Shimano MC40 Brake levers question

[Grarea]

I have some old shimano STX RC MC40 brake levers.

They have an adjustable part for H and L.
I have always assumed that they were for cantilever and V brakes.

I have been trying to find out for sure recently and can't seem to find the information.
Am I correct please?

[Brucey]

yes, I think that is right.

L for V brakes, H for cantis

cheers

[cycleruk]

Initially brake levers were specific to either Canti's or "V" brakes. Whether that ever changed I don't know.
When I changed to V brakes I had to buy new brake levers (1998 LX).
From what I have gleaned on the Interweb is that MC40's are "V" brake type.
Mainly V brake levers pulled more cable than Canti' ones.
I think my LX's have H&L but I don't remember what that was for.

[rjb]

These could be Shimano servo wave levers.
link here to some original instructions for setting up similar levers - http://www.retrobike.co.uk/gallery2/d/7 ... l-m600.jpg

i believe these could be set up allowing for quick travel of the brake shoes to the rim before reducing the travel as the brakes met the rim meaning the mechanical advantage was variable. Someone may be able to explain this better.

[Grarea]

Ah, nice one, thanks.

[gaz]

BL-MC40 listed as V-brake only levers in this tech doc for Multi-Condition Braking System. This also illustrates the mode switching mechanism for V and canti setting, although these tech docs are not dedicated to BL-MC40 and do not show whether it is a function of those levers.

BL-MC40 are listed as being compatible with a "Power Modulator" on the V-Brake.

[Brucey]

I think that the note in that techdoc is trying to warn you not to use a non-V brake lever with the power modulator type V-brake; the reason for this is (I think) that you might suppose that the brake will work OK because the pads hit the rim, but you will always be able to make a standard lever come back to the bars before the brakes come on fully. By contrast if you use a standard lever with a standard V brake it is more obvious what the limitations of the brake are.

This SI doc for the very similar BL-M600 model (also see BL-M570, BL-M571 etc)

http://www.retrobike.co.uk/gallery2/v/Manufacturer+Archive/Shimano+Archive/Service+Manuals/br-m600+bl-m600.jpg.html

shows that the adjustable setting is meant for adjusting the V- brake modulation for racing. They advise that you don't use the 'H' setting if you are a beginner or 'not fully confident'. To my mind this suggests that the levers may in fact be suitable for cantis when set in the 'H' position, but they don't actually say this.

IIRC these levers (when set in H mode) pull the usual amount of cable at the start of the lever stroke but then increase in leverage ratio as the lever comes back towards the bar. I would try the BL-MC40 leversin H mode with cantis and see how they go; worst case is likely to be that the brake isn't quite powerful enough, but you can adjust that with the straddle setting and brake pads too.

cheers