Tyre loses pressure over time

[mike_bike_kite]

I have the tyre on my 16S inflated to around 38psi. Unfortunately over a 2 week period it will slowly deflate to around 25psi. Usually I only notice it's low just as I need to get somewhere in a rush. There isn't any obvious leak. I tried using inner tube sealant and it seems to have lessened the problem a bit but it hasn't really stopped the air from gradually leaking. Is there anything I can do?

[Wild Caribou]

Have a look at the valve. You may have a slow leak coming from the valve core if you don't have a puncture in your tube.

[Circuitmage]

I had the same problem on my 16S.

I would definitely say use the green goop, overall. However, I suspect that what happened on mine, and possibly yours, is the green goo got in your valve stem, causing an incomplete seal. I would say it's worth trying to fix if you can, as a well sealed tube is soooo much more fun to have.

In my experience it is one of 3 things; 1) A small puncture in your tube (green goo should fix that, but maybe not). 2) A bad seal around the valve stem on the tube outside (I have not had that on any EUC tubes), 3) a valve stem leak.

If you have a tool to remove the valve stem (often on the back of metal caps), it might be worth a shot to remove, clean/replace. Otherwise it may be the tube itself.

I also wonder if the valve stem on the 16S is really not rated for bigger people. I am around 200#, so maybe I was just forcing the air out!

As a side note: My 18L seems to NEVER leak air...which is just unspeakably awesome.

 

Edited August 4, 2020 by Circuitmage

[mike_bike_kite]

1 hour ago, Circuitmage said:

I also wonder if the valve stem on the 16S is really not rated for bigger people. I am around 200#, so maybe I was just forcing the air out!

I wondered if it was that as well. I'm just under 200#. I wondered if there was an alternative heavy duty inner tube I could use.

[newbie101]

My Mten 3 has the same problem since I got it, I have less than 100 miles..ewheels told me to try slime/armor-dilloz, I did..still leaking slowly. My Mten3 has tubeless tires.

I do not know what to look for around the valve core?

[mrelwood]

It has been suggested that the cheap factory install tubes themselves seep air out slowly through the rubber. And based on how common this is on EUCs, it does seem probable. I’m used to checking the pressure every few weeks or so, wether my current tire seeps out air or not.

 One thing that’s rarely mentioned but which I think one should do after installing the tire sealant, is clean the inside of the valve core before screwing the valve core back in. Sealants include tiny rubber crumblings, and having some left in the seal between the valve core and the valve is a potential slow leak issue.

[mike_bike_kite]

I guess I can carefully place the wheel in a bath until the valve is covered and see if any bubbles come out but, if I'm only losing 5psi a week, will I actually notice any bubbles?

I don't see any green goo around the valve at all. I can remove the valve stem on a tyre without slime inside it but how do you go about it when there is sealant inside?

Do you just let the pressure out real slow until empty and then remove the stem?

Will the slime solidify while I'm doing this or can I just put the valve core back on and then refill with air?

Are there any heavy duty inner tubes available for the 16S?

[DjPanJan]

Can confirm SLIME completly clogged valve. And i canot tale valve core out. I had to use pliers and a steel needle to loosen and get out.

Results slime "explosion"was 40 PSI  into my face and tshirt lesion learned nextime i take protection or  sunglases. 

I found problem when : The tire did not leak but could not be blown or deflated.

 

[null]

My 16S as well for what its worth, in spite of slime.
I cleaned the valve too (also inside), interested in what can be done other than replace the tube.

Edited August 5, 2020 by null

[Nic]

7 hours ago, mike_bike_kite said:

I guess I can carefully place the wheel in a bath until the valve is covered and see if any bubbles come out but, if I'm only losing 5psi a week, will I actually notice any bubbles?

Remove the inner tube, inflate to expand the tube and hold under water and look for slow formation of bubbles. You will find the problem, but you need to remove the tube to properly check it and repair any problem.

[mrelwood]

6 hours ago, DjPanJan said:

Can confirm SLIME completly clogged valve.

Sounds like the valve stem was filled with Slime when you installed the valve core, since the Slime does not reach or enter the valve stem after a proper install. Seeing that it could happen has made me always clean the valve stem before installing the core. Now I'm glad I did.

 

6 hours ago, mike_bike_kite said:

if I'm only losing 5psi a week, will I actually notice any bubbles?

I don't think you will.

6 hours ago, mike_bike_kite said:

I can remove the valve stem on a tyre without slime inside it but how do you go about it when there is sealant inside?

I let the sealant collect up on the opposite side of the valve, and then turn the wheel on it's side. That way any sealant won't come out even if I squeeze the tube as I empty it. 

6 hours ago, mike_bike_kite said:

Will the slime solidify while I'm doing this or can I just put the valve core back on and then refill with air?

It will not solidify until pressure makes it pass a tiny hole.

 

[Daley1]

My Ks 16s has always dropped psi.Every couple of weeks it go,s from 40 psi to about 30 psi.Its not a hole or leak.It doesnt seem to drop more than this.Dont stuff around trying to fix it ,just buy a small compressor for the garage and top it up every couple weeks.You can play with the pressures and change the experience to see what suits best!Try pumping it up to 50 psi for some extra fun,its like dancing with a 3 legged spider trying to bite u!

[Circuitmage]

On 8/5/2020 at 4:32 AM, DjPanJan said:

Can confirm SLIME completly clogged valve. And i canot tale valve core out. I had to use pliers and a steel needle to loosen and get out.

Results slime "explosion"was 40 PSI  into my face and tshirt lesion learned nextime i take protection or  sunglases. 

I found problem when : The tire did not leak but could not be blown or deflated.

 

OMG, that would have made an awesome Youtube Video.