Modulating V Brakes Vs. Discs
 

Assuming high quality components, which type of brake gives the better fine modulation, V or Disc? Also, do you find the simplicity of V brakes has apppeal? It seems all the new bikes have disc, and without much personal knowledge, the main benefit I see is the superior wet predictability and performance. Something about hydraulics on a bike has me wondering if it is technology for technologie's sake? What are your experiences Pro and Con? Thanks, Bob.

Better modulation with a hydraulic brake system, be it a rim brake or a disc.

No, the simplicity of V brakes doesn't have any appeal for me. A long time ago I thought they were simply the best, and they were, at the time.

I'm in the same position as well. My XTR Vbrakes are great but I am getting ready to build up another bike and trying to decide what to do with brakes. If I keep my Vbrakes, I save a lot of money. However, what am I missing by not going hydraulic? My rides are basically up a mountain (2000ft) and back down.

i'd never go back to v's basically cause i find it hard to maintain a "true" rim..lol i'm always bowing them

Would you want cantilevers on your bike? It's just the natural progression. Other than to save a few grams of weight I would see no reason to switch back from my hydros. They work in the wet, work on an out of true rim, more power, more modulation, easier to set up and maintain.... and they look better:)

I prefer V brakes easier , cheaper to maintain while maintaining a much cleaner look with no toxic & messy chemicals.
V brakes are quite a bit more appealing to me.

wow...i actually have to agree with hank on this one. couldn't have said it better myself.

+1 to hydros. I couldn't live without them. Unless yuo are a weight weenie and/or don't actually need them, they are noticably better

Another +1 for hydros. Better power, feel, modulation, and performance.

And if you really want to save weight and go hydraulic discs...you can. The hydraulic disc brakes on my XC bike weigh less than the Shimano levers/Avid Single Digit SL v-brakes that were on there before.

Since someone has to do it, I'll chime in for V-brakes. Do your brakes stop you now? Do you like spending money on something that really isn't necessary in all but a few conditions but is fashionable? (I gonna catch hell for that :D)

Look, I'm a very large person. I have a touring bike with cantilever brakes and I carry touring loads on it (me plus bike plus touring gear). All told it weights in excess of 300 pounds. The bike also has cantilever brakes and I've never had a problem stopping with them. I've never blown a tire because of excessive heat build up and, when I've broken a spoke, I was able to adjust the brakes so that they would still stop me but not keep me from moving down the road.

I also have a hardtail with V-brakes - more properly, linear brakes - that I ride off-road in some pretty hairy conditions and never had a problem with it stopping either, even in a driving rain storm or snow or mud or sand or just about any other medium you can name except, possibly, jello. But I haven't tired jello, so I can't say.

I also have a dual suspension bike with hydraulic brakes. They are powerful. They will stop you - NOW! But I have yet to experience the so called "superior modulation" that everyone says hydraulics have. They are like an on/off switch. I have to be much more careful in their application or I feel like the bike is going to pitch me on my head! You DO NOT want to grab a fist full of brake lever in a panic with the hydraulics! It's a good way of doing self-inflicted dentistry! I personally find that linear brakes (and cantis) have a smoother, more progressive feel then the hydros. That's what I would call modulation.

that is fine. if it stops you to your satisfaction.

however, some like to stop in X amount of feet rather than 2X amount of feet. no v-brake can stop as fast as a rotor/caliper. save the stopping on dirt/skid argument :D do a quick test on pavement with quality hydraulic (mech:rolleyes: ) and compare to rim brakes. you're experienced...i am sure you already know. rim brakes stop, but not in as short a distance.

now you might argue mtb are used on dirt...fine, many times on a trail going down a hill into a turn etc etc there are times when your front will "driven" into the ground and you can give as much brake as you want. these are the times when disc brakes are nice...for agressive riding.:p

cyccommute - dont take this the wrong way or anything ubt after reading your post i get the impression you like to brake with 2 or 3 fingers ?

if so, try just using your index finger with the hydro's (with the levers positioned inward)

if your already a 1 fingerer (man that sounds dodgy lol) then i take that last couple of paragraphs back :P

I agree, most hydros disapoint when it comes to modulation. Some of the better ones have fantastic modulation.

Sorry but I don't agree. A rotor brake doesn't stop me and my bike in half the distance of a V-brake (or even a canti). There might be a slight advantage but discs have twice the brake power of rims?? If you do an honest test, I doubt that you will find a modern linear brake that would need, for example, 50 feet to stop a bike while a disc could do it in 25 feet. Show me some data and I'll eat my words but discs just aren't twice as good as rims.

But there in lies the problem with say that hydraulic brakes have superior modulation. If they did, it wouldn't matter how many fingers you use. Small amounts of lever movement should result in small amounts of pad movement- that's what modulation means, a smooth transition. Hydraulic brakes have multiplier effect that means just a little lever movement translates into a lot of clamping power on the rotor. That's not modulation - that's digital (or nearly).

