Bit of a newbie question about rotor sizes

Howski

Hi,

I got myself an Voodoo Bantu back in August and I'm trying to work out what disc rotor to get on the front as the one on there is warped. I'm a bit disappointed that its become warped (considering its hardly off road or done a massive amount of miles) but I'm guessing that sort of thing is not covered under warranty.

I think that its got Avid Juicy 3 hydros on it but I'm struggling to find the specs. What is the max size disc rotor I can use? Will I have to bleed the breaks?

Thanks
-Howard

nicklouse

why not straighten it?

see the link in the tech links sticky in the tech section.

no you will not need to bleed the brakes.

max size depends on the fork.

Howski

Halfords have tried, lasted about a month of on-road and an hour of a slightly muddy trails and its back to rubbing.

Actually after doing a little googling there seems to be a lot of people with the same sort of issue:

http://www.mtbr.com/cat/brakes/disc-bra ... 07crx.aspx

Has anyone else come across this, maybe its not just the rotor but the breaks that are causing it?

Thanks in advance!
-Howard

cooldad

Is it rubbing because it is warped, or because the caliper needs adjusting?
Do you need a bigger rotor if you are hardly off road?
What size is it now?

Howski

Well I was planning on doings some in about a months time and I carry a lot of momentum so I'd like some good 'uns ;-)

I *think* its warped but I'm not 100%. They have already replaced the rear rotor as it got warped and straightened the front. Same symptoms less than a month after the first time. Had the bike about 6 months now and its been in like 10 times to halfords, almost killed me first ride. So I have little confidence in the setup. After reading that page though I started thinking maybe the breaks are a bit duff

cooldad

Or maybe do some reading and sort it out yourself - save time, hassle and money, and you will know it's done right. And if not you only have yourself to blame.
10 times in six months seems a bit excessive. Bikes need regular routine maintenance (check things continuously and sort out as required) so DIY for all except the most specialised tasks is the way to go IMO.

I am slightly chunky and have 160mm rotors front and back, plenty of stopping power so don't think you need dustbin lids to stop.

If you fit bigger rotors you will need the appropriate adapters as well.

cooldad

And before some rude member points it out (check the link you posted) they are brakes. When they don't brake, you break when you hit something.

Howski

Ok point taken on the rotor size front, however the link contains descriptions of the same sort of problems (rubbing etc) so I'm wondering if the brakes themselves are causing issues. I (admittedly) have little maintenance skills and I don't trust halfords anymore

cooldad

Could be I don't know much about Avid brakes except I used to use their V brakes and they were superb, but bike maintenance is really quite easy and there is plenty of stuff online - have a look in the Parktools link in Nicklouse's sig for a start. Has good guides on just about everything.
Worth a try - there's not much you can do wrong that can't be undone.

Uchiga

Before blaming the discs see if it's the pads, I dont know if Avide Juicy 3's come with pad adjustment but i know some avid brakes do. another thing to try would be to remove the calliper from the bike and take the brake pads out pushing the pistons all the way back into the calliper body, replacing the pads and calliper back to the bike and re adjusting the brakes relative to your disc. You should be able to see if a disc is warped is you spin the front wheel and check it against something that you know is straight like the front edge of the pad.

Admitedly I don't like Avids they arent the most user friendly of brakes to maintian... But there performance are pretty good...

Atz

Avids are "self adjusting". Yank the brakes hard and the pistons reset to a reasonable place (IN THEORY). Chances are the caliper needs realigning though. Loosen the bolts off a little, pull the brake and whilst the brake is pulled, tighten them again.

BTW, you ARE Checking that the wheel is seated in the dropout correctly? I've seen people moaning about warped rotors, knackered brakes etc who hadn't got the wheels in right.

.blitz

If your brake rotor is making a kind of shing-shing noise it is deffo worth re-aligning the caliper. Avid's wonderful tri-align system allows the caliper to compensate for all manner of manufacturing inaccuracies and by the same token it makes it really easy to align it incorrectly.

The description is in the tech links, just make sure you loosen the caliper-adaptor-fork bolts and not the hydraulic bolts

The J3s on my Rize were very musical until I got into the habit of doing this, sometimes during a ride.