Drop-bar shifters and disc brakes

Jamey

Hypothetically, assuming I had a road frame which had correct mounting points for disc brakes, what would I need to do to get disc brakes to work with STi shifters? Tiagra, in my case, if it makes any difference.

I've heard that Avid make calipers designed specifically for the cable pull generated by drop-bar shifters (STis and Ergos)... Is this true? What's the model?

I assume there are no drop-bar shifters on the market that can work with hydraulic disc brakes, are there?

Jamey

Also, who makes 130mm-spaced hubs that will take a disc rotor?

markos1963

Orbea made a bike called the Diem Drop if you google that it might give you some answers.

Jamey

Hmmm... Seems to be using a Shimano caliper system specifically designed for road levers. Cheers for that.

Now another interesting point has been raised - racks and mudguards needing to fit around disc brakes.Just when i thought I had the spec for my dream bike sorted in my head.

ride_whenever

you either want the avid bb5 road or the bb7 road for your sti. Or you can fit any caliper and use a travel adjuster.

For hubs, re-space a cup and cone mtb hub is probably the best bet.

No drops and hydraulic brakes i'm afraid. TBH it's too much power.

Jamey

Cheers RW. Second time you've helped me out today.

Although I'd prefer a proper 130mm hub with disc mount tbh. But since this is all hypothetical I could just get a custom frame with 135mm spacing, I suppose

But then the rack and mudguard arms would be 2.5mm out on either side. The horror.

ynyswen24

Have a look at the Planet-X website,

www.planet-x-warehouse.co.uk

scroll down to the bottom of the home page, click next page and there's some photos of one of their customer's bikes, an Uncle John cyclo-X. He'd managed to get some Hope hydraulic discs working with Shimano STI's. It looks a bit Heath Robinson, but damnably clever...

Monty Dog

Avid BB7s are more than adequate for a road / cross bike - you can use MTB cable disc brakes, but adjustment needs to be a bit more critical. Shimano do a road disc hub but most just use MTB hubs - many frames are 132mm wide to accommodate both sizes of hub. I've had custom ti cross with discs for about 4 years and would recommend them for all-round use - although a full-carbon cross rig comes in handy too.

Jamey

Cheers again.

I'm basically just dreaming up my ideal commuter bike for the future and all the trouble I've been having with my brakes made me look towards the most hassle-free option available and it seems to me that cabled disc brakes need very little fettling or looking after apart from pad changes.

Or is there an even more maintenance-free option I've missed?

AidanR

Most maintenance free option would be drum brakes, but they're heavy and not great stoppers (though unaffected by the rain).

Or a fixie.

Or a fixie with a front drum brake.

Or a fixie with a belt drive and front drum brake.

Jamey

OK, I'll rephrase... Most hassle-free option that isn't a drum brake and actually has decent stopping power

Jamey

Here's a thought... Let's say I had a custom frame built which was a road bike frame but with 135mm spacing at the rear drop-outs to accommodate a disc hub.

Would that lead to any problems elsewhere on the bike? Like chainline, or mech-to-cassette alignment or anything like that?

salsarider79

No. You just need to get the chain line correct. Thats how MTB's run so why wouldn't it work for road bikes.
Why not look at Sunday bikes? Ti frames, really well made and so beautiful to ride. I know cos I've ridden one. The September has rack and guard mounts and can also custom built so you can have 130mm or 135 mm spacing, horizontal dropouts to run single speed (Can't get much more maintenence free), disc tabs, anything.
Ti frames won't rust, will take out road buzz, oh, I love Ti frames.....


p.s. if you opt for 133mm spacing then you can run either 130 or 135mm hubs.

PBo

Jamey wrote:

Hypothetically, assuming I had a road frame which had correct mounting points for disc brakes, what would I need to do to get disc brakes to work with STi shifters? Tiagra, in my case, if it makes any difference.

