Forum search & shortcuts

V-brake levers that...
 

[Closed] V-brake levers that pull MORE cable - ??

Posts: 25945
Full Member
Topic starter
 
[#995084]

does such a thing exist ? (or a travel-agent type thing for brakes?)

the thread yesterday about Dalby (or somewhere) eating pads got me wondering. The Forest of New does the same sometimes in winter and I wonder if a BB7 could be set with BIG gaps between the pads & disc and then let the long-pull lever sort things out. (I'm sure it'd offer zero modulation, but then so does the metal backing material)


 
Posted : 29/10/2009 9:44 am
Posts: 4789
Free Member
 

travel agent is used to correct between canti pulls and v pulls and the levers pull in different ways.

you can get levers (shimano and avid make some) that do both pulls in one lever - you just move the pivot point in the lever to select - not common though


 
Posted : 29/10/2009 10:36 am
Posts: 0
Free Member
 

From what I remember Canti levers pull less cable, so that wouldn't solve your problem. You could use a BB7 road with a V lever to get the same effect.

Or, I guess, one of those travel adjuster things on a v-lever to make itpull more again.


 
Posted : 29/10/2009 10:38 am
Posts: 21658
Full Member
 

Interesting idea. Maybe some old shimano XT servowave levers would pull more cable initially and then bring the power back. If you had road BB7s, maybe seek out some old Dia Compe PC-8 levers. They were amazing. Shame they were only around for a little while before the V brake took hold.


 
Posted : 29/10/2009 10:41 am
 Sam
Posts: 2390
Free Member
 

For mine it's when you are braking that the pads wear, not when they are running free.

The Shimano and Avid brakes with adjustable leverage rates are designed to change the feel and performance of the brakes, not for use with either V or canti brakes.

More cable pull at the lever would give you less mechanical advantage over the brake and less power but more modulation.

I think the answer to your problem is sintered pads and hydraulic discs which self adjust for pad wear.


 
Posted : 29/10/2009 10:45 am
 Olly
Posts: 5283
Full Member
 

Servo wave V levers, move the point where the cable is fixed to the lever, in towards the lever pivot through the stroke, to increase power.

[img] [/img]

surely it doesnt help that one side of the pad is fixed against the rotor anyway, so it wont help that pad at all?

have you bedded them in properly? if you dont bed them in, grit and shit can rip a pad out in a few miles. bedding them in compresses the pad material into a much denser, harder compound, so makes them last much longer.

i got my last pair of pads unfeasibly hot, and theyve lasted almost a year, with NO real sign of wear.
im mildly worried, i think the rotor is wearing out quicker.
i know of a pair of Avid BBs that got so hot they plastic started melting and smoking. that was quite funny.

considered getting some hydraulics? then the pistons are pulled back on both sides.
servo wave hydraulics are designed to retract the pad specifically to save the pads from grit iirc


 
Posted : 29/10/2009 10:51 am
Posts: 25945
Full Member
Topic starter
 

thanks

rolf/luke - maybe, good idea

canti-pull is less cable I think, so prob not a goer

I really do think it's the non-braking time that does it (new forest, not exactly hilly, or fast & I don't brake that much)

Sam - adjustable levers are NOT for use with either v or canti brakes (???)

Think you're right about mech advantage (I think I really meant how the levers feel when I said modulation)

I do use sintered pads. Have used hydraulic and mech brakes (I don't think the hydraulic retract the pads as far even as my BB7 do)

might try a road BB7 and see what happens (at least might clarify in my mind whether it's JRA or braking that causes the wear - course, a larger gap may let in more grit & make it all worse anyway...)


 
Posted : 29/10/2009 11:00 am
Posts: 0
Free Member
 

Hi,

I have these cams that slot into the top of the cable slot on the brakes. The cable goes round a disc about 270 degrees. It really improves the cable pull.

http://cgi.ebay.co.uk/Travel-Agent-Pulley-Replaces-V-brake-spaghetti-pipe-SIL_W0QQitemZ300351072973QQcmdZViewItemQQimsxq20090926?IMSfp=TL090926145003r8974

I was not sure if you can still get them .. see above link.

They do get bunged up if it is very muddy or wet but I think they do what you want.

Cheers Iain


 
Posted : 29/10/2009 11:03 am
Posts: 25945
Full Member
Topic starter
 

Olly, you're right that the static pad is a bit of an issue but I was thinking I'd set the caliper to allow the static pad to be further over and get the moving pad to move a lot - unwinding both adjusters so that they'd not bite using ordinary levers & need more pull

I do use levers just like those in your pic, still no luck (suspect they pull a bit more than most at the start but then a bit less than most later, so good modulation but no overall increase in cable pull - I need an exaggerated version)

IanAhh - thanks, thought about those but the 90 deg bend is a bit of a pain (guess i could do something though)


 
Posted : 29/10/2009 11:13 am
Posts: 4789
Free Member
 

correct for the same amount of level pull, levers for canti/u-brake pull less cable than v-levers.

<<The Shimano and Avid brakes with adjustable leverage rates are designed to change the feel and performance of the brakes, not for use with either V or canti brakes.>>

Sam:
apart from the ones specifically design to do just that! ie work with both canti in one positon or v in another...

shimano nexus levers (bit commutery) but they can be configured for both types of brakes..

see shimano tech docs:

first panel re cr - mode.

you can also get none shimano levers with the same feature, but this type of lever is hard to get.

think overall you would be better getting some hydraulic brakes and retract more - later shimano with servowave seem good at this


 
Posted : 29/10/2009 11:39 am
Posts: 25945
Full Member
Topic starter
 

later shimano with servowave seem good at this

yeh, hoping to get a look at some of those - have you seen a set, is the gap noticeably bigger or might they be like the V-levers (same overall but variable travel within that)?


 
Posted : 29/10/2009 12:03 pm