Comparing Brakes...

[Johan Bornman]

I agree you are limited by traction, but if the same rider rides two sets of brakes back to back, the rider will weigh the same and the traction will be the same and overturning force will be the same. The harder you brake, the further back you place yourself to compensate and therefor not lock the front, I have not once, even by grabbing buckets full of brakes (then you place yourself way back), manage to lock the front out - therefore a more powerful brake will stop you faster.

 

No, not so. Provided that both are of adequate "strength", the limiting factor is overturning momentum. If both can make the bike lift its rear wheel, the one with more "strength" brings nothing extra to the party.

 

And, no matter how far you hang your butt over the rear wheel, at some point it cannot go further and overturning momentum kicks in. Given enough traction, no matter how you look at it, the first thing to give will be overturning momentum. This is because you cannot get your centre of gravity below the hub level, no matter how big your arse.

 

We see this with cars and motorbikes. On cars, traction is the limiting factor as front wheels start to skid without the car being in any danger of overtuning.

 

On motorbikes, the front wheel never skids (on good surface) before the bike overturns. That's the very reason why you can do a stoppie on a motorbike. If the front wheel skidded, you wouldn't be able to do a stoppie.

 

 

 

I have ridden Shimano and Formula, currently on Formula The One, which by your 'silly and outright dangerous' standards should be banned. The Shimano's did not have adequate modulation or power to confidently stop me and I had to start braking well in advance if I needed to slow down. Yet now I find myself having more confidence and more control while riding and go much faster as I need less distance to slow down. Braking later means an higher average speed. There is a high center of gravity which you counter by placing your but behind the saddle when you brake hard. I think one needs to differentiate between disciplines here I guess. In XC you need less deceleration force than in AM or DH riding.

 

You are misconstruing my "silly and dangerous" quote. Have a look at my use of it once more and place it in the proper context.

 

DModulation and power don't belong in the same sentence like that. Modulation is one thing. Stopping ability is another. Brakes can have excellent modulation but lack stopping ability and vice versa.

 

No matter how poor the Shimano's were that you used, I bet they could lock up the front wheel. Which of course makes the point that they have adequate stopping force. The fact that the brakes may have been grabby, provided a poor tactile experience etc etc is another factor althogether and where better brakes come in as I explained previously.

 

I'll bet money on the fact that both brakes you cite, will stop you within the same distance on typical X-country surface conditions. You may not like the experience the one provides, but that's a different matter.

 

 

 

 

The purpose of more powerful brakes is just that - more powerful. More powerful is not necessarily lighter.

I do agree with Johan that power in itself is not the answer and people just buying the most powerful brake they can get might do themselves a disservice as they might just lock the brakes up and slide or flip over. But as your skill improve, so the benefit will of having more powerful brakes, specially for us guys hovering near the 90kg throwing ourselves down steeper gradients!

 

I mainatain that just about any brake is strong enough to flip you or skid the front wheel and therefore we should be looking for other qualities once the basic hygiene factors are satisfied.

[Wernervdmerwe]

I am the same body, on the same surface, with the same fat arse hanging the same distance over the saddle, yet the more powerful brake stops me faster (shorter distance) and with more confidence.

 

Maybe science works different in the northern part of South Africa than anywhere else in the world, else I fail to see why professional downhill riders would ever need anything more powerful than Avid Juicy-3's given your argument. Maybe it is all just marketing hype implanted on them poor little ignorant professionals. Maybe we can make some bucks out of this!

 

The whole concept of bigger rotor = more stopping power is then also just a well-constructed lie as your overturning momentum will be the same regardless...

 

Let's just agree to disagree

[Wernervdmerwe]

No, not so. Provided that both are of adequate "strength"

 

Maybe we are arguing two different points. You statement above is what I am saying as well.

Not all brakes are of adequate "strength". I ran XT and XTR, new and out of the box for a long period of time - including services etc. They all managed to stop me in time, only now with the more powerful brake am I able to start braking later to achieve the same result.

 

Not that the XT and XTR's were not adequate, the stronger brake just allows me to be be faster given exactly the same circumstance (weight, body position, force applied to lever, overturing momentum, traction, center of gravity etc etc) as they slow me down faster.

 

Not sure if possibly I am misunderstanding your argument?

[Johan Bornman]

I am the same body, on the same surface, with the same fat arse hanging the same distance over the saddle, yet the more powerful brake stops me faster (shorter distance) and with more confidence.

 

Maybe science works different in the northern part of South Africa than anywhere else in the world, else I fail to see why professional downhill riders would ever need anything more powerful than Avid Juicy-3's given your argument. Maybe it is all just marketing hype implanted on them poor little ignorant professionals. Maybe we can make some bucks out of this!

 

The whole concept of bigger rotor = more stopping power is then also just a well-constructed lie as your overturning momentum will be the same regardless...

 

Let's just agree to disagree

 

Let me try once more.

 

Larger disks give you more stopping power but you cannot use it because you'll either skid or go over the bars.

 

In your example where you say you (felt*) you could brake later, I want to ask you this question: Could you lock up the brakes if you wanted to?

 

If the answer is yes, then you have to tell me what a stronger brake would achieve. If the answer is no, I'll argue that the brakes were defective because any disk brake in a serviceable condition will lock up if yoiu pull hard enough on the lever.

 

There is a role for larger disks and I did explain that. Better heat dissipation, longer lasting and less fade. Downhill racers require brakes that can brake for longer without fade than do X-country racers. They don't require stronger brakes (other than perhaps to make up for the extra weight of their rig), just brakes with a heavier duty cycle, hence the larger disk and syntered metal pads.

 

This comes back to the old V-brake argument. Disks over V-brakes give you an advantage other than stopping power. They bring smooth hydraylic lines, less input force and better modulation. However, both will send you over the bars if you use them incorrectly.

 

Stronger brakes will only be useable if you use them on tar or, you can somehow bring your centre of gravity to below the hub level.

 

 

*I say "felt" because you don't explain why you couldn't brake as late with the weaker brakes.