What do you experts think advice needed.

[bad boy]

Hi All,

Just after a it of advice

I have a Mavic Open Pro rim 32 hole with a Deore DISC hub as my rear wheel, and when turning the bike upside down and spinning the wheel noticed the disc is sort of rotating between the pads but at one point it looks like its buckled/bent as it sort of spins mich closer to the pads on one side.

I know this might sound stupid but it looks dead straight I really cant find a bend at all in it.

Could there be another reason why its doing this its not a major problem breaks are fine but just something ive noticed.

Thanks

 

[gbb]

I'm not really conversant with disc systems, but there is a possibility ...i'm just theorising here..
The brake caliper / pads are mounted to the frame ? It can't move.
If the wheel / hub has any slight warp / bent axle / general untrueness (is that a word ?)...although the disc itself could be absolutely true, it could be mounted to a 'wobbly' wheel that will show as you use the calipers as a reference point.

Just theorising...i've no idea based on fact.

 

[bad boy]

I like your logic gbb that makes sense to me, I think you are right and it must be either the hub and or axle has a slight bend to it. I suppose it could be the disk im only taLking about 1mm or less wobble on rotation but its enough for me to notice wasnt there before.

Dont get me wrong they are great in the wet but they are not worth the hassle unless you have an MTB !?.

Hopefully it will not get worse !?.

 

[02GF74]

does the rim wobble? put pencil on frame with end near to rim and spin the wheel.

if not, the disc is warped.

either replace or try to straighten it, 1 mm it too much run out.

 

[bad boy]

I thought being as the disk is attached to the hub as long as there is nothing wrong with the hub the wheel could be buckled and not affect the disk in terms of trueness ?.

Ive tried the pencil trick and it does wobble a little bit but could this not just be independent of my disk problem ?.

 

[tandemman]

Check that the rotor(disc) securing bolts are tight

 

[Cubist]

The disc has a bit of run out. It's nothing major, and is very common. If you can find a perfectly true MTB/XC wheel and or disc out there, you're doing well.

With the bike in a workstand or upside down, turn the wheel slowly until you see the point where the disc is closest to the pad. Note how far you have to run the wheel to get the gap back again. The portion of disc between those two points is where you can tweak the disc rotor back into line with your fingers, or with the jaws of an adjustable spanner.

If you aren't confident enough to do it, take it to an LBS and they'll do it in no time.

 

[Steve Austin]

The disc is warped. that is all.

 

[lukesdad]

Dont ride mtbs with discs but used to ride mx and enduros on m/cycles and every disc I ever came across was warped to greater or lesser degree. I would suppose with mtb discs being even finer the problem would be even greater usually caused by whacks from one thing or another i suppose again.

 

[Steve Austin]

Dont ride mtbs with discs but used to ride mx and enduros on m/cycles and every disc I ever came across was warped to greater or lesser degree. I would suppose with mtb discs being even finer the problem would be even greater usually caused by whacks from one thing or another i suppose again.

mtb discs are really not good enough for what they are supposed to do. the cheaper discs/rotors are really bad and can warp from a less than a minute of heavy braking, and the knocks they can get. its not really a big issue, but singing discs is a real pain when descending on road. avids being the worst ime. they sound like a turkey singing at high pitch.

 

[02GF74]

blimey I must be really lucky as all my discs are as near as damn it straight - shimano XT mostly.

yest, there is a tiny amout of run out, probably less than .5 mm. Maybe I should get a dial guauge and measure ..........

 

[bad boy]

blimey I must be really lucky as all my disc's are as near as damn it straight - shimano XT mostly.

yest, there is a tiny amout of run out, probably less than .5 mm. Maybe I should get a dial guauge and measure ..........

Thanks for all the replies, the discs are on my Cannondale bad boy hybrid, so no jumping and unless someone is sneaking into the carpark at work and giving them a good kicking they arnt getting bashed by anything.

I do think it could be a hub and or axle issue but its nothing major will keep my eye on it.

Thanks