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DOT vs Slicks on MW bikes.

Discussion in 'General' started by Trainwreck, Nov 19, 2020.

  1. 2blueYam

    2blueYam Track Day Addict

    I was having issues, so I asked the Pirelli tire vendor at the track that day. He recommended I try it. I tried it and it worked. The bike felt better, I had more confidence, and the tires were noticeably warmer when I came off the track. The tires didn't show any unusual wear. This worked on both my 2003 R1 and later on my 2004 SV650 (Sc1 front in that case). Maybe it wouldn't work on a different track or on a different tire. If you are having issues keeping heat in the tire on a cold morning it is something to try. If it doesn't work for you, ask your tire vendor for a recommendation or even ask them first.

    Also, these are good ideas for cold morning track days for folks using race tires:
    1. On a cold windy day do not line up early for your session if you are using warmers. Missing a minute or three of track time beats skating around trying to get heat back into your tires.
    2. Don't sit around too long on a red flag on a cold day. If it is more than two or three minutes, head back to the pits and get the warmers back on. I didn't heed this once and ended up crashing.
  2. stangmx13

    stangmx13 Well-Known Member

    Careful with confounding factors, especially with the bolded part. Maybe your tires were warmer because ambient conditions for the 2nd session are almost always warmer than the 1st. Maybe it was because the first session finally warmed your wheels so more heat stayed in the tires (largest factor IMO). Maybe it was because you had more confidence because the tire vendor said it would work, went faster, and built more heat. Maybe it was because the 1st session cleaned/dried the track and you went faster. Chances are slim that lower pressure alone caused a drastic amount of extra heat.

    One of these days, I'll actually run an experiment to measure how much tire pressure affects heat generated. It'll be difficult to account for all the variables, but hopefully possible with a few riders that can turn consistent laps. If I had to guess, 1psi lower is getting you less than 5degF of tire temp (surface or carcass). I have a few reasons to think that, but it's still a guess.
  3. Peter Hively

    Peter Hively Registered

    Interesting discussion.

    I put an aftermarket TPMS system on my SV650 race bike so now I can see the pressure and the internal air temp on my dash.

    Among other things I've learned, if I get a good heat soak into the tires/wheel/air, then get stuck at pit out, it actually takes quite some time for the hot pressure to drop a whole lot. That used to make me really nervous but now I don't sweat it. The surface of the tire may cool off quickly but the carcass holds heat better than I might have thought.

    Also, just like the pros say, if you take it too easy on a cold track your tires will just be cooling off the whole time, you'll be losing temp and pressure, you need to get going, hard acceleration and braking will put heat into the tires, but of course be easy with the lean angle.

    Another time I went to go out and found out my rear tire warmer got accidentally switched off. So I had a hot front and cold rear. I went out and kept an eye on the pressure each lap. It took 10 whole laps for the rear tire to come all the way up to my hot pressure. So if you don't run warmers, the idea that one or two warm up laps then you're good to go is kinda BS, I mean it might be OK but be aware you'll be riding with different tire pressures every single lap of every single session.

    BTW I have found that for me, I get better results bumping the pressure up a little for cold morning sessions. I end up closer to the correct pressure out on the track, I don't get cold tearing, and it works fine. For me. YMMV.
    Last edited: Feb 19, 2024
  4. 2blueYam

    2blueYam Track Day Addict

    Wasn't a onetime thing. I had struggled at more than one cold Shenny morning, which is not unusual from talking to other riders including coaches. Some guys in advanced just didn't go out until the 3rd session. After I made the adjustment, I didn't have the issue as nearly as bad anymore. Sure, the mornings were still cold and slippery, but the bike felt much better, which gave me more pace and confidence which kept the tires from coming back into the pits cold and I had fun.
    I wouldn't try it at a fast track like Summit Main, Road Atlanta, Road America, or Pitt race, as you will likely get cold tearing. In fact, at Pitt Race I had to go up 2lb on the rear from my "normal" pressure to keep the tire from tearing.

    When I switched from my R1 to a 2nd Gen SV650 toward the end of my track career, I tried the same experiment, Worked the same way. With that said, the SV did have to be ridden a bit differently. It absolutely hated to be neutral in the very slow Shenny corners. The R1 was fine with smooth arcing lines through the range esses with just slight throttle adjustments, while the SV wouldn't get through there worth a damn without brakes, gas, brakes, gas, brakes, gas. One end or the other of suspension needed to be loaded at those slow speeds. Thanks to a couple of nice SM riders that I chatted with and followed through there a few times to figure out how to get the SV through there at a decent pace.
    PatricksDad likes this.
  5. Wheel Bearing

    Wheel Bearing Professional low sider

    I find this hobby of riding to be as simple or as complicated as you want it to be, and agree that there's 10 billion factors that are not the same across the board, thus impossible to randomly select tid bits of peoples experience and think it's relevant for your own specific case. People talking about adjusting pressure...ok...so what pace? what track? what temp? What compound? and so on and so on...

    I do agree that I think the universal thing that's applicable is 'don't fuck around on track' in colder temps. Did a lot of October days at PittRace with mornings in the low 40's and the day never broke 50 degrees. Never had a problem running my gold standard compound choice of Pirelli's SC2 front/SC1. No tearing or anything, but I also don't fuck around and sit on hot pit and 'take it easy to warm up' on the outlap and such. I basically go out and go into the first turn (T3 for Pitt) like it's a sprint race. clicked off mid 49s all day, not bad on a trackday that's chilly enough that you choose to keep your leathers zipped up when your in the pits.
    rd400racer likes this.

    MELK-MAN The Dude abides...

    take all this info in, but ALSO , get with your tire guy.. he will know you, your bikes, the track, etc. and if he doesn't now, he will. get the best info including tire psi and the like from him to start off. my 2c.
    rd400racer likes this.
  7. rd400racer

    rd400racer Well-Known Member

    You're right, good advice there. The research I've done this week comes up with 50 different answers. The one plus I've seen is that Tally warms up pretty quick during the day. It goes from 30 to 50 in a couple of hours.
    MELK-MAN likes this.

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