tubeless slow leak

[lazlokovacs]

Hi guys,

converted my Lemans 1000 front wheel to running tubeless a while back... bike is back in daily use now... (can't exactly remember how I did the conversion, but probably would have been in line with advice from this board! used a tubeless valve and some silicon i think)

anyway, front tire is losing between 1 and 2 psi every coupla days...

tried the soapy water trick, but no bubbles anywhere, checked round the valve and all round the rims too...

any thoughts?

[jlburgess]

Maybe take the wheel off and put it in a wheelbarrow full of clear water so you can see it?  That's a pretty slow leak.  That's the way I used to find them when I worked at a tire store years ago.

[Chuck in Indiana]

As mentioned above, that's a really hard leak to find. I had one like that on the Monza, and eventually pulled the tire off, *really* cleaned the bead area, and it's been fine since.

[fotoguzzi]

Maybe over inflate tire, would the leak be easier to detect?

[slopokes]

Inflate the tire to fourteen lbs over normal tire pressure..now u r good for two weeks🤓

[lazlokovacs]

I'm pretty sure it's coming from the stem... wrapped some silicon tape around the bottom of the thread and tightened er back up and I'll just keep monitoring over the next few days

cheers for input

[Diploman]

You could put in a dose of tire sealant (Slime, etc.) to seal the leak.   There is a reasonable chance, IMO, that this could cure the problem.

[Sheepdog]

Try reseating (or replacing) the valve stem core.

[pehayes]

My SPII had a similar slow leak.  Removed the tire to find a rough condition on the face of the rubber bead.  Using a Scotch Pad I scrubbed the tire edge and the rim edge.  Now holds for a pound over two months.

Patrick Hayes
Fremont CA

[Old Jock]

Maybe take the wheel off and put it in a wheelbarrow full of clear water so you can see it?  That's a pretty slow leak.  That's the way I used to find them when I worked at a tire store years ago.

Found one on the LM 1000 that way, well I cleaned the wheel and then used the bath, dunked the wheel partially in and then slowly turned it every couple of minutes.

No way soapy water would work.

Mine was around the valve stem, resulted in one small bubble about every 30 seconds or so, easy to do and not much disassembly required.

I had that leak a year before I got so sick of it and decided to hunt it down, kicking myself that I put up with it and didn't do it earlier

[Huzo]

I'm pretty sure it's coming from the stem... wrapped some silicon tape around the bottom of the thread and tightened er back up and I'll just keep monitoring over the next few days

cheers for input

Again...
Put it under water, that'll show you in 5 seconds.
Where's the mystery ?

[Huzo]

Found one on the LM 1000 that way, well I cleaned the wheel and then used the bath, dunked the wheel partially in and then slowly turned it every couple of minutes.

No way soapy water would work.

Mine was around the valve stem, resulted in one small bubble about every 30 seconds or so, easy to do and not much disassembly required.

I had that leak a year before I got so sick of it and decided to hunt it down, kicking myself that I put up with it and didn't do it earlier

If it was one of your bikes, I'd make sure it was distilled water.
Stuff outta' the tap is too dirty, only fit for drinking...!

[Kiwi_Roy]

Use one of those plastic flower boxes, plug up the holes then lift the wheel just off the ground.
work the box under the wheel and fill it with water, you will see the slowest leak.

I found that some silicones don't stick well to the rim. the best one I found was a general purpose in a small squeeze tube.

[lazlokovacs]

Again...
Put it under water, that'll show you in 5 seconds.
Where's the mystery ?

Uhh mystery? bike's in a friends garage, and I don't have the opportunity to remove the wheel or do much beyond a remedial fix right now. So I'm making an educated guess that its leaking round the valve...

I guess that's the mystery element?

Thanks for your input

[lazlokovacs]

/\
/\

thanks for the helpful tips guys,

really grateful as usual

 

[Wayne Orwig]

This will fix it

http://www.mgcycle.com/index.php?main_page=product_info&cPath=218&products_id=4886

[Kiwi_Roy]

Uhh mystery? bike's in a friends garage, and I don't have the opportunity to remove the wheel or do much beyond a remedial fix right now. So I'm making an educated guess that its leaking round the valve...