I've heard that Avid make calipers designed specifically for the cable pull generated by drop-bar shifters (STis and Ergos)... Is this true? What's the model?

http://www.sram.com/_media/pdf/en/avid/specs/AVID_Mechanical_Disc_Brakes.pdf

I'm guessing that as these 2 of these say road style, they work with dropbar shifters...

ditto these http://www.tektro.com/02products/11lyra.php

I have a flat bar roadie, with discs, and been wondering about converting to drop bars.....

Jamey

Cheers. Had a look at Sunday bikes and if I was going for a pre-built I'd probably consider it but if I do go ahead with this in future (it's all just speculative dreaming at the moment) then I definitely want to build it myself from scratch, starting with a custom paint job on a custom Ti frame.

All I need is a few grand spare

Edit: cheers PBo.

AidanR

If you don't have a few grand spare, check out http://www.xacd.com.cn/ They'll do literally anything you want, but be careful - they will make what they draw for you, right or wrong.

Jamey

Hmmm... Don't trust myself to sketch something properly tbh

I'd need to get fitted first anyway, I have no idea what geometry I need and I suspect my ideal position might be a little eccentric because I broke both of my arms (at the elbows) 16 months ago and I'll never be able to fully straighten them again, so I might need something adjusting to account for that.

Jamey

Oh, one more question, this time a slightly more general disc brake one rather than specifically about using them with drop bars.

I see you can buy different rotor sizes but when I peeked at a few disc-equipped bikes in the car park last night before I went home I couldn't see any obvious way of adjusting the position of the caliper unit to accommodate a larger rotor. How do you move them further out to take a bigger rotor?

Not that I plan to do this, I'm just curious, that's all.

ride_whenever

there is an adaptor between the frame/forks and caliper, you change this when you change the rotor size.

I'd actually say that cable discs are more faff than rim brakes, they need a lot of regular maintenance.

I'd say bodging the hydros would be the best setup, despite the ugliness and difficulty in setting up. In terms of reliability they're miles better than anything else. You can easily go 12-18 months without touching them at all.

Jamey

Oh really? What tends to need most of the attention on cable disc systems then? Surely once the pads are centred they tend to stay that way, don't they?

mister biscuit

Funnily enough, I though about this earlier in the year:, and eventually, for my super-commuter, went for a Kinesis Tripster build: http://www.kinesisdecade.co.uk/product.php?id=1 - it's a 105 spec, with bomb proof hope pro2 Mountain bike hubs built onto A719's (probably!). I'm really happy with it, and the actual stopping in the wet is just brilliant. I've got Avid BB7 Road cables on it, and they work just fine (although there is a little bit more lever throw than on calipers)
I haven't really had much issue at all with adjusting the brakes.
chain line wasn't an issue at all. it just works.

Jamey

Cool, that's the sort of thing I like to hear

So when it comes to adjusting the pads on disc brakes, do you still need to toe-in to avoid squeal? Is it even possible to toe disc pads inwards?

And what about all the other alignments... I presume there's no need as disc pads just clip into the same place each time, do they?

mister biscuit

you don't get toe in on discs, so no need to do that. mine squealed for a little bit, but when the pads are bedded in, they don't make much noise.
New pads just slot in. you're supposed to align new pads, but it's really simple.
- loosen the caliper clamp bolts, do the pad wear adjusters up so they clamp the disc, and then tighten the bolts up, and back the pads off again : alignment done

k2rider

ive got a pair of 700c roadwheels with coda expert 4 bolt disc hubs with 160mm discs that i dont use if your interested, to be honest you wouldnt need anything bigger than 160mm especially in the wet. 135mm oln though.

nicklouse

Jamey
Have a look at the Focus Mares cross disc. as an off the shelf buy.
http://www.focusbikesuk.com/focuscycloc ... s_disc.php


and a road bike with hydro discs. 2 on the front and one on the rear 1, not production.

http://www.canyon.com/_en/technology/pr ... oqcgccgmg7

k2rider

mmmmmmm that canyon is stunning!