Rim brakes working like crap

Clark3y

So I use v-brakes and can't figure out why the damn things don't seem to work any more.
I've been riding through some terrible slop at Cannock recently so I'm sure that hasn;t helped.
Cleaned up the rims with some solvent on a rag and lots of black crap came out even though it looked clean, no improvement in the braking though.
Pads came out, glazed and worn out. This must be the problem, surely, so I put some new ones in and aligned them. I'll be damned though, still not a great deal of improvement.

I used to be able to easily lift the rear tyre up with 1 finger but now it doesn't have any bite at all. Is it possible that the rim is the problem, seems like an unlikely cause to me but running a finger nail over the braking surface reveals it's far from smooth.

Oh yeah, the only other thing is they are clarks cartridge pads, were the black ones before, I put the red ones in. Are the red pads just a harder compound and this is why it's a bit rubbish?

red eye

clean the pads with sand paper, you will see improvement once they bed in.

The Rookie

What solvent? Some leave a residue, some don't.....

You will need to bed in new pads before they bite properly though.

Simon

Arkady001

Some solvents definitely leave a residue that can impregnate the alloy and that can take a long time to 'burn' out again - same as car brakes.
Best thing to wash your rims with is good old-fashioned hot water and washing-up liquid or Muc-Off rinsed off with hot, soapy water.

I gave up in the end as I was forever overspraying my rims with WD-40 - I now use rims with ceramic-coated braking surfaces and shimano ceramic-specific V-Brake pads.

A couple of sweeps with medium sandpaper in the same direction as the wheels turn should sort heavily-glazed pads though.

cooldad

He mentioned he put new pads in. No need therefore to clean them or sand them.

Arkady001

cooldad wrote:

He mentioned he put new pads in. No need therefore to clean them or sand them.

So they say - I usually take the shine off my new ones before installing.

Dave_P1

Check the brakes for any alignment issues

02gf74

are the rims worn? after much use, they tend to end up concave - the new pads being flat means the pad to rim interface is not ideal so you do not get complete rim to pad contact.

hence why you may be having problems.

(not that it helps, but I am now fully disc on all bikes so have waved goodbye to that problem)

Clark3y

White spirit I used, was the closest thing to hand. I get the feeling I'm about to be told that was a bad mistake.

Alignment is spot on, I'll try giving them a quick sanding and see what happens. In the past though I've always found v brake pads work 100% from the word go.

I noticed Clarks have changed their line up of pads now, was going to order another spare set but they are gone. Replaced by 2 new pads, a dual compound and a triple. I suppose i'll go for the triple as that one has a good review on CRC. I see they have taken this opportunity to double the price of them too, can't complain I guess.

Clark3y

Went to give them a sand and found the surface of the pads had turned black (red pads remember). Anyway I got the black off, did a few stops, it's improved and will lift the rear with a bit of effort. The pads went black again pretty soon though, must be pulling ground in dirt out of the rim I suppose. It's good enough that I won't crash into stuff now so will just ride it out and see how it goes.

Any tips on what I can use to thoroughly clean the rims in future to avoid things like this?

red eye

cooldad wrote:

He mentioned he put new pads in. No need therefore to clean them or sand them.

pads can still have mould release on them,

red eye

Clark3y wrote:

Went to give them a sand and found the surface of the pads had turned black (red pads remember). Anyway I got the black off, did a few stops, it's improved and will lift the rear with a bit of effort. The pads went black again pretty soon though, must be pulling ground in dirt out of the rim I suppose. It's good enough that I won't crash into stuff now so will just ride it out and see how it goes.

Any tips on what I can use to thoroughly clean the rims in future to avoid things like this?

they will turn black no matter how clean the rim is.

Clark3y

fair enough, only ever used black ones before so not noticed this.

red eye

its like when you metal polish no matter how bright you get the metal the cloth always turns black :?

Arkady001

Some of the 'black' is dirt, some of it is alloy from the rim...as more dirt gets embedded in the pad, it scours more alloy from the rim, giving you those charateristic parallel lines on the braking surface, hence why you should scuff the pads with sandpaper every so often.