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chopperbill

Slicks Vs Dot Race Tires

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question for the experienced racers: How much of a difference is there in the grip of a dot race tire vs racing slicks. what does your gut tell you in terms of seconds off your lap times?

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That would depend mostly on your riding skills and how hard you are riding now. If you aren't already pushing/sliding the full race compound DOT tires, there isn't much point to spending the extra money on slicks. You aren't going to see any difference except perhaps for whatever confidence they might give you to ride harder. Ultimately, if you are already riding at the limit of the DOT tire's traction, you might gain as much as 1-2 seconds per lap, depending on the track.

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I'm running in the low 1:50's on dot/race pirelli's at Infineon. I've pushed the front once and the back several times. However I'm thinking it was more rider error,(me), then the tires. My question really is more about which class to run in next season. Production class does not allow slicks, but the superbike and formula classes are much faster.

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I'm running in the low 1:50's on dot/race pirelli's at Infineon. I've pushed the front once and the back several times. However I'm thinking it was more rider error,(me), then the tires. My question really is more about which class to run in next season. Production class does not allow slicks, but the superbike and formula classes are much faster.

 

Mm...ok. I'm not sure I follow your question. Are you saying that the superbike class as a whole is much faster than you are? And you are trying to determine if slicks would account for or make up for the diference?

 

Superbike/formula classes allow much more modification than even superstock/supersport classes. Typically, they are faster due to more horsepower and increased acceleration due to mod's that reduce weight from the crankshaft and machine overall, ie. removing the stator from the end of the crank and running a total loss ignition system. This can reduce crank weight by as much as 3-5 lbs and can add as much as 5 bhp instant horsepower, depending on the model.

 

That said, if you can qualify for the superbike/formula classes, why not run up a class? Or two? Lots of guys run production or superstock/supersport spec machines in superbike/formula classes even though they might not be very competitive. It's a great way to get more track time and push yourself trying to keep up with the faster machines. Just be careful not to push too hard... lol. The slicks WILL allow them (and you) to corner faster, so, I'd say get a second set of wheels and mount up some slicks to run in the upper classes and that way you'll know you can at least keep up in the corners. Plenty of guys do surprisingly well that way.

 

That said, if I had to choose, I would upgrade a stock suspension before buying slicks. Not only will a good suspension do more than a fast motor to increase your cornering speed, the slicks will work your suspension harder than the DOT's. So, if you are running stock suspension components, I'd definitely think about a race shock and at least have your forks done by a pro before adding slicks.

 

racer

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question for the experienced racers: How much of a difference is there in the grip of a dot race tire vs racing slicks. what does your gut tell you in terms of seconds off your lap times?

Okay, tires 101 for me here:

 

What's a DOT Race tire? I've heard the term used and not sure what it is?

If possible, please speak in Michelin terms so I will be able to relate (I run Pilot Powers).

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D.O.T = Department of Transportation (approved by)

 

So, the complete phrase would be DOT approved tires, ie. street legal. You could mount them on your street bike and they would pass state inspection (assuming your state requires inspection). Even if your state does not require an annual safety inspection, I think the law still requires DOT rubber on the road. For instance, a state trooper or highway patrol officer could probably cite you for non-DOT approved tires.

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D.O.T = Department of Transportation (approved by)

 

So, the complete phrase would be DOT approved tires, ie. street legal. You could mount them on your street bike and they would pass state inspection (assuming your state requires inspection). Even if your state does not require an annual safety inspection, I think the law still requires DOT rubber on the road. For instance, a state trooper or highway patrol officer could probably cite you for non-DOT approved tires.

Perhaps I should have stated, not that basic. I've heard the term trackday tire used in reference to my PP's. Are they not the same as a DOT Race tire or are they a street tire, with repli-race marketing?

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Ah, I see.

 

"Race" or "Full Race" are the same thing and refer to the tread compound. So, DOT Race is a full race compound tire made for racing yet on a carcass that is still street legal or DOT approved. Not that you would want to put it on your street bike. You'd never get them hot enough to be really sticky and they would probably last about 200 miles. If that. (That's a guess. I've never run a race tire down to the cord, but, Daytona 200 racers go through more than two sets of tires, right?)

 

The idea behind this type of tire is/was a tire for production or production based racing that fits the overall Production Racing philosophy, ie. one tire for all conditions. Just like your street bike. Back in the stone age when I was still racing supersport, there was only one compound and one carcass for a DOT Full Race compound available to the paying public (unless you were a factory rider like Miguel DuHamel, in which case you received "special" DOT tires.) Now, of course, we have DOT intermediates and DOT full wets. And multi-compound DOT tires.

