rando

very basic questions! to what pressure do I inflate my tires? I have a trek Mtn bike that I ride to work. and can I use the regular car tire pressure guage to check the tire pressure on the bike? thanks!

rmwun54

Well if you look at the tire you will see the reconmended tire pressure is on the side wall. Generally it will say inflate from 35 to 65 max psi. I'm 170 lbs., so on my mtb I would inflate the tires to about 55 psi for the road. But if you are on the heavier side I read somewhere that somewhere closer to max would be more beneficial to you. But if the tire is old 55 or less psi is fine. And having a front shock also makes a difference to how much psi is doable. With shocks more psi is doable for the reason of less stress to the tire and ride.

ken cummings

The above post has it spot on. I am 195 and have success with tires 4-5mm larger than normal (32s instead of 28s, etc.) and run the pressure to design max for lower rolling resistance (my butt has gotten hard enough). I watch for sidewalls starting to age, looking for cracking, crumbling and fraying, and replace them fairly soon. Doing otherwise usually means a sidewall blowout is coming.

NoRacer

Try this:

https://sheldonbrown.com/tires.html#width

Michigander

I always max it. So does everybody I know. It avoids pinch flats, and makes pedaling as easy as possible. If your tires are so old that you would consider reduced pressure, I'd say its time for new tires.

ken cummings

I just recalled a story that seems humorous in retrospect. I was managing a major century ride in 1984 when a lady approached me saying she had trouble with her daughters' tire and what could she do? The tire had blown off of the rim, blowing the inner-tube apart and spraying the tire, rim, and lady with green Slime(tm).
"I put the goo in the tire to prevent flats and started filling the tire at a garage this morning when it exploded."
I directed her to the lady owner of the Self-Propulsion bike shop who had brought almost her entire inventory to the ride start for a spare innertube. The lessons to be learned are covered elsewhere on BF.

toolba

I'm about 210 and run near max pressure when riding on pavement. When I'm on a sandy trail or roots, I might lower it a few pounds. Most car tire pressure gauges only go up to 50 lbs. If you know where I can get one that goes higher let me know.

cooker

Bike stores usually sell guages that go higher, since bike tires, being much smaller than car tires, hold much higher pressure. However, the most useful, I think, is to get a pump with a built in guage.
Two guys in this thread recommended the Topeak Road Morph pump.

alanbikehouston

Higher quality mountain bike tires are designed to allow riders to select from a wide range of PSI levels. Some models will allow riders to use any any PSI from around 30 PSI up to 80 PSI. The lowest PSI level works well in sand, muck, mud, or loose dirt. The highest PSI is for riding on smooth, paved roads.

Rider weight is an important factor. On the same bike, with the same set of tires, a 120 pound rider might get the best performance at 40 PSI and a 220 pound rider might get the best performance at 80 PSI. A rider's skill level is also relevant. A skilled rider can ride smoothly at lower PSI levels and never get a pinch flat. Gonzo riders who plow full speed into every rock and every pothole can get pinch flats at maximum PSI levels.

So, to find out what PSI level works best for your riding style, weight, and preferred riding surfaces, experiment. Look for a PSI level that allows the sidewalls to maintain a normal profile, yet flex enough to absorb shock while riding over rough surfaces.

rando

Thanks, everyone, for the advice and links! this helps a lot! Been riding bikes for years and never knew half of this! it is truly amazing I have not had more flats. I will bet that I have never had properly inflated tires. I'm getting one of those pumps!