Impossible to get 120 PSI into my tyre?

[MBosh]

Hi
My tyre says 120 PSI, but using a Joe Blow pump I find it impossible to get anymore then 100 PSI on the pump gauge. I say impossible because the pump just bounces back up when I try to get more air into the inner tubes. So why does it say 120 PSI when I'd probably blow the inner tube trying? Not that I can get anymore 100 PSI in though because the pump just won't do it..

 

[lazyfatgit]

Pump chuck fitted and sealed properly? I’ve got a joe blow and achieve 120psi without difficulty.

If the tyre and rims are rated to 120psi why would the tube blow?

 

[rrarider]

If the pump handle rises when 120 psi is reached, the non return valve in the pump is faulty. I don't know if that's a replaceable part in a Joe Blow; it certainly is for my Rennkompressor.

 

[HLaB]

Do you really need to get 120psi in your tyres ?

 

[rrarider]

It looks like SJS keep non-return/check valves for various Joe Blow models. I'd give them a call to enquire if they have something suitable for your pump.

 

[Old jon]

No difficulty reaching way more than 120 psi with my cheap Scandinavian floor pump, but that is on 700 x 25 tyres. You may have a pump or pressure gauge fault.

 

[cyberknight]

I need a new pump.its starting to blow off the valve at about 85-90 psi, got to be getting on for 8 years old +

 

[rrarider]

I need a new pump.its starting to blow off the valve at about 85-90 psi, got to be getting on for 8 years old +

You just need a new rubber washer in the hose head; there's no need to waste your money on a whole new pump.

 

[Levo-Lon]

Id think the pump is faulty as suggested

 

[cyberknight]

You just need a new rubber washer in the hose head; there's no need to waste your money on a whole new pump.

Not sure i can get spares.
https://www.halfords.com/cycling/bike-maintenance/bike-pumps/bikehut-performance-track-bike-pump

 

[vickster]

Not a Joe Blow Max perchance? Useless things for road bikes.
And as above do you really need 120psi? How heavy are you? How much luggage?

 

[rrarider]

Not sure i can get spares.
https://www.halfords.com/cycling/bike-maintenance/bike-pumps/bikehut-performance-track-bike-pump

Just buy an EVA head for Rennkompressor hose. You can get washers for those and I'll bet you can fit the head to your hose.

 

[ColinJ]

Are you sure that air is actually going into the tube? If you haven't loosened the end of the valve first AND pressed it in to make sure it isn't stuck (they often DO stick!) then all you would be doing is compressing the air in the pump hose, so it wouldn't be surprising if you couldn't pump much more than 100 psi worth.

 

[Ian H]

The pressure on the tyre is the rated maximum. Rarely would you run at that pressure.

 

[raleighnut]

There are 2 different types of track pump, high pressure and high volume (for MTB type tyres)