Braking, or not braking

[allen-uk]

Not a subject I'd ever thought I'd be discussing, but tell me the stopping distances on bikes (over say 25mph - under that I know already!) Are they comparable to cars, or does the lower vehicle weight make them easier to stop from those (to me) enormous speeds?

A

 

[indalo]

allen-uk, my feelings about the massive, (to me) bike speeds being quoted in this thread are much the same as yours, I think.

When I hit 25 mph on my "sit up and beg" style Dutch bike recently, I reckoned that was plenty fast enough on that particular machine. The riding position is such that one is discouraged from going much quicker due primarily to the un-aerodynamic influence, not to mention the wind noise which probably makes one oblivious to traffic approaching from behind.

The old-fashioned handlebars don't lend themselves to fast riding either and I'm sure straight bars would be better in that regard. Having said all that, old-fashioned Dutch bikes aren't really about speed. They're lovely for riding at an easy pace and they're perfect for places like Oxford and Cambridge where they just look right.

If I ever have the urge to cover lots of miles really quickly, I'll buy a bike that's designed for that job. In the meantime, I'm content with riding at speeds in double figures beginning with one!

Indalo

 

[flecc]

I doubt most bicycles could get near to matching the stopping performance of the best cars.

But that's not necessary for what we are speaking of with these high speeds. For example, the hill I've used for my highest speeds has no side road entering it on the test stretch and has plenty of clear view width on the left side to detect any approaching activity, human, animal or machine, so giving plenty of time to slow or stop. The opposite side is a continuous very solid high brick wall.

I wouldn't be cycling downhill at 50 mph on any road that has side roads entering or concealment such as hedges for anything to burst out suddenly.
.

 

[aseb]

I think the 45 mph was mine, aseb - it was a very steep hill near Byker in Newcastle.

Shields Road too busy, I'd guess Byker Bank (but the going up the other side must be fun) or down to quayside. Or Church Bank as it's longer but thats Wallsend way. I'm about 10 miles north of you, fairly similar banks but not quite as long. My bike is a step through style and I wouldn't feel safe going any faster. And I only do that when the roads are clear, I've passed too many lorries using the whole road, and wandering car drivers. It's not something to be done too lightly.

 

[lectureral]

I think it was Byker Bank - I used to live on the Quayside and would occasionally go up to Morrisons. Moved quite far away now, though!

 

[allen-uk]

The opposite side is a continuous very solid high brick wall.

I wouldn't be cycling downhill at 50 mph on any road that has side roads entering or concealment such as hedges for anything to burst out suddenly.
.

Glad to hear it, flecc, although that very solid brick wall causes raised eyebrows!

A

 

[Streethawk]

I can stop considerably quicker on my mountain bike (hydraulic disc brakes) than i can on my 1200cc 240kg sports motorcycle from similar speeds, which has similar, but bigger, brakes. The motorcycle is similar to a car in stopping distance.

 

[flecc]

I can stop considerably quicker on my mountain bike (hydraulic disc brakes) than i can on my 1200cc 240kg sports motorcycle from similar speeds, which has similar, but bigger, brakes. The motorcycle is similar to a car in stopping distance.

From common cycling speeds maybe, but from 50 mph? Somehow I doubt it.
.

 

[aaannndddyyy]

From part of Sheldon Browns web site.

Braking--Front, Rear or Both?
Since your bike has two brakes, one for each hand, if you want to stop as safely as possible, you need to pay attention to how you use each of them.
Conventional Wisdom
Conventional wisdom says to use both brakes at the same time. This is probably good advice for beginners, who have not yet learned to use their brakes skillfully, but if you don't graduate past this stage, you will never be able to stop as short safely as a cyclist who has learned to use the front brake by itself.
Maximum Deceleration--Emergency Stops
The fastest that you can stop any bike of normal wheelbase is to apply the front brake so hard that the rear wheel is just about to lift off the ground. In this situation, the rear wheel cannot contribute to stopping power, since it has no traction.
Braking and Turning Your Bicycle

 

[flecc]

Maximum Deceleration--Emergency Stops
The fastest that you can stop any bike of normal wheelbase is to apply the front brake so hard that the rear wheel is just about to lift off the ground. In this situation, the rear wheel cannot contribute to stopping power, since it has no traction.
Braking and Turning Your Bicycle

And the same for motorcycles of course.
.

 

[Streethawk]

From common cycling speeds maybe, but from 50 mph? Somehow I doubt it.
.

Easily, i suspect the low weight is the biggest factor. On both machines the brakes themselves have enough power to lock the wheels and break traction at that speed with very little effort. I've really pushed the limits of bicycle discs over the years, hard the discs glowing red after coming down Walna Scar once, and the levers were heading towards the bars, so i had to stop and let them cool off for a few minutes.

 

[Streethawk]

From part of Sheldon Browns web site.

Braking--Front, Rear or Both?
Since your bike has two brakes, one for each hand, if you want to stop as safely as possible, you need to pay attention to how you use each of them.
Conventional Wisdom
Conventional wisdom says to use both brakes at the same time. This is probably good advice for beginners, who have not yet learned to use their brakes skillfully, but if you don't graduate past this stage, you will never be able to stop as short safely as a cyclist who has learned to use the front brake by itself.
Maximum Deceleration--Emergency Stops
The fastest that you can stop any bike of normal wheelbase is to apply the front brake so hard that the rear wheel is just about to lift off the ground. In this situation, the rear wheel cannot contribute to stopping power, since it has no traction.
Braking and Turning Your Bicycle

All true, but suspension forks throw in a few extra considerations.If you just use hard front braking the front end will dive and your rear wheel will leave the ground earlier, and as Sheldon's site says, you need to keep it on the ground, if only just. Applying the rear brake a fraction before the front brake helps counter the dive. Of course on full suspension frames "brake jacking" can be much more pronounced. If you watch a MotoGP race, the riders will just about keep the back wheel on the ground approaching a corner, but you'll see how close to lifting it they are, and the occasional unintentional lift, skip or slide.

Carl Fogarty famously claimed he never used his rear brake at all... having spent some time on a race track i dont actually believe him.

 

[Tex]

Remember on a bicycle you can throw your weight right back as you apply the front brake. This will ensure you don't lift your back wheel.

 

[Synthman]

I've hit around 40mph on a steep downhill road. The bike starts vibrating really slightly, and makes a rumbling sound too. I'd assume bikes have less stopping power because they have less wheels.

I tend to use the rear brake more, and often by itself, however now I start by applying the front one first, then the back if I need extra stopping power. My biggest fear is locking the wheels up, did that when the bike was new and fell off!

 

[Biged]

Front brake only

The instructions from 'Gazelle Cycles'


''Beware: If you brake hard, the front suspension will deliver an up and
downward movement that can be dangerous, especially in curves.
This effect is weakened if you use the front brake as well as the rear
brake. Therefore, never brake with the front brake only''

Only applies to suspension bikes obviously.

 

[cogs]

Anyone considered a nexave brake?