Track Tire Question

Chrome Dome · 06-18-2004, 2:59 PM

Question for you track heads:

How many track days should I expect to get out of a set of Dunlop 208 GP?

I have 2 track days on the set I have now (one day was on a track with mostly right handers and the other day was left handers). 2 more track days are coming up 2 days in a row so I'm wondering if it's OK to just use these same tires.

How can one tell when tires are getting close to the end? Traction? Wear indicators? Changes in the oil excrement?

Thanks in advance

tigerblade · 06-18-2004, 3:08 PM

There are going to be a lot of factors that affect this. What's your riding style? Are you using tire warmers? How many sessions per day? Ambient temperature? Abrasiveness of the track? Etc. etc.

I ran a set of 208GP's last year at VIR on the RC51 for two days and I think they still had some life left. I don't think they would have lasted another two whole days though. You'll probably be able to feel when they've gone past their useful life.

I probably change tires too often, so maybe some of the others can give a little more help.

Chrome Dome · 06-18-2004, 3:46 PM

Good questions...

No tire warmers

The track that I ride has a ~1:26.32 lap record and my lap times hover around 1:49. I ride in the intermediate group during track days

The track is pretty rough I think but I only have one other track to compare it to

Ambient temp was 55 in the morning and 65 degrees in the afternoon

6 20 minute sessions per day

How much would tire warmers help preserve the tires under these circumstances? If it's fairly significant then I think I need to get a set as my next purchase

tigerblade · 06-18-2004, 3:49 PM

Apart from just getting the tires up to operating temp, warmers also help cut down on the heat cycles. Race tires will be toast before the actual tread is gone because of the heat cycles they go through. They lose their grip before you're running on the cords. Even on a 90 degree day, as I read somewhere, "90 ain't 190".

Red Rider · 06-18-2004, 3:55 PM

Depending on how hard you ride, typically it's the number of heat cycles that determine how much life your tires have left. Something happens (so I've been told) to the rubber compound from repeated thermal cycling which causes it to lose it's adhesion capabilities. Bluing of the tire can sometimes be an indicator. Tire warmers allow you to keep the tires at operating (track) temperatures between sessions, thereby eliminating the thermal heat cycling. Regular street tires are less susceptible to heat cycling as compared to DOT race rubber. Tires that have reached the end of their cycles usually start to slip and slide more. I have yet to replace a set from excessive tread wear.

The question you have to ask yourself...do I want to save a couple hundred bucks today on new tires or spend a couple grand on new plastic tomorrow!

I'm sure others here more knowledgeable on the subject will chime in...

Ernie · 06-18-2004, 4:00 PM

Given that I have to replace tires pretty often, I will run D208GPs for four days, maybe five. Five is pushing it for me. They are very good about showing their life wear.... Meaning if they are getting too old they will start to slide gradually. Never had a problem with 4-5. This is moderate pace track days with some fast laps. Race pace is a whole other story, you don't want to push it that much.

My CBR1000RR is running 3-4 days on a set, but I think I will start replacing the rears and keeping the front for another day or two.

Ernie

Chrome Dome · 06-18-2004, 4:04 PM

Quote:

Originally Posted by Red Rider

The question you have to ask yourself...do I want to save a couple hundred bucks today on new tires or spend a couple grand on new plastic tomorrow!

Yes, I hear ya... I'm just trying to figure out how close I can get to that line without crossing it. I know the answer isn't as simple as "3 track days per pair of tires" because there are just too many factors. I'm just trying to gather as much info as I can to make a "reasonable guess." I'm new at this whole track thing

Chrome Dome · 06-18-2004, 4:06 PM

Quote:

Originally Posted by Ernie

Given that I have to replace tires pretty often, I will run D208GPs for four days, maybe five. Five is pushing it for me. They are very good about showing their life wear.... Meaning if they are getting too old they will start to slide gradually. Never had a problem with 4-5. This is moderate pace track days with some fast laps. Race pace is a whole other story, you don't want to push it that much.

