Different brake styles and performance

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zombiess

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I just wanted to post that I'm shocked at how well my linear pull brakes work on my mini monster bike. I've only had experience with disc brakes on my Diamondback Recoil Comp which are Hayes MX4 mechanical that I found pretty impressive even though I was told mechanical disc brakes suck by everyone. I can probably flip myself over the front handle bars under 25mph with the MX4's and they aren't anything special.

When I started my mini full suspension MTB I was dreading not having disc brakes. I had never used a linear pull before and I ended up ordering a complete set of Tektro's for a BMX (standard size not minis) for $42 shipped and had low expectations from most of what I've read online including this forum. After I got the bike running I was shocked how well they can stop my 66lb bike + 175lb me from any speed. I have to weight shift back under hard braking to keep the rear wheel from locking up and sometimes lifting due to weight transfer to improve my over all stopping performance. Maybe it's just me being use to using both brakes all the time when I stop and knowing how to threshold brake. Add regen to any of my bikes and stopping performance is even better.

During both of my bike builds two of my biggest concerns were high speed stability and stopping power. My mini FS bike is going to be getting a nicer fork which will allow me to upgrade it to a front disc brake which is going to make it even better. I've already figured out that the cheapest front disc setup is going to be an Avid hydraulic setup on a 20" wheel; I can't wait to get it converted and see how the bike rides (I don't even have regen on this bike yet).

I do know that since buying my Diamondback I have ridden some cheaper bikes such as Walmart and have a stock version of my mini monster that has generic linear pulls. No amount of adjusting I did to either of them could get them even close to the braking force I have on either bike setup now.

I started out as a complete bicycle noob earlier this year and am still green so maybe I don't know what "good" brakes are like on a bicycle yet.
 
I was always under the impression that when comparing bicycle disc brakes and rim brakes in the same quality range that they both offer the same amount of stopping power. The discs just have other advantages.

At least that's how it seems to me. Good rim brakes are cheap. I probably would use them on my bikes if i didn't use smaller wheel sizes.
 
The larger the diameter of the wheel, the better a v-brake is going to work. It's like having a taller rotor.. more heat shedding surface, and more area to rub against per complete rotation of the wheel.

What i like most about disc though is that even if my wheel is out of true.. i'm not gonna get the wobbles. And i like myself some tall discs.. 180mm minimum, 203 preferred. They have a good amount of area to disperse heat and grab.

I would say 160mm disc is a waste of time compared to vbrakes in pretty much every situation.. unless you are running 20 inch wheels or smaller.
 
I have funky 160 mm mechanical disk on the rear wheel of my dirt bike, and rim brakes on the front since I don't have a disc mount on that fork. Always having to use just the front brakes because the disc fades so bad. But in wet conditions, it would be the reverse.

Till I heat up the disc, both seem about the same in terms of effectiveness. Disk wheels need a bit more attention to spokes, since the brakes don't tend to straighten up the rim when used.
 
neptronix said:
The larger the diameter of the wheel, the better a v-brake is going to work. It's like having a taller rotor.. more heat shedding surface, and more area to rub against per complete rotation of the wheel.

...quote]


hi

i'm not an expert in brakes but isn't it the leverage that is increased with a larger diameter, thus increasing the torque applied on a larger wheel ?

I don't think the area to rub against has a major effect. The force applied on the wheel does not really depend on this, apart of better heat dissipation maybe.

but i'm not an expert.
Click to expand...
 
i'm not an expert in brakes but isn't it the leverage that is increased with a larger diameter, thus increasing the torque applied on a larger wheel ?
Click to expand...

Yup.

I was researching brazing on disc tabs old steel frames the other day. It doen't seem that hard, and the tabs are like $10.
 
I'm not an expert either. But just think about it - with rim brakes you typically have a brake pad of X size. The larger the wheel, the more friction happens per complete rotation of the wheel.

Rim brakes fade too. Go down a 7% grade for an extended period of time with 300lbs of bike and rider. Your rims will be hot as hell and fade just like a disc. The big difference here is that you are contacting ( typically ) aluminum with a brake pad material rather than say, the steel of a disc brake rotor.

Being that the front brake does the majority of the work.. that's right where i like the disc brake. I definitely fear getting the rim hot enough to melt or pop off the tire.. in my riding situations. If you live in a very flat area then.. you don't have to make as many considerations with your brakes, for sure.
 
I've had so many different brakes, upgraded so many times because of failure or poor performance...
Now I know that I can't afford to go cheap.

New brakes are often very good, until they aren't anymore. The faster you ride, the more important to invest in the best.
 
Disc brakes have increased my stopping power at least 50%, and probably 100% or more in the rain. I don't feel like I'm riding a suicide machine anymore...as much
 
I don't get it; stopping power is limited to tire traction. Low end rim brakes have more than enough traction to lock the wheel; ergo, disc brakes are unnecessary unless your bike weighs 200lbs and your going 50 mph.
 
auraslip said:
I don't get it; stopping power is limited to tire traction. Low end rim brakes have more than enough traction to lock the wheel; ergo, disc brakes are unnecessary unless your bike weighs 200lbs and your going 50 mph.
Click to expand...

I would agree with this statement, given you are comparing equally good rim brakes to decent disc brakes.

The problem is most of the cheap frames from department stores that many are using for E-Bikes have abysmal brakes that barely worked as bicycle brakes rather than a heavy E-Bike.

IMHO, Drum brakes are the the cat's meow, best of both of the disc (unless you've converted some huge near motorcycle size disc) and rim, as in less maintenance than disc, but nearly unaffected by weather conditions as the drum is pretty much sealed.

