Weight Weenies
* FAQ    * Search    * Trending Topics
* Login   * Register
HOME Listings Blog NEW Galleries NEW FAQ Contact About Impressum
It is currently Tue Aug 22, 2017 12:39 pm

All times are UTC+01:00





Post new topic  Reply to topic  [ 12 posts ] 
Author Message
PostPosted: Mon Aug 14, 2017 4:19 pm 
Online

Joined: Sat May 24, 2014 12:09 pm
Posts: 681
Hi, today, I experienced severe fork chatter twice. Both times, it happend when braking only with the front, at moderate speed, but on really brooken tarmac. Is this common with all disc road bikes? 2 additional things:

* I have light vibrations on the front brake alost all the time, especially when braking hard
* I have the feeling the fork of the Endurace is not the stiffest of the bunch regarding braking forces. Rocking the bike front to back with the front brake locked causes a lot of flex in the fork. Same question here : is this a general behaviour with road disc bikes?

I like the disc "thing" a lot, (the bike has already >8000 km's since purchase in november last year, and the Addict get used a lot also) but today's experience learned me that fork stiffness front to back, is an important criteria for the next disc bike!!

_________________
Canyon Ultimate CF SLX 2013
Scott Addict Orica Greenedge
Canyon Endurace CF SLX


Top
   
PostPosted: Mon Aug 14, 2017 4:31 pm 
Offline

Joined: Wed Mar 15, 2017 5:30 pm
Posts: 70
This sounds more like pad flutter than the fork. Pretty much all disc bikes you will feel the pads moving if you hold the front brake and shift the bike forward and backward.


Top
   
Posted: Mon Aug 14, 2017 4:31 pm 


Top
   
 
PostPosted: Mon Aug 14, 2017 5:16 pm 
Offline

Joined: Sun Jan 08, 2017 12:44 pm
Posts: 42
Are you sure you have stem bolts properly tightened on prescribed torque? I had similar problems and torque wrench made the difference since I always tightened the bolts on lower torque by hand than it should have been.


Top
   
PostPosted: Mon Aug 14, 2017 6:40 pm 
Offline

Joined: Tue Jul 26, 2016 5:21 pm
Posts: 88
How big are the rotors? In any case, maybe clean the pads/rotors with alcohol, dry, and place in oven for a bit.

Does it happen only in high-grip (uphill braking)?

Is your QR tight and of good quality? Do the wheels have adapters that fit right?

Is there verticle play in the headset? Is the headset tq'd down vertically correctly (stem center cap bolt first, then others?)

Are the headset spacers right for the bike and all the same?


Top
   
PostPosted: Mon Aug 14, 2017 7:03 pm 
Offline

Joined: Tue Jan 28, 2014 6:52 pm
Posts: 1284
I had a mountain bike with a shudder in the rear. I fixed it by sanding the rotors with emery cloth and installing new pads.

It's probably just like car rotors where you can get burnt pad deposits on the rotors. When the pad hits that section it grabs harder and makes the shudder.

_________________
Colnago C59


Top
   
PostPosted: Mon Aug 14, 2017 7:24 pm 
Online

Joined: Sat May 24, 2014 12:09 pm
Posts: 681
There is 0 play on any of the components and all the bolts are torqued to spec. The Endurace uses TA's, and those are also torqued to >10 nm. Rotors are 160mm. While shuddering, I coud see the fork go back and forth, the same as while rocking the bike front to back. To me, it's clearly a fork issue. While riding, the confort up front is really good, so there must be some 'give' in the fork, maybe a little too much to cope with the heavy disc brake forces applied to a fork?? I just cleaned the rotors and pads with brake cleaner. Vibrations are a lot less, and i could not make the shudder happen, even if trying to brake hard on bad pavement. But I never had it to happend in 8000 km's neither... But the fact remains : there is (to much for my liking) movement in the fork while braking.

_________________
Canyon Ultimate CF SLX 2013
Scott Addict Orica Greenedge
Canyon Endurace CF SLX


Top
   
PostPosted: Tue Aug 15, 2017 2:31 am 
Offline

Joined: Mon Aug 29, 2016 11:19 am
Posts: 250
I don't have disc brakes but here is my theory...

Only one fork leg should be flexing and as a result the bike should feel like changing direction ever so slightly.

