Can't inflate Presta valve

Amouar

Hi,

I wanted to top up my bicycle tyres for the first time today using a KLS mini pump (Like this one) but I'm unable to get the pump to lock on the Presta valve in order to inflate it. The pump has an interchangeable head that fits both Presta and Schrader valves and a lock lever.

I tried the pump many times on my daughter's bike with Schrader valve and it locks and inflates the tyres perfectly.

When I change the pump's head to Presta and tried to inflate my bike's tyres, the pump wouldn't lock on the valve no matter how hard I tried and just keeps deflating the tyre.

Anyone has an idea on what's i'm doing wrong here?

Thanks!

TheBlaaMan

"Lock" might be when the lever is horizontal....... or or might be when the lever is vertical. Pumps differ

Try it the other way round, if you follow?

Amouar wrote: »

Hi,

I wanted to top up my bicycle tyres for the first time today using a KLS mini pump (Like this one) but I'm unable to get the pump to lock on the Presta valve in order to inflate it. The pump has an interchangeable head that fits both Presta and Schrader valves and a lock lever.

I tried the pump many times on my daughter's bike with Schrader valve and it locks and inflates the tyres perfectly.

When I change the pump's head to Presta and tried to inflate my bike's tyres, the pump wouldn't lock on the valve no matter how hard I tried and just keeps deflating the tyre.

Anyone has an idea on what's i'm doing wrong here?

Thanks!

Amouar

TheBlaaMan wrote: »

"Lock" might be when the lever is horizontal....... or or might be when the lever is vertical. Pumps differ

Try it the other way round, if you follow?

The lock in my pump is when the lever is vertical and i used it several times before to inflate my daughter's bike tyres.

Tigerandahalf

You need to loosen the top of the presta valve. Then push it down with your finger and air should come out. If it does it is ready to take the pump. You only need to loosen it one turn anti clockwise. That works for me anyway.

Zen0

Some pumps I’ve used in the past required you to reverse the rubber washer thingy in the bit that fits onto the valve when changing from schrader to presta.

Amouar

Zen0 wrote: »

Some pumps I’ve used in the past required you to reverse the rubber washer thingy in the bit that fits onto the valve when changing from schrader to presta.

That's exactly what I've done but the pump still doesn't lock on the valve

Duckjob

Is it possible you have deep rims and are using a tube with a standard length presta valve rather than the longer valve for deep rims?

I bought a tube with a standard length valve by mistake to use in my deep rim wheel and its a pain to inflate - I have to remove the valve nut at the bottom and even then the pump head can just about push open the valve to pump the air in.

ED E

Get C02 for the roadside and a track pump for at home. Mini pumps are obsolete now IMO.

C3PO

Is there a little rubber grommet that needs to be reversed under the head?

Amouar

C3PO wrote: »

Is there a little rubber grommet that needs to be reversed under the head?

Yes there is and I reversed it in the correct position but it still doesn't lock.

Fighting Tao

Maybe you said already and apologies if I missed if. Have you tried another pump?

TheBlaaMan

ED E wrote: »

Get C02 for the roadside and a track pump for at home. Mini pumps are obsolete now IMO.

Carry both, but don't use CO2 unless you really have no option. The last thing we should be using is anything that releases more C02 into the atmosphere. Mini pumps ftw

Brian?

TheBlaaMan wrote: »

Carry both, but don't use CO2 unless you really have no option. The last thing we should be using is anything that releases more C02 into the atmosphere. Mini pumps ftw

We probably produce more CO2 when breathing on a spin than one cartridge contains. You should stop breathing heavy if you’re that worried.

Brian?

Amouar wrote: »

Hi,

I wanted to top up my bicycle tyres for the first time today using a KLS mini pump (Like this one) but I'm unable to get the pump to lock on the Presta valve in order to inflate it. The pump has an interchangeable head that fits both Presta and Schrader valves and a lock lever.

I tried the pump many times on my daughter's bike with Schrader valve and it locks and inflates the tyres perfectly.

