Disc brakes for a 700c tourer?

[nurgles]

I have run Hope hydraulic disc brakes on my mtb for several years. I have to say that braking performance is in a different league to either v-brakes or calliper brakes - one finger braking whatever the conditions. However, the most noticeable advantage is in the wet and mud, so if you only ride in dry weather, they are probably not worth the money. I also note that weight is not a huge issue - if you add the combined weight of levers & cantilevers, they are only a little less than a complete disc setup, which is around 400g each end. There's also the opportunity to re-design the rim as there is no requirement to include a braking surface, and many MTB wheels do just that. Pads also seem to last far longer than the ones on my road bike.

Have been using discs on my commuting bike for years as my commute is through seriously steep country park.Other forms of braking would be insufficient.This bike is also my touring bike but after the discs were bent in the bike box on the way to Cambodia I decided that I wouldnt want discs on a touring bike.However for my trip last year to Turkey I removed the discs for airline travel and refitted them at the airport which was a better solution.I also use disc pads like crazy !!

Incidently last week I completed an Enduro on the same bike for which I was glad of the discs again.However if I had a single dedicated touring bike I wouldnt use discs.

[hamster]

Hydraulics are the biggest advantage - I'm an absolute convert to Maguras, both on road and MTB. However I'm still not sold on the extra advantages of discs for road touring.

I have had circumstances when they were a good idea (water froze to my rims on a very cold day after crossing a ford)...

[vlad1999]

I have a CRX zero with Juicy 3 hydros .
I love being able to stop very quickly . Like when taxi's cut you off etc.
Have prevented at least 3 accidents... in 2 years.
I swear by them

[speedsixdave]

I use BB7 Roads on my Battleship. They are much better for stopping than V's or cantilevers with drop bar levers. However if I did it again I think I'd go for BB7 off-road with the Tektro V-brake long-cable-pull drop bar levers - the return springs are a bit weak on the BB7 roads, and they don't return as smoothly as I'd like after a dirty winter. Not an option if you use STIs though.

Some advantages:

They stop better than rim brakes (have a look at the Magura website:
Deceleration in m/sec² according to DIN 79100 (100N handforce) for HS33 hydraulic rim brakes: 4,2m/sec²
Deceleration in m/sec² according to DIN 79100 (100N handforce) for Marta hydraulic discs: 6,8 m/sec² (203mm), 6,3 m/sec² (180mm), 5,8 m/sec² (160mm)
And for Gustav hydraulic discs: 7,9m/sec².
They might be lying, but this seems better than all of us saying well I think they're better)

They don't wear out your rims
They work with a buckled wheel
They work better in wet weather and mud
The braking surface is specialised, which means your rim can be optimised as a rim.

Some disadvantages:

They can overheat and fade (but don't cause blow-outs)
They might weigh a bit more
They might cost a bit more (although BB7s are not too bad compared to, say, XTR V's)
They will probably make your rigid front fork very uncomfortable - this is probably the big one for a touring bike

All in, I'd definitely go for them again on my tourer. Especially on the rear. And discs will only get better, whereas I don't suppose there's very far to progress with rim brakes now.

[speedsixdave]

However, you'll probably end up with MTB hubs if you go the disc route, thus meaning you'll have to have the back end spaced to 135.

That's surely a good thing overall for a touring bike. Less dish, stronger wheels, better sealed hubs. And probably not 10-speed!

[glueman]

Simplicity is everything on tour. My only experience of discs are hydraulics on the MTB and I wouldn't want to be faffing about with those by the roadside. Also lightweight discs are quite thin and vulnerable to knocks.

Vs would be my preference for flat bars, deep dual pivots for drops.

[Bren]

I've just taken delivery of my disc braked tourer and I'm amazed by the performance of the brakes and the control that I have. The gear is BB7 calipers, 203mm discs operated by drops (Campag Veloce levers with an XT drive-train).
I chose discs after I became disillusioned by the performance of the rim brakes on my Super Galaxy. I seem to do quite a lot of cycling on tow paths and tracks and I used to get through brake pads very quickly. The final straw was careering down Kirkham High Street after a 30 mile ride in the pouring rain. I was doing about 20mph with the brakes full on and I wasn't slowing down. I think that there was so much crap on the roads that it had just ground the pads away.
My rear wheel (the factory one) lasted ~3000 miles before the rim was worn through, though the front (Sputnik rim on a SON hub from Spa Cycles) is still going strong.
I have a Ti fork on the new bike so the ride is very smooth (very, very smooth) and I went for the larger discs after reading about the possibility of over-heating. In practise I think that this would only happen if you were staying on the brakes while descending. Better to plummet and then brake hard for corners IMO.
It's early days, but I'm delighted with my discs. I think they're the future. YMMV.

