Fumbles22

I bought a used bike recently, and it's in good order. I've ridden it to and from the shops, to and from the train station and thoroughly enjoyed myself all these times.

However, there are two things that I need to sort. One is major, the other is more of an opinion based question.

1). I noticed that the back brake is off centre. One of the brake pads is touching the wheel rim even when the brake is disengaged. Here's a picture:



I can move the callipers with my hands to where I want them to be, but they spring back into place when I let go. I did some googling on "how to adjust U-brakes", and Sheldon Brown says there's a screw on one of the levers to adjust the spring. Do all bikes have this? Mine doesn't seem to.

The only other alternative I could find is to remove the callipers, grease them and put them back on again. I don't really want to do this since it's a big job and I would have to buy brake housing/cabling.

I should probably mention that I put WD40 where the callipers meet to lube them up. However, this was before I noticed the problem. Also, the wheel appears to be straight in the frame. It's definitely a brake problem, not anything to do with the wheel.

So, does anyone have any ideas for solving this?

2). The tyres have some cracks on them. Here's a pic:



Is this too cracked? I don't want to risk a puncture!

fietsbob

Toss the tire in the rubbish.. U brakes have springs you wind up,
with a wrench on the flats of the piece around the bolt,
then you tighten the bolt to maintain the counter force.

NB,. as the brake pads wear they move outward to begin wearing the tire sidewall .
re adjust them so they stay gripping just the rim.

not all bikes have those brakes, newer the V brake has replaced those..

Airburst

A picture of the brake might help us work out exactly what it is and how to adjust it, not all u-brakes are adjusted exactly like the ones explained on Sheldon's site.

frantik

from the picture i suspect it's a caliper type brake and not a ubrake, but i'm not sure

definitely replace that tire.. and if you can afford it maybe replace the wheels with aluminum ones. it will lighten your bike and more importantly will improve your braking power

krobinson103

If thats what I think it is - a single pivot caliper than getting the thing to stay centered can be a mission. Depends on the quality of the brake assembly and spring. One of mine won't stay centered no matter what. I just gave up on centering it and am currently hunting for a better caliper.

Fumbles22

I messed around a little bit more to see if I could find a way to centre it. I messed around with the bolts holding it in place, but that didn't work. I also moved the wheel slightly to see if I could get the calliper to spring back, even if the wheel was in a different position. It didn't!

I think it's a spring problem. If I could get the spring tighter on one side, i'd be home free!

This is the "problem side" from afar:



..and up close:



As a guide, this is the gap from the other side:



Finally, this is a shot of the brake itself:



This is a U-brake isn't it?

Airburst

No, that isn't a U-brake, that's a sidepull caliper. A u-brake would have two arms that pivoted about studs mounted somewhere above the rim. About the only way to adjust that brake for pad clearance would be to loosen the mounting bolt and rotate the block that the spring fits into. I believe Sheldon Brown does explain how to do that in his article on sidepull brakes, in case my explanation is a little unclear.

sreten

Hi,

Its a sidepull caliper and basically: hold the brake against rotation
as you tighten the rear nut, you want that side to be against the rim.
Once tight, further slight tightening of the rear nut will rotate the brake.

There are other ways of doing it depending on the foibles of the
particular sidepulls, but generally they are all a pain to centre
and keep centred, find out what works easiest for your case.

The tyres are fine, a little tired (ouch!), but still very usable.

rgds, sreten.

krobinson103

I did find one way odd way to get a stubborn sidepull to work. Take a hose clamp and attach it around the frame and cable sheath somewhere near the brake on the problem side. Figure out where you want your brake and then lock the clamp down just enough to keep your offending pad off the rim. It means your brake does work, but it looks a bit off center. Its about the cheapest way I could find without actually replacing the thing.

Messing with the block and spring can be a really frustrating waste of time if the thing is old and worn enough.

bikeman715

Use a hammer and a punch (screwdriver) on the side of the brake not touching the rim . Put the punch (screwdriver) on the spring of the brake arm and give it a tap , it should center the brake . If you over do it , just hit the other side .

sreten

Hi,

Pretty much the same as other methods, it doesn't change the spring.
All methods are get it tight and slightly adjust. None of them stay put.

rgds, sreten.