When I change the pump's head to Presta and tried to inflate my bike's tyres, the pump wouldn't lock on the valve no matter how hard I tried and just keeps deflating the tyre.

Anyone has an idea on what's i'm doing wrong here?

Thanks!

Can you get someone to video what you’re doing. You have me bamboozled.

As an aside. You need to use a better pump that that fella, you won’t get anywhere near the right pressure with it. A track pump is really essential when you own a road bike.

Agreed, mini pump to get you home if co2 fails or you have none. Track pump is so much less effort. I've one I got in tesco last year for a 10er that does the job, actually a better job than the 30 euro one it replaced.

magicbastarder

Brian? wrote: »

We probably produce more CO2 when breathing on a spin than one cartridge contains. You should stop breathing heavy if you’re that worried.

i'd be more interested in the encapsulated carbon in a cartridge than in the actual contained carbon. i suspect it'd be much higher.
either way, i don't think either figure would be in any way significant; from what i can see, the average person breathes out about a kilo of CO2 a day.

edit: seems 16g is about normal for the CO2 in a cartridge. or about 20 minutes worth of breathing. to compare to a car, a car produces about 2KG per litre of petrol, so about as much CO2 as a car does driving 200m.

ED E

A big reason why people bring mini and C02 is the risk of the C02 going wrong, if you get a good inflator and practice it this won't happen.

I'm using C02 around 1yr now and have used 1 capsule myself with a few donated to other cyclists. The bigmacs I ate during that time have had a far bigger atmospheric impact. I'd go vegan(never) before worrying about C02 use.

Remember Airsofters go through one every 30-50 shots :pac:

Mercian Pro

ED E wrote: »

Mini pumps are obsolete now IMO.

Great way to warm up after a winter puncture and an even better source of "is it hard yet?" jokes 😊

doozerie

Amouar wrote: »

When I change the pump's head to Presta and tried to inflate my bike's tyres, the pump wouldn't lock on the valve no matter how hard I tried and just keeps deflating the tyre.

If it's deflating the tyre then something must be pressing on the head of the presta valve. Maybe something in the pump head is catching on the valve head, or maybe (and probably more likely) the pump is pushing too far onto the valve and the valve head is hitting the back of the pump head.

If the latter then my guess is that the rubber washer in the pump head is too loose (or maybe you are just pushing it on further than necessary). I've no idea of the design of your pump but pumps usually have a threaded outer cap that compresses the internal rubber washer as you tighten it, and in doing so it effectively makes a "smaller" hole in the washer so that it fits tighter on the outside of the presta valve body. That tighter fit makes for a better seal between pump and valve and helps prevent the pump from pushing too far onto the valve too.

So if your pump has a threaded outer cap, try tightening it a little and see if that helps. Only tighten it a little at a time though, tighten it too much and you can shred the washer on the valve threads (if it has them) and end up having to replace the washer prematurely.

doozerie

ED E wrote: »

A big reason why people bring mini and C02 is the risk of the C02 going wrong, if you get a good inflator and practice it this won't happen.

There are many reasons why people prefer pumps (mini, or otherwise) to CO2 inflators. In my case, I prefer the fact that my pump won't run out of air (practical concern). I also like the fact that it produces no waste (empty cannisters) no matter how many times I use it (tree-hugger concern). A pump is also a once-off cost (penny-pinching concern). Etc.

Mini pumps are not obsolete, CO2 is a good option for some but it's not the right option for everyone.

check_six

doozerie wrote: »

If it's deflating the tyre then something must be pressing on the head of the presta valve. Maybe something in the pump head is catching on the valve head, or maybe (and probably more likely) the pump is pushing too far onto the valve and the valve head is hitting the back of the pump head.

If the latter then my guess is that the rubber washer in the pump head is too loose (or maybe you are just pushing it on further than necessary). I've no idea of the design of your pump but pumps usually have a threaded outer cap that compresses the internal rubber washer as you tighten it, and in doing so it effectively makes a "smaller" hole in the washer so that it fits tighter on the outside of the presta valve body. That tighter fit makes for a better seal between pump and valve and helps prevent the pump from pushing too far onto the valve too.

