Brakes Deore,XT,XTR,SLX,Hope??

[Captain Fastbastard Mayhem]

What does a lycra lord know about suspension, tyres, brake rotors etc? Pft.

 

bahahahahahahahahahaha!

 

Irony overload.

[Pure Savage]

What does a lycra lord know about suspension, tyres, brake rotors etc? Pft.

 

 

I have been hanging around the hub too long.      I also know that a horizontal shock is the best and that on upside down fork is a fad. 

[Pure Savage]

Someone told him his brakes were ***, and now it's a stumbling block... Instead of getting them bled and slightly better rotors, he's now thinking it's a requirement to get brand new brakes. 

 

If he does - Deore. Same internals as SLX & XT. Exactly the same power. Done. 

I want to replace the Avid's on my MTB with Shimano anything, I will just wait till he sells his useless deore and tiny rotors for the recommended second hand price of around R450.

 

Reason for the replacement, the make a funny noise the DWF doesnt fix. 

[Cu Draad]

Nevermind jusking guys!!! thanks for help!!!

[Cu Draad]

I was in the same boat as you at the end of last year... was 125Kg's and now at 119 after riding so much the last 5-6 months.

 

How the hell did you loose so much weight so quick?????    

 

I upgraded from 180mm-F and 160mm-R to 180/180 and there was noticable difference. Also bled brakes at same time new rear rotor was fitted. I had also only done about 300Km's prior to doing it!

 

I only did the basic entry level Resin only rotor as funds were tight...

 

Not sure if you mentioned it yet but what bike do you have?

 

When the money tree is in full bloom again I will be looking at the XT M8000 brake set with RT81 Ice tech rotors. If they don't show much difference to what I have now then I will go 203/180

Thanks for all the help!! well I am on 105.3kg now from 1st Jan. Just ride your bike more and check what u eat!! For now I will just go with a rotor

upgrade!!! Thanks!

[Nakoota]

I think my XT M785 Brakes will look stellar on your bike, your should buy them

[Oufy MTB (Roadie)]

At 146km the pads must still lekker form to the disc. Bigger rotors my 2 cents, I ride formula C1, so I don't have much of a basis for opinions. Op's weight is coming down, so the physics is becoming more on his side

[chuckza]

1.  Bigger rotors won't give you more stopping power.  The contact area (pads) remain the same, the force applied by the calliper remains the same.  The material of the pads remain the same, so no extra stopping power.  The only real benefit of larger rotors is that they give you a larger surface area to dissipate heat over, so brakes will be less prone to fade over extended braking and your fluid will last longer (see also point 5 below).

2.  Deore is by far the best value for money.  They have exactly the same stopping power as SLX/XT.  Not sure about XTR but if you're not a millionaire or sponsored rider, shouldn't bother with XTR.  

3.  If you really want stopping power, get a pair of Shimano Zee brakes.  They have quad pistons (as opposed to dual on Deore/SLX/XT/XTR) and have significantly larger brake pad surfaces.  However, unless you're riding downhill or proper enduro, you shouldn't really need them.

4.  This post is getting rather long, but I haven't seen anyone mention skills.  The best thing you can do with brakes is to learn when/how to use them so that you increase the efficiency of your riding.  You'll ride faster and have less hassles with brakes.

5.  If you do a lot of heavy/extended braking, you have cooked your fluid and should drain and replace it followed by a proper bleed.  I've drained a couple of sets of Shimano brakes with black fluid.  You get carbon formation in the fluid and that creates a spongy effect.

[Captain Fastbastard Mayhem]

1.  Bigger rotors won't give you more stopping power.  The contact area (pads) remain the same, the force applied by the calliper remains the same.  The material of the pads remain the same, so no extra stopping power.  The only real benefit of larger rotors is that they give you a larger surface area to dissipate heat over, so brakes will be less prone to fade over extended braking and your fluid will last longer (see also point 5 below).

 

Agreed with the rest, but this is incorrect. Larger rotors give you more stopping power as the moment (resultant torque) is larger due to the larger distance between the hub and the braking surface.

 

IE: A 200mm rotor is 25% larger than a 160mm rotor (radius of 100mm vs 80mm) so for a given force at the rotor (pulling the brake lever Xmm, assuming all other factors remain equal) your braking torque will be 25% higher. 

 

There is the added benefit of better cooling as well, but bigger rotors DO give you more braking power. 

