EpicSchwinn

My previous brake (a feeble old Dia-Compe that came on my bike new in 87) didn't do jack to stop me and would barely slow me down, even with new pads. Today I upgraded to a Tektro R536 hoping that it would give me the stopping power I desire. I think I have it all dialed in right (centered, ~2mm gap, fully on the braking surface) but it still won't stop me fast enough to go over the handlebars. Not that that's the point but IMO a good brake should be capable of it.

So I ask you, BFSSFG, what is the weak link in my brake setup that I should adjust/upgrade?

-Specialized Cross lever
-Tektro R536 brake
-Whatever pads came on it
-Braking surface is an Eighthinch Amelia rim.




Yes, I know my brake lever shim is ugly.

homebrewk

Huh. Maybe the cable isn't cut to the right length?

Dannihilator

Cable is wayyyyy too short.

Scrodzilla

Cable length looks fine to these eyes.

The pads that come with most Tektro brakes are junk. Get some Kool Stops.

bikeyboy

The cable is loose in your picture, there is too much play. I can see the end sticking out at the brake handle end. It should be all the way in the hole.

Dannihilator

If that was capped, it's fine, but if he needs to disengage the caliper, he could be in for a rude awakening and there is not enough cable showing for an end plug.

TejanoTrackie 

You nailed it Scrod ! Easily double the braking force.

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Scrodzilla

Oh yeah, and that. It does look a little wonky.

Also check that the inner cable is moving through the housing smoothly and the ends aren't crushed where you cut them.

striknein

If the cable is new, it may be stretching. You'll probably need to pull the cable again after some miles. In fact, pull it again now, and fix whatever's causing the end to bind up in the lever like that. If you give yourself a couple inches of length, the cable's a lot easier to pull as well.

Leukybear 

In your case, the pads; tektro pads do not have enough stopping power in my opinion; get kool stop salmon inserts and you can stop on a dime or go over the bars if you want.

Other than that, the weakest link in any decent brake setup would be the cable, if it snaps when you need the stopping power of a physical brake, bad things happen. Just putting it out there, even through you ride fixed.

EDIT: if you do decide to go for the pad upgrade, grab the "ultegra/ shimano" version; tektro is basically the generic copy of shimano.

Scrodzilla

Jeez...now that I look again, I see what you mean. I thought you were talking about the whole cable/housing between the lever and caliper.

Dannihilator

Yeah the only thing worse than diacomp pads are tektro brake pads. Definitely get something more competent.

TejanoTrackie 

The cable end is too large to sit flush in the lever. A different cable with a smaller barrel would work better with that lever.

jdgesus 

i never had "flip over the bars" braking power until i got dura ace brake(s)
******** expensive just to be able to endo, but still

but the kool stops are close (have them on my tektros on other bike(s))

TejanoTrackie 

Cables don't stretch.

Dannihilator

Also, why does that look like a deraillieur cable?

jgedwa

I think that "shim" might be contributing to the problem. Hard to tell from the picture but it seems like the lever is not completely square to the bar. I wonder if the lever has enough room, at that angle, to be pulled as far as it should.

But more likely is simply that the clamp is rocking back and forth a bit on that shim when you use the lever. Even moving a degree or two there will steal considerable leverage. Put a hard shim under it and clamp it down tight.

jim

EpicSchwinn

Sorry for big pics. I'm a very visual learner...

This. The lever was meant to be used in tandem with a regular drop bar lever so the hole won't fit a barrel (even the small kind)


And dan - Here's a pic of how much cable I have past the pinch point. So I should get a new cable and make sure there's a good 2-3 inches extra? The quick release slackens it up enough to get the front wheel off.



And here's the pad gap. Is this really too much slack?



I'll try to pick up some koolstops after work tomorrow.

EpicSchwinn

This was my first instinct. There definitely is some play back and forth in the lever. Any recommendations for hard shim material? It needs about 4mm of shimming which would be a lot of tin can.

Dannihilator

I would definitely get a new cable with a smaller head on it. The cable that is on there is a hazard, with not only having it that short and with it well on it's way to being completely frayed. Trust me on this, you don't want to get your fingers on a brake or deraillieur cable strand, they hurt like the dickens. 2 inches will suffice and put a cable end on once brake is adjusted and the cable trimmed.

EpicSchwinn

I'll go see what kind of cables I have lying around. I may just bore out the hole in the lever ever so slightly. The hole is only a hair too thin and since most cables have a pretty standard sized barrel on them it might be difficult to find one that's unusually small.

Dannihilator

Get new, never reuse used cable. Standard shimano brake cable will work and the head will fit.

EpicSchwinn

Got it.
I'll just work on the lever shim for now then.

Thanks for the help!

striknein

Please describe what actually happens then.

TejanoTrackie 

Calipers flex, cable housings deform, brake pad material compresses, brake levers flex, cable ends seat into the levers etc. But steel cable does not stretch. If it did it would break. It is also so stiff that it stretches elastically so little as to have no impact on the firmness of the braking.