Al1943

Floor pump with gauge at home.
Floor pump with gauge in my truck.
CO2, threaded 16gr, on the road.

rawly old

My rule of thumb depends on what I'm planning to ride. Because I ride all
manner of surfaces, I have 700 x 40 tires. On asphalt I run about 80-85,
which with a strong thumb compresses 1/4" to 3/8". On the trail I let some
out, not having suspension, to 65 or 70, or 1/2". This excess gas usually
winds up in really old threads.

Retro Grouch 

I wonder how they come up with that number. I'd think that arm strength would be a significant factor in determining how much air pressure you can achieve with a mini pump. I doubt I could do it and, even if I could, at my age I might not have enough time left to get to 140 psi.

jyl

I run about 120 psi rear 100 front in 700 x 23 tires, at 185-190 lb. Around 80 starts feeling soft (sort of cushy, shading to mushy), and 60 is much too soft and borderline rideable, the tire feels scary in curves (rolling off) and jarring over bumps (rim hitting). Going much over 120 just makes the ride harsh, it doesn't feel any faster.

Everyone's hand strength is different so it is impossible to calibrate one's thumb via Internet. Just get your tires pumped properly - at a bike shop, say - and then remember what pinching the tire feels like.

A mini pump will work for a roadside fix, but it will take a long time to get 120 psi. I carry a full size pump on my commuter.

02Giant 

6 year 8 month revival.

achoo

I wonder if there was any air in those tires after all that time?

And how it was measured.

Reynolds 

I'm amazed, not by the resurrection, but by the guy who claims he can feel 1-2 psi differences.

noglider 

I believe your thumb is more accurate when you squeeze both of the tire's sidewalls than when you press down on the tread.

wheelreason

Different meds and wider tires?

rpenmanparker 

When comparing one tire to another, you can use the tuning fork effect to approximate pressure. Just flick the known tire with you finger and listen to the "tone". Inflate the other tire to match. Differences between tubes, rims , hubs, and spoke gauges and counts can screw this up but not by too much.

1 Miyata Biker

You'd probably have a tremendous struggle getting even 110 PSI in the tire with any mini pump. These pumps are meant more for road repairs to get you back home, than they are for maintenance at home. You're in need of a few items. First you should get a hand pump with the air gauge built in for at least 120 pounds PSI. Quality is the name of the game here! Save the mini pump for the road emergencies. Then you need a air pressure gauge that will read up to 120 PSI. They can be purchased at any LBS or automotive type store. They cost anywhere from $5 to $15 depending on what you want in an air gauge. Some take batteries for the gauge to work. Then you just need to "get the feel" of a tire with the pressure you will usually use. You'll learn how much it takes to use your fingers to squeeze a tire with 110 PSI if you get caught with a tire repair and you pocket gauge is at home. You can over inflate a tire by 10 or 20 PSI without worry that the tire will explode off of the rim. You'd really struggle to even get close to 140 PSI in any tire using a mini pump. 90 to 100 PSI in a repaired tire out along the road should get you home safely if you watch where you're running the tires. I have 700c x 32c tires rated at 70 PSI. I regularly pump them up to 80 to 85 PSI on the rear and 80 PSI on the front. No problems with flatting out along the road.

Drew Eckhardt 

I wouldn't worry about that. Boredom will set in or your arms will feel like they're about to fall off before you get reasonable pressure with a mini-pump.