Braking distance 30mph downhill

Cool4catz
Cool4catz Posts: 76
edited May 2013 in Road beginners
Hi guys, anyone know what the braking distance is on a standard road bike hoofing it downhill in dry conditions. Without using your face as an auxiliary brake. Also other than just holding tight and hoping for the bet, is there any techniques to stop quicker and staying upright?

Comments

  • markos1963
    markos1963 Posts: 3,724
    Find a hill you can go 40mph and then you don't have to worry about stopping from 30mph!
  • sharky1029
    sharky1029 Posts: 188
    Braking distance depends to much on weight of bike and rider, brakes and tyres on the bike.
    The best technique is to pull the levers as hard as possible without locking up the wheels however if you know you have to stop you want to be a little more controlled so brake earlier than you would.

    To find out braking distances find a straight hill you can easily get up to speed on and safely stop abruptly and then you can work out rough distances from various speeds and how hard you have to pull your brakes to stop ASAP.
  • Cool4catz
    Cool4catz Posts: 76
    sharky1029 wrote:
    Braking distance depends to much on weight of bike and rider, brakes and tyres on the bike.
    The best technique is to pull the levers as hard as possible without locking up the wheels however if you know you have to stop you want to be a little more controlled so brake earlier than you would.

    To find out braking distances find a straight hill you can easily get up to speed on and safely stop abruptly and then you can work out rough distances from various speeds and how hard you have to pull your brakes to stop ASAP.

    Good point on the weight which I could do with losing. I cycle around very quiet Ayrshire roads and you get complacent about transit vans coming up the single track road. I'll take your advice and practice some hard braking, though might wrap myself in bubble rap first!
  • sungod
    sungod Posts: 16,547
    for hard braking, the priority is to have your weight low and right to the back, the usual position for descending

    most braking force is on the front, if your weight is too far forward the rear wheel will unload and you'll lose control, so keeping weight at the back is vital, then you can use a combination of front+rear to get maximum braking force

    it's a matter of experience and reading road conditions, practicing hard stopping when you don't need to will prepare you for the time you have to do it for real

    on skinny tyres, any gravel, grit, dirt on the road can play havoc with grip, and in the rain wet rims+pads will increase the time before brakes are effective, if i'm following traffic i leave waaaaay more space than a car would
    my bike - faster than god's and twice as shiny
  • keef66
    keef66 Posts: 13,123
    A question I was left pondering when I was meant to be revising for my A levels but was in fact out riding my bike. This was back in the 70's when the police were allowed / inclined to take an interest in a lone teenage cyclist who appeared to be at large during term time. I was coming down off the N York moors at Sutton Bank. Plod was parked up in a layby and tried to flag me down. I must've been doing 35mph when I went past him, brakes squealing. Probably 150 yards before I'd slowed sufficiently to effect a U turn and grunt my way back up the hill for a mild inquisition.
  • Pross
    Pross Posts: 40,535
    Sit up high to use your body's air resistance to slow you down and get your weight back. Feather the brakes.
  • farrina
    farrina Posts: 360
    keef66 wrote:
    I was coming down off the N York moors at Sutton Bank. Plod was parked up in a layby and tried to flag me down. I must've been doing 35mph when I went past him, brakes squealing. Probably 150 yards before I'd slowed sufficiently to effect a U turn and grunt my way back up the hill for a mild inquisition.

    Brings back happy memories of me descending a hill at circa 35 mph and going through a radar trap. Plod confined himself to shouting slow down, which was just as we'll as if he had stepped out in front of me to stop me I would not have been writing this now!
    Regards
    Alan
  • markhewitt1978
    markhewitt1978 Posts: 7,614
    Was going down a hill towards Grinton last weekend, hands clamped around the brakes as hard as I could, still going 10mph. Luckily I didn't need to go any slower, as the only way I could have gone slower would have been crashing.
  • kingstonian
    kingstonian Posts: 2,847
    keef66 wrote:
    A question I was left pondering when I was meant to be revising for my A levels but was in fact out riding my bike. This was back in the 70's when the police were allowed / inclined to take an interest in a lone teenage cyclist who appeared to be at large during term time. I was coming down off the N York moors at Sutton Bank. Plod was parked up in a layby and tried to flag me down. I must've been doing 35mph when I went past him, brakes squealing. Probably 150 yards before I'd slowed sufficiently to effect a U turn and grunt my way back up the hill for a mild inquisition.


    I had a similar experience in the 80's, went flying down a long hill in Enfield where i grew up (think it was Lavender Hill) and went past a copper at well over 40 mph. Took at least 100 yards of serious braking to stop and then get a 10 minute lecture !!!
  • pride4ever
    pride4ever Posts: 510
    These threads are fast becoming a joke.
    the deeper the section the deeper the pleasure.
  • dodgerdog
    dodgerdog Posts: 292
    It seems this thread is going downhill fast :lol:
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