Downhill braking, what should the balance be?

[Kajjal]

I have dragged the hydraulic disc brakes on my road and mountain bike on longer steep downhills with no problems and i weigh 16 stone.

 

[ColinJ]

Not heard of that design before.

Presumably, the venting adjustment was done by the knurled wheel on top of the reservoir.

All sounds - and looks - a bit clonky by today's standards.

I doubt you'd have any problems with a modern hydraulic disc.

View attachment 156629

Yes, that's what I was talking about. I agree that the design was fundamentally flawed. Having to add those dials to make the system usable is an admission of defeat. Unfortunately I didn't know much about such matters at the time!

The old Hope system was a 'closed' system - that's why the dials were there otherwise when heat was generated the pistons would move and lock on the rotor. Giant had a similar set up with their MPH3 brakes ( perhaps Hope sold them the technology). The problem with the adjustable thumbwheels was always that they'd seize up very quickly and they are a stupid shape to get hold off. The Giant ones were so poor that if you left your bike in the sum you'd come back and find the brakes locked on! If the thumbwheel was stuck then the only option would be to let a little fluid out of the system - but you can't do that too often obviously as there isn't a lot of fluid in there in the first place. Modern systems have a rubber diaphragm which allows for this expansion of fluid thereby avoiding this problem

That is exactly what happened and why my mountain bike is off the, er, off road!

I have been torn between trying to find the spare part, and just giving up and putting new brakes on the bike.. I think I will go for the new brakes option since the overheating problem would always be there!

So ... any recommendations for a bargain-priced, reliable MTB disk brake system? (For a hardtail bike used for general cross-country riding and moderate descending.)

 

[Kajjal]

Clark do a cheap option if you check the reviews.
Cheapest quality option is shimano deore..

 

[Pale Rider]

Yes, that's what I was talking about. I agree that the design was fundamentally flawed. Having to add those dials to make the system usable is an admission of defeat. Unfortunately I didn't know much about such matters at the time!

That is exactly what happened and why my mountain bike is off the, er, off road!

I have been torn between trying to find the spare part, and just giving up and putting new brakes on the bike.. I think I will go for the new brakes option since the overheating problem would always be there!

So ... any recommendations for a bargain-priced, reliable MTB disk brake system? (For a hardtail bike used for general cross-country riding and moderate descending.)

You can't go wrong with Shimano hydraulic discs, even the basic ones are excellent.

They come pre-bled, so provided you are not overly fussy about hose length the brakes will bolt straight on.

Looks like there's a market for the Hope brake as a retro component.

 

[mickle]

That might apply to overheating brakes, but there's your rims to think about too (unless you have disc brakes). My mate Lennie once descended Mont Ventoux at 60mph because he was too worried about braking too much and and blowing a tube by overheating his rims, having been warned of that possibility! Admittedly that was an extreme descent in hot weather ... but I have since witnessed someone exploding his front tube by braking too much on a shortish, steep hill near Stroud in very mild British weather conditions. In fact every single one of us who was with him that day thought there was a farmer standing behind the hedge discharging a shotgun until his mishap became apparent! To this day I greet him as "Shotgun Rob" when I see him on club rides..

I don't believe that it was 'over braking' which caused the 'tube' to explode. The final straw perhaps on a worn /damaged rim or tyre, but not the cause.

 

[keithmac]

Another vote for Shimano hydraulic disk brakes here as well, never had any issues with mine either.

 

[Ice2911]

It depends on the pad compounds but you can get some rim brakes hot enough they go soft and wear very quickly even on some UK descents, including some in the south west.

My best brake failure was a lever coming away from the bars after something snapped in the clamp, leaving it bobbling around in the air, supported only by the cable. At least it was only a descent into Norwich from the south, so not too taxing to do on only the back brake.

This was on Harvey Lane heading towards Yarmouth road.

 

[Ice2911]

Many thanks to you all for the advice, it is very much appreciated. What is the thought behind moving your weight back in the wet please?

 

[ColinJ]

Many thanks to you all for the advice, it is very much appreciated. What is the thought behind moving your weight back in the wet please?

To make it less likely that the rear tyre will lose grip on a slippery road surface?

It is a good idea to practice braking in less than ideal conditions. Do it somewhere safe like an empty car park. You can get a feel for what you can and can't get away with. Start off with gentle braking and then gradually brake harder. Be very careful not to lock up the front wheel because front wheel slides are very hard to recover from. You should be able to control a rear wheel slide though and it is a good idea to get used to them so you don't panic if you get into one out on the road.