I know it's not going to apply to most of us, but even on a light weight pedal bicycle with good sized wheels I have heard of rim brakes being used on a long steep down hill over-heating a rim to the point of a bursting tires, and if you're riding fast on an E-Bike, that might be a serious consideration, as you will have a ton more heat created by high speed riding even with out a long hill.
 
Yeah... I definetly agree. I always say, "if using a wal-bike upgrade to big round tires, and upgrade the brakes." Give that the bottom line avid brakes are $40 for the brakes and levers and that the bottom line avid discs come out to $120, I don't think it's a fair comparison.

That being said, disc obviously have perks.
 
auraslip said:
I don't get it; stopping power is limited to tire traction. Low end rim brakes have more than enough traction to lock the wheel; ergo, disc brakes are unnecessary unless your bike weighs 200lbs and your going 50 mph.
Click to expand...
That would be true if locking the wheel was the fastest way to stop. Precision control of the brake caliper, and its constance under extreme abuse and in various conditions, is what makes braking more efficient. Nothing can beat the best disc brake sets, combined with regen.
 
One further thing rim vs. disc: Disc brakes still work even after you bend up a rim so much that you wind up having to disconnect the rim brake cable and spread the calipers apart. ;)

Conversely, rim brakes are still pretty safe to use for hard braking even if you have multiple broken spokes (assuming the wheel is still alighned well enough for them to permit riding). Disc would probably further damage the wheel, or evne cause it to fail, depending on conditons.
 
The bigger and stickier the tire, the harder it is to lock up.. the more brake can be useful...

Case in point.. I've got 3 bikes as of now.. one is just an ordinary pedal bike that i ride 25% of the time just for pure excersize. It's got maybe 1.0 wide tires. Rim brakes will slip the back tire and sometimes even the front.

60 pound ebike.. 1.85 wide tires.. sticky type.. can't lock up those wheels no matter how hard i try.
 
I've flipped over the bars enough to know good rim brakes set up right work bitchin for normal periodic or emergency use. Even good ones will have problems with heat though, if you're talking "high duty cycle" use. I'm talking like how welders are rated. You can see the heat limits of rim brakes by looking at tandem road bikes. Because of their weight and speed its common for them to have problems with heat going down hills. Enough heat to blow tires off the rim. For decades those guys have used non-rim brakes on the rear to scrub speed off, then for emergency braking they still have the nice cool rim brakes ready to go.

If you go fast enough on a heavy ebike with repeated stops, maybe similar to above heat problems would arise? Don't know.. I'd think it would have to be race like use to get to that point?

Oh, and I have used some crap xmart bike rear discs that couldn't even lock the wheel up!.. But yea ok, disc are usually really good.
 
MadRhino said:
auraslip said:
I don't get it; stopping power is limited to tire traction. Low end rim brakes have more than enough traction to lock the wheel; ergo, disc brakes are unnecessary unless your bike weighs 200lbs and your going 50 mph.
Click to expand...
That would be true if locking the wheel was the fastest way to stop. Precision control of the brake caliper, and its constance under extreme abuse and in various conditions, is what makes braking more efficient. Nothing can beat the best disc brake sets, combined with regen.
Click to expand...

Agree with this.
Think of what ABS has brought to car brakes.
Locking the wheel is not the most efficient and safe way to stop.

Disc brakes and regen seems the way to go, plus you add resiliency. If one system fails, you have the other.

Coming back to ABS, if we can find a way to easily play with the regen braking level, then it would not be that difficult to program an ABS system reading the hall sensors signal.

That's definitely the way to go.
 
Alan B said:
Anyone consider having both a front disc and vbrake? For backup/heat fading/whatever?

On the rear have both a vbrake and regen ebraking?
Click to expand...
I have double front Hydro brakes on my road racer. Magura Gustav M disc brake, and Magura HS 33 rim brake, both operated by the same Magura Julie brake lever. The rear has an HS 33 and regen.

imag0303s.jpg
 
I saw someone in spain with no rear brake and a front rim and disc brake, actuated by different levers. I assume it was mechanical.
On another note, one of my friends has a single-speed steel pedal bike, the kind hipsters ride. The handlebar, which he states is expensive and useful, is a just a straight piece of tubing with shiny rounded end caps. No grips. He only has one brake and it's a cantilever, on the rear. I asked him why the rear, and he says "I don't wanna flip over!" :roll:
 
Hugues said:
MadRhino said:
auraslip said:
I don't get it; stopping power is limited to tire traction. Low end rim brakes have more than enough traction to lock the wheel; ergo, disc brakes are unnecessary unless your bike weighs 200lbs and your going 50 mph.
Click to expand...
That would be true if locking the wheel was the fastest way to stop. Precision control of the brake caliper, and its constance under extreme abuse and in various conditions, is what makes braking more efficient. Nothing can beat the best disc brake sets, combined with regen.
Click to expand...

Agree with this.
Think of what ABS has brought to car brakes.
Locking the wheel is not the most efficient and safe way to stop.

Disc brakes and regen seems the way to go, plus you add resiliency. If one system fails, you have the other.

Coming back to ABS, if we can find a way to easily play with the regen braking level, then it would not be that difficult to program an ABS system reading the hall sensors signal.

That's definitely the way to go.
Click to expand...

Regen braking by it's nature is anti-lock. If the wheel slows down or stops because traction has decreased then less motor braking force occurs.

So far my rear wheel has never slipped while regen braking. That's both on dusty streets and in rain. Not sure how it does off road though as I've only used it for street commuting.

Gary
 
So far, ABS systems are not as good as an experimented pilot. The system helps the average driver, but is a nuisance to a good one. I guess the human brain and hand is faster than any "intelligent" mechanism, as long as the human knows what he's doing and is not disturbed by emotion. That is why regen combined with precise brakes, is the best way to decelerate the closest to traction loss, thus a shorter stopping distance with your E-bike, once you are good at it.
 
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