Kornowski

Hey,

I have a Kona Blast 2006, and when I brake I feel and see the forks judder, why is this? Think I need new pads?

Thanks for any help!

I_bRAD

YOu need to turn up the anti-judder adjustment.

Kornowski

What!?

kenhill3

LOL. Yuk.

Kornowski

Yuk? So you guys aren't going to help me out!?

kenhill3

Sorry, Bud-

Usually people need to post with a little more information before people are willing to respond. It helps to read this first: https://www.bikeforums.net/bicycle-mechanics/338432-new-posters-please-read.html

Also, you can do a search on this forum to help.

What you describe could be one of MANY things: loose headset, loose caliper, loose rotor, disc/pad contamination, etc.. It's hard for us to help given your limited information.

If you don't have much experience in working on your bike, it may be good to go to your LBS (where you bought the bike?) and their help to fix it or show you how. The thread linked above will also help you to learn how to work on the bike.

Try to at least get a little more info and then come back and post again.

Hope this helps.

cyccommute 

Are you feeling the judder through the brakes, Kornowski, or just seeing the fork flex? Forks will flex during braking normally. You're putting a lot of force on a rather flexible part of the bike. If the forks are flexing too much, you might also have a worn fork. Like Ken says, talk to the bike shop.

Kornowski

Ok, Sorry for not being a bit more specific, I'll have a go at tightening everything up and see how it goes...

Yeah, I'm feeling it through the brakes, it seems to be in time with teh waves on my disc, if that makes sense, my disc look like this 07 Blast:
I can also see it in the forks, they actually move, so that makes me a little more worried...

Ok, I'll see what the BS have to say, but any more help will be greatly appciated!

cyccommute 

I had this problem with the Polygon discs that came on my Juicys. The top of the pad would squeeze in as the point of the disc passed and it sounded like a tea kettle boiling. First time it happened I thought my brake fluid was boiling. I replace the disc with a rounder Avid version and the problem when away. Look and see if you pads can possibly flex inward and/or look for a disc without the 'cool' cutouts.

I don't think this is much of a problem, really, but it can be very disconcerting.

Kornowski

So the pad may just be bending over onto the pad wave things?

Would getting new pads possibly solve this?

cyccommute 

Probably not. The bottom of the pad is in contact with the rotor but the top of the pad is squeezing on empty space (the Polygons have about 1/4" from the peak of the wave to the valley). The pressure on the bottom allows the top of the pad to bend inward slightly and then, as the peak comes around, it's forced apart. Since you are likely to keep the same lever pressure through braking, the pad will flex in and out. A smoother, rounder rotor will help or, and I'm not sure how much adjustment you have, moving the rotor inward to avoid the peaks could help.

Kornowski

Ok, Well, I'll give everything a tighten and see what happens, then, if the problem carrys on, I'll see what the LBS have say... Thanks a lot for you help! I'll keep you posted as it happens.