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How much does rain actually effect tyre grip / performance?

Discussion in 'New Riders and Riding Tips' at netrider.net.au started by aerodynamic, Feb 12, 2009.

  1. So ive been riding around in the rain the last couple days, ive been being VERY cautious going around corners / round abouts and what not.

    I just wanted to know in like, a fraction or w/e how much the rain actually effects the tyre grip? I dont really notice anything, but im not as happy to freely bring the bike down into turns.

  2. I think last time this sort of thread came up, FLUX, Robsalvv and I devised this equation:

    When you plug all the variables in, the answer comes out to be 0.68.

    (If only it were that simple :grin: )

    Short answer is:
    If the road surface is good and the tyres have plenty of tread left, and are warm, the difference isn't that great. But that assumes that there's no oil or whatever on the road.

    Too many variables to give a good answer though. There could be diesel or oil - especially at traffic lights and intersections. That stuff's like ice. Pooled water causing aquaplaning at speed, painted markings, steel plates, wet leaves, cold tyres.....
  3. Manhole covers, bridge connections (those steel girder like things) and those black 'road snakes'... all slippery as hell in the wet.

    I am the world's biggest pansy when the road's wet though :).
  4. Its actually amazing how much grip tyres have in the wet once they're warm of course. Even in heavy heavy torential rain i'm always suprised as to how planted a bike feels.

    Having said that be sensible and ride to the conditions.

    I just try to be smooth, give plenty of braking room, don't accelerate too hard and don't lean the bike over too much.

    When its wet i just try to get from point A to B as smoothly as possible...leave high speed corner/lean angles for those nice dry sunny days.
  5. +1 ^^^ what they said
  6. I only choose wet days to crash! :LOL:

    Just take it easy for the first 20 minutes and avoid all the crap on the road.

    I hit a tar snake going 80K's around a slight bend near my place and let me tell you that very nearly ended in tears.... If you have the slightest of angles in the wet, make sure you have warm grippy tyres and that you are NOT going over anything but tar at the time!

    Whilst the bike can feel very stable in the wet, it doesn't take much to lose traction as things that are already slippery like painted road markings or tar snakes are just that little bit better lubricated for a healthy dose of shiny side down.
  7. once the tires are warm. theres plenty, obviously not as much as when its dry though :p

    oh and. i prefer to ride after a huge rain then a small shower. :)
  8. what are "tar snakes"?
  9. Joel will probably chase after me for incorrect use of terminology or something, but they're a type of repair used to seal cracks that have formed in the road surface.

    They look like glossy black 'snakes' on the road surface, and they are quite slippery when wet. Not exactly grippy in the dry either.

    Edit: Found a photo!

    Visit images.google.com and search for "Tar snakes" for more :)
  10. I went riding yesterday through the rain and I too was curious to know where my traction limit was. After about 40mins riding I was getting up a little confidence and decided to go a bit faster through a round about to see how the bike would handle with a bit of lean angle... I really didn't go that fast or lean the bike that much (esp compared to how fast I can go through that round about in the dry), anyway I had the front tire lose traction and slide out a good foot before I managed to stand the bike up again. Scared the absoloute Bajeesus out of me. I was sure the bike could handle it and even though I thought the road surface was fine, it must have been too smooth and too wet.

    I don't think I'll try that again in the rain. Better to take it easy than to risk dropping your bike and having to fix it :p
  11. + another (what they said)

    ohhh. bloody tram tracks are fun in the wet :mad:
  12. I'm little cautious of round abouts in the dry. For some reason alot of em can have oil build up.
  13. I found a nice oily, fuel covered corner last Wednesday and had my first spill since getting my license a little over 4 months ago. As soon as I started to turn (only at about 20kms max, with little to no lean, was being super cautious.) front decided to step out completely and throw me off the back of the bike, face first into the road.

    Good thing it's only a posite, would have been well annoyed if I had upgraded already.

    I only need a new right mirror though, probably should get a new helmet visor too..
  14. a road with good drainage and a fairly new DGA (dense graded asphalt) surface will give you moderately less grip in the wet than in the dry, however - in practice most roads in Australia suffer from the tar rising to the top and pancaking during hot days, leaving a smooth slick surface.

    the biggest difference i feel is what happens just after you break traction:

    in the dry you can end up with a controllable power slide because there is still a decent amount of friction.

    in the wet, once you lose traction, the water gets between the wheel and the road and acts like a lubricant, causing 'catastrophic failure' so to speak.
  15. There are corners which just collect all that grub. Especially in industrial areas.

    There was a roundabout around the back of an industrial area in rydalmere, I learnt a lot about about opposite lock at ~10-15km/h because it was just that slippery in the wet, you had to go sooo slow around there. I even drifted flatbed trucks around the thing.

    I would never take a bike there in the wet, some places are just deadly.
  16. No, it's amazing how little of the available grip most riders use in the dry.
  17. Rain itself doesn't effect traction as much as you'd think, but the oil coming out of the road because of the rain - thats the killer.

    The places to be extra careful are at intersections, roundabouts, carparks - anywhere that cars are slow/stopped often as obviously thats where the oil will be most concentrated.

    The time to be extra careful is when its raining after a long dry spell as there will be alot of unwashed away oil. Especially if its a light rain as the oil comes out but isn't washed away its just sitting on the surface.