acape

Recently installed new Kool Stop brake pads. As far as I can tell, I have them adjusted properly...aligned well on the rim and slightly toed in. However, it seems that the rear brakes are now giving me more stopping power than the front. I know this is the opposite of how it should be, and this was not the case before the change. Any suggestions on what might be causing this?

Thanks.

Brillig

What happens when you apply the front brake alone? Does it feel like you're going to endo if you squeeze too tight?

acape

No, that's the thing. It used to, but now it doesn't. I can stop much quicker applying the rear brake alone than I can with the front brake alone.

powers2b

If the brake handle can touch the bars you need to adjust the brakes.

acape

Nope, got them tightened up.

Brillig

Something is wrong then with the front brake pads.

Hambone

What kind of brakes?

On mtn bike brakes (which some touring bikes have right?) if you change the angle of the cable which connects the top of the brake arms, you change the mechanical advantage and increase or decrease the force your handles apply to the brake pads.

I'm not a wrench so the vocabulary may be off here, I'm a reformed mtn bkr and used to do my own maintenance. (I learned this the hard way...)

Miller2

I thought the rear brake was supposed to be more powerful and the front was just to be to complement the rear?

Brillig

Define powerful, I guess. Fastest braking is strong on the rear brake (short of lockup) with just the right amount of the front (short of endo).

But both brakes should be strong enough to lock up their respective wheel on dirt. And the front brake should be strong enough to strike the fear of endo.

merlinextraligh

Nope. Any vehicle has more braking force on the front wheels, because of the transfer of forces foward as you brake. That's why the calipers on the front disc on your car are bigger than on the back. In a panic stop on a bike most of the weight is on the front wheel. The back gets very light, and locks up easily. And a locked wheel doesn't provide as much braking force as one on the threshold of locking. You can shift your weight way back to counteract this effect, but you've still got more braking force coming from the front.

XC99TF00

Nope, because when you break your weight gets transfered forward putting more weight on the front wheel and very little on the rear (hence you see kids leaving skid marks on the road when they clamp down hard on the rear brake, because there is so little weight being placed on it). People tend to use the rear break more because they feel more stable when they know they won't be going over the handlebars. The front break ends up doing a vast majority of the stopping if you were to squeeze both levers simultaneously... Provided the brake setup is correct, which is most likely isn't somehow on the initial poster's bike.

EDIT: [So I was a little slow posting the message since its nearly identical to Merlinextralight's]

merlinextraligh

This doesn't make physical sense, assuming the brake is properly adjusted. Can you lock the front wheel? If you can you have all the braking force you need. I guarantee you that if you take the front brake and apply enough pressure to bring the front wheel to the threshold of locking that will stop you faster than using the back brake. If you can't apply enough force to the brake lever to cause the front wheel to lock , you need to adjust your front brake. (Of course you never want the front wheel locked and skidding, but the brakes should be powerful enough to do that.)

All any bike brake needs to do is have enough force to lock the wheel, and enough control to allow the modulation of that force, so it can be controlled up to the threhold of locking. Any modern bike brake can do that. Past that, stopping power front and back is a function of physics.

Miller2

Yea I realize that it works that way on vehicles, thats why I have slotted and cross drilled rotors on the front of my truck. I thought the potential endo would be the reason for less powerful brakes on the front of a bike. Obviously endo is not an issue on a car or truck. Interesting..learned something new today!!

acape

I guess I should clarify, sorry...I could definitely lock the front wheel with the front brake, that's for sure. But locking the front wheel takes more force on the lever than it takes to lock the rear wheel.

XC99TF00

Is this when riding, or when testing the brakes while the bike is on a repair stand or something? Cause the rear would lock up more easily when riding anyhow, since the weight is being transfered forward.

Eatadonut

clean your front rim/brake pad with rubbing alcohol? Maybe you got grease on it.

pedex

the new Kool stop brake pads need some use to get broken in and wear to match the rim, they will get better, cant have instant gratification all the time, have some patience

unlike regular road pads which can be gone in 10 days of winter riding the kool stops last a bit longer cause the rubber is a harder compound, mine did the same thing

merlinextraligh

that's exactly as it would be expected to be. Because the weight is shifting forward, its going to take more force to lock the front than the back. In fact in a panic stop at speed the back will lock with exceptionally little force. This has the positive effect of allowing both brakes to be applied with equal pressure without locking the front wheel and washing out or doing an endo. However, if you wan to stop the bike as quick as possible you need to learn to modulate each brake independently.

Nims

You should take those off before you crash and die. I can't tell you how many cross drilled rotors that cracked in pieces I've held in my hands.

mayukawa

The Kool Stop (road) pads that I've used don't come with a flat braking surface like a lot of other brake pads that I've used. The trailing part already protrudes a bit out (sort of a built-in heel-in), so I think you should just have the pads parallel to the rim, so that when you brake, the trailing edge would grab first and then the rest of the braking surface-->don't use any toe-in. Another thing I notice about KS pads is that they tend to be thinner, so that you've to readjust your calipers closer to have the same amount of play from your brake levers.

zzzwillzzz

you're kidding right? every sportbike on the planet has drilled rotors. most performance cars have drilled or slotted or both on their front discs. i know drilling them yourself is a very bad idea

Ozrider

I am a wrench in an LBS. Here are some answers.

First, 70% of your stopping power comes from your front brake. Check sheldonbrown.com for a more complete explanation.

Second - there is no way the rear brake should be applying more force than the front. So, here's what I would check:
A. did you put new cable and cable housing on the front brake? If you did, did you make sure the cable housing wasn't too long - that can hang up a brake. did you lube the inside of the housing - again, a brake can hang up because of failure to lube. Is the cable itself adjusted properly? No kinks or bends? Did you route the housing properly? If there are cable stays, did you make sure you ran the cable through them?
And, what housing did you use? If you used derailler housing - yes there is a difference - that can cause problems with the cable hanging up.
B. Is your brake toed in properly? The front of a brake should hit before the back. If your pads are not lined up correctly, that can affect stopping. The bottom of the pad should be even with the bottom of the rim.
C. How much space is there between the rim and the pad? It should not be more than 2 mm on either side.
D. Did you remember to close the brake on the front? Seems obvious, but we get that one a lot.

Good luck.

operator

Nope.

Nims

No I'm not kidding. I have two sportbikes with drilled rotors so I know what you're talking about. This isn't an automotive forum and I don't want to threadjack, so I'll be quick.

On a bike or actual race-car if you see rotors with holes, 99.99% of the time those holes are cast with the rotor. On street vehicles when you see rotors with holes that someone bought on ebay or similar 99.99% of the time those are blank rotors that someone drilled. Mechanically there is a significant difference in the strength of the rotor.

Feel free to do what you want, but as I said, I have personally replaced multiple sets of cracked "cross-drilled rotors" on cars of people who didn't believe me.

-James

mac

#1 - Don't ride until you get your front brake fixed! That can cost you your life if you need to do an emergency stop in traffic and can't.

#2 - I installed Kool Stop brake shoes on my Shimano V-brakes. I can now pop my rear wheel off the ground, even with a load on the back of my tourer, when I slam on the front brake. Now that's stopping power. My rear brake really sucks, though, maybe about 25% power as my front.

#3 - Get your wheels trued. This way you can put the brake shoes as close as possible to the rims.

#4 - Keep tweaking your brake cable until the shoes are almost barely touching the rims.