Help - Tire Pressure / Floor Pump Issue

[Dubz]

I've just got a bike and am really looking forward to getting into cycling. I'm a complete beginner in that I haven't cycled since I was about 12, so my question may seem really obvious.

Love this website btw. I think that it's hard to ask technical questions when you're a woman, as sometimes guys give you techie answers which are impossible to understand versus breaking it down into normal English!

I've got a turbo trainer to work on my fitness when I can't cycle outdoors as I've promised to train for a ride later this year with my friends. My problem is that I'm trying to pump up my training wheel which my LBS put my training tyre on. I need to ensure that every time I use my turbo trainer it's at the same setting. I bought my bike from my LBS, so they recommended the training wheel and training tyre.

On the training tyre itself, it says that the maximum pressure should be 120 psi. Other websites recommend only pumping it up to 110 psi, although the maximum is 120 psi. I'm going to pump it up to 110 psi and keep it at that pressure.

I finally figured out how to use my Bontrager Recharger Track Pump with the Presta valve on the wheel after a lot of Googling. The tire wasn't completely flat when I pumped it. The problem is that when I pumped it to about 60 psi, I felt that the tyre felt as if it was at maximum inflation and the pump didn't seem to be adding any more air. I'm afraid to pump it any more as it feels like it will burst.

I thought that the pump would automatically show what pressure the tire was at and that you would just pump it where you need it to be. I feel like I'm missing something so obvious. How do I manage this issue in the future? Surely cyclists don't empty their tires just to pump it up to the right pressure? Is there some gadget I'm supposed to buy that tells you the tire pressure and then if you're low you just pump the difference with your floor pump?

Help!

[Dubz]

Thanks, Muirenn. That's very helpful.

How do I know how much pressure is in the tire to begin with? Can I know this from my Floor Pump?

Cheers.

[Dubz]

Cheers, Muirenn.

I actually have a pressure gauge on my pump. I got the same one that my LBS uses (Bontrager Recharger Track Pump). They recommended it. When I connect the pump, the current pressure doesn't show. The gauge says zero. It's only when I pump that the needle moves up. This is why I'm confused.

Also, noob question here: what are valve caps on the stem and washer nuts?! I'm seriously technically deficient when it comes to biking. I'm trying to learn though. I've learned so much in the past few months since I first decided to buy a bike.

I thought the stem was the bit the handlebars attach onto because when I got my bike my LBS said that they switched around the stem to give me a more comfortable reach. I'm 5' 3" but prefer the unisex model of the bike I got versus the WSD. With the WSD, my arms felt wrong - like they were too bent. With the unisex model, I felt like my reach was too far until the LBS switched around the stem. Then it felt fine.

On my wheel, I only have a black cap which I take off the Presta valve. There's no other cap. I had to unscrew the silver round thingy to loosen it. I pushed in the silver round thingy in slightly to make some air come out and then fixed on the floor pump to the narrower hole (my pump can do Schrader valves too so it has a wider hole as well) and locked it in place. Then I pumped.

[Dubz]

Oh ok. That makes sense now. Cheers.

Do you think it would be best for me to always pump the tyre up to max (assuming that this means it's at 120 PSI which is the manufacturer's maximum tyre pressure) and then let some air out and then pump up to what the correct tyre pressure should be (using the formula you linked to)? Otherwise, I could buy a separate type pressure gauge which would measure the pressure and then use my pump to get to the PSI I need.

[Dubz]

Thanks for all the help, Muirenn. I'm probably being a bit of a pain here. Are you Irish by the way? Muireann (with an 'a' usually) is an old Irish girl's name?

That last link was really useful. That girl is amazing. How she kept going with all those injuries is unbelievable. Fair play to her. Great info too.

Basically, my problem is that I can't guess how much air to pump into my tire when it's already inflated because my gauge doesn't say how much pressure it's at already. So if I was able to attach my floor pump and see that it was at 100 PSI already, then I'd know that I just had to add 10 PSI more from my pump (as an example) to make the pressure inside my tire become 110 PSI. At the moment, I can only attach the pump and add more pressure until the tire goes hard (so I start at 0 PSI on the pump gauge and go up to 60 PSI as an example). But this doesn't allow me to know what the total PSI in the tire is at that point because the pump gauge would read 60 PSI at this point, when the pressure inside the tire could be 110 PSI because I started with pressure already in my tire (or I'm guessing even 120 PSI if the pump isn't allowing me add more air and the tire feels completely rigid, since 120 PSI is what the manufacturer gives as the maximum tire pressure). I hope that makes sense.

[Blueberry]

So once your pump gauge starts reading, it is usually reading the pressure in the tire. You usually hear a little whoosh when the pressure in the tube of the pump exceeds the tire pressure. Reading the gauge when you hear that will tell you the approximate pressure in the tire. You can always remove the pump and depress the center portion of the valve to let air out of the tire if you are afraid you have overinflated it. So - if you want the tire to be at 110, you would pump until the gauge on the pump reads 110. Make sense?

[BikeDutchess]

As soon as you pump it once, the gauge should move to show the then-current pressure for the tire. The gauge doesn't just show what pressure you add (by pumping), it shows the total pressure in the tire (some show the total pressure as soon as you hook it up, and some may not show the total pressure until you actually start pumping). You would rarely start from zero (in the tire) unless you had a flat and/or just mounted a new tube in the tire.

ETA: Blueberry and I were writing at the same time.