Difficult tyre pumping

[alancube]

Cube EMTB with 29 x 2.6 Maxis tubeless tyres and the rear tyre very difficult (sometimes impossible) to pump? Decided the valve was blocked with sealant and have removed it, tyre goes down ok, cleaned valve and replaced it. Tyre pumped up ok but just before today's ride wanted to top it up and my pump, with a gauge on, goes full scale! Blocked again!
What's going wrong?

 

[whitymon]

I do not think this is related to the valve.

When you put sealant, you need to spin the wheel, personally the wheel is off bike and I smash the floor with the wheel nearly horizontal with turning the wheel etc. This place sealant all over it.

Still if you place too much sealant and for example the bike is horizontal down, and the valve is down too then the sealant will locate itself over there and it can stick to the valve.

Each ride I would recommend you play with the valve too unscrew a little lite as you would inflate and push with your finger before, son air should flow out maybe not the first time so push several time - some sealant could come off, more if the valve is down and there are still tons of liquide.

Never ever had any issue like you mentioned doing that.

That said, remember that first time tire and sealant, you can use an airshot compressor (like a big bottle - not anything electric), sometime it is pretty hard to place everything in place correctly.

 

[alancube]

Thanks for your response! Tyres and sealant have been fitted for several months and the problem has only recently occurred.
I think I shall try and park the bike (it hangs up) so the valves are at the bottom so shouldn't fill with sealant?

 

[Bones]

I always put vaseline on the valve core. Not for any particular reason apart from the fact that I have a tub of it!
Anyway it does a reasonable job of keeping the valve core in working order.

 

[timo2824]

My specialized bike pump from 2010 does this sometimes. The part that clips onto the Schrader/Presta valves has a rubber seal in it that's gotten old and hard. More often with Schrader valves, but it doesn't fully depress the core so you build up air pressure until it pushes it's way past the valve. You can get new ends for them, I just haven't gotten around to ordering one yet.

 

[Bndit]

Cube EMTB with 29 x 2.6 Maxis tubeless tyres and the rear tyre very difficult (sometimes impossible) to pump? Decided the valve was blocked with sealant and have removed it, tyre goes down ok, cleaned valve and replaced it. Tyre pumped up ok but just before today's ride wanted to top it up and my pump, with a gauge on, goes full scale! Blocked again!
What's going wrong?

Change the pump

 

[RustyIron]

Cube EMTB with 29 x 2.6 Maxis tubeless tyres and the rear tyre very difficult (sometimes impossible) to pump? Decided the valve was blocked with sealant and have removed it, tyre goes down ok, cleaned valve and replaced it. Tyre pumped up ok but just before today's ride wanted to top it up and my pump, with a gauge on, goes full scale! Blocked again!
What's going wrong?

The problem is that you don't have Fillmore valves.
Order from Amazon now, and your problem will be solved by your next ride.

 

[alancube]

Hadn't heard of Fillmore valves but not cheap! Although I can see how they would solve the problem.

 

[James_C]

I've had this loads. Stick a new valve core in, and press the valve a few times to free it before pumping.

 

[alancube]

Freed and cleaned them yesterday put back and working well but will get a couple of spare valves as I don't have any.

 

[irie]

The problem is that you don't have Fillmore valves.
Order from Amazon now, and your problem will be solved by your next ride.

Or maybe not solved

Bye-bye Fillmore valves

As said here: What did you buy your ebike this week? Bought four new Presta valves. Why? Changed four tyres and at same time fitted Fillmore valves. Clogged up several times while injecting Muc-Off tubeless sealant, probably due to Muc-Off sealant particle size. After fitting Fillmore valves...

www.emtbforums.com

 

[steve_sordy]

Get into the habit of parking your bike with the valves either side of the bottom. Give gravity some assistance to help any sealant to flow away from the valve. If the valve is at the very bottom, a drip will form and set. It will not stop the problem from occurring, but it will delay it.

