PunctualAlex

Well, not actually my bike, a friend's bike which I was borrowing due to extenuating circumstances. It was a Trek 600 (I think) with V-brakes, but that's all I really know about it. Anyway, here's the part I was curious about: One a few occasions I had to brake very suddenly and from high speeds because I was biking behind a very inexperienced and cautious rider. On the first occasion the rear wheel lifted off the ground of it's own volition and I did a surprise front-wheelie for 3 or 4 seconds before crashing back down. The second occasion wasn't quite as fun: The bike stopped dead and I got tossed over the handlebars into traffic. I'm perfectly OK after the crash, just a little sore, but I am curious:

I usually ride a road bike and even during extremely quick stops I've never had any problem with balancing my weight or staying on the bike or anything. But the first two times I tried to stop this bike, I end up airborne. The only explanation I could think of is that when I braked, my weight was shifted to the front suspension which compressed and my center of gravity carried me over, but the suspension didn't have a great deal of travel and the difference was extreme. So why is it that the mountain bike tossed me but my roadie usually doesn't?

Chone

Body position I wager.

C Law

mountain bike brakes usually have more power than road brakes. Therefore, your mass will be rotated forward more quickly and you have to brace yourself and keep your weight from moving forward on the bike.

Jr8Fan

Could it be partly the tires too? Mountian bike tires are more knobby = more grip. Just as that helps in travel traction, could that also help in braking traction? Slippers slide across carpet, hiking boots and shoes catch on the same carpet. Could be part of itmaybe, or maybe I'm just grasping at straws here.

cryptid01

Yep.

cream.soda

try getting off the seat and shifting your weight over the rear wheel. maybe his brakes were tuned so that the front brake was a lot more sensitive than the rear brake.

gattm99

yeah the more rubber on a surface the better the traction, knobbies are designed to hook up with uneven rough surfaces. A smooth tire will have more traction on a smooth surface.

PunctualAlex

Yeah, it was on pavement so the tires wouldn't've had anything to do with it. The only explanation I can think of is that I will have to balance my weight differently on that bike as opposed to my normal bike (duh)

redallerd

May be also because of the smaller wheels of the mtb. The rider is higher than the wheels compared to the road bike's and its easier to go over the bars when stopping sharply so that's my point of view

a2psyklnut

I think the issue is body position on your bike. With a road bike, you are in a tucked position with your shoulders dropped down. This distributes your weight across a horizontal plane. With a mountain bike, you are sitting up more. When you locked up your brakes, you had less weight shifted rearward.

Another thing that probably added to the situation is that you were on a borrowed bike. The brake setup may have been different to what you are used to.

dalmore

I'm kinda new to mountain biking and I've been a little unsettled by the suspension compression so I hear you.

But I really suspect it's a matter of mountain bikes having stronger brakes than road bikes and a matter of not being used to them more than anything else.

Chrizz

yep, get off the seat and lean back using both brakes, that should give you the quickest stop. If you start to fly then release the front and find an alternative route... quick

skiahh

Well, technically, you fell off the bike. A bike is an inanimate object and can't "throw" anyone. Riders, on the other hand, can screw up and throw themselves OTB or wherever.