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Tyre Pressure on SIP tubeless rims

Technical help for Series one, two and three Lambrettas. Models include the Li, Li Special, TV, SX, GP, Serveta and API/SIL models

Re: Tyre Pressure on SIP tubeless rims

Postby nickw » Wed Jul 15, 2020 8:40 pm

69GP225 wrote:
I haven’t seen a tubeless Sip rim lose pressure yet so it’s a first. Could it be that not much pressure had been pumped to seal it and movement of the bike and weight and impacted the integrity of the bead?



Whilst riding up the mountains near Rapello following the Italian Euro my tyre came off the SIP rim. I had my girlfriend on the back. Thankfully because we were behind traffic and going up hill it wasn't too bad. I could only think I hadn't inflated tyre hard enough. Never thought more about it until I read this
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Re: Tyre Pressure on SIP tubeless rims

Postby 69GP225 » Wed Jul 15, 2020 10:27 pm

Thanks for comments,

Sash in lowestoft resolved the issue and re-inflated the tyre.
After inspection the o-ring in the valve was the wrong size
So always check you SIP rims for leaks with water just like
You do with checking an inner tube. Valve was leaking air.
The rim was new and unused.

I’m guessing it lost pressure during the past month and was
Too flat. It then came off the rim because it was under pressured.

Be careful out there I was lucky.

Lee
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Re: Tyre Pressure on SIP tubeless rims

Postby Linford Li » Sat Aug 08, 2020 2:03 pm

Hi all my tubeless rims are also losing air so about this o ring do i have to take the tyre off to get to the valve, or can you do it by just deflating the tyre and getting to it that way and one last question where do you get the o ring from.Thanks Paul its my first post after just joining.
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Re: Tyre Pressure on SIP tubeless rims

Postby missing lynx » Sat Aug 08, 2020 2:32 pm

I presume the o ring is the one behind the value holder. All you have to do is let the air out the tyre then unscrew the value holder and the o ring is there as for what size it is I'm not sure. I would check the value it self I had one that wouldn't seat properly changed it for another one and it was fine
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Re: Tyre Pressure on SIP tubeless rims

Postby rossclark » Mon Aug 10, 2020 12:16 am

The valve thread is fine and very easily damaged - take care when removing / replacing the valves or you scrap your rims.

I have one set with a rim leak after the third tire - they're very soft alloy and it doesn't take much ...

I'm honestly starting to question whether the supposed safety advantage is out weighed by the hassle of -

a) finding somewhere that will try to fit tires more than once
b) putting up with the leaks
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Re: Tyre Pressure on SIP tubeless rims

Postby coaster » Mon Aug 10, 2020 8:04 am

No harm in putting slime in your tubless rims if you are experiencing leaky rims. Alloy rims leak on cars too and I have used a can of emergency tyre inflator on numerous occations.
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Re: Tyre Pressure on SIP tubeless rims

Postby rossclark » Tue Aug 11, 2020 10:13 pm

I did try to get slime in ONCE ...

I ended up with it all over the place and more of it outside the tire than in the valve and tine hole inside on SIP rims make it very hard to get it in ( oooer)
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Re: Tyre Pressure on SIP tubeless rims

Postby Loneranger » Thu Aug 27, 2020 2:38 pm

Just for info, I had a valve fracture on a rear SIP rim last year.
Tyres were fine when I put the scooter away but when I went to take the scooter out next time, rear tyre was very flat!

Went to pump it up and as I fitted the pump to the valve, the valve came away. It had fractured level with the surface of the rim. How or why, I have no idea.
I managed to extract the remaining piece of valve with suitable extractor tool and a new valve obtained and fitted.

Moral of the story: always check your bolt-in valves carefully.

Ride safe.

Ady
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Re: Tyre Pressure on SIP tubeless rims

Postby Linford Li » Tue Oct 06, 2020 4:27 pm

Just to let everyone know had the valve cores checked and both was not tightened up so just worth a check before taking off the valve altogether.
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Re: Tyre Pressure on SIP tubeless rims

Postby coaster » Tue Oct 06, 2020 5:24 pm

Linford Li wrote:Hi all my tubeless rims are also losing air so about this o ring do i have to take the tyre off to get to the valve, or can you do it by just deflating the tyre and getting to it that way and one last question where do you get the o ring from.Thanks Paul its my first post after just joining.


Maplin used to sell sets of o tings covering all popular sizes in a plastc box. You shouyld be avle to fing something similat on ebay for not very much, always usefull to have in the shed 8-)
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