Greetings,

I have a fulcrum 3 wheelset and its only 15C and therefore will only fit up 32MM tire per recommendation chart. Anyone here use a 33 MM cross tire with a 15C wheelset? I will be running this with tubes.

thanks

It'll work. Only potential concern is "wallowing" if you use low pressures.

That set up is what we used to call “totally normal.” It’s fine. The ETRTO recommendation chart everyone refers to is literally 25 years old and was never any good.

Good to know! I have an old front wheel with sun m13 rim (13mm of course) that I'll try to put into duty as a backup. Congrats on the podium, that one was unusually tough for me. When I'm on, that type of profile suits me, but not this weekend. Quad went more smoothly!

Thanks for the reply. The 15C will primarily be used for CX and running at most 40 PSI with tubes. Will that still be an issue?

40psi on a 33mm tire? That should work. I've ridden my tires like that, and they get a little squirmy on pavement as the tire is pinched a little.
ETRTO chart recommends 15c for up to 32mm, so you should be fine. The steering will be a little better with say a 22c, but run what ya got.

Depending on how much you weigh, they may get squirmy on any off-camber stuff. But other than that, it should be fine.

Thanks all. I weigh 160 lbs and right now run 40 psi using Schwalbe CX Pro which is 30mm. Coming from road it just "looks" too low.

The CX guys on my team are saying i should go 30-35 psi for better rolling resistance which seems counter intuitive since higher PSI has lower rolling resistance or tarmac at least.

So with 33mm tire can i go lower than 40 PSI?

Only one way to find out for sure.

Every tire, rider and course is a bit different, so it's something you should experiment with, but generally speaking your teammates are probably correct in saying that 30-35psi will be faster than 40+, assuming you can run that low of a pressure without pinch flatting. Lower psi will smooth out the ride and roll faster over bumps, give you more traction in wet/mud, but it also comes at a greater chance of pinch flatting. This is the basic risk/reward factor in CX tire pressure.

Generally you want to run the lowest psi possible. Clinchers with inner-tubes pinch flat much easier than tubulars, and they also have stiffer sidewalls so the benefits of running them at ultra-low pressures more diminished and also come with higher risks. Keep going down this rabbit hole and you'll quickly learn why tubulars are so popular for CX.

I weigh around 165lbs and 35psi is about the minimum I feel comfortable running my 33mm clinchers, but I'll run as low as mid 20's on my 33mm tubulars, and the newer Donnely tubulars don't even have an inner-tube to pinch (it's a tubeless casing), so I would imagine they can be run extremely low and still not flat.

Challenge accepted, bunny hopped a curb poorly at ~25psi and put 3 holes in my new PDX tubelss tubular. Was able to use a plug on the hole in the tread but the sidewall holes won't stay sealed. I think its done for...

Oh wow. That sucks, and your warning is noted. I haven't run mine below 30psi yet, but was gonna mess around in a park this weekend and see how low I could go with them.

I'll watch out for curbs.

I didn't think it was really an issue either with sealant but i guess sidewall cuts are always an issue. My fault for being careless and first time I've actually cut through the sidewall of a cyclocross tire tubeless or tubular

Any particular reason why you would just get a wider wheel? I'm guessing cost? Although, older rim brake wheelsets can go for like $125-200 around here. Pretty inexpensive, just want to look for the good hubs so you can rebuild them in future if needed. I picked up a beat up Major tom, White Industries set with tubular glued, used it a season, then re-built it and have it on backup bike now.

I run 28-32 psi with tubes on aforementioned set...but 19mm internal rim. Obviously depends on course. So with a 15mm internal you're kind of hot air ballooning the tire, which could lead to more pinch flats and squirmy feel.

My first cx wheelset was just stock generic, cheap and man it was squirmy. I didn't know it until I upgraded. Gives a lot more confidence in corners now and much more predictable.

Uh Oh!

I'm 170 and have gone down to 40psi on my ghetto tubeless set up. My kid is 130 and run his in the low 30s. I was afraid he would burp them on off-camber stuff, but he was fine.

And FWIW, Cody Kaiser advises going high pressure in muddy conditions to help the tire dig down to more solid ground. He says if you go low pressure in mud it will tend to float and skate over the mud. YMMV.