Yet Another Cycling Forum
General Category => The Knowledge => Topic started by: robgul on 10 July, 2013, 07:53:57 pm
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My Dahon folder is fitted with Schwalbe Kojak 20 x 1.35 (35 - 406) tyres - bought new and ridden less than 25 miles (with new correct size Presta valve tubes) .. The bike lives, folded up, in the back of my car.
Both front and rear tyres have a "flat spot" - one is opposite the valve, the other is at about 3 o'clock from the valve. I've checked that the beads are seated and tubes aren't pinched etc - pumped them up to correct pressure and let them down again several times.
Spinning the wheel in the frame looks like an oval wheel - rims are OK - it's visible on the tyre casing.
I get a sort of "rolling undulation" ride caused by the flat spots.
All ideas why welcome please . . . .
Rob
Edit - I should add that the tyres I replaced (whatever came with the machine) were fine - I changed to the Kojaks as they are supposed to be a bit quicker
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Poor tyre construction.
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Been a lot of problems with Kojaks in the 17inch size used on Moulton AMs, and unfortunately they are the only tyre currently available in that size.
Return them to Schwalbe or your dealer.
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I've fitted the original tyres back on and all is well - albeit they don't roll as well - so, must be the tyres that are faulty.
Coincidentally one of my neighbours has a Dahon 20 inch and has just fitted some new Schwalbe, I think, Big Apple tyres are they're giving him the same undulating ride ... looks like Mr Schwalbe's 20" tyre making men are cocking it up?
... I'm awaiting a response from the Avon Cyclery emporium from whence my tyres were purchased
Rob
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Between us, barakta and I have an extensive collection of 20" tyres, mostly Schwalbe, and haven't encountered this. We did have a mysterious sidewall bulge on a not-very-used Marathon Plus at one point.
(The difference in rolling resistance between a set of M+ and Kojaks is impressive.)