[PhilipV]

1. Bigger rotors won't give you more stopping power. The contact area (pads) remain the same, the force applied by the calliper remains the same. The material of the pads remain the same, so no extra stopping power. The only real benefit of larger rotors is that they give you a larger surface area to dissipate heat over, so brakes will be less prone to fade over extended braking and your fluid will last longer (see also point 5 below).

.

You forgot about the leverage provided by the larger rotors.

[PhilipV]

Koperdraad, don't spend money too quickly. Those pads are still bedding in. If the brakes feel spongey or go completely soft after the bike is put upside down for a while then it definitely needs a bleed. If they feel firm then a bleed may not do much.

There are a myriad of other reasons why brakes feel inadequate, it could be the tyres not providing enough traction, it could be wrong technique, ie predominantly using back brake instead of predominantly front brake, grabbing brakes and locking up the back.

 

I use 615s on both my bikes, I weigh slightly less than you, but I work brakes very hard, and let me tell you, there is nothing wrong with those brakes. Upgrading the brakes itself won't make much of a difference, but better heat management may provide some improvement over long descents, but you shouldn't be dragging your brakes anyway.

[chuckza]

Agreed with the rest, but this is incorrect. Larger rotors give you more stopping power as the moment (resultant torque) is larger due to the larger distance between the hub and the braking surface.

 

IE: A 200mm rotor is 25% larger than a 160mm rotor (radius of 100mm vs 80mm) so for a given force at the rotor (pulling the brake lever Xmm, assuming all other factors remain equal) your braking torque will be 25% higher. 

 

There is the added benefit of better cooling as well, but bigger rotors DO give you more braking power. 

 

What you say is correct, in theory at least.  In practice, the biggest limitation with stopping power is wheel traction.  The fastest possible stop will be when you apply just enough brake force on the disc so as to not drag your tires on whatever surface you are riding on (which is why we fit ABS on cars/motorbikes).  Any of the brakes mentioned here (Deore/SLX/XT or even XTR) should be able to apply sufficient brake force on a 160mm rotor to drag your wheels and therefor I argue that rotor size is not the limitation; certainly not for the "average" rider.  If you increase the mass of the rider/bike or speed substantially, you may in fact reach a point where the limitation is no longer that of mechanical grip between the wheel/trail but in fact the amount of braking torque you can apply to the wheel and in that case you may in fact see a benefit from using a larger rotor.   

[Mr lee]

You forgot about the leverage provided by the larger rotors.

 

Yes exactly. In simple layman's terms...try stopping a wheel in the center vs. the outer edge!

[Captain Fastbastard Mayhem]

What you say is correct, in theory at least.  In practice, the biggest limitation with stopping power is wheel traction.  The fastest possible stop will be when you apply just enough brake force on the disc so as to not drag your tires on whatever surface you are riding on (which is why we fit ABS on cars/motorbikes).  Any of the brakes mentioned here (Deore/SLX/XT or even XTR) should be able to apply sufficient brake force on a 160mm rotor to drag your wheels and therefor I argue that rotor size is not the limitation; certainly not for the "average" rider.  If you increase the mass of the rider/bike or speed substantially, you may in fact reach a point where the limitation is no longer that of mechanical grip between the wheel/trail but in fact the amount of braking torque you can apply to the wheel and in that case you may in fact see a benefit from using a larger rotor.   

IE larger rotors give you more braking power, or allow you to use less hand force to stop in the same distance. Yes. It's far more apparent on the front, though. And trust me - you can feel the difference pretty clearly. 

[GrahamS2]

IE larger rotors give you more braking power, or allow you to use less hand force to stop in the same distance. Yes. It's far more apparent on the front, though. And trust me - you can feel the difference pretty clearly. 

Yep, and more available braking power means better modulation, which means more traction, allows for later braking, more fun...

[chuckza]

IE larger rotors give you more braking power, or allow you to use less hand force to stop in the same distance. Yes. It's far more apparent on the front, though. And trust me - you can feel the difference pretty clearly. 

 

Totally agree with your point on modulation and hand force.  It will give you better control etc., but not make you stop any faster.  I run a set of Shimano Zee M640 with 203mm rotor upfront and 180mm rear.  It is more a function of where and how we ride though.  Never had any hassles stopping, have absolute control and have never managed to cook them either.  Interestingly enough they are not that expensive either.  Just got a set for a mate from Evan's in the UK for ~R3.5k including shipping/VAT/duties.