How to evaluate life left in used slicks?

mdhokie

Member
I recently bought a track bike for next season, and the seller gave me 5 sets of used race slicks (Dunlop) and a set of race rain tires. Some are smooth, some are rough, some have the blue on the outside and some don't, but I know the outside appearance changes pretty quick and can go from gooey and shredded to looking pretty smooth with just a few low speed cool down laps, and vice versa. I see the little holes which I assume are wear markers, but I'm not sure what the depth is new, and how low is okay. I have also been told that tread wear is often less of a consideration than heat cycles, though I don't really have any way to evaluate that just from looking at it do I?

Anyway, I'd like to get the useful remainder out of the tires if I can, but does anybody have any useful advice for determining which of the tires are best and how long it's safe to use them?

On a related note, if anybody is reasonably local to Annapolis MD and wants the rain tires (in excellent shape), let me know. I don't plan to ride in the rain if I can help it, and I will probably have Q3s on my spare wheels instead of rain tires.
 

Ron R

Member
It’s just my opinion But I look at it like this. I’ve bought a $2000 suit , made reservations at the best restaurant in town and got my lady a great piece of jewelry. Now I’m getting in the shower at the 5 star hotel we’re staying at and instead of using my favorite shower gel I see a used bar of soap someone left behind. Couple of hairs stuck to it But I’m thinking that bar has got a few showers left in it right!?
Nah
Hope I painted a picture.
 

mdhokie

Member
I answered one of my own questions from Dunlop's FAQ:
How many Heat Cycles can I get out of a tire?
Heat Cycles is not an issue with Dunlop racing tires as it would be with other brands. The more important factor is how much tread is left on the tire. Stable fact: thicker rubber has more grip and develops more heat, thinner rubber has less grip and runs cooler. After each session you have less grip. As the tire wears out, you have less and less grip. It could be slight or it could be large.

Some riders call it heat cycling, but, in actuality, its the rubber getting thinner and thinner. It truly depends on how much the tire is worn out, and your specific demands for grip that determines when the tire is not usable for you.
 

mdhokie

Member
@Ron R -- I understand the logic and sentiment behind what you're saying, but there is always a calculated money/risk tradeoff to consider. If I can save $1000 on tires, that's over half the entire amount I spent on track days last year including registration, gas, tolls, and lodging. It's not quite the same ratio as your extravagant night on the town and the bar of soap. It depends on how much money you've got to spend though and how measured a risk you're evaluating. If it's not going to make it harder to pay the bills either way, why risk your bike and health...why not get new tires for every track day? Not advocating disregard for danger either, but I think riding a motorcycle on the track at all shows that we are all willing to take calculated risks.

Another tradeoff I've had to contemplate: If I had ABS I probably wouldn't have had a 100mph crash last year from my front tire locking up while braking. It cost me $50 in first aid supplies, $700 bike parts, $900 gear replacement, and two months of changing bandages. But I got a 2010 R1 without traction control and ABS instead of a 2015 R1 with both of those, because it was $5000 cheaper. I'll just have to be more careful.
 

Ron R

Member
Believe me I look for ways to save a buck and I tried the used tire deal. Mine were actually brand new in use but older in years. They worked really good until they got very greasy very quickly and I went down. So I’m a little jaded on tires. A better rider may have saved it. I see people buying take offs all the time so I’m sure some of those are probably fine. And I hope you get some good info and I wish you all the luck.
 

mdhokie

Member
So let me phrase the question another way: for everyone who uses those tires or similar...do you have a notion of what depth your tread life indicator was at when you decided the tires were done?
 

bmart

Control Rider
I'm glad that you posted something about heat cycles. A lot of folks continue to talk about this but I've never seen it as an issue in modern times, and I heat cycle the crap out of my tires...

With regard to wear on the used ones you got, I would say look at two things:
1) high/pointed spots. If you have those, you're going to have decreased grip when using that part of the tire due to a smaller contact patch, even though it is thicker than the rest. You can gently wear that area down with some gentle, careful work in a few sessions. Just ask my buddy Bryan!
2) thin spots. You're going to be challenged to keep the proper heat in that portion of the tire. The high points usually come with one thin area next to the high spot or two creating the high point in between. Those thin areas cool off a lot quicker than the thicker rubber.

At NCBike for instance, you can wear down a high spot in the looooong left turn, if you are very careful and patient. At the same track, you would have to be very careful on a thin left side in turn 3 and the looooong left hand turn, as heat would have quickly been wicked out of that area of the tire starting before the end of the previous lap. When you're looking for grip for a very tight turn 3 or for consistent grip in the loooong left turn, you are likely to be disappointed.

