Under Pressure

A couple of things recently made me think about tire pressure and size. The first was a friend who was talking about the ‘feel’ of larger tires and lower pressures. The second was yet another good little GCN+ documentary; this time on Andrea Tafi. Tafi was a winner of 3 Monuments when he was riding for Mapei, including his favorite – Paris Roubaix, in 1999.

GCN’s Dan Lloyd asked Tafi, while riding with him in Tuscany, what he rode for tires in that race. He said 23s, at a pressure of around 90 psi. After a nice show of shock, Dan then asked him what he was riding right now, to which Tafi replied, ‘same’. They were riding on the gravel strade bianche and Dan said, ‘I’m riding 28s’! Tafi quickly says ‘too much’, in an unapproving manner.

I’m sure we’ve talked about the ‘wider tire, less rolling resistance’ thing before, which I have no opinion on, but here’s what I ride, for the record:

Colnago C59: 23s, usually at 100 psi

Bianchi Infinito: 25s; 90 psi

I think that once I get down to race weight, I’ll reduce those numbers by 10 psi each. I can feel the difference between my two bikes, by the way, but I don’t think I can say I prefer one over the other too much. The Bianchi feels a little ‘spongy’ in comparison to the Colnago, and not necessarily in a good way. I like to feel the road a little.

What are all you riding out there?

28 thoughts on “Under Pressure

  1. 25’s on the Canyon but I will try to go up to 28’s if possible on the rims I have. I think I have 23’s on the Cannondale but may have changed those to 25’s. By the way ‘Under Pressure’ – good song. Been trying to learn it on guitar over last couple weeks.

  2. Ask tony martin. 25, 70psi no tubulars.

    On my new wheels it will be front 23 back 25. Recommend by the designer to get more aero. Aero is my new argument, as i don’t get lighter..

    • Tony rides tire/tube? It’s certainly not slowing him down.

      I saw small-on-front, big-on-back recently, but can’t remember where. I’m not getting much lighter, either, so maybe should start thinking ‘aero’.

  3. For me the big win/win going to 25’s was not so much the rolling resistance argument, it was mostly for road conditions. I tended to slip in this damn road cracks much easier with the 23’s and therefore ended up with more punctures.

  4. 23s…. LOL!! I’m now riding 35’s with 40-45psi…when we rode to ADH I was riding 32s with 50psi, both tubeless. Comfy and not slow….for gravel racing, I ride 38’s tubeless with around 40psi sometimes 35 depending on terrain. A far cry from when I started racing 100 years ago on tubulars with120psi.

  5. I’ve got 26mm Specialized Turbo Pros on 25×50’s on the Venge at 85 psi. On the Trek, 23×38’s with 25mm Michelin Pro 4’s at 88 psi. I’m quite a bit heavier than you, though.

    • The Trek, btw, is a 99… I can’t fit anything wider than a 25 without rubbing the chain stays when I climb. I won’t go wider than 26 because they get too squishy during a sprint. I can feel the tire absorb energy at full power.

      • I even feel that way with my 25s a bit, but it’s probably my imagination. Also, we haven’t talked about aesthetics – a big, bubbly tire bulging out of your rims is just ugly!

        • Exactly! This is why I also gave the rim width with the height (23 x 38 mm). A 25 mm tire looks sleek on a 23 mm rim and slightly ridiculous on a 19.5 mm rim. My 26’s on the Venge’s 25 mm wide rims look fantastic – and they do smooth the ride out considerably. I’ve got friends who will go to great pains to make sure their tires are 1 mm less than their rim width (24’s on a 25 mm-wide rim) for aero’s sake. I’m not quite that picky about the whole thing because my top speed is about 35 on a flat… if I needed 40+, I might take it a step further. That said, I’m a lot happier with the wider tires as ride characteristics go. Both bikes are fantastically comfortable as I’ve got them now – and that’s saying something for the Venge (a notoriously stiff frame).

        • My next wheels will probably be wider because I don’t think I’ll have the choice anymore. Looking forward to the 25s looking normal!

      • I watched a video a while back that recommended finding a balance between cutting road chatter and squishy during a sprint… 88 is a little ridiculous but that’s where it came out. The ride is fantastic and I can give it my best in a sprint. And of course, this all depends on the pump I’m using, because the gauge only measures the pressure in the pump hose and pumps/gauges vary, even over identical pump models (I have two identical floor pumps and they’re about 10 pounds off at 85 psi).

      • On 700 cc wheels I can fit a 40 mm Schwalbe G One, but that leaves only 2 mm space between the tire and the stay bridge. Fine in dry weather, less than ideal in the wet. Right now I’m using 33 mm Schwalbe X-One at 2 bar. I’ve not yet tried 650 cc wheels.

    • I’m glad I had a coffee in front of me for that video – my head hurts now! Very interesting stuff, though, if you can follow it. Those guys make lovely pumps, too.

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