[limzjun2002]

Have something i've noticed on me fixed gear. hope u guys can help.

Bike has only front brake. When braking (even with some light resisting) the steel fork vibrates quite visibly. Is there a problem? Btw the rims are steel rims. Is that why its vibrating?

thanks

 

[tubafreak]

Try lightly sanding the pads and braking surfaces with some fine sandpaper, it might help smooth the transition between not braking and braking. Also, check for surface inconsistencies, the vibration indicates an on/off style braking, caliper flex could account for this as well (although it's not fixable).

 

[BianchiJoe]

I'm familiar with the vibration you're feeling. On my Bianchi Pista, the round fork legs chattered a lot under braking loads; they just didn't have the front-to-rear stiffness of more ovalized fork blades. It never gave me any trouble, however, and it wasn't a control issue, but it was a bit disconcerting. I found myself braking with my legs most of the time and only using the brake for quick stops.

 

[geoduck]

Keep an eye on it

I had a similar thing going on with a steel bianchi cyclocross frame and fork. One day I went to wipe what I thought was a smudge off of one of the fork arms and I noticed there was a crack almost all the way through the left fork arm about two thirds the way up. There was literally no more than an eight of an inch of metal holding that fork arm on. The word catastrophic came to mind.

I'm not sure if my issue was a cause or effect, but just make sure to keep an eye on it and keep a look out for cracks developing with that vibration going on.

Bianchi replaced my fork and the problem went away. I did have to put on a new headset on since they didn't stock threaded anymore, so that may have been part of the equation.

 

[wooliferkins]

A loose fork crown did it for me. Are you paranoid yet? You know it's falling apart. On One is good for fixie gen and they sell ace carbon forks as do dotbike and others

 

[limzjun2002]

thanks for suggestions.

observing fork more closely. the contact between pads and rim seems ok and the fork doesn't seem to be vibrating right from the top.

so it probably means there's a bit too much load on the front fork during braking. geoduck might be right...

was wondering...would rear brake ease the load on the fork? would it work long term? or is it just a quick fix?

 

[tamu]

contact between the pad and the rim? thats where I would start.. make sure everything is tight... then i would try and see if the pads to rim contact was what is cauing the vibartion..

if everything below the frame is solid (pull on it and see if it flexes.. the fork/wheel/brake arms)

then i would check to see if the whole thing jiggles through the headset

 

[Mel Erickson]

Also check the brake mounting bolt to make sure everything is tight.

 

[Mr. Peabody]

I experienced a similar problem on my commuter. In my case, the front rim wasn't perfectly flat, that is, it had some dings that were straightened out, so when braking I felt a pulsing from the front brake; also, my old headset kept loosening, which only made the problem and shudder/pulsing feel worse, as it moved the headset with each revolution of the wheel when applying the brake. I put in a new threaded headset, and changed my rim. That solved the problem nicely. Hope this helps.

 

[limzjun2002]

tq for additional ideas. I'll check them out.