Jim’s Tech Talk
By Jim Langley
Proper tire inflation is all important for a comfortable ride and pinch flat protection. It also protects rims and ensures optimum performance.
So, when I received an email from regular RBR commenter “fixieguy,” asking what psi to pump his new tires to, I was eager to help. Here’s his expertly explained question and after is my response. You’ll see that I need an assist.
Please read his question and my answer then, if you have used the tires fixieguy has and have inflation recommendations, it would be great if you posted your wise words in a comment.
I suspect you’ve addressed this subject in the past in Road Bike Rider or elsewhere, and I’ll be happy enough if you just send me a link to a prior piece of yours that addresses my question.
The question involves a pair of new Vittoria Corsa Graphene 2.0 tires (700 x 25) that I recently bought. I had reacquired a beautiful 1990 celeste Bianchi SLX fixed gear bike that I had sold to a friend back in 2015 and I wanted some tan wall tires to reflect the style of its vintage. These tires were well rated.
It happens that the recommended tire pressure is 85-147 psi. My usual tire is the Michelin Pro Race 4, which recommends 73-109 psi. In my young and foolish days, I would pump to the max, which usually was 120 pounds, until I was enlightened to the joys and benefits of bringing the psi down by a lot by your predecessor on RBR, Uncle Al.
It’s my custom now to pump to the midpoint of a recommended range. On the Michelin that is to 91 psi, which I find comfortable (BTW, I weigh 180 lbs.). The midpoint on the new Corsa tires is 116 psi, which just seems high. Now, I realize the simple solution is to ride the bike and try different pressures until I find whatever feels right; but that seems too subjective and I like objective criteria when it is available.
Besides that, it’s still winter in New England, and I’m riding my winter bikes with 30mm cross tires for now. I won’t take the “new” bike out until mid-March when the sand and salt is off the roads and I need not be concerned about ice patches.
Notwithstanding, I’d like your advice generally on the subject. I do not race so marginal differences in speed are not important. Comfort, tire wear, puncture and pinch flat avoidance are important. Other than the trial and error method, what is a better way to decide the tire pressure to use on these new Corsa tires or, for that matter, to choose to use generally?”
Thanks for the email and great question, Martin. What I’ll do is use it for my column this week. And that way readers should weigh in with comments on what pressure they run and hopefully for the same tires you’re using.
Unfortunately I have no experience with that specific tire to help me and I’m a 150 pound rider, which doesn’t help either. I did grow up in New England so I do know about winters there.
But at your 180 pounds and with the tires being 25c – fairly narrow by today’s trends (I still ride 25c) – I’m thinking 95 psi. That ought to give you a reasonably comfortable ride with plenty of pinch flat resistance. I have ridden other Corsa tires in 28c and they were supple tires that rolled great.
In case you haven’t seen them, there are at least a couple of online calculators for tire pressure. One is based on the late former Bicycling Magazine technical editor/engineer, Frank Berto. (I worked with Frank when I was with Bicycling 1988 – 1999.)
As far as I know, his was the first published research into tire pressure testing. It resulted in a chart you could use for determining your optimum psi/bar. Now, it’s available as an online tool at the link below. (Frank Berto is deceased so I have no idea whether there’s any affiliation).
Frank’s chart is older and his research was done before road rim and tire widths started changing so much and so frequently. Yet, you’re asking about a rim and tire width he would have studied so his data should be good.
Here is the Frank Berto online calculator:
Jan Heine in his publication Bicycle Quarterly also published and used Frank Berto’s chart and wrote about how to choose the best tire pressure. Here’s a link to his take:
And, Silca recently came out with their pressure calculator. That only makes sense for a company selling awesome pumps. That’s their gauge in the photo. An accurate one is key to ensuring accurate pressure settings and theirs is among the best.
I also recommend Josh Poertner of Silca’s blog posts on all things tires. Start with this one titled Tire Size, Pressure, Aero, Comfort, Rolling Resistance and More! https://blog.silca.cc/tire-size-pressure-aero-comfort-rolling-resistance-and-more.-part-1-how-we-got-to-now
I hope something here helps you find pressure perfection fixieguy. Now, it’s your turn readers. Thank you!
Ride total: 9,927
Jim Langley is RBR’s Technical Editor. He has been a pro mechanic and cycling writer for more than 40 years. He’s the author of Your Home Bicycle Workshop in the RBR eBookstore. Check out his “cycling aficionado” website at http://www.jimlangley.net, his Q&A blog and updates at Twitter. Jim’s streak of consecutive cycling days has reached more than 8,000. Click to read Jim’s full bio.