Podcast: PLEASE address tire pressure guidelines!

I just started cycling in April, so I have to “get faster” and “get smarter” at the same time. I’ve learned a lot by reading online, watching the podcast, and asking the awesome folks at Mack Cycle… but on tire pressures, I can’t seem to get a straight answer on tire width, tire pressure, even whether to use the same pressure front/back: the recommendations are all over the place.

What’s the official TR position (if any) on tire width, pressure, and front/back differential? More specifically, how should a specific rider determine the right tire pressures for him/her given rider weight, tire width, road surface type and quality, and so on?

If additional data is helpful, I’m a chubby (100 kg) 47-year-old male, riding a Cannondale Synapse Carbon Hi-MOD Red eTap in flat, hot Miami (Florida). I’ve just switched to Vittoria Corsa Control tires, 28mm wide, both at 100 psi. My priorities are: #1 avoiding flats, #2 going faster, #3 comfort, and I’m hoping to race 50km and 100km time trials eventually.

Thanks for all you do to help the rest of us GET FASTER. Remember the beginners in the group too! :grin:

This has been addressed on the podcast many times.

Yes, they agree with the trend toward wider tires and lower pressures.

Thanks for your reply. I’ve just edited the question to add specificity. So OK, the trend is toward wider tires and lower pressures. But for ME, on MY bike, how the heck should I determine what the “ideal” pressure should be, and/or what a reasonable range would be?

Some people say I should be running 80 psi or less on my new 28’s, while others say I’m at huge risk of pinch flats unless I run at 100 psi or above. And most of the examples I can find are for people who are 20 to 40 kilos lighter than I… and obviously that’s going to make a difference.

Check out the Silca Tire Pressure calculator https://info.silca.cc/silca-professional-pressure-calculator

While the TR folks are knowledgeable on many subjects, tire pressure isn’t one of their specialties

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Thanks, @AlphaDogCycling. I would think tire pressures are something EVERY serious rider, especially a racer or coach, should be interested in and aware of. But it’s bloody hard to find serious data or research out there. That Silca link you posted looks fantastic, and I’ll read my way through their blog to understand it better. Thanks for that.

Silca says I should be running 78 psi front, 81 psi back. I find it unsettling that there are such wildly different recommendations out there from serious people… :grimacing:

Don’t stress so much over it and go ride.

You’re in the right ballpark, but there are a ton of variables here that make it hard to have a specific recommendation.

Basically without a lot of fancy testing equipment for your setup specifically, nobody will be able to tell you exactly what pressure to run given your tire/wheel/weight/road condition combo. You’d have to spend a whole bunch of money to save like 1-2 watts?

Basically what I’m saying is you’ll never know, so why get stressed over it. It’s close enough. Let it go.

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Pay attention to Silca recommendations. Josh made a living out of helping world tour cyclists find (among other things) the right pressure for the surface/tires/weight they were riding.

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I’m a big guy (circa 95 kg + bike) and I’ve just put my details into the Silca page and got very similar number to those I’ve found by trial and error over the years. Seems like a great starting point to go from!

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+1 on the Silca calculator. In addition to those guys knowing their stuff when it comes to tire pressure, everyone I know who has used it (myself included) has found it gives them a number very close to what they’ve determined to be their optimal pressure.

As for why you get so many different recommendations, it takes time for the collective mindset to change on these things. They become habit. We used to think that the best ride was from 19mm tires at 120+ psi. Some people still can’t wrap their heads around the fact that a wider tire and/or lower pressure might be faster, or they just haven’t tried it. Those are the people telling you that you need 100+ psi in your 28s.

Getting the right pressure will make you faster, but it will also make riding so much more enjoyable. You’ll be more comfortable, you’ll have better control and more confidence. The one thing is pinch flats. Avoiding pinch flats requires some skill at un-weighting the bike, and that will come with experience. Personally I am of the opinion that anything that is going to pinch flat my tire is going to get me whether I’m at my optimal low pressure or a much higher one. So I’d rather run the lower pressure. Or you could go tubeless, and then you can’t really pinch flat. Now there’s a concept.

I have opinions on tires. They are what I researched at university, and now they’re one of the cornerstones of my performance in bike racing. I’m happy to answer any questions to the best of my ability, just give me a holler.

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Also be sure to give the Marginal Gains Podcast a listen. Lots of great info from Josh on it along with great hosts Eldon “Fatty” Nelson and Michael Hotten from the Leadville podcast.

