brett jerk

is there a trick to figuring out what 120 psi feels like? as in I have a set of tires I'm looking to fill up to that level

AndrewP

Get a floor pump with a gauge. For knowing what it feels like when fixing a flat without a gauge, push the wheel against the edge of a curb to see how the tire bulges.

Raiyn

No more than there's a trick to finding proper torque without a torque wrench. Air gauges are cheap.

brett jerk

yea I've kinda just been feeling it out because I lost my psi gauge and don't have any disposable income at the moment

Bill Kapaun

If you LOST your gauge, that infers you should have an idea how the tire feels from when you HAD your gauge?

JanMM

If it feels soft to your fingers, it's not 120 psi.

Pig_Chaser

I tried to do exactly that a yesterday when changing tires at work, all i had was my cheapie frame pump. I checked em at home and i only had about 80psi in em. At 120psi there shouldn't be much deflection when you put your weight on the tire.

brett jerk

Yea, but I was looking for something a little more technical. I have a rough estimate of what a 120, 80 and 60 feels like but I didn't know if there was some trick that could help me out until I buy another gauge

I_bRAD

You could calculate the surface area of the piston in your pump and then attach a scale to the handle and pump until the appropriate force is achieved.

OR you could just pump them up until you feel they're good enough to ride and then pop by your LBS and borrow their floor pump to make it perfect.

Camilo

Oh for crying out loud, go to Walmart and spend the $3 on a tire gauge.

brett jerk

Walmart? really? walmart?

brett jerk

like... thats your advice? support walmart?

Barabus

Compare it to the other tire that is properly inflated!! Or a buddy's tire that is properly inflated.

Grimlock

In a 23c slick, it feels pretty solid. In a 2.5" knobby, it feels like exploded. Generally I'll pump my 700c tires until they don't deflect too much and I feel comfortable riding on them until I am able to check properly on something with a guage.

Wordbiker

This is exactly why I recommend keeping a thumb dug into a tire whenever it is pumped. When you have an accurate pump, you'll get a "feel" for what the right pressure is. When you don't have a gauge available, you can still get it in the ballpark and not explode a tire with a gas station compressor.

Bikedued

Wal Mart is out? Oh well, Brookstone carries a very nice digital. Mine has lasted about 6 years without changing the battery.,,,,BD

Sixty Fiver

That maximum pressure is only a suggestion and the best way to check a tire's pressure is to measure the tires deflection / compression when the bike is loaded. If the tyre has no compression then it has too much pressure unless you are going to be riding on perfectly flat surfaces.

At just a spec under 150 I won't run my tyres at such high pressures as the ride is harsh and is actually detrimental to the bike's ride and handling. From experience I find that for my weight, 95-100 psi is where I can max out all the tyres riding qualities.

The same applies to my higher psi mtb tyres... I get a way better ride and get way more speed if I run them at 65 psi on the road instead of their 75 and 85 psi ratings.

Bobby Lex

No. His advice is to buy a tire pressure gauge at the lowest price, since you claim to have limited funds.

I'll bet you can find $10.00 in loose change in your couch cushions, sock drawer, or car ashtray.

(Maybe you can pawn your watch, buy a tire pressure gauge, and then post a question about how to tell what time it is from the sun's position in the sky....)

Bob

brett jerk

I already know how to do that

I_bRAD

You're gonna end up with a nice set of pitcher's arms if you do that for enough 120psi tires!

Camilo

About my Walmart suggestion, it was only to suggest going somewhere where you can buy a gauge cheap. Believe me, I know student-dead-broke, but I'll bet a tire gauge is worth less than 2 beers, coffees, whatever you currently spend discretionary money on.

As another suggestion, if you have a frame pump: chances are, you would get a consistent pressure at the maximum you can pump the thing.

I remember back in the old days (70s) when my buddy and I had road bikes with full length frame pumps. He was a big 6-4 former HS football player. I was 5-8, a wimp compared to him. We rode together a lot. He could pump his tires up to about 110-120 (iirc) with the frame pump, working really hard. That's all he ever did - pump it up as hard as he could with that frame pump knowing it was around 110. I don't think I could get it past 90 or so.

It would take you at least one check with a gauge to make sure, but I'd bet if you have a full length frame pump (as opposed to a mini pump which are tough to get good pressure with), you'd find that if you really grunt on that pump it will be right there at 110-120.

oilman_15106

Yep, Wallymart. Or you could do what we did back in the day, pump up your tire and bounce the bike on a cement floor. If it bounces up it has enough air in the tires.

JanMM

What it comes down to is that you really can't tell how much air is in a tire without a gauge. That doesn't mean you can't ride a bike without having a gauge.

BikeTales 

some gas station compressors have a gauge built in. maybe it will be 50-75 cents or even free for air. or check dad's glove box. I can't believe this thread has so many replies

brett jerk

I can't believe it does either. I was honestly just expecting a "no, theres no trick" and then for it to fall off the front page.
Clearly I get by with guesstimating and I really like the "bounce the tire" idea, I was just wondering if there was some quick/easy math or something along the lines of 'if you lean 150lbs on the tire on the curb and it compresses about a quarter of an inch its good' kinda thing.
I'll buy a tire gauge some time soonnnn