Have you tried comparing a somewhat looser skewer to a tighter one if you get any difference?

Is there any difference when going down a 10 degree slope braking hard at lower speeds and with braking hard on flat or gentle descents at high speeds?

How about trying different brake pads, these are perhaps too grippy under hot temperature conditions.

/a


Top
   
PostPosted: Tue Aug 15, 2017 3:36 am 
Offline

Joined: Tue Jun 30, 2015 3:30 am
Posts: 186
I got brake chatter until the LBS re-installed the fork, preloaded the headset properly and tightened the stem bolts up to spec. No harm for you to check them out.


Top
   
PostPosted: Tue Aug 15, 2017 4:22 am 
Offline

Joined: Tue Apr 22, 2008 4:31 am
Posts: 329
+1 for the issue at the disc/pad interface.

The reason for this (although you don't mention it) is that the presumption is that it has started, but wasn't always there.

Based in similar experience some time ago on my disc roadie.


Top
   
PostPosted: Tue Aug 15, 2017 12:28 pm 
Offline

Joined: Fri Feb 18, 2005 6:50 pm
Posts: 147
Location: Wilmington, DE
The only time I experienced fork chatter during braking I didn't have the headset bearings tight enough. They felt plenty tight in the stand and I couldn't detect any play when holding the brake and rocking the bike but hard braking with the front disc made the minuscule play very apparent. Preload your headset bearings until they get tight then back off just enough to loosen them up. That ought to fix it. I used to set headset preload by only going tight enough to remove any apparent play but that only works with loose ball headsets, not cartridge bearing like everything modern.


Top
   
PostPosted: Tue Aug 15, 2017 1:00 pm 
Online

Joined: Sat May 24, 2014 12:09 pm
Posts: 681
joejack951 wrote:
The only time I experienced fork chatter during braking I didn't have the headset bearings tight enough. They felt plenty tight in the stand and I couldn't detect any play when holding the brake and rocking the bike but hard braking with the front disc made the minuscule play very apparent. Preload your headset bearings until they get tight then back off just enough to loosen them up. That ought to fix it. I used to set headset preload by only going tight enough to remove any apparent play but that only works with loose ball headsets, not cartridge bearing like everything modern.


Will give it a try. Headset is tight, but i can imagine braking forces tend to highlight the tinniest amount of play in the headset

_________________
Canyon Ultimate CF SLX 2013
Scott Addict Orica Greenedge
Canyon Endurace CF SLX


Top
   
Posted: Tue Aug 15, 2017 1:00 pm 


Top
   
 
PostPosted: Tue Aug 15, 2017 3:19 pm 
Offline

Joined: Tue Jul 26, 2016 5:21 pm
Posts: 88
I had the same experience when I tried changing spacers from one diameter to another. Is your fork compatible with that topcap?


I'll get chatter on dirt when there is more grip. Have you lowered the tire pressure recently?

You can try loosening the front wheel TA and checking the disc bolt(s).


Top
   
Display posts from previous:  Sort by  
Post new topic  Reply to topic  [ 12 posts ] 

   Similar Topics   Author   Replies   Views   Last post 
There are no new unread posts for this topic. Aftermarket aero road disc brake fork

in Road

Epic-o

5

1040

Tue Jul 04, 2017 9:12 pm

eliflap-scalpel View the latest post

There are no new unread posts for this topic. How many of you have converted to Disc Brake?

[ Go to page: 14 5 6 7 8 ]

in Road

gravity

111

7980

Mon Apr 10, 2017 7:53 am

jlok View the latest post

There are no new unread posts for this topic. RE: Enve Road Disc Fork (Which one?)

in Road

Y26

2

288

Fri Jul 28, 2017 6:00 am

Y26 View the latest post

There are no new unread posts for this topic. Disc brakes : new pads = brake rub??

in Road

Delorre

3

572

Sun Feb 19, 2017 11:09 pm

wheelbuilder View the latest post

There are no new unread posts for this topic. Building a disc brake bike

[ Go to page: 1 2 ]

in Road

L3X

26

2463

Fri Dec 23, 2016 11:51 am

Broady View the latest post


All times are UTC+01:00


Who is online

Users browsing this forum: Bondurant, lovemyway, MattC, pyrahna, racingcondor, Yahoo [Bot] and 44 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Limited