My CBR1000RR is running 3-4 days on a set, but I think I will start replacing the rears and keeping the front for another day or two.

Ernie

Hmmmmm.... Very interesting Ernie, thanks for the info.

I pushed 4 track days out of a set of BT012 and on the 4th day they were sliding (no surprise... they were ragged). I think the 208 GP should wear slightly better...

Are you using tire warmers?

rawrider · 06-18-2004, 4:42 PM

Quote:

Originally Posted by Chrome Dome

Hmmmmm.... Very interesting Ernie, thanks for the info.

I pushed 4 track days out of a set of BT012 and on the 4th day they were sliding (no surprise... they were ragged). I think the 208 GP should wear slightly better...

Are you using tire warmers?

If you were able to do it on the BT012's then you should be able to do it with the Dunlops. But there's nothing like knowing you have good rubber underneath ya

02FBlade · 06-18-2004, 5:43 PM

The most grip you will ever get out of a tire is on lap 2 (or after it's scubbed and hot) then it's all down hill for the grip. You can run them until there not much tread left but they get to slippn for me after 3 20 min. sessions....2 really. They still have about half the tread left but are not for running your best times. I usually go through 3 rears to one front. (standard 240 compound rears).

You may get 2 full days (lol) out of a set if you not laying darkies out of turns yet....so much to this answer depends on your riding. Chassis setup along with tire pressure also make a difference...your tires should be relatively 'clean' from edge to edge. If they are chunking really bad you got a setup problem.

Warmers....another thing they help prevent is cold tears. The tears eat up a little more rubber. They won't give you that many extra laps than if you didn't use them. They mainly save on heat cycles. Race rubber isn't designed to go through many cycles like street tires. Each cycle gets the tires just a bit harder (less grippy). Warmers are nice to have but not nessicary just for track days. But it's nice to know the tires are nice and toastie when you get out on the track. Without them give your tires at least 5 laps to completely get up to temp...easier said than done..I always had some cold tearing on the fronts casue I can't wait. Race rubber normal operation temps are around 175. Even with warmers you still have to be careful. They are a must for racing.

If you want I can sell you a spare used rear...assuming there will be tire service at your trackday. Most of mine are 70-80% tread on the good side, 40-50% left on the bad/worn side. Just tell me what side you need the most rubber on and I see if I can hook you up. They are all 180/55/17 std-240 compounds.

Reckless929 · 06-21-2004, 9:51 AM

Quote:

Originally Posted by Chrome Dome

Question for you track heads:

How many track days should I expect to get out of a set of Dunlop 208 GP?

I have 2 track days on the set I have now (one day was on a track with mostly right handers and the other day was left handers). 2 more track days are coming up 2 days in a row so I'm wondering if it's OK to just use these same tires.

How can one tell when tires are getting close to the end? Traction? Wear indicators? Changes in the oil excrement?

Thanks in advance

You should be able to get 3 1/2 - 4 days on set of GP's for an intermediate rider. I have gotten four days before feeling them slip around on track days.

In Racing usually two days using warmers.

You can read the tire pretty well by no only the bluing but look at the profile of the tire from behind or front, you will see the an angle forming the shape of a A when the sidewalls wear out and center tread still looks new.
Hope this help, if you feel them slipping around when hot you usually know they are getting worn.

Listen to the feedback of the tire or you will suffer the message if ignored! I found that the hard way ..... highside!

Reckless929

Chrome Dome · 06-21-2004, 12:09 PM

Thanks for the advice... I'm going to try 4 on this set and see how it goes. Normally, I'll shoot for 3 but one of the track days on this current set is on a right-hander track and the remaining three will be left handers (not sure if that matters much).

Also, the next two track days are back-to-back so I won't have time to change out the tires. But if I notice any slippage I'll just buy a new set at the track