September 18, 2014 Login  


disc brakes for cross
Last Post 02/23/2014 04:23 PM by Kenny Gonzales. 55 Replies.
Printer Friendly
Sort:
PrevPrev NextNext
You are not authorized to post a reply.
Page 2 of 4 << < 1234 > >>
Author Messages
pabiker

Posts:80

--
11/18/2013 11:40 PM
see above.

I would use disc brakes on any cross bike without hesitation. Kicking up a rock doesn't bent rotors they get bent by running into or side-swiping a rock that doesn't move.

Again, hydraulic disc brakes today don't need to be adjusted. That is, unless you fooked them up.
jrt1045

Posts:361

--
11/19/2013 08:55 AM
if you by Avid you better be familiar with your bleed kit, the idea of SRAM selling integrated brake/shifter combos would is enough to send me scurrying for something else. Everything I have encountered from SRAM, brake and drivetrain wise has been junk. Road and mountain, can't believe they get away with selling it. Compared to Shimano it is poorly manufactured and executed at every level. If Shimano came out with something hydraulic for road/cross I would be interested, SRAM - no way

FWIW: I have a set of XT's that I pulled out of the box and installed 2 years ago and have done nothing but replace the pads now and then. Like PA, I ride in an environment that eats bike parts so think that is pretty good. For the record, the only rotor I ever bent also destroyed the wheel

As far as rotor rub, centerlocks. Biggest problem I see is having to true a perfectly straight rotor around the 6 contact points of a hub. Centerlocks and thru axle? - magic

Back to point of the OP, I see disc as a very viable option as long as they are made by someone other than SRAM
dkri

Posts:80

--
11/19/2013 08:58 AM
PA and I agree for the most part, except I wouldn't choose to use mechanical discs on a cx bike. I did it for a season and didn't like it. Lack of pad clearance is the issue. Your rotors need to be hyper true to be able to set them up without rub, and with QR wheel attachment your hubs can shift the tiny little bit needed to cause rub. Rotors can come out of true by being bent or being warped. Stream crossings or puddles at the bottom of hard descents pose a risk for that.

I've got probably 50 hours on my mountain bike's X.9s without doing any adjustment. On BB7s with road levers on a cross bike, I don't think I've ever made it through an hour without some small adjustment being necessary.

**edit after reading jrt's post - I've had better luck with Avid brakes than apparently anyone else, with 3 years on them with no issues, but I bled them all at the outset.  I've also apparently had worse luck with bending rotors than anyone else because I've got a pile of bent rotors, bent in both cross and mountain bike use.**

Talking about "discs" almost needs to be cut in threes - hydraulics ("hooray!!"), mechanicals with mountain levers (slightly less enthusiastic "hooray") and mechanicals with road levers ("boo hiss" in my experience).
formerly dkri
gabbard

Posts:27

--
11/19/2013 09:17 AM
So, if you are looking at hydraulics on road levers, what are the options? It looks like SRAM is the only integrated option. TRP makes a hydraulic, cable actuated brake, but is this the worst of both worlds? Would the recommendation to be to go with SRAM shifters and brakes, or wait until Shimano comes out with hydraulic road brakes? I don't like the option of buying Shimano mechanical brakes, only to change out levers and brakes in 1-2 years.
longslowdistance

Posts:664

--
11/19/2013 09:30 AM
Regarding the TRP cable actuated hydro, I've been using one on an adventure bike for a few months with a Shimano ice tech rotor. It is an improvement over the Hayes CX mechanical it replaced in terms of feel and power, but haven't had a chance to truly challenge it on a long steep descent. I have no personal experience with dedicated road hydros so I can't compare with what should be the current gold standard.
Dale

Posts:485

--
11/19/2013 11:38 AM
Posted By Steve Gabbard on 11/19/2013 09:17 AM
TRP makes a hydraulic, cable actuated brake, but is this the worst of both worlds?


Best of both worlds-- lighter than full hydraulic, cheaper levers; important when racing cross where levers get whacked and you're not a sponsored rider
Oldfart

Posts:472

--
11/19/2013 04:14 PM
Gabbard: Shimano has a set of hydraulic cross/road brakes too but it is only DI2 which means you need the derailleurs too.

I think some of the issues some people have had with keeping a rotor centered has to do with the hub end caps or lock nuts not being perfectly square. I had that issue with XTR hubs which were and still are cup and cone. I found that every time I took a wheel out and put it back, the rotor was no longer centered. I also discovered that if I marked the position of the lock nut with a reference dot on the frame as well that I did not have that problem. This was with standard qr axles. Never an issue with DT hubs or with through axles. I like that Giant has made their cross forks with a 15mm qr and mountain spaced hubs.

