Vee brakes and STI levers
:?: Some riders are using this setup successfully so I am considering it for a new tandem. The front is not an issue but the long cable makes the back a bit trickier. Any thoughts on this? I have tried the "vee adaptor" in the past but it was so spongy that it was not worth using. Are any of the "dual-pull" brakes any good for the rear of a tandem? :roll:
Chris (Tandem Club Technical Officer)
Chris (Tandem Club Technical Officer)
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Comments
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'V' brakes with non 'V' levers will always be spongy due to the lever pulling less cable but having a bigger mechanical advantage. The blocks need to be set very close to the rims or you will run out of lever movment. The use of a well setup adapter should improve things. Make sure the cable is going the right way round it. The long cable run will be spongier especially if you use a full length outer.
I guess you mean 'Dual pivot' brakes. These are a big improvment on single pivot calipers but are not as powerful as 'V's.0 -
Yes :oops: "Dual pivot" was what I meant!
Can the left hand STI lever be made to pull more cable if the front changer bits are not used or removed?
Do any STI levers pull more than the normal length of cable :?:
Chris0 -
It may not be what you want to hear, but try cantis, they require less cable pull so should work better with STI levers.0
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I'll look into that. Thanks John.
Chris0 -
There's a dia compe drop bar gear lever designed for v-brakes so you could swap to that and have mis-matching brake levrs at the front if you're not worried about the looks and don't need one to shift0
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I'm sorry, but suggesting that dual-pivots aren't as powerful as Vs is a load of rubbish. The effective leverage ratio from brake lever to caliper is exactly the same for both, and given that there isn't more flex in dps then given the same pads they will stop just the same. The reason for not using them is a clearance issue - if you have sufficient clearance above the tyre, including mudguards if necessary, then you can use them (long reach ones help and have exactly the same leverage ratio as normal ones, though a tad more flex). The reason they don't tend to come on tandems is that people normally use tyres which are too big to fit through them.
Your best bet for brakes on a tandem if you can't fit dps and want to use STI are some form of modern wide angle canti (not the latest MTB cantis - the leverage ratio doesn't match), as also used by the cyclo-cross crowd. We have Avid Shortys on ours and they work fine - though Shimano have also jumped on the bandwagon now with something with almost identical geometry. Alternatively the ultimate as used by the cross boys are Froglegs (and imitations). You really won't ever get Vs to work properly with STIs - surprised you got the front to work, the pads must have been awfully close to the rim.
Finally a bit surprised to find you are the Tandem Club Technical Officer and don't already know all about this. You should try reading some of the archives at http://hobbes.ucsd.edu/tandem/ or even subscribing and asking your questions there - this is the sort of topic which has been discussed ad-nauseum.0 -
I can vouch for the Shimano wide profile canti's - I use them on my cross bike with STI and they work great. If you are using narrow rims you might want to pack out the brake blocks, or use deeper ones than the modern slimline ones to get the correct geometry. You can tune the feel of the brake much better as well if you go for an old fashioned straddel wire and hanger instead of the modern ones that fix the cable geometry.
I had an idea for a mod to STI's to get them to work ok with Vee's, but I haven't tried it yet.
On shimano road STI, the cable anchor point slides to change the mechanical advantage through the lever travel ( Servowave, I think they called it on MTBs).
Unless I've got it all topsy turvey, if you can stop the cable anchor from sliding up, then the mechanical advantage will be closer to that of an MTB lever, and you may find it works ok with a vee.
I should patent this, and make some little stops out of plastic and sell them for a fiver a set!
On a different tack, consider mechanical road disks if you can. I have also run a BB7 Road disk on the front of my cross bike, and it's amazing. I have had canti's working nearly as well, but it's a lot more effort to keep them that good, whereas you can forget about the disk once it's set up.0 -
Campag make V brakes (linear pull in Campag speak - Veloce range)) to work with their STI levers. I am using them and am well pleased with their efficiency. I have fitted in-line cable adjusters which make it easy to keep the pads close to the rim. The maximum tyre size you can use with them is about 32mm.0
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John Tiffany wrote:Aracer. I can not argue with you on leverage ratios but my comment was based on personal experience with the 'V's on my MTB and the Dual Pivots on my road bikes. The 'V's always seemed to be that bit better. Perhaps just the longer blocks.
Indeed, in the real world, the v brakes on my MTB are far far superior to the dual pivots on my road bike...both of about the same quality.
I personally think this is becuase you can exert more power and more accurate control of the brake lever on flat bars.0 -
Finally a bit surprised to find you are the Tandem Club Technical Officer and don't already know all about this. You should try reading some of the archives at http://hobbes.ucsd.edu/tandem/ or even subscribing and asking your questions there - this is the sort of topic which has been discussed ad-nauseum.
Go on, be friendly. I would. Even if you don't think the question should have been asked.0 -
bill reay wrote:Campag make V brakes (linear pull in Campag speak - Veloce range)) to work with their STI levers. I am using them and am well pleased with their efficiency. I have fitted in-line cable adjusters which make it easy to keep the pads close to the rim. The maximum tyre size you can use with them is about 32mm.
I'm after a pair of these for my newly restored touring frame. Where did you get them from?0 -
bill reay wrote:Campag make V brakes (linear pull in Campag speak - Veloce range)) to work with their STI levers. I am using them and am well pleased with their efficiency. I have fitted in-line cable adjusters which make it easy to keep the pads close to the rim. The maximum tyre size you can use with them is about 32mm.
Which isn't really a big improvement on long drop dps - particularly if you also want to have mudguards. Not a new idea, as Tektro made some short arm Vs ages ago, but they do suffer from not having a huge amount of clearance, which is where wide arm cantis come in.cooper.michael1 wrote:I personally think this is becuase you can exert more power and more accurate control of the brake lever on flat bars.
Was actually about to suggest the same thing. It does also possibly depend on what you're used to - still find I can brake just as well on a road bike from the drops (you are braking from the drops, not the hoods aren't you?), or even on the tandem with drops, STIs and Avid Shortys as on my MTB with good disc brakes. But then I did do all my early serious riding on a road bike.0 -
I think Condor fitted these to their Heritage tourer reviewed in C+ a few months ago - might be an alternative source.0
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bill reay wrote:Campag make V brakes (linear pull in Campag speak - Veloce range)) to work with their STI levers. I am using them and am well pleased with their efficiency. I have fitted in-line cable adjusters which make it easy to keep the pads close to the rim. The maximum tyre size you can use with them is about 32mm.
Yes - I use them, and they're a considerable improvement over the Avid v-brakes I was using with STI before. You do have to make sure the adjustment's good (optimal centering, and as close to the rim as you can get) - once that's done they'll stop you good and proper. Condor stock them.
I tried a Travel Agent, but it just felt horrible - very hard on the wrists. Plus, if I'd had a cable snap on a long ride I'd have been swearing for ages while I had to go through the ritual of rethreading the Travel Agent.0
