Brake lever crunching/stretching sound

[Bryan H]

I am getting a crunching sound at the lever side of a V brake install. I am using simworks nissen housing/cables, when cutting the housing I inserted a old a brake cable and cut it with park tool cutters. Overall the cut seemed sufficient where the cables move in and out smoothly. Not sure why i keep getting this sound, i have tried a few attempts at the front brake and keep getting a similar sound. I am fairly new to working on rivendell bikes, would love any advice, thank you much!

Bryan 

https://imgur.com/a/brake-c5qq22b

[Garth]

The sound appears to be coming from where the cable end is seated on the lever.  That's where the movement is when you pull all the way. There's an abrupt movement. I assume you used the mtb end of the brake cable and these take those ? Many have both types. Take a look underneath the lever where the cable end is seated and pull on the lever, for some reason it's moving. 

[Josh C]

I agree with Garth. Looks like the ball end of the brake cable is moving in the lever quite a bit. Is it the correct shape ball end for that lever? 

[Seung Vo]

Thanks for the responses, it’s def MTB, the bigger round ones. Am I not giving enough tension when installing the cable? Or maybe I didn’t set up the Paul motolites with enough tension? I actually had a similar problem with my Brompton so it’s making me think I’m doing something wrong….

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[Bill Lindsay]

It is a fundamental flaw to that type of brake cable - to - lever interface design, that was inherited from BMX bikes.  If that interface between the head of the cable and the brake lever is sufficiently slippy, then it just pivots nicely as the brake lever pulls in.  If that interface between the head of the cable and the brake lever is exceedingly grippy, then the cable head stays put as the lever travels and we flex the cable as we pull in the brake lever.  If it's in between grippy and slippy then you get what you are seeing.  The better design, in my opinion, is to have the thing that holds the head of the cable be on a pivot, not requiring the head of the cable to itself BE a pivot.  All drop bar brake levers have the cable head holder object on a nice pivot.  Some flat bar brake levers (including all the shimano models that Riv sells) have that feature.  

The model that has that pivoting feature out in the open and really easy to see is the Tektro CR750:  

If it bugs you, I guess the thing to try to do is make the interface between the head of the cable and the brake lever more slippery.  Have a look at that leading edge of the cylindrical head of the cable.  Is there flashing from when that cable head was cast in place?  Can you clean that up with a jewelers file and make that leading surface smoother?  Maybe a drop of chain lube would help also, but lube is not a substitute for smooth surfaces.  

Bill Lindsay

El Cerrito, CA

[Bill Lindsay]

Oops.  I got my prefixes wrong.  The lever pictured is the FL750.  

BL in EC

[Garth]

Brian, I always make sure the cable end is fully seated and the cable tensioned by holding the end of the loose cable(where it's going to attach to the brake) with one hand,  and actuating the lever with the other hand. With the lever actuated, pull on the cable, alternating pulls from lever to cable end, back and forth. It ought to be a solid, direct feel back and forth, with an easy glide to it and no catching ! 

This said, are the raw cable ends you cut filed flush and the hole open with no burrs ? And are the cable end ferules fully seated against the flush face of the cable ends ? Are both end of ferruled cable butted tight against their respective cable stops ? Just covering the basics as they're important with brake cables.