CR720 or v-brakes on a tourer?

[Brucey]

^ FWIW I agree with Colin, this matches my experience too.

I'm (unusually) looking forward to seeing how 2012 tiagra STi levers work out; they are meant to have a choice of cable pull available.

cheers

[mrjemm]

Aha, sorry Colin, just got what you're saying about STIs and now I grasp the use of Mini-Vs...

As an aside... Is the touring brake equivalent of Godwin's Law the mention of a certain other type of brakes? (A big smelly elephant in the room).

[531colin]

I notice the Spa tourer has changed spec from CR720s to mini V brakes.

http://www.spacycles.co.uk/products.php ... b0s21p2554

My experience of using the CR720s is that they are a lot of fuss and I wonder if it all got too much hassle for new owners or is it just that the mini V's are more powerful.

The bikes are fitted with 32mm tyres will that be their limit with the mini-Vs?

Mini vees are more powerful, which is appreciated by people who are used to bikes with V brakes or discs, and its pretty difficult to set them up wrong. Whats not to like?
we generally fit marathon 368 in 700x32, with some fresh air under the guards, I expect you could go to 700x35 but I havn't checked it out.

[meic]

Having suffered much hassle at the hands of CR720s, fork judder and uphangers for a start. I can see that mini Vs have a lot to offer.

I can make my hassle and having a bike with more fancy cables than a WW1 biplane more acceptable by reminding myself I can still fit Schwalbe Winter Marathons in there.

[531colin]

I seem to recall from when I had a Jake with cantis and looking into improving braking, the mini-vs were supposedly a bit rubbish and lose some benefits from what they are crossing between- cantis and Vs. But that WAS just web-say, which is as we all know, worse than hearsay.

Sorry Colin if this seems to criticise Spa's product choice, but I would guess that fitting the mini-vs suggests an interim period between stock brazed for cantis and an impending model brazed for Vs. A very strange choice as standard spec in my very opinionated opinion. Hmmm.

Edit, just seen your post and think your last line pretty much sums up my previous post.

I'm getting very confused with all these posts turning up at once......whats Godwins law?
Please feel free to criticise all you like, just as long as I'm allowed to point out that the brazings are all the same for cantis, vees, and mini vees, and we fit whichever the customer wants!

[tatanab]

Campag mini V from Campag Ergo with good quality after market blocks (Swissstop green). I have to recalibrate the ABS computer between my ears when I ride this because the brakes are extremely strong. I like lots of lever movement because I brake from the hoods and find that the blocks are perhaps 2mm from the rim, perhaps not that much. On a similar machine with CR720 and Ergo I had much more clearance, possibly as much as 4mm from memory and certainly nowhere near as strong as the mini V.
This supports 531Colin but leads me to wonder how people have mini Vs setup if they find them poor.

[531colin]

^ FWIW I agree with Colin, this matches my experience too.

I'm (unusually) looking forward to seeing how 2012 tiagra STi levers work out; they are meant to have a choice of cable pull available.

cheers

Yes, I'm cautiously almost optimistic about them.....
I'm afraid my enthusiasm is tempered by the following, in no particular order;-
I don't want to be forced into 10 speed....8 is quite enough, if only they would make 14 -34 cassettes.
The more gears, the sooner customers wreck the transmission, the more they complain about the cost of parts (rightly, IMO)
Why oh why did they have to go and make 10 speed mountain a different cable pull to 10 speed road?

To briefly glance on the bright side, surely, Shirley, even Shimano can't make the option of 2 cable pulls as complicated and un-serviceable as the STI things themselves, and flush-riveted 10 speed chains........or can they?

[mrjemm]

I really thought V and canti bosses were a little bit different. Ooops.

Godwin's Law reference was not very elegant way of saying it would be uncouth, and not really relevant for me to follow temptation and mention discs...

[Brucey]

To briefly glance on the bright side, surely, Shirley, even Shimano can't make the option of 2 cable pulls as complicated and un-serviceable as the STI things themselves, and flush-riveted 10 speed chains........or can they?

we'll just have to wait and see.....

[CREPELLO]

I really thought V and canti bosses were a little bit different. Ooops.

You are partly right, in that old frames had different spacing for canti's. There seems to have been an evolution in spacing, the history of which I'm not certain of. 1980's bikes would have the studs closer and also a different height, but somebody more knowledgable will need to give you the precise dimensions.

From my own experience, it's only in the last 10-15 years that the front spacing on touring forks become more suitable for V brakes; ie, the studs are spaced at 85mm on my Hewitt Cheviot forks - good for v's. Previously, the studs could be as narrow as 65mm, possibly more so. My old Galaxy had them at 75mm*, which worked ok fork canti's, but trying to use the supplied V brake blocks that come with most modern canti's could result in obstruction with the fork blades - more so when removing the wheel.

*With the supplied fork. It also had two replacement forks:
A narrow cast crown fork. Stud spacing must have been 65mm
A uni-crown fork, spacing at 85mm.

[Brucey]

^ +1 on that.

AFAIK the reason for the closer spacing on older brakes was

a) the only limit for 'too close' was if you couldn't get the wheel in and out

b) marginal improvment in MA with bosses closer

c) brake block motion closer to right angles WRT the rim plane.

the last of these used to be a greater concern because old-style rims were generally much shallower, and as the brake block wore it would develop a nasty ridge or even disappear beneath the braking surface (incredibly bad!)

I have older frames with bosses in the range 57-63mm spacing. Height was usually set by the dimensions of non-height adjustable Mafac cantis so about 24mm below the centreline of the braking surface.

cheers

[Malaconotus]

^ FWIW I agree with Colin, this matches my experience too.

I'm (unusually) looking forward to seeing how 2012 tiagra STi levers work out; they are meant to have a choice of cable pull available.

cheers

Yes, I'm cautiously almost optimistic about them.....
I'm afraid my enthusiasm is tempered by the following, in no particular order;-
I don't want to be forced into 10 speed....8 is quite enough, if only they would make 14 -34 cassettes.
The more gears, the sooner customers wreck the transmission, the more they complain about the cost of parts (rightly, IMO)
Why oh why did they have to go and make 10 speed mountain a different cable pull to 10 speed road?

To briefly glance on the bright side, surely, Shirley, even Shimano can't make the option of 2 cable pulls as complicated and un-serviceable as the STI things themselves, and flush-riveted 10 speed chains........or can they?

Sora 2012 will pull V-brakes, and will be 9-speed, not 10, and will have Tiagra-style double paddles. Hopefully will be under £150 RRP. I shall purchase some the day they come out. I have LX V-brakes ready to fit to my Dawes Horizon in place of the Alivio cantis I have now.

[mrjemm]

Thanks for clearing that up guys.

[fatboy]

My experience of using the CR720s is that they are a lot of fuss

I think that they CAN be a lot of fuss but are actually quite simple. The thread on getting them working well basically concluded that fiddling with straddle height was a waste of time. Once you've set them up once they are easy with a couple of reservations.

1. You seem to need a complete set of allen keys and a spanner to change the brake cable! I think there are three different allen key sizes required
2. Fitting the cable into the straddle is a complete pain as the cable needs to bend almost immediately to pass the straddle cable

Whether they are better than V-brakes/mini-Vees I can't comment but if you are using STIs they are a good option IMHO.