View Full Version : Front brake pulsing

05-19-2009, 02:16 AM
OK, frustration is mounting. I bought an '06 Uly last month and have put on 1,000 miles commuting. The brakes were superb at first but recently I've noticed a pulsing that rises/falls with speed. Heck, the thing even grabs when slowing to a stoplight! Feels like it's grabbing one 'sticky' spot on each revolution.

At speed the pulsing is not violent, just annoying and bad enough to fix asap. I do ride in the rain. In fact, the pulsing may have developed since then... I'm a bit fuzzy on the start date. I know the last owner stored the beast outside in winter (his wife let that one slip [smirk])

In the last week I have:
1st - checked tire pressure / fitment
2nd - checked brake fluid level
3rd - cleaned off rotor w/brake parts cleaner
4th - loosened rotor fasteners enough to release tension. Then re-torqued in proper criss-cross manner
5th - removed pads, scuffed them with emory paper, brake cleaner-ed everything then lubed the brass slider/retainer pin in the center before re-assembling all with loctite blue (that was tonight). Interestingly, the brass guide pin had 2 wear marks on it where the pads rest, looked normal. Pads have plenty of life in them and replacing them wouldn't fix it anyway.

(thanks for the to-do list from another post LeFox [up])

Can anyone advise? Is rain riding not allowed on XBs? Could improper storage have jacked the brakes up?

05-19-2009, 03:20 AM
I wonder if the Rotor is warped. Have you had it off and checked it? When you walk your bike, do you hear it rubbing on a single spot or all the way around the disc?

05-19-2009, 09:19 AM
were brake-pads changed? which brand/type?
how thick is your disc?

it is quite possible your disc is deformed...

05-19-2009, 06:10 PM
Sounds like a perfect time to upgrade to wave rotors.

05-19-2009, 09:41 PM
Coasted the bike down a hill 3 times today and the front brake rubs on one spot. Thickness is 4+not quite 5mm.
Haven't changed the brake pads, they're stock, I assume.

Apparently, the rotor is warped. Should that be happening at only 3,800 miles and 3 years on the bike? It's possible that it was warped when I bought it and it just took me this long to notice. How does a rotor become warped? I noticed some of you mentioned storage or riding in rain as a cause of brake problems in other threads (yes, I did search before posting :)) If I go replace this thing, I want to make sure I don't warp it again.

All I can think of that I've done is riding through the rain or practicing high-speed braking. I sometimes practicing braking in a corner at speed (50-65 mph) just to keep my skills sharp. Most I've done it is 3 times in like 2 miles. Shouldn't the brakes handle this ok?

On replacing, is there an aftermarket rotor that is more warp-proof? I'm not a sport-hooligan rider so I'd rather not pay for ultra-hyper race brakes. But I will pay for longer lasting ones. Suggestions?

Also, should I replace pads at the same time? Current pads have plenty of life.

Wow, that 's a lot of questions. Thanks for the education all! :D

05-19-2009, 10:14 PM
PS, what do you think of this thread on bad weather bikers:

or this article on "warped" rotors:

Could it be a pad problem?

05-20-2009, 09:04 AM
normally a brake rotor/disc will get warped when it's overheating.

this could be cause by pads, hard braking and fast cooling, a manufacturing error in the disc/rotor, etc.

how one manages to warp one and another doesn't is a mistery to me.
my girlfriend manages to do this all the time with both her bike & her car, replace the discs and she starts over.

if you change, i would go for wave rotors for several reasons:
- better cooling = better performance
- looks
- price (cheaper than stock)

04-17-2010, 12:20 AM
you need a new roter i had the same thing i wunder if we can reserfis it