 

The "track day" tires are marketed as an "in between" compound(s) made to heat up and get somewhat sticky similar to a full race compound, however, not quite as sticky as full race and designed to last much longer. And, for the Qualifiers and other multi-compounds, with a harder compound strip in the center that allows them to be ridden on the street without wearing square and down to the cord in less than a week.

 

r

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The "track day" tires are marketed as an "in between" compound(s) made to heat up and get somewhat sticky similar to a full race compound, however, not quite as sticky as full race and designed to last much longer.

Gotcha

 

I've never run a race tire down to the cord, but, Daytona 200 racers go through more than two sets of tires, right?

Off Topic: Daytona 200 is won/lost in the pits. IIRC, they have always run slicks in the 200 and for the last few years have allowed special rules just for tire safety concerns at Daytona and is the reason the track was reconfigured.

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I've never run a race tire down to the cord, but, Daytona 200 racers go through more than two sets of tires, right?

Off Topic: Daytona 200 is won/lost in the pits. IIRC, they have always run slicks in the 200 and for the last few years have allowed special rules just for tire safety concerns at Daytona and is the reason the track was reconfigured.

 

Oh, aye.

 

They do run slicks, but, they also have special tires made just for Daytona. That's where the whole dual compound thing started I think. Longer lasting compounds and left side harder for the banking.

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I've never run a race tire down to the cord, but, Daytona 200 racers go through more than two sets of tires, right?

Off Topic: Daytona 200 is won/lost in the pits. IIRC, they have always run slicks in the 200 and for the last few years have allowed special rules just for tire safety concerns at Daytona and is the reason the track was reconfigured.

 

Oh, aye.

 

They do run slicks, but, they also have special tires made just for Daytona. That's where the whole dual compound thing started I think. Longer lasting compounds and left side harder for the banking.

They even have triple compound tires now.

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yes, My question is directly related to how much do slicks lower lap times. My lap times are low enough to qualify for the superbike or formula classes. My bike (749r Ducati) comes with Ohlins front and rear already and could handle the presure forces from slicks. I'm trying to determine if an 848 kit plus slicks will lower my times enough to run in the faster classes or should I just run production for a year and get more experiance racing.

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yes, My question is directly related to how much do slicks lower lap times. My lap times are low enough to qualify for the superbike or formula classes. My bike (749r Ducati) comes with Ohlins front and rear already and could handle the presure forces from slicks. I'm trying to determine if an 848 kit plus slicks will lower my times enough to run in the faster classes or should I just run production for a year and get more experiance racing.

I think it has to do with traction. The racers at the track are more trusting in the bike for braking, accelerating out of a corner with more throttle, and leaning the bike into the corner with slicks because of the increased traction. If you're doing competitive laps on Pilot Powers (DOT approved) you should feel the difference in your riding and see the difference in your laptimes once you start trusting them more and pushing them harder.

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Some of the modern DOT's are basically cut slicks, but if I had my choice, slicks any day.

 

C

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I read somewhere that sometimes amateur racers will cut slicks to look like DOT tires so they can race slicks. Sounds time consuming.

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Sometimes slicks are hand cut to run in the rain when rain tires aren't available. Cut slicks would be disqualified from a DOT only race.

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Chopperbill - I don't think anyone can answer your question. I think it is something that you will have to try to figure out for yourself.

 

There is no garuntee that if you put slicks on your bike you will be able to go x number of seconds faster then you would on DOTs. Some times riders will actually go faster on DOTs if they are more comfortable on them. I know this was the case for our mechanic Will a while back. He was racing multiple classes with WSMC and some classes required DOTs (Superstock) and others woudl allow slicks (ModProd, Superbike and F2). I remember Will saying one weekend that he was gong faster on the DOTs then he could on the slicks because Dunlop had just released a new DOT that he really liked.

 

Also depeneding on the brand of tire you may not be able to get the exact same profile tire in both a DOT and slick. This would mean that you may need to make chages to your bikes geomatry to really get the best out of a set of slicks. These are changes you wouldn't want to make on a race weekend and this is why many times riders will run DOTs even in classes where slicks are allowed.

