|   Avid disc back to HS33 - Lure of Frogs | CapeShaun
Nov 16, 2002 10:08 PM | | I am currently running an Avid front disc and LX-V at the back. Performance of the Avid has been great in the dry, but on one very wet, muddy ride I did which had a very long downhill, I lost all brake power / adjustment (lever at the bar) before the end of the hill and was able to hang on thankfully due to the LX V-brake - exactly the opposite reason for me having bought the Avid in the first place.
As a long time admirer of Magura HS 33s I recently uncovered a set of used limited edition Frogs at a very good price and am very tempted to ditch the Avid disc / LX Vee setup and succomb to the brilliant looks / reliability of the Frogs - am I crazy ?
Any advice, experience or comments would be appreciated.
Regards,
Shaun in Cape Town. |
| Well first of all
| Spar¡cus
Nov 17, 2002 1:20 PM | | .there are thousands of Avid disc users who can tell you that your disappointing experience with your particular brake in the wet is an anomoly. So let's set about discovering what went wrong.
How old is your brake? I don't mean how long have you had it, but is it one of the earliest versions produced? Although the caliper did not change until this year, 2000 and some 2001 Avid discs were shipped with the earliest model brake pads, called "APC's" for All Condidtions Pads. These pads were organic and performed adequately in dry use but left something to be desired in the wet. They also tend to howl in damp conditions. The APC pad's backing plate was black in color.
Later came "UCP's" for Ugly Conditions Pads. These are the pads currently shipped with Avid discs. They are sintered metal pads, which perform much better in wet (and dry) conditions. They have a copper colored backing plate.
If you are currently running ACP pads you will probably be able to improve your disc brake performance significantly by switching to UPC's.
If the problem is not the pads, there could be a few of other solutions to your Avid problem. One is that setup could have been done incorrectly, causing the rotor to deform excessively under braking or causing only one pad to be engaging (to a signficant degree). Do your pads still have plenty of friction material on them, or are they worn out? If the brake lever's barrel adjusters were used to adjust for pad wear (in lieu of the red dials, which should be used exclusively for this purpose), the brake's actuating arm could possibly be "preloaded" to the degree that it is bottoming out before the pads are fully engaging the rotor.
Then again if, when your brake was initially set up, someone attempted to "stretch" the brake cable by working the brake lever as hard as possible with the pads fully engaged, the ramps that the ball bearings inside the caliper roll on could have been damaged. This will result in a brake that never comes close to its potential for good stopping.
Second of all, I have no info or experience with the frogs. But rim brakes come with their own set of performance aspects, some advantages, some disadvantages. I have owned a set of Magura HS22's and in my personal experience, while the Maggies were the most outright powerful rim brake I've ever used, in the wet they didn't hold a candle to a good disc brake.
And the Avid is a good disc brake, although your particular unit sounds deficient.
Good luck.
--Spary |
| re: Well first of all
| CapeShaun
Nov 18, 2002 12:22 PM | | Mate,
Thanks for your interest and advice. The brake is a 2001 model and sadly has the new coppery coloured base pads. From what you say, and other stuff on the net I have read, the problem may have been cable stretch, but I am satisfied that the setup etc were spot on. It may be that the pads, which still have reasonable material left on them were faulty - only problem is that Avid support does not reach out here in darkest Africa.
I read ALL the reviews and your and many other opinions before plumbing for the Avids and dry weather performance has been fine. I remain somewhat nervous about my next long wet downhill though.
I use XT levers which seem a good match. Is there anything else I am overlooking ?
Cheers,
Shaun in Cape Town. |
| Hmmmm
let's dig deeper | Spar¡cus
Nov 18, 2002 6:18 PM | | In your initial post you said: ".on one very wet, muddy ride I did which had a very long downhill, I lost all brake power / adjustment (lever at the bar) before the end of the hill."
I understand what "lost all brake power" means, but do you mean by "adjustment (lever at the bar)" that your lever simply bottomed out against the handlebar before full braking power was achieved?
If you're like me, you prefer your brakes to come on late in the lever's throw. During the dry season, I can set my brakes up so that they engage just before the lever hits the handlebar. I find I get less hand fatigue with them set up this way. But during the wet season I do not have the luxury of setting them up this way because, well let's face it, even though the performance gap between dry and wet performance with good quality discs is not as pronounced as it is with rimmers, a performance gap still exists. I must put a bigger squeeze on the lever to get my machine and I slowed down when conditions are sloppy.
Is is possible that you might have remedied your situation simply by dialing the red knobs inward a couple of clicks before going down the hill? If that's not it, I'd next suspect the cable &/or housing, though I personally may be barking up the wrong tree. Obviously you're in the best position to troubleshoot the hardware.
Let's keep digging.
--Spary |
| Hmmmm
let's dig deeper | CapeShaun
Nov 19, 2002 2:20 PM | | Thanks for your continuing insight.
Yes I do like my brakes to reach max effect closer to the bar. On that particular ride I did not loosen them further before the hill.
My summation is that the brakes were probably adjusted with too much throw and that there was probably some cable stretch involved as well.
You clearly have a lot of experience with brakes - do you think that my setup : Avid disc front and LX Vee rear is better than HS33s front and back ?
Your opinion would be most interesting.
