Tyre shape

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cybicle
Posts: 5
Joined: 11 Jun 2014, 1:07pm

Tyre shape

Post by cybicle »

OK. going to risk showing my ar*e here a little, but hey ho.....

So I've got a decent wheelrim, its true (having been done by LBS) and I'm going to fit it.

Thing is, I'm fitting the new tyre (which admittedly is a budget item) and the tyre when properly inflated seems out of shape radially and laterally.

When its all fitted on the fork (its a front wheel) and run to check brakes etc, the wheel looks as though it well out of true, when I know its not.

Is there anything I'm missing?

Cheers
Hobbs1951
Posts: 480
Joined: 15 Apr 2014, 10:48am

Re: Tyre shape

Post by Hobbs1951 »

You say it is a budget tyre, is this the reason the tyre appears out of shape: because it is of poor quality ?

Photos always help...

John.
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squeaker
Posts: 4114
Joined: 12 Jan 2007, 11:43pm
Location: Sussex

Re: Tyre shape

Post by squeaker »

Does the tyre have bead lines marked on its sidewalls? If it does, do they run parallel to the rim? If no, then try re-seating the tyre, but if yes then (potentially) faulty (or just really cheap) tyre.
HTH
"42"
tim-b
Posts: 2106
Joined: 10 Oct 2009, 8:20am

Re: Tyre shape

Post by tim-b »

Hi

+1, check that it's seated properly
With the tyre fitted and with a little air in the inner tube, push the valve towards the outside of the wheel, i.e. inside the tyre. The tyre bead can otherwise rest on the base of the valve rather than in the well of the rim where it should be

Video here http://bike.michelin.co.uk/advice/how-to-fit-video/fitting-road-tyres-with-inner-tubes

Regards
tim-b
~~~~¯\(ツ)/¯~~~~
PT1029
Posts: 1751
Joined: 16 Apr 2012, 9:20pm

Re: Tyre shape

Post by PT1029 »

Also check the rim tape is centred inside the rim. Sometimes if the rim tape is off centre, the extra friction (when inflating the tyre) stops the tyre bead from sliding up out of the central well of the rim onto the space on the rim where it is meant to sit. A bit of the tyre thus sits too low (which also allows another section of the tyre to sit too high if you are really unlucky). This is particularly true if you have thick black rubber rim tapes (usaully on cheaper bikes/wheels).
For this reason, I'm always weary of Schwalbe's instructions about using a rim tapes that fills the full width of the rim - I guess not a problem if the edge of the rim tape is thin enough.
Re other answers, budget tyres usually are really hard/impossible to seat evenly on the rim.
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