 

When I raced with WSMC on The Streets last year I ran DOT rear tires in all classes, even the ones where slicks were legal. I likeed the DOT rear better then the 17" slick that was available. Although I did run a slick fron in classes where it was allowed. In any case I set three lap records and won every race I finished that year racing on a DOT rear.

 

 

My point is, you will have to try it for yourself. Get a new set of DOTs mounted up and see how fast you can go. The mount up a set of slicks and do the same. Just know that you may have to make some settings changes to take advantage of each tire.

 

My advice, if you are somewhat new to the sport, is just run DOTs in all your classes, I doubt you will find that slicks are going to knock seconds off your lap times. DOTs are pretty darn good these days.

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Chopperbill - I don't think anyone can answer your question. I think it is something that you will have to try to figure out for yourself.

 

There is no garuntee that if you put slicks on your bike you will be able to go x number of seconds faster then you would on DOTs. Some times riders will actually go faster on DOTs if they are more comfortable on them. I know this was the case for our mechanic Will a while back. He was racing multiple classes with WSMC and some classes required DOTs (Superstock) and others woudl allow slicks (ModProd, Superbike and F2). I remember Will saying one weekend that he was gong faster on the DOTs then he could on the slicks because Dunlop had just released a new DOT that he really liked.

 

Also depeneding on the brand of tire you may not be able to get the exact same profile tire in both a DOT and slick. This would mean that you may need to make chages to your bikes geomatry to really get the best out of a set of slicks. These are changes you wouldn't want to make on a race weekend and this is why many times riders will run DOTs even in classes where slicks are allowed.

 

When I raced with WSMC on The Streets last year I ran DOT rear tires in all classes, even the ones where slicks were legal. I likeed the DOT rear better then the 17" slick that was available. Although I did run a slick fron in classes where it was allowed. In any case I set three lap records and won every race I finished that year racing on a DOT rear.

 

 

My point is, you will have to try it for yourself. Get a new set of DOTs mounted up and see how fast you can go. The mount up a set of slicks and do the same. Just know that you may have to make some settings changes to take advantage of each tire.

 

My advice, if you are somewhat new to the sport, is just run DOTs in all your classes, I doubt you will find that slicks are going to knock seconds off your lap times. DOTs are pretty darn good these days.

Is it not also the case that slicks can introduce or manifest instability issues in a chassis? IIRC, Superbike teams will often strengthen a production bike's chassis to account of the use of slicks to eliminate or reduce chatter issues.

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For sure Jay I have expeienced this myself.

 

It is interesting that chassis stiffness seems to be such a black art. A while back they used to brace frames to make them stiffer. Then that started getting more chatter and found they had to let the frame flex some. I remember the 998 had removeable frame struts so you could adjust the flex for differen tracks/tires. Yamaha even built a test frame for their motogp bike with dampers on it so the whole frame kinda acted like a shock. I hear ducati is going to a carbon frame next year, seems like a good idea as they can tune the flex in any direction.

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Chopperbill - I don't think anyone can answer your question. I think it is something that you will have to try to figure out for yourself.

 

There is no garuntee that if you put slicks on your bike you will be able to go x number of seconds faster then you would on DOTs. Some times riders will actually go faster on DOTs if they are more comfortable on them. I know this was the case for our mechanic Will a while back. He was racing multiple classes with WSMC and some classes required DOTs (Superstock) and others woudl allow slicks (ModProd, Superbike and F2). I remember Will saying one weekend that he was gong faster on the DOTs then he could on the slicks because Dunlop had just released a new DOT that he really liked.

 

Also depeneding on the brand of tire you may not be able to get the exact same profile tire in both a DOT and slick. This would mean that you may need to make chages to your bikes geomatry to really get the best out of a set of slicks. These are changes you wouldn't want to make on a race weekend and this is why many times riders will run DOTs even in classes where slicks are allowed.

 

When I raced with WSMC on The Streets last year I ran DOT rear tires in all classes, even the ones where slicks were legal. I likeed the DOT rear better then the 17" slick that was available. Although I did run a slick fron in classes where it was allowed. In any case I set three lap records and won every race I finished that year racing on a DOT rear.

 

 

My point is, you will have to try it for yourself. Get a new set of DOTs mounted up and see how fast you can go. The mount up a set of slicks and do the same. Just know that you may have to make some settings changes to take advantage of each tire.

 

My advice, if you are somewhat new to the sport, is just run DOTs in all your classes, I doubt you will find that slicks are going to knock seconds off your lap times. DOTs are pretty darn good these days.

