Fork Shudder under braking - ROAD brakes

[Big GMaC]

Starting recently when under heavy braking (descending) the front end of my bike is shuddering and juddering.

I was wondering it there was anything I can do to stop this. At the shop they said I should first toe the pads and see if that changes anything, and while it has reduced the effect slightly, it is still pretty shaky.

The bike is a 2009 Cannondale CAA9, SRAM Rival Front Brake, Swiss stop pads on aluminium Fulcrum 5's. Front fork is stock, Carbon with Alu steerer.

The frame is a 58cm and I weigh 88kgs.

Mostly it is during aggressive braking from above 50 kp/h

Any advice?

 

[erader]

Starting recently when under heavy braking (descending) the front end of my bike is shuddering and juddering.

I was wondering it there was anything I can do to stop this. At the shop they said I should first toe the pads and see if that changes anything, and while it has reduced the effect slightly, it is still pretty shaky.

The bike is a 2009 Cannondale CAA9, SRAM Rival Front Brake, Swiss stop pads on aluminium Fulcrum 5's. Front fork is stock, Carbon with Alu steerer.

The frame is a 58cm and I weigh 88kgs.

Mostly it is during aggressive braking from above 50 kp/h

Any advice?

you could have a wimpy fork or a bad headset.

erader

 

[allstar56]

Fork Juddering under braking

It does sound like the headstock bearings to me, but it's only a 2009 bike so how much abuse are you giving it ? I would check the bearings first. Have you crashed the bike ?

 

[hungryjoe]

front brake shudder

Hi I seem to eternally suffer from fork shudder, I ride a Kuota Kross with Tektro brakes I have toed the pads loads of times and tightend the headset etc etc but sure as a bear ****s in the woods it everything will remedy the situation for a short period then bingo the shudder comes back. I do ride long distances on the bike (3- 5 hours off road) has this got anything to do with it???

check out Lennard Zinn's column about this:
http://velonews.competitor.com/2009...l-qa-with-lennard-zinn-return-to-cross_101807
... you might have front end flex under braking causing the brake to tighten up. A low stiff cable hanger makes this go away.

I've also sometimes had nasty brake shudder if I drip sports drinks, get weed sap, anything sticky, on my rims. It makes sidepulls shudder and howl too, especially when really hot at hi speed. When this happens I scrub the rims with a green abrasive pad, and then they work well.

 

[Big GMaC]

It does sound like the headstock bearings to me, but it's only a 2009 bike so how much abuse are you giving it ? I would check the bearings first. Have you crashed the bike ?

Nope I haven't crashed it, but it has been ridden on some pretty rough roads, all tarmac but in London there are some dodgy patches, I have never really tanked anything though

 

[Big GMaC]

Why have these threads been merged?

They are two completely different questions. Only about a road bike, one about a cross bike using a completely different braking system

 

[Martin318is]

Why have these threads been merged?

They are two completely different questions. Only about a road bike, one about a cross bike using a completely different braking system

Pulled the trigger too fast before I realised that - sorry.

 

[Big GMaC]

Pulled the trigger too fast before I realised that - sorry.

No worries.

But the thing I am getting at is do I have any need for worries that it is going to give out on me?

 

[usedtobefast]

Starting recently when under heavy braking (descending) the front end of my bike is shuddering and juddering.

I was wondering it there was anything I can do to stop this. At the shop they said I should first toe the pads and see if that changes anything, and while it has reduced the effect slightly, it is still pretty shaky.

The bike is a 2009 Cannondale CAA9, SRAM Rival Front Brake, Swiss stop pads on aluminium Fulcrum 5's. Front fork is stock, Carbon with Alu steerer.

The frame is a 58cm and I weigh 88kgs.

Mostly it is during aggressive braking from above 50 kp/h

Any advice?

the brake pads or the rims may have a build up of dirt on the them so they don't grab like they should. some 0000 steel wool on the rim and fine sandpaper on the pads should bring them back to normal.

 

[purpletezza]

Check the headset for any movement. Do this by standing over the top tube like normal, activate front brake so front wheel is clamped and try to move the bike forward and backward. You will feel headset movement if there is any.

Clean rims with ethyl alcohol/spirit to remove and lub/grease.

Lightly sand the brake pads so they do not look glazed, but a bit rough.

 

[Big GMaC]

Thanks everyone, I am pretty sure it was because the pads had become smooth and I was having to really grab the brakes hard to get any effect.

So I sanded the pads and steel wool on the rims and it is much less now

 

[durianrider]

I gotta Caad 9 too big mac, and no hassles with it.

I had superlight carbon fork on it but gave it to a mate in Thailand as it was flexy and you would feel every rut in the road. The fork in the photo is a heavy duty specialized fork OEM. Works great. Alloy steerer for strength and stiffness.

Id check some things.

1. Hold your front brake on and move your handlebar front and back and there should be no real knocking. If there is, your headset could be loose.

2. Make sure your front wheel is in proper.

3. Make sure your front brake pads are tight and the caliper is tight in the frame. If the front star washer that sits on the brakes fork insertion axle is too thin, the contact point may have some slack in it.

4. Check that nobody did a half *** job and put in a short fork nut vs a long fork nut and you only have a couple of threads holding it all together.

5. Doesnt hurt to take out the fork, wipe it down and check the steerer for any cracks. Those cannondale forks with the alloy steerer came out of a taiwanese factory called 'advanced tech' and are really, really tuff. Ive never seen a problem with em once.

This all should take about 20 mins. and give a lot of peace of mind. Check a mates bike to see how much stationary play there is when your rock if back and forth with the front brakes on.