Strange problem with tube in R460 rim

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jessand
Posts: 51
Joined: 6 Dec 2009, 7:50pm

Strange problem with tube in R460 rim

Postby jessand » 11 Aug 2019, 5:10pm

Had a puncture the other day and when I took the tube out I found that it had ripped near the valve. On closer inspection I realised that the tube had been pushed into the valve hole causing a shoulder to appear - this is where the tube had split. The hole in the top of the rim is big enough to put a schraeder valve in although the hole on the underside isn't. The rim is DT R460 which is tubeless ready, is this why the top valve hole is so big? Pic shows the shoulder that has formed on the tube. I'm obviously concerned that this will happen again. The tube is a decent quality Schwalbe SV by the way. Any suggestions on preventing this?


Tube.jpeg

colin54
Posts: 1053
Joined: 24 Sep 2013, 4:34pm

Re: Strange problem with tube in R460 rim

Postby colin54 » 11 Aug 2019, 5:26pm


pwa
Posts: 9876
Joined: 2 Oct 2011, 8:55pm

Re: Strange problem with tube in R460 rim

Postby pwa » 11 Aug 2019, 5:29pm

Yes, wot he said.

Brucey
Posts: 34868
Joined: 4 Jan 2012, 6:25pm

Re: Strange problem with tube in R460 rim

Postby Brucey » 11 Aug 2019, 6:32pm

as a kludge fix (which works surprisingly well) you can fit a locknut to the base of the valve stem before fitting the tube to the rim. Schwalbe locknuts have a ridge machined on them which means that they locate in the larger hole quite nicely.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

jessand
Posts: 51
Joined: 6 Dec 2009, 7:50pm

Re: Strange problem with tube in R460 rim

Postby jessand » 11 Aug 2019, 7:05pm

Thanks all.
Am I right in thinking the hole is larger to accommodate a tubeless valve?

Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: Strange problem with tube in R460 rim

Postby Brucey » 11 Aug 2019, 9:53pm

jessand wrote:Thanks all.
Am I right in thinking the hole is larger to accommodate a tubeless valve?


Maybe; however many rims were (badly) made like that before tubeless was a thing for road bikes. Oftentimes a stronger than average rim tape protects the base of the valve to some extent, but there is no doubt that the valve itself is best supported by a close-fitting metal collar. If you look closely the valve stem will have a small ridge at the base; this will allow full support of the valve provided the collar is a close fit.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

jessand
Posts: 51
Joined: 6 Dec 2009, 7:50pm

Re: Strange problem with tube in R460 rim

Postby jessand » 12 Aug 2019, 9:40am

Thanks Brucey,

I'm using 'plastic' rim tape - Schwalbe I think. I'll fit the locknut as suggested. I bought the R460s as folk said the were easy to fit tyres to but I struggle with them and Michelin Pro 4 SC, not helped by geriatric hands! :(

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NATURAL ANKLING
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Joined: 24 Oct 2012, 10:43pm
Location: English Riviera

Re: Strange problem with tube in R460 rim

Postby NATURAL ANKLING » 12 Aug 2019, 11:41am

Hi,
Always check for burrs on any valve hole.
Even with the correct hole size on Presta valves I Like others here make a washer from an old innertube in place that over the valve before fitting.
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MikeDee
Posts: 572
Joined: 11 Dec 2014, 8:36pm

Re: Strange problem with tube in R460 rim

Postby MikeDee » 12 Aug 2019, 3:36pm

jessand wrote:Thanks all.
Am I right in thinking the hole is larger to accommodate a tubeless valve?


Do tubeless valves need a larger hole? I don't think they do.