Tubular Repair

Everything about building wheels, glueing tubs, etc.
urbanspaceman
Posts: 15
Joined: Thu May 25, 2017 7:05 pm

by urbanspaceman

Thanks sungod - very grateful.


Was looking for some advice as I noticed that a chunk had been taken out of one of my tubs (see below).

I've absolutely no idea how it happened, and have now replaced it, but I'm curious as to how it happened so it hopefully never happens again.

Does anyone have any thoughts at all?

Image

sungod
Posts: 1538
Joined: Fri Dec 24, 2010 9:37 pm
Location: it's raining, it must be uk

by sungod

i've had that a couple of times with a momentary lock-up of the wheel, both times it happened when braking hard and then hitting a patch of grit/dirt on the road

urbanspaceman
Posts: 15
Joined: Thu May 25, 2017 7:05 pm

by urbanspaceman

Brilliant thanks mate

Sleepless
Posts: 223
Joined: Sun Feb 23, 2014 7:58 pm
Location: Istanbul, TR

by Sleepless

In last 2 days, my rear Veloflex Roubaix tire lose air after hard descends. I thought it was a puncture on the first time and used Vittoria Pitstop but it went flat in like 20 minutes again. Luckily I've arrived home at that time. I tightened valve extender and shook the tire a bit and it was back to normal. Today it happened again. There seems to be no puncture as there's no sealant leak visible. Any ideas?

sungod
Posts: 1538
Joined: Fri Dec 24, 2010 9:37 pm
Location: it's raining, it must be uk

by sungod

i never found pitstop any use as all

have you tried putting a bit of ptfe tape on the threads of the extender?

now that you have sealant in the tube, you need to work very fast once it is deflated as otherwise the tube may stick to itself and then tear apart when re-inflated

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dj97223
Posts: 663
Joined: Sun Nov 06, 2005 7:27 pm

by dj97223

I've had good experience with PitStop but, like other sealants, it won't fix everything. And I haven't had the dreaded tube sticking to itself. You could try a little orange seal, but first try to locate the source of the leak (inflate and dip in a shallow tub of water) to see whether the problem is the tire or the valve.
“If you save your breath I feel a man like you can manage it. And if you don't manage it, you'll die. Only slowly, very slowly, old friend.”

1415chris
Posts: 1076
Joined: Sat Apr 18, 2009 8:59 am
Location: Surrey UK

by 1415chris

Very tiny puncture, when the air is leaking slowly from the tub, may not give you obvious sings.
I had one in Veloflex Carbon. Even with the sealant it re-opened itself on one or two occasions after the period when the tubs were not in use.
If you use valve extenders with removable core (if not, strongly recommend start using) you have more chance with normal sealant like No-tubes, Orange (have a good experience with both) than with the Pitstop (applied twice, failed twice). In the era of Co2 pumps there is no advantage of having sealant in pressurized canister, especially if its effectiveness is very questionable.

Sleepless
Posts: 223
Joined: Sun Feb 23, 2014 7:58 pm
Location: Istanbul, TR

by Sleepless

Thank you guys. I was on holiday so couldn't do more than just pumping. I'm back home now. I'll investigate and report back.

sungod
Posts: 1538
Joined: Fri Dec 24, 2010 9:37 pm
Location: it's raining, it must be uk

by sungod

btw another thing i've seen... when sealant gets in a presta valve, it can actually clog it so that it does not close fully unless manually tightened

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dj97223
Posts: 663
Joined: Sun Nov 06, 2005 7:27 pm

by dj97223

Yes, Orange Seal can do a number on the valves and cores, and I suspect other sealants can cause the same problem. I think the clogging can be largely avoided by storing the wheels with the valves sitting at 4:00 or 8:00.
“If you save your breath I feel a man like you can manage it. And if you don't manage it, you'll die. Only slowly, very slowly, old friend.”

Sleepless
Posts: 223
Joined: Sun Feb 23, 2014 7:58 pm
Location: Istanbul, TR

by Sleepless

Yep, it's the valve. I removed and cleaned it. So far so good.

sabba
Posts: 8
Joined: Mon Feb 20, 2017 4:14 pm

by sabba

man just when i though i have tubeless tires maintenance under control you learn something new.

i have this happen to me recently too. thanks

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MikeMoore
Posts: 76
Joined: Mon Jul 27, 2015 2:19 pm
Location: Midlands, UK
Contact:

by MikeMoore

Just bought a pair of cross tubs that had been stored flat with sealant in. Of course one blew up when I tried to inflate it. As they only cost me £20 I thought it was a good opportunity to try and repair it by replacing the tube (http://www.sheldonbrown.com/brandt/tubular-repair.html).

A massive ball ache, but I managed it! Lots and lots of talcum powder seems to be the key :)
Weight 72kg, FTP 289W => 4.01 W/kg

Custom ti 650B Kingdom Double9 (with tubs)
Kinesis Aithein
Kinesis Racelight 4S "Rain Bike"
Ventana El Conquistador

bcmf
Posts: 63
Joined: Fri May 22, 2009 5:00 pm

by bcmf

Anyone ever have a valve stem come clean out of a tube?
Have a Conti comp with loads of thread left and very few nicks in it and the valve starting turning when trying to inflate it and the whole valve stem/neck came clean out of the tube.
Be a real shame to bin it!

sungod
Posts: 1538
Joined: Fri Dec 24, 2010 9:37 pm
Location: it's raining, it must be uk

by sungod

you could fit a new inner tube, it's a bit fiddly but might be worthwhile if the tub is otherwise ok

of course you can use a latex tube too :)

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