CX brakes - mix disc and canti?

tgotb

Mrs TGOTB has finally admitted she needs a better bike, and for what she wants to do I'm pretty confident a CX bike is the way forward. I've got to the standard discs vs cantis dilemma; I'm very happy with my discs, but I'm 95kg and relatively strong. She's not much more than half that, and bike weight is more of a consideration. If I was her size I'd go for cantis, but I probably have better-developed powers of SMIDSY-prediction, and I don't really want to let her loose on a bike with brakes which only sort-of work.

Since the front brake does most of the work I'm wondering about giving her a front disc and rear cantis. Is this sensible? Will the differential braking power cause unforseen handling issues?

mudcovered

TGOTB wrote:

Since the front brake does most of the work I'm wondering about giving her a front disc and rear cantis. Is this sensible? Will the differential braking power cause unforseen handling issues?

Well that's the way round to do it. I was thinking of doing the same to my CX bike if I could identify a suitable carbon disc fork that would fit the frame. No matter how light the rider the weight of the different components is going to be pretty minimal so if the frame can take a rear disc I'd fit them front & back.

Also canti brakes aren't any worse then any other rim brake system in terms of performance providing they are set up right so its really not that big a deal. I'm only looking to switch to disc brakes to cut down on rim wear on my rather muddy commute.

Mike

nicklouse

discs give better braking (consistant) not just more. I would fit discs if possible always.

roger_merriman

TGOTB wrote:

Mrs TGOTB has finally admitted she needs a better bike, and for what she wants to do I'm pretty confident a CX bike is the way forward. I've got to the standard discs vs cantis dilemma; I'm very happy with my discs, but I'm 95kg and relatively strong. She's not much more than half that, and bike weight is more of a consideration. If I was her size I'd go for cantis, but I probably have better-developed powers of SMIDSY-prediction, and I don't really want to let her loose on a bike with brakes which only sort-of work.

Since the front brake does most of the work I'm wondering about giving her a front disc and rear cantis. Is this sensible? Will the differential braking power cause unforseen handling issues?

I think i'd say it's making life more difficult for your self, there will be extra weight but not that much.

shame it's all still cable on the road though.

ride_whenever

TRP parabox or the hope disc thingy.

You know it makes sense, cable discs are a total PITA

bails87

My BB5s have been trouble free (so far, ~10 months).

rhext

I have an Airnimal with cable discs on the front and V brakes on the back. I'd only ridden it a couple of times and I was having a look at the fork to see if it had V brake mounts. It didn't!

I have no handling issues, it's just that the V brakes on the back feel better, and setting up the disk brake without it rubbing is a pain. I'd happily buy a road bike with hydraulic discs, but I'd not buy one with cables.

walkingbootweather

You kids don't know how lucky you are - when I was a lad brakes really were rubbish. Modern rim brakes (well calipers and v-brakes anyway) can be excellent for road riding. Cantis on the other hand er can't (at least I've never been as satisfied with them). Disks have a place, particularly off road and in the wet. For cheap, reliable commuting I'd be perfectly happy with decent v-brakes on a mtb with wider tyres, or calipers on a road bike with narrow tyres.

No reason why mix and match wouldn't work, but might not look very elegant and perhaps more fiddly to maintain.

meanredspider

FWIW I weighed a 105 caliper with pads versus a BB7 caliper, pads and disc and the difference was tens of grams - certainly not worth worrying about. Buy lighter tyres or inner tubes - it will make a much bigger difference to the weight.

BB7s are easy to set up (use the Volagi BB7 guide on YouTube) and, if she's light, wear will be light too so any adjustment (which is easy anyway) will be infrequent.

pangolin

To further muddy the waters, I have canti's on my kaffeback and they are excellent. Didn't take ages to set up which is the main complaint I hear. Possibly I just got lucky but I have done it twice and neither was too bad.

I think they stop better than my ultegra brakes on the dolan. The front one does have noisy days though. Very noisy.