I am a bit leery of the SRAM kit because their hydraulic mountain bike brakes are not easy to bleed and some of their brakes howl like a banshee no matter what you do. I know this from experience with numerous Avid brakes. They do function well from a feel and power perspective but the last pair of XO brakes needed to be bled every three or four months. My Shimano brakes maybe one a year.

I have read a cure for the howl is as easy as applying tape to the back of the brake pads. The adhesive on the tape provides a gummy sort of damping effect or so i have been told. I sold the bike I had that squealed like Ned Beatty.

http://www.youtube.com/watch?v=WqNMjZpSbnU

pabiker

Posts:80

--
11/19/2013 05:45 PM
My comments are entirely about hydraulic disc brakes. Why anyone would use mechanicals at this point is confusing to me.
longslowdistance

Posts:664

--
11/19/2013 06:08 PM
PA, here's the scenario: Because the bike in question is a road bike and the rider already has $400 invested in brifters.
dkri

Posts:80

--
11/20/2013 09:09 AM
^^ what he said. In one case (SRAM) you need an entirely new mechanical drivetrain, in the other (Shimano), you need an entirely new electronic drivetrain. Paraboxes are dead ends. The mech-to-hydro TRP things are your only hydro solution that doesn't require a new drivetrain. Seems like a pretty profound barrier to hydros to me.
formerly dkri
Cosmic Kid

Posts:1100

--
11/20/2013 10:12 AM
The success of discs in cross will lie in OEM spec, not so much in people converting. As racers / riders want new bikes, hydro discs will become more prevalent, IMO.
Just say "NO!" to WCP!!!!
gabbard

Posts:27

--
11/20/2013 10:38 AM
I learned something new - I didn't even know what a Parabox is.  Even after googling it, I can barely figure out what it is.  Some sort of stem mounted box that converts cable pull to hydraulic pressure?  Seems like the TRP Hy/Rd has replaced it, and at $470, it is a good thing.

Just from looking at that device, with cables coming in and out, it is what we used to call a "frappus" at a previous job - a made up word for an overly complicated and expensive looking device, whose purpose or function is not clear just by looking at it.  Frappus performance is typically poor, and requires constant tweaking and tuning, with the end user limping along until someone comes up with a proper engineering solution.
dkri

Posts:80

--
11/20/2013 12:47 PM
And "frappus" becomes part of my vocab. Anyone else remember Sniglets?

CK - since you pretty well need a new bike to convert...
formerly dkri
Cosmic Kid

Posts:1100

--
11/20/2013 12:52 PM
It seems there is a fair amount of bikes form the alst year or so that were "disc ready" off the factory lines, but either used mechanicals or just had the tabs in place. This was similar to the MTB segment when discs were on the cusp of breaking through.
Just say "NO!" to WCP!!!!
jrt1045

Posts:361

--
11/20/2013 01:57 PM
performance will come in steps and as CK said, OEM spec

ahh, the dawn of the disc age in the mountain bike world, brings back some memories. Road/Cross disc will probably be a similar journey. I really wanted to like the concept back in the day but it wasn't until I got a set of Hayes Mag hydraulics that I was satisfied with their performance. The road there was fraught with with a year or 3 of danger, confusion and re-reading the directions. but once headed in that direction there was no turning back. That road consisted of:

1) a cable actuated hydraulic front that was marketed by rock shox. similar to the parabox concept and worked like crap. couldn't even scare up replacement pads and I don't think I was ever able to bleed the caliper itself. a waste of a few hundred quid
2) 1st generation cable actuated, probably tektro. didn't work much better but simpler to set up and what not and much cheaper.
3) CODA - Cannondale pushed these during their heyday. 4 bolt rotors, some kind of crazy mineral oil. 1 piston or 2 piston - didn't matter as neither really worked. They were like no piston brakes In chronic need of bleeding, chronic BS from Cannondale engineers how that it was all my fault and my set-up that made them crap. How'd that moto x bike/marketing project work out? (stream of consciousness thought here). Might be the only brake I have encountered that was of worse quality than avids
4) Hayes, they worked - like really well. Simple, easy to work on and completely rebuild-able; many times with parts that can even be found at a hardware store. Genius. Fished an old set out of the parts bin and tossed them on my son's first MTB, worked like new after a few minutes of service

(I have had a lot of disc brakes, scary)

From there, mountain disc have generally improved with each new iteration. Road/cross will be similar, each new step is progress
You are not authorized to post a reply.
Page 2 of 4 << < 1234 > >>


Active Forums 4.1

Latest Forum Posts
Odile posted in The Coffee Shop

Milano posted in Off-Topic

A rational (and refreshing) view posted in The Dark Side

Jens Voigt Hour Record Tomorrow posted in Professional Racing

XTR Di2- I'll pass posted in Gear Advice

nude kits posted in The Coffee Shop


No articles match criteria.
  Terms and Conditions | Privacy Policy  Copyright 2008-2013 by VeloNation LLC