Cheers,
Shaun in Cape Town. |
| My opinion? I wonder if we might invite Mike T into this conversation
? | Spar¡cus
Nov 19, 2002 10:02 PM | | My opinion is that the Avid disc (or any good quality disc) would be superior to any rim brake, including the Maggies. But as I mentioned, I've only experienced the HS22's and I believe the 33's utilize a different piston that might make them more powerful. Even so, I believe that even rim crushing power will not be as big a benefit as a good disc, as it is the sloppy, slippery rim surface combined with marginal performance friction materials (read: inferior brake pads) that keep rim brakes from matching the performance of good discs in the wet.
But let's hope Mike T chimes in. He has experience with all things Magura -- every disc and rim brake model. His opinion would be based on more actual experience with the Magura brake you're interested in.
--Spary |
| Oh sure, drag meeeee into this! | Mike T.
Nov 20, 2002 4:50 AM | | Even though I love Magura's rims brakes all to heck you know what i'm gonna say doncha Sparty?
The HS22 was a fine brake and the smaller piston of the HS33 made it even more powerful but when we're dealing with a relatively soft aluminum braking surface combined with a brake pad of compromised material (can you imagine a sinterd pad on an alum rim?) then when we combine water and/or muck we will have less than optimum performance.
The Avid disc brake is a fine brake (Ok I said it. Stop hyperventilating Sparty) and Shaun's problem has been covered by you other guys in this discussion already.
Shaun's question was - "Avid disc front and LX Vee rear is better than HS33s front and back?"
Well I gotta start by saying that I'm not a fan of rim brakes anywhere on a bike (relative to a disc brake) and unless a disc brake just can't physically be mounted then the users are fooling themselves. It's like outfitting your kid with one rubber boot and one flip-flop. He may play in the sandbox for many hours but sooner or later he's gonna wander off, get a wet foot and start yelling.
But that's not the issue here.
I think in normal circumstances - which is everything working as it should and Shaun's experience with the Avid was abnormal - then sooner or later any rim brake, when the conditions get bad enough, will be a non-functioning brake. At that point, most disc brakes will have some resemblance of their original power available.
So my conclusion has to be, even though my Cult helper CODMAN (a dedicated HS33er on some wicked Quebec rides) will disagree, is that a disc brake linked to any rear rim brake (yes even a v-brake - ptoooeee!) will, in my opinion without any hard test data, will be better than a pair of Maggie rimmers - even the rare, almost neon-green Frog version.
Mike T. (mcm # 717) |
| Good catch | Spar¡cus
Nov 20, 2002 1:27 PM | | Whenever somebody tosses me a hot potato, my policy is always the same. Toss it to the next guy as quick as I can. Nice catch, SeenYour T.
Remember, you said it, not me.
With never ending admiration & undying respect,
Spary |
| How.... | Roy
Nov 19, 2002 8:04 AM | | much do you weigh? It looks like you're running the 165 rotor so I'm curious what you weigh. It's possible you could have overpowered the front Avid by the lengthy downhill and constant braking and experienced some serious brake fade. I'd consider a larger rotor if lengthy downhills will be more common for you. Remember, when it's muddy you can't go as fast and have to brake a lot more while trying to be more careful. Dry you can let it rip more so I'd guess it was more braking style (your need to go slower in the mud) than the brake itself.
The only other thought I'd have is if some gunk got in the caliper/rotor during the run causing problems but this is way more likely on a rim brake than a disc brake.
I would definately not got a rim brake (they just don't cut it anymore) and would try a bigger rotor. Or next time try pumping the brakes (instead of constant pressure - like how you would brake on an snowy/icy road when driving your car) to ease the heat build up and brake fade. |
| How.... | CapeShaun
Nov 19, 2002 1:54 PM | | Roy mate,
I weigh about 105kg which is a lot more than 200 pounds. While I accept that I may have overpowered the front brake, its nevertheless disappointing that under the circumstances I was getting better performance from my ancient LX-Vee brake in the rear.
I am also on the poorish side of the tracks and the thought of having to cough up more hard earned dosh on a bigger rotor hurts and maybe goes to prove my original gripe - that maybe Avids are a bit overrated in the wet.
Thanks for you insight and advice though. Sparty also had some good advice. I might just give the Avids a last chance.
Cheers,
Shaun in Cape Town. |
| I guess.... | Roy
Nov 19, 2002 5:19 PM | | I didn't do a very good job of explaining my thoughts. My point is the Avid didn't fail because it was wet out, rather it was *overworked* because you were doing far more braking than you normally would have because it was wet out.
The rear was okay cuz on a lengthy downhill you have even less weight over the tire and it takes even less pressure to brake and cause it to lock up (with the slippery conditions on top of that). So overall the rear brake effort probably wasn't much different than the dry.
Had you had your LX in the front, it would have been far worse. Next time it's wet out, do that run but put your old LX front on. It's a good test and you don't have to spend any sheckles. If you don't have your LX front, use the one in the rear and borrow another V from someone for the rear. |
| Is there any chance the cable slipped? | Brandon
Nov 20, 2002 3:20 PM | | At the clamp on the brake lever arm? When I first installed Avids on my FSR I neglected to tighten that clamp bolt enough and didn't notice till I got on a downhill section where I had to pull harder on the lever which pulled the cable causing a loss of power. |
| |