I've had BB7's too, on a pompetamine. The first time I set these up it took ages. This was just me not really knowing what I was doing though, now I could do it quite fast. Once set up they were very good.

walkingbootweather

Also, what does it cost for a set of BB7's pads and rotors? Must be £150 or so. You can get a good set of rim brakes for less than a third of that. I guess you pays your money and takes your choice.

tgotb

Not really worried about setting up the discs. I have that sussed on mine; once you've got the hang of it, it's probably easier than cantis. Purely a tradeoff of weight vs stopping power (plus the fact that the current preferred frame doesn't have disc mounts, but could be combined with a fork that does).

Has to be either discs or cantis, as the bike will (hopefully) be doing some actual cross racing. This is also one of the drivers to keep the weight down.

walkingbootweather wrote:

Also, what does it cost for a set of BB7's pads and rotors? Must be £150 or so. You can get a good set of rim brakes for less than a third of that. I guess you pays your money and takes your choice.

The set I bought for my own bike were around £100 (including rotors).

meanredspider

Certainly no reason why you couldn't use cantis on the rear and a disc up front. Most rear brakes work too well anyway.

bails87

BB5s are £35 per end, including rotors, on CRC.

walkingbootweather

bails87 wrote:

BB5s are £35 per end, including rotors, on CRC.

That does look good value and a great saving against RRP of £60 each. On CRC the BB7s are £55 each not including rotors (RRP is allegedly £70 each)

bails87

bails87 wrote:

BB5s are £35 per end, including rotors, on CRC.

Actually, I think those are the MTB ones, not sure how much road versions are.


Still, a lot cheaper than top spec hydros at £200+ per end. And not that much (if any) more than Ultegra level calipers at £100/pair. Especially when you factor in there's no need to have a wheel rebuilt due to rim wear.

phy2sll2

nicklouse wrote:

discs give better braking (consistant) not just more. I would fit discs if possible always.

Do cable discs have better modulation than decent cantis?

What about mini-Vs?

MichaelW

The problem with CX bikes and brakes is in the cable pull. Pangolin's Planet X CX bike above uses non-STI brake levers, probably a long-pull variety so they work well with cantis.
There is a version of Avid BB7 matched to STI road levers. I have no idea how it compares to the MTB version but even if it is not as powerful, it should be better than STI levers and cantis.

I use Cantis on my touring bike and discs on my commuter and prefer discs any day.

Initialised

I have some 2nd hand disc brakes to fit to my son's 20" wheeled MTB, iirc only the front has disc mounts. I'll let you know how long it takes him to faceplant!

Seriously... does anyone know of a review of the Hope V-Twin system?

phy2sll2

MichaelW wrote:

The problem with CX bikes and brakes is in the cable pull. Pangolin's Planet X CX bike above uses non-STI brake levers, probably a long-pull variety so they work well with cantis.
There is a version of Avid BB7 matched to STI road levers. I have no idea how it compares to the MTB version but even if it is not as powerful, it should be better than STI levers and cantis.

All brakes (cantis, discs, V) have long pull and short pull versions, except road callipers, right? (And coaster brakes, I suppose!)

In the case of v-brakes and cantis, the short pull versions have shorter arms (I think).

I don't know what the difference between long-pull and short-pull (i.e. road) discs is, really. Leonard Zinn tries to explain it here:
http://velonews.competitor.com/2012/08/bikes-and-tech/technical-faq/technical-faq-throwing-ice-water-on-road-disc-brakes_235280

Cantis are great. Light and powerful if you set them up right. Get some Tektro CR720s, nice and easy to set up. If you have a fork that's drilled, you can also fit a fork crown hanger which makes the whole system a bit less susceptible to shudder.

If you want discs at the front, Kinesis do some nice (not too pricey) carbon CX disc forks.

I wouldn't fit mini-Vs if you / your GF is going to be mostly using this on the road as I can see the lack of modulation could give you a few endo-tastic moments.

prawny

I remeber when discs first came out it was quite common to just have a disc on the front. I was going to do the same to my boardman when I was riding regularly just stick a disc fork on and one BB5/7 jobs a good un

el_presidente

I've got a disc front / v-brake rear on my MTB pub bike. Works fine, never really notice either at all.