Are Clarks Mechanical Disc Brakes CMD-23 Worth Setting Up Or Are They Garbage?

[Cletus Van Damme]

I got my daughters Apollo bike to repair after she crashed it at her mum's house, going down a hill, I'm not surprised really, as I couldn't of imagined it stopping any time soon..

I've already had the wheel repaired (2 spokes and new skewer), replaced a snapped front brake lever, straighened the handle bars direction. But the brakes are shocking on it. I'm guessing the bike came like that, as the back one is trash, the front one I changed the cable. The pad that is moved by the pulling the cable looks too far away from the disc, the stationery pad is catching on the rotor. I know it's a cheap bike, but it's actually not as bad as you would think considering what it cost. Are these always going to be crap? I take it I need to set them up, as Halfords haven't. If they are crap is there a cheap replacement? Currently the brakes won't even hold the bike, you can push it quite easily with the levers pulled right in.

I've just bought her a Liv Tempt 3 mountain bike for my house, obviously it's 3 x the price. That has entry level Tektro hydraulic disc brakes, the difference in performance is just on a different level to the Apollo, and to any other rim braked bike I've had. Seems like a lovely bike. The Apollo is not worth spending much money on, I wish it had V brakes to be honest.

Just wondered if anybody had made this type of cheap brakes, operate in a half decent manner please? (I looked on youtube couldn't find anything specific to this brand).

 

[si_c]

They're servicable but they won't be better than an average set of rim brakes however set up properly they should work OK. If there is quite a bit of space between the rotor and the moving pad, then it's probably worth moving the caliper inboard a little - there will be a bolt on the inside of the caliper to move the static pad inwards to centre the rotor between the pads. Clarks have a full setup video here.

I'd go through the process of setting the brakes up properly again - at least then you will know how to maintain them in the future - it may be worth keeping an eye open on ebay for a good set of second hand hydraulic brakes, something like the shimano M315s would be a good option.

 

[Moodyman]

They're not the sort of brakes one would put one one's own bike but for a kids bike, ridden a handful of times in the summer, they're adequate.

They'll just need adjusting. Plenty of videos online.

Just remember kids hands are not as strong, so pads need to be far enough away to have a bit of modulation but not too far they don't grip the disk.

 

[Cletus Van Damme]

Thanks very much for the replies. I think I've got the idea now, I was just confused about the stationery outboard pad binding, but now I see how you adjust it with mounting bolts. Pretty poor from Halfords.

It's useful to watch those videos regarding the hydraulic brakes on the Liv. When I picked it up today tried the brakes spinning both wheels, then spinning again and there was no binding. I had to take the front wheel off to get it in the car. After putting it back on it is binding, ever so slightly. I checked again a couple of times to make sure that I had got the wheel centered correctly, but still the same thing. Hopefully it will go away with a bit of use, otherwise I guess they need re-centered. Never had bikes with disc brakes, worked on lots of cars though. Just be a pain if you get this often when removing the front wheel to put it in the car. But we'll see, thanks again.

 

[roadrash]

easy enough to re-centre, loosen the two mounting bolts and apply brake , retighten the bolts with the brake still applied

 

[Cletus Van Damme]

Thanks always good advice on here..

 

[PpPete]

If braking performance is still inadequate after appropriate adjustment, the performance of most mechanical disc brakes can be improved by using "compressionless" brake cable outers (in which the reinforcing metal in the housing runs longitudonally (like gear cable does) rather conventional spiral "bowden" cable).

 

[Cletus Van Damme]

I've managed to get them setup pretty well, the front is done better than the back. They are a bit of a pian, due to the brake pad adjusting bolt, grub screw lock, being in a crap place. No big deal, just took the front wheel off to get at it on the front, and took the caliper off on the back. They are not bad when you get used to them, but I don't think I'll ever buy a bike with mechanical discs.

The more I've looked at this bike, the more I can see why it's cheap. It's worth the money, but there's some real crap on it. It's a triple and the shifter is a grip shifter, but its a friction shift. It has lots of increments to set the position of the front derailleur. On a bike that's kids use ffs. My daughter finds gears not straight forward as it is. I'm going to get a regular 3 position grip shift, I'm sure it will work with the front Shimano Tourney derailleur.

Thanks for the info on the cable outers Pete.

 

[Gunk]

easy enough to re-centre, loosen the two mounting bolts and apply brake , retighten the bolts with the brake still applied

That doesn’t work with cable disc brakes as the rear pad doesn’t move it’s only the outer pad which moves. You need to stick a thin piece of card between the inner pad and disc, then get someone to pull the lever whilst the caliper is loose and then tighten it up.

 

[si_c]

That doesn’t work with cable disc brakes as the rear pad doesn’t move it’s only the outer pad which moves. You need to stick a thin piece of card between the inner pad and disc, then get someone to pull the lever whilst the caliper is loose and then tighten it up.

Depends on the disk brake - there are plenty of mechanical disc brakes which have two piston action to move both pads - TRP Spyres being the most well known and best liked.

but I don't think I'll ever buy a bike with mechanical discs.

Again depends on the particular brakes, TRP Spyres or Hy/Rds are both excellent mechanical disc brakes and I would have no problem buying a bike with either in fact I have. Full hydraulic brakes are slightly nicer to live with overall but braking is good on both.

 

[Gunk]

Most of the cheaper cable operated calipers as fitted to lower end mountain bikes and hybrids have a fixed rear pad, they are tricky to set up but work quite well once they are positioned correctly. Wheel positioning in the dropouts is also really important, if they’re not in completely straight the disc will drag on a pad.

 

[Cletus Van Damme]

Thanks this is really good advice. I'm going to change the shifters to trigger shifters. The thing is with this bike, it was cheap, it's alluminium (not a light weight), some of the components are really not great (the front mech shifter, the fork). But just spending a little bit of money on some trigger shifters, setting the brakes up better, I think it's really good value for money. The setup was really not very good. But for somebody that knows a bit about bikes and can sort its gremlins, spend time setting it up etc, replacing poor components, for better low cost alternatives etc.

It's really good value for money, I feel a bit bad for rubbishing it. The Giant Liv is a better bike, but 3 x better is debatable, more so if your on a budget, it's way better than I had as a kid, all those years ago Thanks again for the advice.

 

[Nigelnightmare]

If it's got 'sintered' pads you could try 'organic' or 'resin' pads to give better stopping power.
They wear out quicker though.

 

[Dorkingian]

Most of the cheaper cable operated calipers as fitted to lower end mountain bikes and hybrids have a fixed rear pad, they are tricky to set up but work quite well once they are positioned correctly. Wheel positioning in the dropouts is also really important, if they’re not in completely straight the disc will drag on a pad.

I had problems getting my Clarks CMD-23 rear caliper set up properly, but seem to have got it sorted now.
When I tightened the cable, there was too much rotation on the caliper cam/lever so it moved beyond the point at which it worked - there was just a click and then no braking. Alternatively, I found that the caliper would lock the brake full on, and to move the bike I had to push the lever/cam back (with my foot) to free it.
To check what was happening internally, I took it apart, which is easy - and instructive. There are three ball bearings each in an angled, sloped slot so that as the lever/cam rotates the bearing housing, the bearings move up the slopes and press the pad inwards. If there is too much rotation on the housing, the bearings reach the 'top' end of their slopes so can't push any further.
Make sure you get them properly located on reassembly! Are all bike calipers designed like this, I wonder?
The best solution for me seemed to be to move the fixed piston/pad as close as possible to the disc. This reduces the movement needed by the other, moving pad and so avoids the problem of rotating the cam/lever beyond its maximum pressure/braking point.