Discs or canti's on a new tourer

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bealer
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Discs or canti's on a new tourer

Postby bealer » 29 Apr 2012, 2:22pm

I'm currently stuck deciding which Soma Double Cross frame to get, the Disc version, or Canti version.

I could obviously get the Disc version (as it has canti mounts) but annoyingly can only source the Disc forks with it.

Aside, I was wondering peoples thoughts about Discs on modern tourers. Here's my list so far:

Disc:
- Danger of damaging the rotor during transport
- No rim wear, and can use them with a buckled wheel
- Work well in the wet
- Last ages (I'm still on a set of pads after 6,000km)
* Won't interfere with rack as the Soma has chainstay mounts
* Braking not an issue as I'll be using brake levers with enough leverage

Cantis
- Nice and light (360g lighter, BB7's compared to CR720's)
- Simple design
- From what I remember, a pain to set up
- Cheaper

I recently did 10,000km across Europe and Asia with discs (and about 5 flights, unboxed) and didn't suffer any problems. But I always wondered, did I really need discs.

My new bike I'm building up, so was wondering if I stick with discs or go back to canti's (or v-brakes if they don't obstruct the rack). I do like that they're 360g lighter, as I would like my tourer to weigh under 11kg with all the rack, guards etc.., on (I'm a big believer in a light, fast, but sturdy bike = more enjoyment).

Brucey
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Re: Discs or canti's on a new tourer

Postby Brucey » 29 Apr 2012, 2:48pm

well I think you have covered most of it.

However one thing you haven't mentioned is that some steel frames with rim brakes can have a nice responsive characteristic whereas with discs this isn't so likely; the forks in particular generally need to be a lot stiffer with disc brakes. With panniers and fat tyres there isn't so much difference , but otherwise there can be.

360g isn't much weight in the grand scheme of things but you might notice it when running without a load.

cheers
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meic
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Re: Discs or canti's on a new tourer

Postby meic » 29 Apr 2012, 2:53pm

I have been put off fitting discs mostly by the fact that they were seat stay mounted and this had a stream of consequences with racks etc.

I agree with the weight being a problem. Which exceeds the other benefits for me.

I think that the sticky-out CR720s are much more of a liability in transit than the rotors would be.

I had to ditch a fairly good Chrina rim because a dint caused the spokes to hit the deraileur, even though it still went through my dual pull callipers without an issue.

Also I was after something that would soak up the heat energy of a long descent only to be told that the discs have less capacity than the rims!
Yma o Hyd

bealer
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Re: Discs or canti's on a new tourer

Postby bealer » 29 Apr 2012, 4:47pm

That's a good point, I guess the CR720's would be exposed to knocks in transit too. I'd imagine they may be more fragile than a disc rotor. Are there any better less exposed canti's?

I didn't really know about the heat issues with discs but discovered it on my tour. They make a horrible noise when they overheat. Just have to get used to pumping the brakes.

360g in terms of my bike is fairly heavy. I'm building it with downtube shifters, partly to save weight, but also because they're more robust/simple compared to STI's. Saves me another 400g. A double XT chainset save another 350g over a Deore triple. When you start adding it all up, you start shaving off 1-2 kilos. That's 1-2 kilos more I could (should I wish) carry in luggage. Which would equate to a whole set of clothes + shoes, or the weight of my tent/sleeping bag/matt (it's super light weight). Obviously there are some things I won't cut back on, my Brooks, mudguards but they are removable for day trips or short tours.

Stripped down for a day ride, the bike will be sub 9.5kg. Spec'd for touring with rack et al, it will weigh just under 11kg. My previous tourer was nearer 14kg.

Brucey
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Re: Discs or canti's on a new tourer

Postby Brucey » 29 Apr 2012, 5:28pm

maybe Vs or mini-Vs are the way ahead for you

cheers
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andrewjoseph
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Re: Discs or canti's on a new tourer

Postby andrewjoseph » 29 Apr 2012, 6:06pm

Disks can be damaged in transit, but they can be taken off and put on easily. once this is done there is less risk to damage than there is to the wheels.

A well designed frame will take into account the unique 'features' of disks.

Our Ti tourers have been designed for disks, the ride qualities have been made so that it is compliant when loaded and responsive when not.

it's not a race bike by any means, but i didn't want a race bike, I wanted a tourer / long day ride bike.

I wouldn't go back to canti's.

my bike weighs about 12kg with guards and rack, saddle bag. But it is over built.
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horizon
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Re: Discs or canti's on a new tourer

Postby horizon » 29 Apr 2012, 6:31pm

On a recent trip I was going down a very long fast hill loaded with about 20 kg in the rain/hail. I realised my cantis weren't as gripping as I would like and adjusted my descent accordingly. I don't know how discs would have done in the same conditions. What I do know is my cantis generally perform very well and I don't think about them very much apart from the usual maintenance and keeping the rims clean. They are brakes. For me, discs would have to do something very much better even for me to think about knowing what to do with them. I would never try to argue that discs aren't better nor probably would I worry too much if I bought a new bike with discs on. If I had to choose however, I would choose what I know and whichever is simplest because cantis already do the job.
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reohn2
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Re: Discs or canti's on a new tourer

Postby reohn2 » 29 Apr 2012, 7:00pm

Cannondale Tandem,BB7 discs with 203mm rotors,absoutely no problem bringing it and 153kgs of riders to a stop PDQ,we've toured on it with another 15kgs of luggage without problems,yep the discs got hot but they still stopped better than the V brakes/Arai drum brake on our other tandem.

Kona Dewdrop BB7's 160mm rotors,stops better than V's or D/Pivots on the other two solos.

