Bicycle pump question

serg,zador

Hi
I recently bought a second hand cyclocross Ridley X-Ride but I only use it on-road.
Today I bought a AUD15 floor pump and tried to inflate my tires up to recommended 90-100 psi, however after 80 psi it got really hard - I was afraid my tiers blow up. So I am seeking for advice if this is how it's supposed to be? Do people put their entire weight on the pump after 80 psi, or I need to consider that the pump/gauge is faulty?

Killerclown

serg,zador wrote:

Hi
I recently bought a second hand cyclocross Ridley X-Ride but I only use it on-road.
Today I bought a AUD15 floor pump and tried to inflate my tires up to recommended 90-100 psi, however after 80 psi it got really hard - I was afraid my tiers blow up. So I am seeking for advice if this is how it's supposed to be? Do people put their entire weight on the pump after 80 psi, or I need to consider that the pump/gauge is faulty?

Check to see if it’s got a switch on it, that changes it between a ‘high pressure’ and ‘high volume’ mode. If it has, ensure it’s set for high pressure.

serg,zador

Killerclown wrote:

Check to see if it’s got a switch on it, that changes it between a ‘high pressure’ and ‘high volume’ mode. If it has, ensure it’s set for high pressure.

Thanks, no switch. So I assume when it's over 80 psi it's expected to go really hard?

joe_totale-2

People can't really help you unless you say what the tyres were and how wide they are.
For example if they're cyclo-cross tyres then 80psi is way too much for them.

First.Aspect

Joe Totale wrote:

People can't really help you unless you say what the tyres were and how wide they are.
For example if they're cyclo-cross tyres then 80psi is way too much for them.

True, but that wouldn't be relevant to the back pressure felt at the pump.

Should be a "two arm" job to get to around 100psi - you do have to put some force into it, not *that* much. If it is a real struggle to get air in at all, check the valve is fully open and the pump properly installed on it.

ayjaycee

If by 'floor pump' you mean 'track pump', however you dress it up, there's something wrong somewhere - any even half decent track pump should go well beyond 80psi easily. If it's actually a 'foot pump' that you are using (ie. the sort of thing with one or two barrels that is often used on car tyres), I've never tried to use one on a bike wheel but I wouldn't be surprised if it gave problems getting to higher pressures - I've just looked at one of mine and it only actually goes up to 90psi on the gauge (and none of the tyres on my cars go anywhere near that!).

ollie_cr80

Most £20 track pumps from general bike stores or online will pump to >160 psi easily.

I pump my road tires up to 120 psi every couple of weeks with no issue.

serg,zador

Thanks everyone for the input. Yes it’s a track pump.
I checked the tyres. It’s Shwalbe Marathon plus 28mm.
People write on forums they pump them ranging from 55 to 100 psi. I will try the pump again and if can’t go over 90-95 will return it and try another one.

joe_totale-2

serg,zador wrote:

Thanks everyone for the input. Yes it’s a track pump.
I checked the tyres. It’s Shwalbe Marathon plus 28mm.
People write on forums they pump them ranging from 55 to 100 psi. I will try the pump again and if can’t go over 90-95 will return it and try another one.

Why do you want a 28mm Marathon Plus at 90 psi? IMO that's far too high unless you're a particularly heavy individual.
70-75 psi should be plenty.

ollie_cr80

It should say on the tyre wall what the max PSI is.
I wouldnt go above that... It will hold but is more likely to end up blowing out on you while riding which wouldnt be fun.

I would suggest pumping up to the max recommended, taking it out for a ride and adjusting down as you see fit.

webboo

ollie_cr80 wrote:

Most £20 track pumps from general bike stores or online will pump to >160 psi easily.

I pump my road tires up to 120 psi every couple of weeks with no issue.

Why

N0bodyOfTheGoat

serg,zador wrote:

Thanks everyone for the input. Yes it’s a track pump.
I checked the tyres. It’s Shwalbe Marathon plus 28mm.
People write on forums they pump them ranging from 55 to 100 psi. I will try the pump again and if can’t go over 90-95 will return it and try another one.

https://www.schwalbe.com/en-GB/tour-rea ... -plus.html

700x28 is 80-110PSI

Personally, I pump 28mm tyres with tubes to ~85/95 (front/rear). I'm ~77Kg, all-in (kit, water, mobile etc.) I'm something like ~89Kg on the Cube and ~92Kg on the Voodoo (depending upon tyres and season, I will go for longer rides on the Cube with more water bottles).

imposter2.0

Marathon 28s at 100psi, Jesus. Do you still have your own teeth?

big_harv

All as above but are you giving the head of the valve a little tap (or push) before you connect the pump? Just to let a little air out and free it up. Makes a difference on presta valves I find.

serg,zador

Big Harv wrote:

All as above but are you giving the head of the valve a little tap (or push) before you connect the pump? Just to let a little air out and free it up. Makes a difference on presta valves I find.

Thanks, I will try.
Just to clarify: I started this thread as did not expected that much resistance at 70-80 psi. Last time I had to pump a tyre when I was a kid.
This is a fairly cheap pump (A$15): https://www.kmart.com.au/product/steel- ... ed/1602312
so my main concern was/is that the gauge shows pressure wrong.

lesfirth

Your pump has a diameter of about 1.5 inches. That is a cross section of about 1.75 square inches. If you weigh 12 stone i.e.168 lbs. and you hold your entire body weight on top of your pump,keeping your body still, you will generate a pressure of about 95 psi.
The answer to your original question is yes. You do have to put a lot of weight on your pump.
For road bikes a pump with a smaller diameter is better.

javanman123

if you are ever in the the market for a new pump, might I suggest the Joe blow pump, it is fantastic, I've owned for many years now and it has served me well! best pump in my humble opinion

davebradswmb

Imposter wrote:

Marathon 28s at 100psi, Jesus. Do you still have your own teeth?

It might not make sense to fit fat tyres and give away most of the benefit by pumping them up to such a high pressure, but 28s at 100psi are still going to be more forgiving than 23s at 100psi so I don't think serg's teeth are at any risk.

topcattim

lesfirth wrote:

Your pump has a diameter of about 1.5 inches. That is a cross section of about 1.75 square inches. If you weigh 12 stone i.e.168 lbs. and you hold your entire body weight on top of your pump,keeping your body still, you will generate a pressure of about 95 psi.
The answer to your original question is yes. You do have to put a lot of weight on your pump.
For road bikes a pump with a smaller diameter is better.

Brilliant answer, makes sense.

keef66

"28s at 100psi are still going to be more forgiving than 23s at 100psi.."

Is that actually the case? I thought as tyre volume went up the pressure required to produce the same ride quality came down. I run my 25s at 80psi max, and imagine 28s at 100psi would be pretty harsh. Conversely a 23 at 100psi would still deform enough to take the sting out of a rough surface.

I'll grant you that an appropriately inflated 28 will be a lot more forgiving than a 23 at any pressure

I know I'm comparing apples and kippers, but car tyres generally use about 30 psi, and tractors can be into single figures.