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You won’t pinch flat at that weight at 80psi.

Trust me (sadly)

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I am a similar sized rider and had good success this year running 87 PSI at the start of rides on a similar set up. I would drop to 90 PSI and then play around with it from there +/- a couple PSI.

Tyre ‘size’ and your weight is only part of determining pressure.

Rim width changes tyre width, rim width and shape can impact volume, your bike and position on a bike can change weigh distribution (which also changes under riding).

I run Schwalbe One 28mms on one bike and they run over 30mm. Mega comfy, grippy and seemingly not cost to speed.

Road surfaces encountered also should be considered. If a route is marble smooth I would up pressure no doubt, if rough go lower, if wet likely lower anyhow.

Trial and error is the answer then assuming little variance in road surface maybe one go to dry pressure and one go to wet pressure.

If you want such a specific number then why not test it for yourself? Go out on the lower pressure and see if you get pinch flats

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I’ve used the SRAM tirewiz app (or however you spell it). Yes it’s for use with their expensive little pressure doo-dad but there’s a suggest pressure button in there that asks for all the pertinent info and spits out a decent pressure. I use the suggestion with my 25c GP4000s and it feels almost as good as my 28s.

On a side note, in regards to all these lower pressures where do manufacturer minimums come in? Like if my specialized roubaix 28c has a minimum pressure written on the side of the tire that says 80 psi but the tirewiz app says run 70, what’s the concern with going below the manufacturer minimum? I haven’t had any issues but I’m just curious why some companies list a minimum and some don’t and when/why we should pay attention to them.

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Just tried the TyreWiz app. Seems to be bit loe on the pressure compared to what I’ve used. But that could be me playing it too safe for pinch flat prevention.

It doesn’t address tubes vs tubeless or road conditions, but it is a decent starting point from my tests on road and MTB setups.

FWIW, my road bike setup is 25cc tubeless @ 90psi, I’m 160lbs. Never a pinch flat. I’m also a mountain biker and used to lower pressures for a more supple ride.

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I’d say that’s pretty close. I have 28mm gp4000, which are probably a hair larger than your tires, and I,m a bit lighter at 185lbs.

I run about 68F, 72R. Never had a pinch flat save for ramming into a couple massive potholes in a pace line that I never saw. Ones that would have easily flatted larger tires, and I’m surprised didn’t damage my rim.

I’ve run my tires as low as 50-60 psi on the road. They ride just fine, with no pinch flats. I don’t think they were significantly slower either…but they do FEEL squishy when below 65 or so.

I’ve dropped pressure down below 40 for some impromptu CX practice or trail riding, which then led to road riding home on the road. They were fine (but noticeably soft).

Don’t stress about lower pressures. You have a much, MUCH greater margin for error with a 28mm+ tire than you do with a 23. Also…so much of this comes down to personal preference IMO. There is a very large range of reasonably acceptable pressure for any given tire. And there won’t necessarily be an optimal pressure that is the same for speed, handling, comfort, reducing risk of pinch flats.

That said, prioritizing puncture resistance and speed, you can probably assume the best pressure is somewhere between 65-85psi. So play around in that range and just go with what you like the best in terms of feel.

And sorry about the long post - I keep thinking of things to add on. Don’t necessarily assume that higher pressure will reduce the risk of flats. I’m of the opinion that higher pressure and harder tires can INCREASE punctures, as glass shards and things have a stiffer surface to press into when run over.

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One more plug for the info Josh Poertner (Silca) has put together on this. He has a deep-dive blog post on tire pressures here:

It was covered on this podcast:

I get my ongoing deep dive fix by listening to Coach Chad (Ask a Cycling Coach) and Josh Poertner (Marginal Gains).

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This. Toh-tally this.

For serious competitors and serious bike nerds, geeking out over a few psi is fine.

My method? I’d air up my 25s to 110psi (68kg rider) Monday morning and commute all week. Being lazy, I would do no more than a pinch test before each ride to check for a flat or slow leak. The tubes lost pressure slowly over the week, and before a long weekend ride, I’d air up, noting how far the pressure dropped (70s?). Monday had been harsh, Friday had felt a lil squishy, so I’d go 85/90 on Saturday.

I repeated the pattern out of sheer laziness, and if I changed tires or wheels, that laziness would inform me what I liked best. Easy and informative.