So if your pump has a threaded outer cap, try tightening it a little and see if that helps. Only tighten it a little at a time though, tighten it too much and you can shred the washer on the valve threads (if it has them) and end up having to replace the washer prematurely.

Those mini pumps where you have to switch around the rubber seal for different valve types are very tricky to get working properly. I used to have one and there was a lot of fiddling about required to get it to work on Presta valves including taking a valve bit out of the pump and reversing it along with the rubber seal. Then you had to start messing about with the tightness of the cap as described above in Doozerie's post. A whole lot of trouble to get it to work right.
A track pump is the correct fix long term. I also recommend a minipump with a flexible hose like a Lezyne Pressure Drive.

tomasrojo

doozerie wrote: »

There are many reasons why people prefer pumps (mini, or otherwise) to CO2 inflators. In my case, I prefer the fact that my pump won't run out of air (practical concern). I also like the fact that it produces no waste (empty cannisters) no matter how many times I use it (tree-hugger concern). A pump is also a once-off cost (penny-pinching concern). Etc.

Mini pumps are not obsolete, CO2 is a good option for some but it's not the right option for everyone.

Penny-pinching and tree-hugging are inextricably entwined in my heart, so it's mini-pumps for me .

tomasrojo

check_six wrote: »

Those mini pumps where you have to switch around the rubber seal for different valve types are very tricky to get working properly. I used to have one and there was a lot of fiddling about required to get it to work on Presta valves including taking a valve bit out of the pump and reversing it along with the rubber seal. Then you had to start messing about with the tightness of the cap as described above in Doozerie's post. A whole lot of trouble to get it to work right.
A track pump is the correct fix long term. I also recommend a minipump with a flexible hose like a Lezyne Pressure Drive.

There are mini-pumps with a double Presta/Schraeder head. The ones where you turn around the rubber insert (I think) are really for you to adjust once for your type of bike and leave alone. If you need a pump that can flexibly deal with different valves, get one with the double head.

Track pumps in the house are great. I regret that I didn't know about them sooner.

tomasrojo

It seems to me, as to others, that the contribution of cartridges to the atmosphere's carbon budget is very modest. How often do people use them anyway? A few times a year for somebody doing about 7000km?

I wouldn't make comparisons to a human breathing though, as that carbon isn't directly derived from fossil fuels (though I suppose there is the attendant fossil fuel used in fertiliser production and farm machinery, if you're being strict about it).

Joe1919

On many mini pumps there are two things that need switching around. The first is the rubber as already discussed. But before putting back the rubber, there is a little plastic pin thing that normally presses down on the Schneider valve pin. This need to be turned inwards as its not required with presta and gets in the way. You might need a tweezers/long nose pliers to pull it out.

check_six

tomasrojo wrote: »

There are mini-pumps with a double Presta/Schraeder head. The ones where you turn around the rubber insert (I think) are really for you to adjust once for your type of bike and leave alone. If you need a pump that can flexibly deal with different valves, get one with the double head.

You're right. I managed to have my crappy minipump at the same time that I had a mix of valves on my bike. Presta on the front and Shrader on the back. This was also combined with the world's most uncooperative rims meant that each puncture repair was an exercise in misery and swearing!

check_six

Joe1919 wrote: »

On many mini pumps there are two things that need switching around. The first is the rubber as already discussed. But before putting back the rubber, there is a little plastic pin thing that normally presses down on the Schneider valve pin. This need to be turned inwards as its not required with presta and gets in the way. You might need a tweezers/long nose pliers to pull it out.

That was what I was attempting to describe previously (but clearer!).

07Lapierre

doozerie wrote: »

There are many reasons why people prefer pumps (mini, or otherwise) to CO2 inflators. In my case, I prefer the fact that my pump won't run out of air (practical concern). I also like the fact that it produces no waste (empty cannisters) no matter how many times I use it (tree-hugger concern). A pump is also a once-off cost (penny-pinching concern). Etc.

