Crash , New brake block - fail

stealf

Morning... anyone heard of this happening before?

So nearing the end of a 50mile Sunday run coming back into town when a driver pulls out in front - normally distance would have been okay to stop but when i pulled the brake my rear failed. CRASH. I'm off in the middle of the road cramping up , driver stops, checks car and all is okay, then checks to make sure i'm okay, asks what happened? etc... all quite nice really.
Upon looking the actual block had dispappeared from it's cartridge housing ???????? I was on some poor quality roads so can only imaginge the screw holding them in worked itself loose. Weird as only been on the bike for a week.
Apart from the minor issue at the end, I had a great time on the bike in some lovely country side - A joy to be out

rolf_f

Yes - this sort of thing does happen when you put the cartridges on back to front. The screw really shouldn't make much difference and Campagnolo cartridges don't use them at all - the open end of the holder (ie the end that you push the pad in from) should always face the back of the bike. That way, the rotation of the wheel is always pushing the pad towards the closed end.

What happened to you can only really happen if you have the holders the other way round. Worth noting that because the calipers face in opposite directions, the screws should appear on opposite sides of the calipers if you held them side to side. It is slightly confusing!

And, of course, you probably shouldn't have been using the back brake at all; normally just the front is used as that is where the stopping power is.

Grill

1) Was it installed the right way around?
2) Are you certain it was screwed in properly?
3) Glad you're okay.

goonz

Glad to hear you are ok, is the bike brand new? Maybe it wasnt fully tightened up at the manufacturers. May be worth giving it a quick look over to make sure there are no other issues. Was the bike damaged?

iPete

If the cartridge is still in the other block take a look at the direction it is installed in.

stealf

Thanks Rolf F, Grill and goonz - glad to say nothing dented other than a bit of pride.
I will check to see when I get home about the pads and right or wrong way round, I brought them new last weekend and installed them myself - a really simple job - so I thought...

On the subject of which brake to use - I generally use front for slowing down but in this nede to reduce speed urgently It was plainly obvious that both would be needed..
we live and learn.

navrig

Back to front. Screw doesn't really hold them in but the direction of movement pushes them against the closed end of the shoe.

rolf_f

stealf wrote:

On the subject of which brake to use - I generally use front for slowing down but in this nede to reduce speed urgently It was plainly obvious that both would be needed..
we live and learn.

I believe that under normal conditions, when braking at maximum force, the rear brake makes no contribution at all because maximum force on the front means that there is minimal grip between the rear and the road. Effectively, if you were braking any harder you'd be over the bars and if you weren't braking that hard, then you'd still have mileage to increase pressure on the front. If your brakes are crap, or it's wet etc etc, then other circumstances may apply.....

In other words, in your incident the rear brake was just a placebo that caused you to crash!

stealf

Right, just got home and blimey!!. They are on the right way round. the gap in the cartridgento slot the blocks in is at the rear of the set up, meaning they are in the right way round... correct? So all I can fathom is that they were faulty when i got them out of the box. I'll be off to LBS wed night (late night) to inform, replace and check the bike over.....
RolfF - I agree in what your saying if I was a dead weight - but years of mtb riding has taught me to move around the bike(s) when required, so if I need to stop suddenly a bit of weight over the rear wheel and pushing the legs straight to gently force tyres into the road give added grip when needed, stopping you quicker without going over the bars or performing a child like skid. So if my brake had worked, I would ( i know from experience) have stopped in good time.

edten

if the screw was loose the pads can move forward out of the block from vibration...I say this from experience as I once forgot to tighten the little screws up and I noticed (luckily) at the first junction I got to, both pads were almost falling out the front of the cartridge. If the pad was sitting forward of the cartridge and you broke hard it could have been enough to force it out.

Your front break has much greater stopping power, and saves trashing rear tyres.