On a tire not on a rim, it is very easy to feel how thick the rubber is with your hands, one inside and the other on the outer tread in the same spot. It is also much easier to see the high points when the tire if off of the rim.

Also, most slicks have dots to check for rubber depth, but only in limited locations on the tire.

Feel free to post pics!
 

Kruizen

Control Rider
Everyone has covered the slicks above.

Might be interested in the rains. Can you send me a picture.
757-814-198 seven
 

Motofun352

Control Rider
Another thing to consider is age. Check the imprint on the sidewall, 4413 means the 44th week of 2013 and the tire will be nearly 5 years old by next season. Tires do age (very slowly) as the volatile components in them out gas. The blue tint you see is a sign of this. How old is too old? Well, now you're on your own here. For me, 3 years with track rubber...assuming proper storage over winter.
 

vinny337

Vin is in...Beastmode!
Control Rider
Congrats you just bought a new to you bike for this season, why not sell the take-offs and get yourself some new tires? There's nothing wrong with take-offs if you have the experience to use them. Look at it this way, if you crash using another riders take-off consider the cost to repair your bike, the cost for gear and not to mention you will still need new tires. Also, just for the record, the ABS on the new R1 will NOT prevent you from crashing, you still need to be smooth with your controls.
 

D-Zum

My 13 year old is faster than your President
New Tires are cheap insurance. Buy a new set to start the season so you know what you have to start with.

http://stores.racetireservice.com/DUNLOP-SLICK-KR448KR451-SET-120-200/

It was easier to give you the 5 sets of used tires than to take them to the dump for the seller.

I mean when the Home Coming Queen finally says, "Yes" do you go with a used condom, or do you rip the wrapper off a fresh one?

Cutting corners never ends well.
 

bmart

Control Rider
Aside from the Q3 rears I run sometimes, I never run new or current tires, but I hear that they feel great! My budget for track time would never accommodate such an extravagance!
 

LarsDunaway

Rat Boy
Staff member
Control Rider
I'm in the same boat, Brad. I won a few novice championships on take-offs :) That said, I wouldn't recommend it to anybody unless they're riding at a level sufficient to explore the limits on each set of tires, and not go any further. Otherwise, it can cost them a lot more than just buying a new set of tires. Basically, unless the rider rides in our advanced group, probably not worth the risk.
 

2blueyam

Member
My bike is fairly easy on tires and I have been doing track days on it for 9 years, so I generally know when something is amiss with the bike or tires by now. I run my Pirelli or Michelin slicks until one of the following happens:

Rear tire:
  • One of the wear dots is basically gone.
  • The profile is shot (usually the shoulder area in between the middle of the tire and edge of the tire for me and my R1).
  • I start to feel it spinning up coming out of corners (usually this is a sign of the profile being shot - see above). I usually finish a day on these if there are only 2 or 3 session left by taking it easy with the throttle coming off the corners. I use it as a time to work on BP or corner entry.
Front tire:
  • One of the wear dots is basically gone (never really happens in the 6-8 track days I do per year).
  • I put an a fresh one to start the year, even if it looks like there is still a little life in it.
It was interesting to hear about the left side at NCBike. I pretty much never have an issue there as I am not really accelerating hard coming off that corner. Actually I rarely get rear tire spinning anywhere at NCBike or Shenny. Exiting Summit Main turns 2, 9, 10, Pitt Race turns 5/6 and 17/18 are where the old R1 likes to get the rear spinning as it starts to wear out.
 

buzz-06

Member
Congrats you just bought a new to you bike for this season, why not sell the take-offs and get yourself some new tires? There's nothing wrong with take-offs if you have the experience to use them. Look at it this way, if you crash using another riders take-off consider the cost to repair your bike, the cost for gear and not to mention you will still need new tires. Also, just for the record, the ABS on the new R1 will NOT prevent you from crashing, you still need to be smooth with your controls.

I'd like to touch in this particular line right here @mdhokie. How much experience do you have running take-offs? Do you know how to feel a tire out and figure out what it's still capable of? Take-off's are great, infact I normally race on take-offs, it's very rare that I buy new tires. But I also have a lot of experience riding on an old tire and know how to feel it out and find it's limits. If you're confident in your ability to ride on the tire and feel it out then ride em. Otherwise sell them cheap and buy a new set
 

mdhokie

Member
@Kruizen has the rains.