 

[Stihldog]

I’ve switched over to Filmore valves on all my bike tires. They suggest adding sealant through the valve with a syringe and clear tube. This doesn’t work with some sealants.(chunky, particles or very thick). I now release one bead and add sealant directly into the tire.

On a typical or conventional presta valve a blob or colliflower looking mass can develop around the smallish air holes of a presta valve. This can prevent adding psi or worse, releasing psi.

Replacing valve cores each time you install a new tire is a good idea. Those are cheap. I keep about 1/2 dozen in the bike cave as spares.

A Filmore valve has no value core that can slowly leak air or fail. Instead it uses a round plunger seal. (I don’t know the correct term). The problem is adding chunky sealant, with a syringe method, through this type of valve.

There can be a problem when you use a CushCore and Filmore valve. Simply make room for the plunger to function properly by removing a small amount of CushCore at that point.

Adding or reducing psi is easy now …and it can be months before I need to add psi.

 

[Mikerb]

I think you can suffer a repeat of the presta valve insert not working well once it has clogged despite cleaning it. i suspect the reason is that when the insert gets clogged with sealant, the place it sits in the valve stem can also have semi solidified sealant on it. I am usually carefull to park my bikes with the valves at 3 or 9 oclock but if I do get one clogged up I remove and clean it but then also use a pipe cleaner to dislodge and sealant that may be stuck in the stem. Seems to work!!

 

[alancube]

The bike hangs up and when passing it in the garage I will sometimes give the wheels a spin to distribute the sealant. However this might not be a good idea? I also have the valves at 3 or 9 o'clock position to see if there's any improvement.

 

[Streddaz]

Another tip is to always have your valve at the top when letting air out or inflating to reduce chance of sealant entering the valve.

 

[irie]

Always park our bikes with valves at either 4 or 8 o'clock, only occasionally had Presta valves clog up (use Muc-Off sealant) and if they do simply remove and put in a new valve. They're very cheap.

If they do clog up just run a pipe cleaner through the valve body before replacing the valve. Get packs of long white pipe cleaners from Hobbycraft. Also use them to clean around fork seals when using WPL Forkboost.

Buy White Pipe Cleaners 100 Pack for GBP 2.00 | Hobbycraft UK

Buy White Pipe Cleaners 100 Pack at Hobbycraft UK.

www.hobbycraft.co.uk

 

[Bndit]

I have never had problems with presta valves. I mainly use Stan's sealant, but in one bike I have Panzer because bottle came with inserts. I don't know what sealent Trek and Santa Cruz used from factory but hadn't any problems with those either. Lot's of pumping and pressure adjusting, no issues.

 

[Mikerb]

Always park our bikes with valves at either 4 or 8 o'clock, only occasionally had Presta valves clog up (use Muc-Off sealant) and if they do simply remove and put in a new valve. They're very cheap.

If they do clog up just run a pipe cleaner through the valve body before replacing the valve. Get packs of long white pipe cleaners from Hobbycraft. Also use them to clean around fork seals when using WPL Forkboost.

Buy White Pipe Cleaners 100 Pack for GBP 2.00 | Hobbycraft UK

Buy White Pipe Cleaners 100 Pack at Hobbycraft UK.

www.hobbycraft.co.uk

I smoke a pipe so always have pipe cleaners handy! I also use them to clean pivot bearing spacers........everytime I clean the bike I use a stiff brush to clean those areas, the I drip some oil on each pivot bearing area and then use pipe cleaners to clean 360 degrees. Obviously the only part of the pivot assembly that is visible/accessible are the spacers but it is from there that mud and grit can migrate to the bearing seal.

 

[irie]

I have never had problems with presta valves. I mainly use Stan's sealant, but in one bike I have Panzer because bottle came with inserts. I don't know what sealent Trek and Santa Cruz used from factory but hadn't any problems with those either. Lot's of pumping and pressure adjusting, no issues.

Looks like the issue is caused by the larger particle size of Muc-Off tubeless sealant, Stans sealant doesn't seem to be a problem.