Originally Posted by
prj71
Tire pressure matters. It just depends how anal retentive people want to be about it. Most of us aren't. In the end, it's a personal thing that no online calculator or chart will be able to help you with.
Unfortunately there are people that overthink this stuff and think there is some perfect number that they should use all the time. But the reality is between tire casing, rider weight, terrain, rider speed, etc. there is a wide range of possible pressure combinations that no online calculator or chart will be able to give you.
And what hasn't been discussed here is that the tire pressure guages on the pumps or a stand alone guage are rarely accurate and very few people (myself included) don't have them calibrated. I have a pump that reads ~10psi less than my pressure gauge, then I have another pump that reads ~5 psi more than my pressure guage...which one is right? And how are you suppose to reference an online calculator that tells you what pressure you are supposed to be at with a 15 psi spread between three different guages?!
Best to just go by feel and if you must use a guage...Pick one guage and use that number all the time.
The good online calculators simplify all those variables you keep mentioning. That is the whole point. It's dead simple:-
1. Check with the calculator what pressure it recommends for your setup (maybe 20 secs effort)
2. Set your tyre pressure with a decent quality gauge (I have at least 3 gauges and they all read within a couple of psi. I do check them against each other occasionally)
3. Ride
4. Tweak the recommended pressure if you feel the need. (I very rarely do)
5. Make a note of your preferred pressures and check them regularly
My observation is that most people who don't bother to look up what pressures are recommended for modern wider tyres almost always set them way too high. Typical case is someone who has been using 23/25C tyres for years at 100+ psi buys a new bike with wider tyres and sets them at 80 psi because that seems like a reasonable drop - just a guess basically. It kind of works okay like that so they never even experiment with lower pressures and miss out on the potential benefits. Then there are those who don't even bother with pressure measurement at all and just use their super-sensitive thumb gauges. I'll do that at the side of the road if I get a flat, but it's a very low bar for anything else.