How much experience do you have running take-offs? Do you know how to feel a tire out and figure out what it's still capable of? Take-off's are great, infact I normally race on take-offs, it's very rare that I buy new tires. But I also have a lot of experience riding on an old tire and know how to feel it out and find it's limits. If you're confident in your ability to ride on the tire and feel it out then ride em. Otherwise sell them cheap and buy a new set

None. This is a very big part of why I am asking all the questions about tire life. I would very much like to gain the experience to be able to feel what my tires are telling me, but I don't know if I'm there yet. As of the end of last year (my first full season going to the track) I was riding the slower half of intermediate group. I am usually very smooth on the throttle, and quite cautious that I have taken away almost all the lean angle before I go WOT. So I will probably not be pushing the limits of the tires except under braking. At the pace I was riding last year on my FZ1 and the Q3 tires, I never felt the tires give me any complaint except for a few bad downshifts and once under low acceleration when I hit some wet spots on the track (that sealant patch in the horseshoe turn at NJMP). There was a little shimmy/slide, and it recovered full traction pretty quickly. How do you get experience for the feel of tires at the edge except by taking them to the edge? Is it safer playing with the edge of traction with used-up tires at a lower threshold, or with new tires when you have to push a lot harder to get there?
 

bmart

Control Rider
Now there's a can of worms question!

A lot of riders come to the track to see how fast they can go (MPH or lap times). I'm a firm believer that the whole point of track time is to develop the rider...not the bike.

While I don't suggest that folks explore the limits of their '80s GoldWing on touring tires in the advanced group, you can learn a lot inching up to the edge-limit of whatever package you have (including the tires). My $.02 (surely worth less) would be to run the tires you have assuming that they don't have a significant point/high spot, and that you can still see some depth to the holes in the slicks.

I've run significant pace on bikes with 10+ year old street tires. Up to a point, they work fine...then they don't. I've also had my VFR (and previously FJ1200) on the track on sport touring tires. Those tires show their limits pretty early in a track environment, but then you know where that limit is, and you can adjust your riding (building skills and your toolbox) to adjust. Throttle and braking application, body position, etc.

Tires aren't likely to just "up and fail" everywhere. Just about every slick, sport, and sport touring tire made in the last ten years or so is pretty outstanding and beyond most of our capabilities. Many of the tires I ran this year were 2011/2012 vintage. They never moved a mm at any speed or lean angle I threw at them. And none of those were slicks, they were all DOTs. Your comment about smooth should be taken to heart. It is the skill that will help you the most by allowing you to keep from having grip issues, or be able to get through them safely when they do occur.
 

buzz-06

Member
@Kruizen has the rains.



None. This is a very big part of why I am asking all the questions about tire life. I would very much like to gain the experience to be able to feel what my tires are telling me, but I don't know if I'm there yet. As of the end of last year (my first full season going to the track) I was riding the slower half of intermediate group. I am usually very smooth on the throttle, and quite cautious that I have taken away almost all the lean angle before I go WOT. So I will probably not be pushing the limits of the tires except under braking. At the pace I was riding last year on my FZ1 and the Q3 tires, I never felt the tires give me any complaint except for a few bad downshifts and once under low acceleration when I hit some wet spots on the track (that sealant patch in the horseshoe turn at NJMP). There was a little shimmy/slide, and it recovered full traction pretty quickly. How do you get experience for the feel of tires at the edge except by taking them to the edge? Is it safer playing with the edge of traction with used-up tires at a lower threshold, or with new tires when you have to push a lot harder to get there?

safer with used vs new...eh.... tires sliding around is a byproduct of speed, the faster you go the more you start accelerating sooner and therefore the more the tire is gonna move. You can be smooth and still slide the bike around, it's just part of what happens when you go faster. Will the used tire start moving sooner than the new tire, well sure the level of grip is less...but if you don't accelerate hard on the side of the tire it won't really move at all. Feeling out the rear is much easier than the front, but I'd be willing to bet those tires have more than enough life in them and will treat you just fine.

As far as your actual question, I look at the shape of the tire, does it have a low spot in the middle of the side (this is where hard accelerations happen). If it has that low spot then it's junk, it'll feel terrible when you roll over the edge into that low spot and it'll spin a lot easier. Do the tires have wear dots on each side? Are they pretty defined or almost gone? Defined dots is a good sign, almost gone is junk. When you poke the tire with a fingernail does the indentation come back out? If it does that's good, if it stays in the tire is getting hard and therefore less grip.

Compound codes, the fronts are gonna be 7455, look at the rear's....do you see a 7455, and 8477 or a 2662? 2662 is the soft and they suck after being heated up and cooled down, 7455 is the medium, works pretty good till it's worn out, 8477 is the medium+...I hate that tire lol. Hopefully this information helps
 
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