is around 2.5 degrees. Note that more negative camber will wear the inside edges of your tires prematurely if driven on the street a lot.
I wear out my tires on the track so I don't care and run neg 2.5. I prefer the Pirelli Corsa because it works decently in the wet and is safe to drive to and from the track (only 90 miles in my case). The Dunlop SS Race or the new Pirelli Corsa System would be an even better choice for street and track as both combine a sticky race compound with a tread pattern with good water evacuation. The Corsa System is the OEM tire for the Ferrari Stradale and the Porsche GT3 RS.
Enjoy!
It sounds like you've progressed to the level of consistency and you pass Redline's test (a very good one!). If you are going quickly you should have already experienced premature wear on the outside shoulder of your tires. If not, you're not carrying enough speed in the corners yet.
The R compound tire will also wear at the shoulder unless you dial in more negative camber. As PRG mentions, an R compound tire like the Michelin Cup, Toyo RA1, Pirelli Corsa or Dunlop SS Race will work well with street camber but you'll wear out the shoulder. Performance and tire life on track will improve with more negative camber. Pirelli and Michelin claim their tires will work well with only 1.5 deg negative but that best performance is around 2.5 degrees. Note that more negative camber will wear the inside edges of your tires prematurely if driven on the street a lot.
I wear out my tires on the track so I don't care and run neg 2.5. I prefer the Pirelli Corsa because it works decently in the wet and is safe to drive to and from the track (only 90 miles in my case). The Dunlop SS Race or the new Pirelli Corsa System would be an even better choice for street and track as both combine a sticky race compound with a tread pattern with good water evacuation. The Corsa System is the OEM tire for the Ferrari Stradale and the Porsche GT3 RS.
Enjoy!
07-09-2004, 03:44 PM
#10
Rennlist Member
Somebody once told me that if your street tires are not squealing in every corner than you should not go up to R-Compounds. I am not sure if I totally agree with that but I think that only 7 weekends is probably too early. What run group are you in? I dont think you need R compounds until you get up to black. In my opinion, you should be able to be faster than most everyone on R compounds in white with your street tires until you should think about upgrading yourself. Seeing that you have a twin turbo, you probably are faster than everyone but you know what I mean.
07-10-2004, 12:33 AM
#11
Just curious. I can relate completely to the points made regarding R-compund tires relative to cornering, etc. However, no one talked about braking. I find braking to be my biggest issue with street tires....I can stay with most in the corners, but my "street" tires lock up way early upon heavy threshold braking (I know it assumes I know how to brake, which may be debatable). Anyway, is this a reason to consider R-compounds? It seems like I lose more time in the braking zone than corners, having to be careful not to lock up the tires (I have an 87 930). Just a thought.
Mike
Mike
07-10-2004, 12:53 AM
#12
Mike,
The same increased coefficient of friction that helps you corner faster also helps you brake faster. You will stop faster, but you may also expose weaknesses in your brake cooling, pads, etc. You may get away with being less than fastidious about frequent bleeding and brake fluid changes with street tires, but don't count on it with the stickers. I don't know if its an issue for your 930, but it is in a porky 996tt.
The same increased coefficient of friction that helps you corner faster also helps you brake faster. You will stop faster, but you may also expose weaknesses in your brake cooling, pads, etc. You may get away with being less than fastidious about frequent bleeding and brake fluid changes with street tires, but don't count on it with the stickers. I don't know if its an issue for your 930, but it is in a porky 996tt.
07-10-2004, 02:14 AM
#13
Race Director
If you are locking street tires you will also be locking up R-tires. The damage from flat spots will just be ALOT more expensive with R-tires.
Now R-tires like MPSC are farily resistant to flat spoting, but hoosiers I am told are quite sensitive.
You need to learn to threashold brake just like cornering at the limit on streets before you move to R-tires.
Now R-tires like MPSC are farily resistant to flat spoting, but hoosiers I am told are quite sensitive.
You need to learn to threashold brake just like cornering at the limit on streets before you move to R-tires.
07-10-2004, 08:57 AM
#14
Burning Brakes
Join Date: Oct 2001
Posts: 855
Likes: 0
Received 0 Likes
on
0 Posts
Switching to "Dot R" compound tires and you will find that you :1. Corner faster... exciting!
2. Exit corners with way more speed... a good thing!
3. Carry more speed into braking zone... watch out for this!
4. Are able to carry more speed at corner entry... careful here too!
5. Will EAT "R" compound tires faster... $$$
6. Have to move up to "Track brake pads",stainess steel brake lines & high temp. brake fluid... $$$
7. Wear out brake pads quickly.... the best pads are EXPENSIVE!
8. Replace worn out Rotors, often! Glad I got a Chebby, Napa Rotors are Cheap!
9. Costs go UP, a bunch... sooner, rather than later, your gonna need a trailer!
10. You will have... WAY MORE FUN !!!
Good luck... and remember... take small bites in improving speed.
07-10-2004, 09:44 AM
#15
Pro
Join Date: May 2001
Location: Charlotte, NC
Posts: 648
Likes: 0
Received 0 Likes
on
0 Posts
Originally posted by M758
If you are locking street tires you will also be locking up R-tires. The damage from flat spots will just be ALOT more expensive with R-tires.
If you are locking street tires you will also be locking up R-tires. The damage from flat spots will just be ALOT more expensive with R-tires.
). Braking is no different. I see no reason that you'd have increased brake pad/fluid use through R-comps, actually strikes me it would help w/ the amount of work the braking system needs to perform.
PRG, this could be one of those cultural things but most folks I know will hear stickers and think tires w/ the stickers still on them (as in not heat cycled yet). This vs. stickies which I think of as a generic term for DOT Rs or slicks.