The plus is, wet or dry I know when I squeeze the lever it'll be the same performance from the disc equiped bikes,which is better than,will it won't it,scenario of rim brakes in the wet.
Did I mention the superbe modulation..........whatever the weather................. :)

Yep they're heavier,that said if the OP is that concerned about weight if I were him I'd go for v's,they're better than canti's.
As for overheating discs on a solo,it would need a very long descent with a very big load and even then I'm not so sure, if the rider alternates between front and back brakes I can't see there being any worries.
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bealer
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Re: Discs or canti's on a new tourer

Postby bealer » 29 Apr 2012, 9:45pm

I'll have to wait to know about v-brakes. Problem is the rack obstructing them, I don't know if that'll be an issue. If I did go for the Canti frame, I'd buy the rack and I have some old/broken v's kicking around. I'd see if they get in the way of each other.

If the 540g BB7's (inc rotors) were nearer 400g I'd have no hesitation in getting them. 450g I'd definitely be tempted. 540g = unsure.

My original thoughts were actually v's, Avid SD7's, but as mentioned I don't know about rack clearance. They weigh around 370g. CR720's are 240g.

There's something simple I like about canti's although SD7's would be less exposed than CR720's during transit.

PH
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Re: Discs or canti's on a new tourer

Postby PH » 29 Apr 2012, 10:14pm

If you're counting the grams, don't forget the extra weight of the frame and fork, both for the fittings and the strengthening. I haven't looked at Soma, it's typically an extra 200g on the frame and 300g on the fork.

reohn2
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Re: Discs or canti's on a new tourer

Postby reohn2 » 29 Apr 2012, 10:49pm

bealer wrote:.......If the 540g BB7's (inc rotors) were nearer 400g I'd have no hesitation in getting them. 450g I'd definitely be tempted. 540g = unsure........


These should get the weight down a bit:- http://www.chainreactioncycles.com/Mode ... elID=67569

Ashima make some light rotors too:- http://www.ashima.com.tw/products_01_01.html
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bealer
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Re: Discs or canti's on a new tourer

Postby bealer » 30 Apr 2012, 12:07am

PH wrote:If you're counting the grams, don't forget the extra weight of the frame and fork, both for the fittings and the strengthening. I haven't looked at Soma, it's typically an extra 200g on the frame and 300g on the fork.


The Soma Double Cross is 1.9kg for the frame and just under a kilo for the forks. That's for the standard version, the disc version I think is only rated at 300g more. Which is heavy, but for under £500 and steel, it's pretty good value for my budget.

Cheers for the rotor links. That would shave off a bit, meaning BB7's would weigh in a 310g+170g for the rotors (480g a pair), over 370g for SD7 v-brakes and 240g for CR720 canti's.

I have a feeling I'll be going for a canti frame, and seeing if I can fit v-brakes on it, but probably going for canti's. It'll be cheaper and lighter (lighter frame and lighter brakes). Plus I'd like the feeling of curved forks once again I think.

andrewjoseph
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Re: Discs or canti's on a new tourer

Postby andrewjoseph » 30 Apr 2012, 6:19am

horizon wrote:On a recent trip I was going down a very long fast hill loaded with about 20 kg in the rain/hail. I realised my cantis weren't as gripping as I would like and adjusted my descent accordingly. I don't know how discs would have done in the same conditions.


you can get inline adjusters. I use them occasionally for the same purpose.

Dunno your budget, but my Justin Burls made my Ti frame and Ti forks for ~£1200.0.
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Burls Ti Tourer for tarmac
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reohn2
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Re: Discs or canti's on a new tourer

Postby reohn2 » 30 Apr 2012, 9:31am

horizon wrote:...... I would choose what I know and whichever is simplest because cantis already do the job.


We bought Cannondale as a winter tandem and because a friend had one and was vey pleased with his.We borrowed it for a day,the braking performance(among other things such as very good handling and very stiff frame) was enough to convince us to buy one.
Initially I was a little concerned about servicing the brakes,pad and rotor wear etc,three years and approx 10,000miles down the road,my conclusions are that discs(BB7's at least) are the best thing since sliced bread,needing little attention between servicing.
I've changed the pads twice at £6 a pair and I've serviced the calipers once,which took about half an hour per wheel.
Inbetween that it's just a case of a couple of clicks on the adjusters now and again.The key is to set them up properly initially for long trouble free use.
TBH if I could get the right frame to build up a disc equiped bike that weighs 20to23lb I'd sell two of my three solos and have two bikes with discs,they are that good.As my friend says "they seem to thrive on neglect" :)
NOTE:-Though I didn't know it at the time but the C/dale was fitted with one of if not the best cable discs available,with road and MTB cable pull caliper options so they can be used either with drops or straights,take your pick :)
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mrjemm
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Re: Discs or canti's on a new tourer

Postby mrjemm » 30 Apr 2012, 9:43am

I just noticed the canti mounts on the disc version are removable. So is the disc version that much heavier after all? Surely if you use the discs, you'd remove the canti mounts.

For me, BB7s are far easier to set up and adjust. But I am a mere beginner in this world. One thing I have mentioned elsewhere though, is that spare pads for discs take up rather less room (and are perhaps lighter?)- you could even keep in your wallet probably.

Sorry to once again divert a thread... Andrew, I'm curious to hear about your Burls Ti, it's a current pipe-dream for my next build. The price seems very good for a pretty Ti bike, but on his site some welds look poor- http://www.burls.co.uk/images/ti/largeForks.jpg (perhaps worth another thread or PM, sorry guys).

Cheers, Jem.