I guess that's the mystery element?

Thanks for your input

Your friend is letting the air out, has he suggested you sell the bike to him LOL

[Groover]

Isn't the Le Mans 1000 wheel tubeless already? Either way, I would replace the inner valve as a starting point and since it's the easiest.

[Kiwi_Roy]

Isn't the Le Mans 1000 wheel tubeless already? Either way, I would replace the inner valve as a starting point and since it's the easiest.

No, find out where it's leaking first, replacing the stem is a tire off or at least break the bead job, typically the stem is inserted from the tire side.

[Chuck in Indiana]

I'm telling you.. a leak of one pound ever two days is impossible (for me) to find. BTDT. <shrug> The most likely cause is either a valve core or a leak at the bead. I'd put a new valve core in it and if that didn't cure it, pull the tire off and really clean that bead area. I'd probably put a new valve stem it it while I was there.. really slow leaks like that can drive you to drink. 

[Ncdan]

Put a tube in it and forget it.

[MMRanch]

Tire sealer & blancer ( slime )  the Green stuf

[mtiberio]

I have seen where the rubber casting threads (little rubber hairs sticking out of the tire) in the bead area are enough to give the air a slow path out. I used to be a big advocate of tubeless conversions. I have no issues with the lack of safety bead as far as safety (tire jumping off rim) goes. What I have been hearing lately from the dirt bike crowd which do a lot of tube to tubeless conversions with non-safety profile rims is, that the safety lip built into the inside of the bead seating area besides making it more difficult for the tire bead to unseat, also adds sealing area (because the metal wraps around the bead more) which could help stop slow leaks.

[Groover]

No, find out where it's leaking first, replacing the stem is a tire off or at least break the bead job, typically the stem is inserted from the tire side.

I used the wrong term. Chuck in Indiana called it valve core, which is what I meant when I said inner valve. You can take the valve cap off and rubberband a tiny balloon to it and let it sit and see if in inflates over a few days.... that's a brand new trick off the top of my head, right off the press here today!

As far as the valve seat goes, I brushed some of this on last time where the valve meets the rim (that is if replacing the valve) It's a sticky thin rubber glue type thing.

https://www.napaonline.com/en/p/BK_7101204

[MMRanch]

  Yea

  8 oz's  of green slime while the valve core is out = problem gone for the life of the tire.   There is a wash job when its "New-tire time" ... 

[lazlokovacs]

thanks for all the further replies guys...

While you all were typing, me and the bike did over 500 miles today through some pretty gnarly weather.

Weirdly, the rear tyre, which is still tubed, is also losing a bit of pressure....

Anyway, front and rear both held up for the trip and I'll be investigating further next week when I'm back home with tools and workshop space.

[Kiwi_Roy]

Weirdly, the rear tyre, which is still tubed, is also losing a bit of pressure....

If you think it's hard finding a slow leak in a tubeless, it's harder with a tube because it can leak anywhere but it will come out at the valve stem, the tubeless can only come out where it's leaking.
Perhaps your rim is a bit corroded where the bead sits.
I was surprised how easy it was to get my 1972 Eldorado spoked wheels airtight, my friend who taught me how to do it has a 46 Indian converted to tubeless.

[mtiberio]

If you think it's hard finding a slow leak in a tubeless, it's harder with a tube because it can leak anywhere but it will come out at the valve stem, the tubeless can only come out where it's leaking.
Perhaps your rim is a bit corroded where the bead sits.
I was surprised how easy it was to get my 1972 Eldorado spoked wheels airtight, my friend who taught me how to do it has a 46 Indian converted to tubeless.

Please share your method.

[Kiwi_Roy]

I'm off to China on Monday, probably won't have time before then, I have a rear wheel to do so I'll document it here when I do.

[redrider90]

Maybe over inflate tire, would the leak be easier to detect?

80 PSI