 

[mjr]

This was on Harvey Lane heading towards Yarmouth road.

Yeah - not one I'd do for fun, that road that cuts a corner off the Ring Road, over 15% downhill into a light-controlled T - and the other way is an annoying slog with motorists tailgating and close-passing. If you've a few extra minutes, Wellesley Avenue doesn't feel as sharp and the bit in the woods is no-motors, but I don't know what state it's in these days.

 

[Kestevan]

Many thanks to you all for the advice, it is very much appreciated. What is the thought behind moving your weight back in the wet please?

When you apply the brakes (wet or dry) the weight is transferred mainly to the front wheel, this in turn reduces the amount of grip on the rear wheel. If you fail to move the weight backwards enough and continue braking hard the rear wheel can actually come off the ground (a stoppie).

Usually before this (esp if turning) the reduced grip while still braking the rear will cause the rear wheel to stop rotating or "lock up" and you will skid... in the wet this much easier due to the reduced grip to start with,
You can skid the front (or go over the bars) but it's much harder, unless you have too much weight forward.
A rear wheel skid is usually recoverable, a front wheel skid almost inevitably ends with the rider hitting the deck.

Best braking technique is to get the weight back on the bike, straighten your arms, level the pedals at the 3/9 o'clock position and drop your heels. Majority of actual stopping effort can then be put through the front brake with the rear being used upto the point just before it all goes a bit slidey ( with experience you'll know when this is about to happen). You'll actually be amazed at how much speed you can scrub off quickly like this... but its best to find your own limits somewhere safe.

 

[Ice2911]

When you apply the brakes (wet or dry) the weight is transferred mainly to the front wheel, this in turn reduces the amount of grip on the rear wheel. If you fail to move the weight backwards enough and continue braking hard the rear wheel can actually come off the ground (a stoppie).

Usually before this (esp if turning) the reduced grip while still braking the rear will cause the rear wheel to stop rotating or "lock up" and you will skid... in the wet this much easier due to the reduced grip to start with,
You can skid the front (or go over the bars) but it's much harder, unless you have too much weight forward.
A rear wheel skid is usually recoverable, a front wheel skid almost inevitably ends with the rider hitting the deck.

Best braking technique is to get the weight back on the bike, straighten your arms, level the pedals at the 3/9 o'clock position and drop your heels. Majority of actual stopping effort can then be put through the front brake with the rear being used upto the point just before it all goes a bit slidey ( with experience you'll know when this is about to happen). You'll actually be amazed at how much speed you can scrub off quickly like this... but its best to find your own limits somewhere safe.

Um, just wondering if I should take advice on this From someone whose tag line is 'fall guy'. I really appreciate the advice,thanks!

 

[Racing roadkill]

A little help please. As I was going down a hill today, 32mph ( fast for me) with traffic lights at the bottom, the above question came to my mind, especially as the road was a little damp. Kept thinking I should know this before I get into these situations. Should you brake (nearly typed break which could be very apt if I get this wrong) more with the back or front brake or try to keep it even. I was on the drops and had my weight forward. I've got into the habit as I get to the finish of my rides, to do a little circuit near home, which means I do this descent an extra mile and then finish myself off with a nice uphill slog!

Don't forget to 'cycle' the brakes ( alternately pull harder on the front, then the back, without fully realeasing either of them ) otherwise you risk the tyre unseating itself a bit ( due to rim heating ). This nearly always ends up with the tube popping out a bit, followed by the 'bang - hiss' which is always.

 

[RichardB]

A rear wheel skid is usually recoverable, a front wheel skid almost inevitably ends with the rider hitting the deck.

More simply stated as - a front wheel skid will land you on your face, where a rear wheel skid will land you on your *rse. Your choice.

 

[Mr Celine]

[QUOTE 4629877, member: 9609"]a slow descent would give more time to cool, same amount of energy being converted into the brakes as heat but longer to cool.
[/QUOTE]
Whether descending fast or slow there is the same amount of potential energy at the top of the hill. A fast descent will lose more kinetic energy to wind resistance than a slower descent, so leaving less energy for the brakes to deal with. (assuming both descenders are freewheeling.) Hot components would also cool more rapidly when exposed to a faster air flow.

Whether this makes enough of a difference to matter I have no idea.