I use a battery-powered electric pump that has a built-in pressure gauge. It seems to be accurate as far as I can tell.
That calculator is telling me I should have my front and rear tires at 28.5 and 30.5, though, which is lower than the minimum pressure labeled on my tires and considerably lower than what I’ve actually been keeping them at (45 and 55). I don’t know if it’s wrong or I am.
If it were me, I’d pump the rear one to 60 and the front one to 50. This should give you plenty of time before it starts to lose enough air to bother you.
If you don’t like it, 55 and 45 sound fine to me.
The pressures the calculator reports for my weight/tires are pretty much bang on.
Did you select some other more exotic road surfaces/speeds?
I was also struck by this in the OP:
I put air in my car tires about five times per year, and this across a number of vehicles over many years. At the very least, whenever I put on summer vs. winter tires, the pressures are out of whack to a varying degree.
I’m not a car guy, but even I can easily tell my car tires aren’t inflated enough, or are inflated unevenly, just from how the car handles itself. Wouldn’t dream of just ignoring it, knowing how much effect it has in the long run / in an emergency.
Agree with this as a good starting point - pump to the max indicated on the sidewall. If the ride is all paved but feels harsh, let out some air until it feels comfortable yet efficient. Once you have it dialed-in, use a guage to see what PSI each tire is, and just keep them there.
That’s not entirely true, though tire construction definitely is a factor. Racing bikes have been moving to wider softer tires at lower pressures because vibration/suspension losses from very high pressure tires outweighs the benefit of lower rolling resistance and lack of deformation.
I vaguely recall inflating my plain one or three speed bike tires to 30psi as a kid. Back in the mid-60’s - remember Sturmey-Archer 3-speed bike hubs? a derailleur 5 speed was high tech. One idiot I knew cranked the gas station pump to maximum (100psi?) and proceeded to fill his bike tire. It went “BANG” and the sidewall ripped open about 6 inches long. Stupid is as stupid does.
Because of that, I always thought filling my bike tires today to 60psi was pushing limits, but apparently it’s normal. Of course, the tire is thinner and I weight about 3 times what I did back then. If it dips below 40psi, there’s a noticeable bulge and corner slide. OTOH, I have yet to get a flat tire in the last few decades, and I was constantly fixing flats back then - plenty of bike maintenance experience.
(Another fun task was replacing the front axle after one too many times trying to jump the curb. Canadian Tire had a full set of bike parts for kids like me.)
Really interesting read. Let’s hear it for actual, experimental science.
Well, that’s all good information, but I wouldn’t think it applied to Smapti’s question. That data set is a fair ways from the bike he’s riding, and the conclusion, that a harsh ride is too much pressure, is in line with my own.
Hard agree, I can’t tell you how many times I’ve seen something that ‘everyone knew’ get some actual science done on it and have surprise results.
The problem with the tests on that site is that they are not examining the effects of the whole system including the bicycle and rider. That’s the point of the testing that the Rene Herse people did. Their point is that a tire turning a steel drum is not a sufficient test.
I will caution that there’s lots of room for apples and oranges in tire discussions.
I disagree - neither apples nor oranges are likely to provide sufficient grip whether fitted to a car or bike.
… And the ‘everyone knew’ crowd doesn’t believe the science, right?
I went with “worn pavement/some cracks” and “recreational”. I have 27.5"x2.1" tires and myself, plus my bike, plus my gear probably comes to somewhere around 340-350 lbs.
Those numbers plugged into the calculator are recommending a pressure that’s below the minimum marked on my tires, so I think I’m gonna stick with 45/55, which gives me a fairly smooth ride, lets me get a decent speed if I’m pedaling on level ground without the motor on (with the motor I can cruise at 20 MPH effortlessly) and I don’t get pinch flats anymore like I did when I was first getting used to biking after not having owned a bike for 20 years.
And bananas are right out!
What about coconuts? I’ve heard that swallows carry them around effortlessly.
Not European swallows…
That’s my point.
I guess you plugged in ~52mm tyres?
Did you measure those inflated on the rim or is that what it says on the box?