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[Closed] Can you flat spot a rim ?

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[#7924420]

Looking over the rim on my wife's road bike I noticed its out of true a bit. Not side to side, but in the direction of the radius.

When I spin it round and measure the gap between the tyre and seatpost I can see it varies by about 2mm.

I don't think its the tyre. Is that something you can fix by twiddling the spokes ? Would she even notice it riding ?


 
Posted : 04/07/2016 8:40 am
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Firstly, are you sure it's the rim and not the tyre - deflate and reflate to make sure the bead is seated correctly all around? Yes you can flat-spot a rim, e.g. kerb-hopping. It depends on where the 'hop' is on the rim and how far around it goes - if it simply between 2 spoke holes then there's little that be done but if the wheel is a bit oval, you can adjust by releasing / tightening opposite pair of spokes around the wheel. FWIW British Standard for new bikes allows something like 5mm radial deviation, so wheel may have been like this from new. If the bike is new / in-warranty I'd ask the bike shop to look at it before you get the spoke-key out.


 
Posted : 04/07/2016 8:53 am
 D0NK
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Yes
No
maybe

Got a flat spot on one of my rear wheels, spokes [i]pull[/i] so can't do much to push a flat spot out, can't say I notice it. Mine still mounts tubeless tyres so no biggy.


 
Posted : 04/07/2016 8:53 am
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- Yes you can flat spot a rim
- Yes/no to getting it out with spoke twiddling, depends how bad it is and if it is actually flat spot in the rim (in which case no) or just crap build (in which case yes/maybe)

But... Are you sure it's rim not tyre? Look at how the rim varies WRT brake blocks, not tyre to seat.

2mm is not good, but it's also not terminal.


 
Posted : 04/07/2016 8:53 am
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OK, I will remove the tyre and recheck it all just in case its not the rim. Cheers.


 
Posted : 04/07/2016 9:11 am
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spokes pull so can't do much to push a flat spot out,
So you tighten spokes elsewhere and loosen those where the flat is. Tadaaaaaaa. Round wheel. (doesn't always work, depends how flat it is and why it's flat.)


 
Posted : 04/07/2016 11:04 am
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Yes, done it.

Not easy on a modern roughty toughty MTB wheel and associated 2.4" tyre mind..!


 
Posted : 04/07/2016 12:46 pm