 

 

I was running Pirelli DOT, Mediums. I bought a set of Dunlops DOT Race,(soft/front & soft-medium/rear) from the Superbike school. I did a track day,(at Thunderhill) last Saturday on the Pirelli's then switched to the Dunlops on Sunday. The tire guy at the track was a Pirelli dealer so he told me my bike would be set up completly wrong for the Dunlop tires and said that hey would over work my suspension. so I took two turns out of the ride height on the rear and increased the rebound damping on both front and rear. The Dunlops felt way better to me. Better holding power coming out of the turns, and the suspension seemed to work better. I'm going to Infenion this Saturday and Sunday, I'll report back what I think on Monday. By the way as soon as I'm finished with this post I'm signing up for level 3 & 4 for Infineon in March!

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I was running Pirelli DOT, Mediums. I bought a set of Dunlops DOT Race,(soft/front & soft-medium/rear) from the Superbike school. I did a track day,(at Thunderhill) last Saturday on the Pirelli's then switched to the Dunlops on Sunday. The tire guy at the track was a Pirelli dealer so he told me my bike would be set up completly wrong for the Dunlop tires and said that hey would over work my suspension. so I took two turns out of the ride height on the rear and increased the rebound damping on both front and rear. The Dunlops felt way better to me. Better holding power coming out of the turns, and the suspension seemed to work better. I'm going to Infenion this Saturday and Sunday, I'll report back what I think on Monday. By the way as soon as I'm finished with this post I'm signing up for level 3 & 4 for Infineon in March!

 

There are a few guys that have use both tires, and the normal comment is the Pirellie's are much softer, and that requires different suspension settings (as you are finding out).

 

Not familiar with your ride height adjuster, but for sure it was ride height, not preload?

 

Maybe Stuman will chime in, pretty sure he has run both tires.

 

CF

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I was running Pirelli DOT, Mediums. I bought a set of Dunlops DOT Race,(soft/front & soft-medium/rear) from the Superbike school. I did a track day,(at Thunderhill) last Saturday on the Pirelli's then switched to the Dunlops on Sunday. The tire guy at the track was a Pirelli dealer so he told me my bike would be set up completly wrong for the Dunlop tires and said that hey would over work my suspension. so I took two turns out of the ride height on the rear and increased the rebound damping on both front and rear. The Dunlops felt way better to me. Better holding power coming out of the turns, and the suspension seemed to work better. I'm going to Infenion this Saturday and Sunday, I'll report back what I think on Monday. By the way as soon as I'm finished with this post I'm signing up for level 3 & 4 for Infineon in March!

 

There are a few guys that have use both tires, and the normal comment is the Pirellie's are much softer, and that requires different suspension settings (as you are finding out).

 

Not familiar with your ride height adjuster, but for sure it was ride height, not preload?

 

Maybe Stuman will chime in, pretty sure he has run both tires.

 

CF

Wouldn't running a softer tire, mean that you need more compression damping to reduce "bounce"?

You'd change ride height if the tire change changed your geometry. Tire sizes can vary (from what I hear) even among same brand/type (production variances).

I don't understand why you'd increase rebound damping in this case.

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I was running Pirelli DOT, Mediums. I bought a set of Dunlops DOT Race,(soft/front & soft-medium/rear) from the Superbike school. I did a track day,(at Thunderhill) last Saturday on the Pirelli's then switched to the Dunlops on Sunday. The tire guy at the track was a Pirelli dealer so he told me my bike would be set up completly wrong for the Dunlop tires and said that hey would over work my suspension. so I took two turns out of the ride height on the rear and increased the rebound damping on both front and rear. The Dunlops felt way better to me. Better holding power coming out of the turns, and the suspension seemed to work better. I'm going to Infenion this Saturday and Sunday, I'll report back what I think on Monday. By the way as soon as I'm finished with this post I'm signing up for level 3 & 4 for Infineon in March!

 

There are a few guys that have use both tires, and the normal comment is the Pirellie's are much softer, and that requires different suspension settings (as you are finding out).

 

Not familiar with your ride height adjuster, but for sure it was ride height, not preload?

 

Maybe Stuman will chime in, pretty sure he has run both tires.

 

CF

 

 

I only changed the ride height because Thill is a faster,(more straights/less turns) then Sears Point where I had been running. The damping I have been playing with to get the right setting, (also based on the track). The tire change just added one more dimension to the equation. That's what I love about this sport. I'm a rookie at it, and it seems like there is ALWAYS something new to learn!

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