[Neil Fat Man On A Bike]

I've just taken delivery of my disc braked tourer and I'm amazed by the performance of the brakes and the control that I have. The gear is BB7 calipers, 203mm discs operated by drops (Campag Veloce with an XT drive-train).
I chose discs after I became disillusioned by the performance of the rim brakes on my Super Galaxy. I seem to do quite a lot of cycling on tow paths and tracks and I used to get through brake pads very quickly. The final straw was careering down Kirkham High Street after a 30 mile ride in the pouring rain. I was doing about 20mph with the brakes full on and I wasn't slowing down. I think that there was so much crap on the roads that it had just ground the pads away.
My rear wheel (the factory one) lasted ~3000 miles before the rim was worn through, though the front (Sputnik rim on a SON hub from Spa Cycles) is still going strong.
I have a Ti fork on the new bike so the ride is very smooth (very, very smooth) and I went for the larger discs after reading about the possibility of over-heating. In practise I think that this would only happen if you were staying on the brakes while descending. Better to plummet and then brake hard for corners IMO.
It's early days, but I'm delighted with my discs. I think they're the future. YMMV.

A 203mm disc
Have you got quick release hubs?
If so this could be a problem......the braking force acheived with hydraulics has been known to rip a QR wheel from the fork !!!!
MTB tend to run smaller disc unless running on a 'maxel' ( a 20mm axel that secures/theads into the fork and can withstand the extream forces involved).
I have 210 on my On-One, bot it has the bolt through. I've never had any problems with over heating. Heat transfer to the brake fluid is minimal and floating discs will help if it is a problem.

[CREPELLO]

(disadvantage) - They will probably make your rigid front fork very uncomfortable - this is probably the big one for a touring bike

I'd suspect this. The disc designed fork is an oversized affair to deal with twisting forces the disc exerts on the fork under heavy braking. Are there any Dawes Sardar (it has the disc mounts on the fork) riders on the forum who could disagree with this - is the Sardar fork springy?

Jerry

[CREPELLO]

I have a Ti fork on the new bike so the ride is very smooth (very, very smooth).

Having said what I've just said in my last post, if custom built Ti forks were readily available and affordable then there's not going to be a problem with a harsh ride!

Jerry

[Deckie]

We have a disc drag brake on our tandem - a Dawes Galaxy Twin, and V brakes. The disc is great for controlling speed on descents, but I have to be aware of overheating it & fade. If we need to stop quickly, the V brakes are far more effective.

We don't go off road, so muck on the rims is not a problem.

[Neil Fat Man On A Bike]

On a solo without too much cargo weight, a good disc will hold out long after a rim brake has heated the tyre enough to blow it. Tandems and very heavily loaded tourers are different because of the extra momentum.

Disc fade is not a common occurance with normal riding, otherwise they'd not be so popular with MTBs who tend to go down hill at speed quite often.

However, you'll probably end up with MTB hubs if you go the disc route, thus meaning you'll have to have the back end spaced to 135.

I'd quite happily run a cable disc on a road bike, thus allowing good braking with drop bar levers (just check that your chosen disc does have the correct cable pull for drops). However, I think that it may be a little over kill for my needs!

I have riden with cable pull discs and I can not see any improvement in braking.
In fact I thought they were aweful.
Hydraulic brakes are superb.
They offer fantastic modulation and power.

[speedsixdave]

I have riden with cable pull discs and I can not see any improvement in braking.
In fact I thought they were aweful.

Well there are cable-pull discs and cable-pull discs. We replaced the cheap Alhonga cable discs on our tandem with Avid BB7s and the BB7s are much better.

As more unsubstantiated opinion, I rode my Randonneur to work this morning (57mm drop Tektro dual pivots on Campag Centaur ergo levers, on Mavic Cosmos rims), rather than the BB7'd Battleship.
After nine months on the Battleship commuting the same way, I have subconscious braking points for all the corners (which I hadn't realised until this morning). Today every braking point was too late! I might have been going a bit faster, though (no speedo on either), but there was certainly less bite with the DPs than the discs. And that was in the dry.

[EdinburghFixed]

I used to think rim brakes were good, until I got a mountain bike with discs. They are really in quite another league, and I can't see how anyone who has ridden a well set-up disc system could compare it with even the finest rim brake and keep a straight face.

I can see the arguments either way but personally, if I could equip my fixed-wheel with a front hydraulic disc I would be a *very* happy man.

I gather it adds a couple of hundred grams an end, which I could certainly live with in exchange for reliable, predictable performance in bad weather, and the longevity of the wheel.

[NewHorizon]

I've just taken delivery of my disc braked tourer ... I have a Ti fork on the new bike so the ride is very smooth (very, very smooth) and I went for the larger discs after reading about the possibility of over-heating. In practise I think that this would only happen if you were staying on the brakes while descending.

Can you expand on what these Ti forks are or where from? I have a Van Nicholas Amazon with their carbon touring fork, which I may replace in due course with a Ti one, but they seem quite hard to come by. Presumably if its on a tourer it has mudguard eyes? Front rack eyes?