Weird front wheel question
Hi all
Have just discovered a strange occurrence in my front wheel. When braking, I get a judder that feels a little like the sensation you get when the headset is loose. The problem is that the judder only comes around once per revolution of the wheel when the brakes are on fairly hard. I've checked and replaced the brake pads and checked the headset (which seems fine) but the rims are about 1mm out of true (although I can't quite tell whether that would affect the judder). They are fairly old DuraAce rims (can't remember the precise versions) that have done a fair few miles, but the rim surface seems OK to me. Any ideas? Cheers
Have just discovered a strange occurrence in my front wheel. When braking, I get a judder that feels a little like the sensation you get when the headset is loose. The problem is that the judder only comes around once per revolution of the wheel when the brakes are on fairly hard. I've checked and replaced the brake pads and checked the headset (which seems fine) but the rims are about 1mm out of true (although I can't quite tell whether that would affect the judder). They are fairly old DuraAce rims (can't remember the precise versions) that have done a fair few miles, but the rim surface seems OK to me. Any ideas? Cheers
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Comments
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I don't think this sounds that weird, assuming that the brake blocks are clean and fine, it sounds like it is just that the wheel probably needs to be retrued. Adjust the centering of the brake blocks so that one is just missing the rim and spin. If the wheel sticks you know that side needs to be pulled back (de-tension that side, increase tension the other), repeat with the other block to make sure. Little dabs of masking tape help to clearly identify the area that needs to move.
Retruing is fairly simple with the right spoke key, just try not to do too much and be very clear about what each 1/2 turn on the nipple will do (as in, turn one way will relieve tension and move the rim away, and vice versa). Sometimes a VERY CAREFUL application of WD40 helps the nipples to move but clean it up before using the spoke tool or you may increase the chances of rounding the nipple. You should only need to back two spokes off and wind one up for most minor issues.
Simply repeat the brake block/spin test once completed.0 -
Cheers for that. I've had wheels go out of true before, but not with this effect. Will get the spoke key out...0
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If the rims are that old you may want to just check to ensure there is still 1mm left in them. Spring calipers can work well but usually give a bit of an approximation because it is hard to get an accurate measure across the rim surface. See if the brake track is tangibly concave as a starter for ten, if it is then chances are that the rim may need replacing. Might be worth a second opinion at some point soon as sudden rim failure is seldom pretty.0
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This is quite common if you have a slight lip or imperfection where the rim is joined which the brake blocks then hit when breaking; find the join in the rim and see if you can feel anything?0
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Ta gents. I have a feeling that the rims might be on their way out, even though they look fine to the naked eye. Time to head to the LBS methinks.0
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Bobbinogs wrote:If the rims are that old you may want to just check to ensure there is still 1mm left in them. Spring calipers can work well but usually give a bit of an approximation because it is hard to get an accurate measure across the rim surface. See if the brake track is tangibly concave as a starter for ten, if it is then chances are that the rim may need replacing. Might be worth a second opinion at some point soon as sudden rim failure is seldom pretty.
This was my thougt too. If in doubt, don't risk it. Shudder.0 -
Bungalballs wrote:This is quite common if you have a slight lip or imperfection where the rim is joined which the brake blocks then hit when breaking; find the join in the rim and see if you can feel anything?
Sounds like a good idea.
Just thinking about the wear issue, it might be worth checking to see if there is a wear indicator dot. I know my RS80s had them and it did give a useful reference point mid rim. Then again, it could be the rims have worn so the indicators don't show :-)0 -
Knowing me, I might have just worn right through them!0
