Cheap Old MTB - Brakes

lucernarian

Hi there,

I've got a problem with the front caliper brakes of an old second hand mountain bike I have. They're very weak! Now after removing the brake pads and dismantling the caliper it looks like the spring of the caliper (side-pull, I understand) is simply weaker on one side, on top of the issues with the arms being a bit flexible and the poor cable housing etc.

I want to get a replacement spring or suchlike but I'm having no joy on the net. I haven't had the chance to call into a bricks and mortar shop either. It also looks like only the worst mountain bikes even use this sort of brake and the fork has nowhere to mount more conventional v-brakes or suchlike.

As I've only got about €20 to spend on it (long story but that's the way it is) I want to see what can be done about the mechanism to give it stronger braking action. I'm waiting on some new brake pads but even still I can't see them making a massive difference. Currently using my foot works better as a brake in very wet conditions:(

If someone could help with any of these questions I'd be very grateful! I'm jaded with trying different search terms to bring up results on caliper brakes instead of the usual cantilever brakes.

Edit: just to clarify, I definitely do not have any cantilever brakes even though most MTBs apparently do.

abcdggs

if your brakes are this sort

you should be able to simply move where the spring goes into the boss on the weak side to increase tension on one side(if you have a boss like the cant bosses below)


unfortunately the most likely situation if it's a cheap bike is that the callipers and levers are bad and need to be replaced

if not more information would be very helpful

lucernarian

Hey, thanks for that. I did mention in my first post that they were side-pull caliper brakes, and that the fork had none of those mounting posts for cantilever brakes. Is that the info you mean or something else?

Tonyandthewhale

Cheaper canti brakes (assuming that's what you have) tended to have very poor quality plastic caliphers that flex under-pressure meaning very little braking power. From the way you describe it though, as abcdggs said, it sounds like the tension hasn't been set as strong on one side as the other. Take the brakes off and put them on again properly.

New brakes pads will also help of course although they're effect will be limited if the caliphers are of very poor quality.

Single Malt

Tell me what material the front wheel is made of, and if its corroded. Then I can offer some advice.

lucernarian

It appears to be steel, and the wheel is only slightly rusty. The odd speckle here and there. And no specks of rust on the braking surface.

Single Malt

To_be_confirmed wrote: »

It appears to be steel, and the wheel is only slightly rusty. The odd speckle here and there. And no specks of rust on the braking surface.

OK. Be aware, unless you can get leather impregnated brake blocks, wet weather performance is shiite with steel rims. Switching to alloy wheels and appropriate blocks should yield the most measurable brake performance boost. A cable using teflon lined outer casing should help a lot too. In your budget, the cable is the only viable option, but do not expect miracles, as side pull brakes are crap, and steel rims are crap in the wet anyway. Do ensure that the braking surfaces do not corrode, as rust impacts severely on the brake performance by interrupting heat flow.

anthonyvbyrne

1. 8 Euros will get you a good set of servicable blocks in any decent bike shop.
2. If you cant 'tighten' the weak spring, try to loosen the 'strong' spring on the other side. It is a question of balance.
3. If yout wheels are not like special 100Euro+ wheels, you can vastly improve the braking performance by 'roughing up' the rims with some fine sandpaper. the blocks will grab hold of a slightly rough surface much tighter than a shiny surface.

It is all emminently fixable ad relativerly little cost.

BostonB

Caliper Brakes
http://sheldonbrown.com/calipers.html
http://sheldonbrown.com/brakes/index.html

How old is this bike. Must be 20yrs old or something.

lucernarian

Hi again,

I've done a few bits and pieces on the bike and it's running better now. The problem still lies with brakes unfortunately. The caliper was not perfectly aligned and was a bit sticky so after I adjusted the nut which holds the caliper to the stem of the fork, and gave the whole caliper another good cleaning and oiling, the brakes are more responsive. But it's not particularly impressive. My friends' bikes have far better brake performance.

I got a new inner and outer cable and some leather impregnated rubber brake blocks but they made virtually no difference. Tightening the caliper is the only thing that has really helped.

The rubber brake pad with the strip of leather in the middle has made no difference to wet braking performance. If I go down a hill in wet conditions with more than a slope of roughly 1 in 6, the brakes don't even give enough friction to resist gravity:(

BostonB

The pivot on mine had rusted, had to sand it down and re grease it and it improved no end. I PM'd you some photos of mine. The main improvement on mine was setting the pads very close to the wheel. Previously I'd had them set too far back. But it really only became a problem commuting, when the bike was fully loaded, going down hill on a rotten wet night.

If the brakes are quite cheap, maybe they are flexing, rather than applying pressure. Perhaps better quality arms might help. If the bike is that cheap though, you might just be better getting a better used bike with better brakes.

anthonyvbyrne

Are the rims really shiny ? if so, a rub with some fine sand-paper will make a huge difference.