going downhill

[gavroche]

Makes a change from going uphill threads.
Tomorrow, I am planning a 30mile ride. My longest so far. The problem is that I will be going down a very steep hill at some point and would like some advice on controlling braking safely. Can the pads overheat if on for too long? This slope is quite long , on the side of a mountain. All advice welcome.

 

[Sittingduck]

How long is the steep hill and what speed do you anticipate reaching?

 

[gavroche]

How long is the steep hill and what speed do you anticipate reaching?

I would say about 2 kms long. Because of its gradient, it would be possible to reach 60mph, which I dont intend to do. I would settle at about 45, that would be enough for me, but keeping it at that speed would require constant careful braking and I dont want the back wheel to lock up.

 

[Matthew_T]

I would say about 2 kms long. Because of its gradient, it would be possible to reach 60mph, which I dont intend to do. I would settle at about 45, that would be enough for me, but keeping it at that speed would require constant careful braking and I dont want the back wheel to lock up.

Yes, the rims heat up quickly when braking hard. ( I have actually burnt myself after a steep hill). If you want to go fast but not too fast then I suggest you dont apply a constant brake, but sharp hard braking shoudl keep the rims cool and slow you down.

For stopping the rear wheel locking up, try to put as much weight over the rear wheel to give it more grip, and alter your front brakes so that they are tighter. Unless in the wet, the front wheel should never lock up, even when performing an emergency stop, because your whole body weight is puttingg pressure on it.

 

[Sittingduck]

I would dab the front brake to give the rim a chance. Wouldn't want it overheating too much... have heard this can cause a blowout - which is not something you want to happen on a very steep descent. Not sure what kind of temperature the rim would need to reach, in order for this to happen mind you.

Good Luck!

 

[GrumpyGregry]

a downhill blowout caused by an overheating rim years ago put me in a French hospital and converted me to disc brakes for touring bikes but

I had lousy technique and was dragging the brakes all the way down (didn't know any better)
I was/am a big unit
I was riding a fully (over)loaded bike
I was in the Pyrennes

These days I alternate brakes on the way down and only brake on the straight in advance of the bends. Sitting up creates a lot of drag and will shed quite a bit of speed too. On road I top myself out at about 60kph, I've only gone faster off road in the Alps on a closed course, as I'm not sure I'd want to interact with other vehicles and roads users much above that speed. A pedestrian is likely going to badly misjudge your approach speed if you are doing anything above 25mph for instance.

btw 2,000m isn't really that long a hill in terms of brakes overheating, 20,000m will do it though!

 

[Friz]

Just feather the brakes when it feels appropriate...

And try and hit 60. It's a rush.

 

[HLaB]

Overheating of the rim can happen but I'd be surprised if it can happen on the relatively short descents here in the UK. Somebody might update me on this though The longest I've found so far was the String Road in Arran; its a bit over 2km and I'm sure folk could do 60mph + there but I wused out at 47.6mph. I've done longer descents abroad and touch wood, despite my heavy braking, I've never had a problem, I just try to modulate my braking on longer descents.

 

[gavroche]

And try and hit 60. It's a rush.

I am 60! it is no rush..
dont really fancy doing 60mph on just half inch of rubber on the road. May be quite a few years ago but not now.

 

[John90]

dont really fancy doing 60mph on just half inch of rubber on the road.

Agree absolutely. I am utterly wet when it comes to downhills. Never go above 25 mph without grabbing a fistful of brake. I don't know how people can trust their reaction time at higher speeds - just one more cycling skill I will never master I guess.

I haven't yet found a hill where I couldn't keep my bike well below 30 by feathering the brakes with an appropriate degree of enthusiasm, however I have discs on both my bikes, and wouldn't want to be without them.

 

[lulubel]

Unless in the wet, the front wheel should never lock up, even when performing an emergency stop, because your whole body weight is puttingg pressure on it.

I've managed to lock up my front wheel in the dry when the vibrations from bad road surface made my front light fall apart on a country road at night, and everything suddenly went dark! It was pretty scary for a few moments, but I fortunately managed to release the brake in time, and come to a stop safely. It took a while for my eyes to adjust to the dark so I could go back up the road and search for the pieces of my light, which fortunately worked after I put it back together.

 

[Angelfishsolo]

I am 60! it is no rush..
dont really fancy doing 60mph on just half inch of rubber on the road. May be quite a few years ago but not now.

I would love to find a hill I could even approach that speed. 45.7mph is my max and that was spinning out.

As others have said feathering brakes is the best option but a hard pull from time to time may be necessary if you are building up too much speed. Riding on the brakes is not a great idea as the friction build up reduces effectiveness and also damages rims.

 

[Matthew_T]

Have a look at this video:

View: http://www.youtube.com/watch?v=VAkEY3cJFug


It is me going down the fastest hill around my area. It is definately not the steepest but as it is quiet and very straight, you can get up to some high speeds.

 

[Angelfishsolo]

Have a look at this video: http://www.youtube.c...h?v=VAkEY3cJFug

It is me going down the fastest hill around my area. It is definately not the steepest but as it is quiet and very straight, you can get up to some high speeds.

Cool video. As I say I would love to find a hill I could get remotely close to 60mph on.

 

[Matthew_T]

Cool video. As I say I would love to find a hill I could get remotely close to 60mph on.

As this hill wasnt very steep, I found myself pedalling hard after i went around the sharp left hander in order to pick up speed. the max you could ho on this hill would probably be 50 but thats with pedalling like made.