As for the one finger thing, I just can't do that. Old dog, new trick and all that :rolleyes: . I'm sure I'll get used to it eventually but it doesn't necessarily mean I'll like it. GRAUMPH!

And don't forget to mention that a rim brake IS a disc brake - with a 26" diameter disc. I don't know much about mountain bike parts, but the really fancy high-end super powerful DH disc setups all use larger discs, right?

Hydraulic systems and discs have certain advantages over rim brakes, but power is not one of them - it's dependent on the size of the rim (or disc) to pad contact area and the amount of distance the pads move for any given amount of hand movement. Road racers use caliper brakes to slow down from extremely high speeds, and have for probably a century.


Disc brakes are definitely cooler, though. And anybody who says they're only interested in functionality is probably named Sheldon Brown.

Optimum size of 8inches. Companies tried bigger but got to much power and not enough modulation. Companies have gone the way of more pistons instead of size. There was one trials bike with a 24" rotor. Damn funny looking thing :)

There is an optimum distance from the centre of the hub for both modulation and power.

One reason I'm thinking of converting to hydro is that you never have to worry about cable friction. On a bike like mine that's pretty important, because the cable routing is crazy and the amount of cable it takes to get from the front to the back means there's a lot of resistance at the lever.

Hah, I've seen a picture of that bike. Rad.

Do you have a link to a technical article explaining why 8" is the optimum distance, or could you at least lay it out for me in a little more detail? It's not that I don't believe you, rather that I have the general impression that you know what you're talking about, and I'd like to learn more.

Is it just that larger rotors move too quickly for the pads to get a good grip on them with a light touch? How do power and modulation vary in % terms with different size rotors?

I have never had a problem with modulation using linear-pull or hydraulic rim brakes... Aren't mud clearance and mounting issues relating to large tires and suspension designs the most important reasons to use discs?

Interesting thread.

the reason I say this is because I actually did some testing of my hayes hydros today vs my old linear brakes.

Why? Because my wife insisted that the disc brakes were only for looks.

The setup: Empty country road in West Baton Rouge parish. Ride until I reach 25 mph and then SLAM on the brakes. Measure the distance with my trusty STANLEY tape measure. Note that for accuracy's sake, the disc brakes on my new bike are NOT broken in yet. A Nissan Sentra (the wife's car) verified the 25mph speed.

First my Kona with hayes discs: 25mph - a dead stop in 12 feet approx 4 inches.

Wife's Trek 3900 with linear brakes: 25mph - dead stop in 21feet approx 7 inches.

Note that this was on pavement (asphalt) and not gravel. In BOTH cases, had it been gravel or even hardpack the distances not only would have been longer, but the distance difference would have been less due to tire slide.

In either case though, BOTH brakes will hold their respective bikes at a dead stop on a 40-45degree levee with no problem.

I dont think the issue is that discs are better in every way....they are better if shorter stopping disatances are the most important thing. HOWEVER, linear brakes modulate MUCH better, they just aren't as strong.

My opinion on the matter would be that if you wanted to use the money to upgrade a different component, I see no problem with using linear brakes and forgoing discs to get a better fork or rear shock or crankset, etc. If you already have the bike set with all the components you wanted, and you find you have a REAL NEED for disc brakes, then go ahead and get them.

I can honestly say from my experience thusfar that 90% of ppl with a bike do NOT need disc brakes. If you DO have a real "OH CRAP!!" moment and jam the brakes, the discs won't stop you any faster if the wheels are sliding on loose stuff anyhow.

I find they are most useful because the disc being wet doesnt affect braking power as greatly as a wet rim does linear brakes.

No I don't have an official article. I just remember there being lots of trial and error early on with sizing. They tried 10 and I think even 12 and pulled back due to the sizing being toooo effective and causing damage. I think there was even a company that tried dual sided disc's for a proto. Common theory is power goes up by about 33% per 2 inches. Numbers I don't have, nothing beyond internet babble and some truth from my own experience.

My big seller for hydros is 3 fold
1 - power and modulation are consistent. linear pull on a downhill bike will burn through the rubber causing inconsistent power and modulation as well as REALLY wear down the pads ;) Keeping in mind I am talking quality. The same downhill run can affect poorly made hydros in similar ways. Oil heats up etc...
2 - warp a tire much? I don't really have to elaborate
3 - muddy wet conditions do not affect braking at all.

Ummm...Huh? Perhaps you should elaborate. Tires bend and flex and "warp" all the time. Not sure what you are trying to say here. Maybe I'm just being dense today;)

Maybe...

He meant the rim. If the rim warps, the disc brake isn't affected.

I've got Juicy 5's on my new bike. I started a thread a while back about issues with modulating the rear brake (it's to grabby), and were basically told to "learn how to ride noob". :rolleyes:

I'm a total convert to the Juicies now since they've made me lazy and I like the lack of effort they allow me to put in. But in no way is their modulation anywhere near the precision of well setup V's.

interesting....where is cyccommute's comment on this?:D