Tire Pressure Calculator

Edit: 10/26/15 – I’ve removed the link to the google Doc. The locked fields didn’t work, and people have defaced it pretty severely.  Download this XLS file for your own use: Tire Pressure – salvaged doc

You can use the tire pressure Excel file to calculate pressures for different kinds of bikes. Put in your weight and tire width, and it gives you the optimal pressure for Road, Cross, Mountain Bikes, Low-trail randonneur bikes, Fat Bikes and Triathlon bikes.

You can fudge the numbers based on your experience, tire casing, riding style, and road surface.  More info about the pressure calculator.

There is also an Android app available. You can save your bikes and easily access them later. You can even do custom calculations for cargo bikes, which the doc doesn’t do yet.

From Dave Adams, bsed on research by Frank Berto, as published in Bicycle Quarterly.

27 thoughts on “Tire Pressure Calculator”

1. Robert Barr says:

Thank you – I appreciate your making this available. Works very well for me.

1. My pleasure, Robert! We’re upgrading the Android app shortly, and have a design on paper for v 2.0 later this year.

2. Mr Blimp says:

What this doesn’t tell you is how to determine the actual pressure only the theoretical pressure.

Example:
My bike and I weight 210 lbs together – the app says my 23c tiers should be 130Rear/84 Front
My tires maximum PSI rating is 90 psi
Does this mean I need to find a tire that can handle 130 psi to use for my front tire?

1. Robert says:

Just run it at 90 psi, or get a different tire, or lose weight.

1. I don’t understand. I did fix some busted links to the pressure app, though.

3. Charley says:

Thanks for the spreadsheet!

Question… A 23c tire could very well measure 22 on a narrow internal width rim or 24 on a wide internal width rim. Does this change actually affect the proper inflation pressure for a particular tire? Its seems like its still the same amount of rubber and therefore the same volume, just distributed “taller” on the narrow rim and “wider” on the wide rim. Therefore one would use the same pressures for both rims. But that doesn’t seem correct somehow. Thanks.

1. I think you could get a little more volume on a tire with a wide rim. I’d use the measured width, not the supposed width, but either will get you in the ball park.

4. Steve says:

All I saw was the inputs to 4 unknown bike styles and Low Trail. Will this spreadsheet ever show all the bikes you mentioned at the beginning of your blog?

1. Hi Steve,
No, probably not. Google Sheets couldn’t keep the protected cells protected, and the human visitors just made a giant mess of everything.
If you want to do Triathlon bikes, just use “Low Trail” and switch front and rear tire values.

Philip

5. Turtles, Man says:

Thank you for the xls, I’ve been looking for something like this.

Are you the app’s author/will you see revenue if I buy?

Many thanks, again.

1. Turtles, Man…
Excellent – enjoy the XLS!
I worked on the app, but my royalties have expired. If you have an Android phone, you should try it out.

Philip

6. Robert says:

I weighed my front and back wheel with me on the bike and a book under the other wheel.

It was 121 rear and 60 front lbs.
That is 33.2/67.3% ratio.

I love this spreadsheet, but concerned that it doesn’t factor in the front/rear weight distribution. How would my distribution effect the optimal results?

1. That’s a pretty big difference. Very upright bike? The old Google Docs had a couple settings for normal and low trail bikes with different front/rear weight distributions, but none as extreme as that.
I usually just run the front 5 lbs lower than the back. There’s less weight on the front, until you start braking.

7. Damian says:

Looks good, but why doesn’t it account for riding conditions (eg, street / mountain). I put in mine and it said (28mm and 165lb) and it says 52 / 65, but tire says 70-80. Trek style bike for road use.

8. Damian says:

Ah. I see, should include weight of bike as well. That makes a bit more sense.

9. Damian says:

Still, should there be some compensation for terrain? street vs offroad etc…?

1. The number is for street. You can vary your pressure with terrain, for comfort, traction, or rim protection. Generally you’d go with lower pressure offroad.

10. Jay says:

Quick Q. I used the excel sheet and it gave me a 34-44 psi set up for 20×1.75in and 240lbs (bike+weight) but the thing is that I have the shwalbe marathon plus and they are rated for 45-70 psi. Any advice on how to set them up? Its for an ebike. Thanks!

1. I’d run them both at 45. Your basic takeaway is that lower is better.

1. Jay says:

Thanks Philip!

11. Herman Kloet says:

Spreadsheet can’ t be opened because it contains older graphic objects.

1. Rats. I’d like to start from scratch with a fresh sheet.