Mini pumps are not obsolete, CO2 is a good option for some but it's not the right option for everyone.

I used to be indecisive, now i'm not so sure!

I use one of these:

https://www.google.ie/aclk?sa=l&ai=DChcSEwj7uKr7nc_fAhUCtO0KHVYbBrwYABALGgJkZw&sig=AOD64_1Xyk3HVXRvhSEWdqxVz7l5qnCT-g&ctype=5&q=&ved=0ahUKEwjvzqP7nc_fAhViqnEKHWJlCBoQ9aACCEY&adurl=

tomasrojo

I was surprised to see a refillable compressed-air canister system on the market.
https://www.pinkbike.com/news/sks-rideair-tubeless-inflation-bottle-review.html

It's rather large, given that you can't get air to liquefy at relatively high temperature and relatively low pressure the way you can get CO2 to do it.

ED E

tomasrojo wrote: »

I was surprised to see a refillable compressed-air canister system on the market.
https://www.pinkbike.com/news/sks-rideair-tubeless-inflation-bottle-review.html

It's rather large, given that you can't get air to liquefy at relatively high temperature and relatively low pressure the way you can get CO2 to do it.

Yeahhhhhh....no.


Mini pump fans: Do you manage 120psi? Or is it roll home on a soggy 80?

magicbastarder

soggy 80? i never go above 80 regardless.

magicbastarder

so yeah, you might need 120psi if the bike is carrying 120kg on 25mms.

ED E

Specialized:

700 x 23mm, PSI 110-125, approximate weight 285g
700 x 25mm, PSI 110-125, approximate weight 315g
700 x 28mm, PSI 85-95, approximate weight 350g
700 x 30mm, PSI 85-95, approximate weight 400g
700 x 32mm, PSI 85-95, approximate weight 430g

Conti

Article ETRTO Dimension Technology Color/Sidewall/Bead TPI BlackChili g PSI
0101626
32-622 700 X 32C Vectran Breaker black/black Skin foldable 3/330
295 85-100
0101625
28-622 700 X 28C Vectran Breaker black/black Skin foldable 3/330
250 95-115
0101624
25-622 700 X 25C Vectran Breaker black/black Skin foldable 3/330
220 95-120
0101623
23-622 700 X 23C Vectran Breaker black/black Skin foldable 3/330
205 110-120

tomasrojo

ED E wrote: »

Yeahhhhhh....no.


Mini pump fans: Do you manage 120psi? Or is it roll home on a soggy 80?

Oh yeah, I wouldn't use that compressed-air canister. I can't see it appealing to a very large section of people who cycle either.

I think I can get up to about 3 bar with a mini-pump. Maybe I could get further, but it's a perfectly tolerable ride at that pressure (for utility cycling till i get home anyway, which is all I need it for). When I get home, I use a track pump to get up to 5 (bakfiets) or 6 bar (everything else).

tomasrojo

As a matter of interest, are all these charts of what pressure to use based on tyre deflection?

https://janheine.wordpress.com/2016/03/09/tire-pressure-take-home/

Much of it depends on the tires you run. Berto measured the tire drop (above; how much the tire deflects for a given load and pressure) for dozens of tires. He then averaged the values, and drew his chart for a tire drop of 15%.

magicbastarder

ED E wrote: »

Specialized:


Conti

i'd be very curious as to how many riders run 110psi on a 25mm tyre nowadays, especially anyone under 100KG in weight.

Fighting Tao

magicbastarder wrote: »

i'd be very curious as to how many riders run 110psi on a 25mm tyre nowadays, especially anyone under 100KG in weight.

Over 100kg and I ran 110psi on 25mm contis for over 4 years.

I changed to Vittoria Corsa G+ 25mm and I run 125psi front and 135psi rear.

jamesd

I got a minipump that also takes co2, so I use the co2 side if in a rush or otherwise just pump manually - handy to have the option.

