New tubeless rims (is this normal)

[fraz101]

Finally got round the setting up my new wheels.

Got them seated using just a track pump,however where the rim is sealed together on both wheels I had a leak straight away before pouring in sealant.

Decided to go ahead and inject sealant and see. Still leaked for a good while on both wheels. First wheel eventually sealed but noticed this (unsure of normal)

2nd wheel I had to break bead and pour sealant directly between wheel and tyre where it was leaking to get to seal.

Thoughts on this ?

 

[geocycle]

Might be just the light but is the rim deformed above the joint?

 

[fraz101]

Might be just the light but is the rim deformed above the joint?

Just the light

2 hours inflated and seem to be holding pressure ok now.

 

[Ian H]

If air is getting out there is a hole.
If there is a hole then the weld is incomplete.
If the weld is incomplete in one part, what is the weld like elsewhere?
If the weld is imperfect the weld might fail.
If the weld fails the wheel might collapse.
If the wheel collapses......
YMMV.

Once the wheel is built it's all held together quite safely.

 

[Jody]

My initial thought is there must be a gap or break somewhere in the rim tape. If the tape covered the rim bed sufficiently and the tyre is in contact with the tape then air/sealant shouldn't be able to get by and out via the joint.

Also seems weird that it hasn't come out of a spoke hole first.

 

[C R]

Once the wheel is built it's all held together quite safely.

Even if the rim seam weld fails?

 

[Ian H]

Even if the rim seam weld fails?

The joint is under compression.

 

[T4tomo]

you could theoretically saw the rim into 4 pieces (other numbers exist) if spokes are all correctly tensioned and still ride it

(provided you didn't puncture the tube as you sawed the rim).

 

[C R]

you could theoretically saw the rim into 4 pieces (other numbers exist) if spokes are all correctly tensioned and still ride it

(provided you didn't puncture the tube as you sawed the rim).

That would only be safe if there were no lateral forces that would make the rim sections slide with respect to each other. Might make corners interesting.

 

[fossyant]

Wait till your tyres start 'seeping ' goo - another 'issue'.

I'll stick with tubes.

 

[fraz101]

Got a reply from Dave at DCR who thoroughly explains what is happening, completely normal on first install. See below


Yes, so you have the Kinlin XR-26RTS rim. So it isn't a welded rim. It has what is called a sleeve joint - far better than a pin joint and is popular on a large number of higher end rims but generally (although not all for reasons that I can go into, a lot of it is driven by factory tooling) most are not also welded (welded rims are generally also sleeve joint rims). Pinned is undoubtedly the low end option and sleeve higher end. However, where you have a sleeve and an actual seamed joint which is naturally, always, not airtight. The sealant is always going to be required to fill the air gap here - some sealants do this better than others and part of the challenge is liquid latex is intended for filling rubbery holes not holes in metal. I've never known one not heal or open up again though as the gap is very small - far far smaller than the sealant is designed to heal. As a point of interest, this is generally the direction of tubeless - so the tubeless ready standards tend to remove the butyl liners now - so once upon a time you used to fit a UST tyre for example on a rim with no holes, with a welded joint and an airtight valve and essentially the whole thing would hold air without sealant. They realised this was a needlessly heavy system with higher rolling resistance and better to have a lightly porous tyre which had its tiny holes sealed with sealant.

Anyway, bottom line is there is nothing to worry about. The joint won't consistently leak - only with the first setup.

Kind regards,

David

 

[fraz101]

Ok so I have a new issue with this wheel set.

They are holding pressure perfectly fine and have done around 200 miles on them.

But what I have noticed is,sometimes (not always) when I attach my track pump to check pressures, I have a small 3-4 second leak of air through a spoke nipple, happens on both wheels……doesn’t deflate the tyre and once I pump up tyre and detach the pump they hold pressure fine…..

 

[geocycle]

I replied thinking you were talking about air escaping from the valves. Sealant can escape when they get sealant dried around the valve core. But then I re-read and you said spoke holes which I can’t understand I’m afraid.

 

[Dogtrousers]

If air is getting through spoke holes doesn't that suggest something wrong with the taping of the rim, not the rim itself?

 

[C R]

If air is getting through spoke holes doesn't that suggest something wrong with the taping of the rim, not the rim itself?

Could it be that the valve is moving and disturbing the tape? Where are the spokes that leak in relation to the valve?