C3PO

magicbastarder wrote: »

i'd be very curious as to how many riders run 110psi on a 25mm tyre nowadays, especially anyone under 100KG in weight.

Always run 115psi on 25mm at 85kgs kitted out! Basically always inflate tyres to maximum indicated pressure. Probably should reduce but rarely get punctures!

Duckjob

C3PO wrote: »

Always run 115psi on 25mm at 85kgs kitted out! Basically always inflate tyres to maximum indicated pressure. Probably should reduce but rarely get punctures!

I'm also 85kg and used to pump religiously to 120psi on my 700/25s until I realised I was losing lots of power due to bouncing up and down on some of the very knobbly roads in my locality. These days I do 100psi max and find it makes for a far easier and more comfortable ride.

magicbastarder

i'm 72kg, and run at 80psi. have had two punctures in the last 15k km or so, and one was definitely a pinch flat from leaving the tyres too long without topping up, i reckon it was about 50 or 60psi at the time.

triggermortis

I pump my commuter tyres to 105 psi (front and back) at the start of my shift and re-check then halfway through my shift as I can’t be bothered checking every day ( around 85kg on Durano max tyres). If I go out on the good bike I always check before I go and put in 100psi (conti tyres) in both. Last year I only had 1 puncture - in a conti

C3PO

That's very interesting lads - you've persuaded me .... but I'll be back to you if I start getting punctures!
I'll reduce to 100psi and see how I get on.
What about 28s GP4000s on carbon rims ... about 90psi?

ford2600

C3PO wrote: »

That's very interesting lads - you've persuaded me .... but I'll be back to you if I start getting punctures!
I'll reduce to 100psi and see how I get on.
What about 28s GP4000s on carbon rims ... about 90psi?

Pressure recommendations would depend on rim width and surface quality.

I've used 28mm gp4000 for years on 19-20mm internal width on predominantly really poor quality roads and zombie roads. At 83kg with a 10kg bike 75/65 is my typical rear/front split. Over 70 on front feels horrible now

That's exactly what I used for Paris Roubaix sportive.

If I was riding on really nice tarmac there probably would be an advantage to higher pressure but then I'd have to share that road with cars and it would probably be boring and flat...

Brian?

Did that tyre ever get inflated?

doozerie

Re tyre pressure, another benefit of lower pressure is potentially better grip. A tyre pumped to very high pressure will typically deflect far less then one at significantly lower pressure, and while it's easy to focus on the effects of this when rolling along a straight road, don't forget to consider too what happens when you are leaning into a bend at speed.

A lot depends on your tyres of course (tyres with stiffer walls will deflect less, etc.), and some of it on your tubes (latex tubes deflect more than butyl), and on how much you like to lean into bends in the first place. But certainly for me I feel a lot more confident pushing my bike into bends on 25mm tyres with latex tubes at 85psi then I've ever felt at higher pressures on the same tyres, on narrower (23mm) tyres at 100psi, or even when using butyl tubes.

And when you are feeling more confident you use your brakes less, so you maintain more speed or basically you effectively go faster. So whatever about the science, of which there is quite a bit on this topic (not all of it reliable though, I reckon), perception plays a big part too. I perceive significant benefits for me from all of the options of slightly wider tyres, latex tubes, and lower pressures. And if I'm wrong, well at least I am happy in my ignorance as I "feel faster"

Amouar

OP here. I just wanted to update this thread that I managed to solve my issue by buying a Presta adapter (Like this one) and my mini pump worked like a charm when I switched the pump's rubber valve from Presta to Schrader

Mickiemcfist

Amouar wrote: »

OP here. I just wanted to update this thread that I managed to solve my issue by buying a Presta adapter (Like this one) and my mini pump worked like a charm when I switched the pump's rubber valve from Presta to Schrader

I bought one of those recently for the saddlebag, just in case my minipump broke or something I could still get sorted at a petrol stations pump.

tomasrojo

I carry one of those because one of my bikes has Woods valves, and to use a mini-pump with those, you need to use an adapter and the Schraeder part of the pump head.