Tubeless options for CX racing

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sqber
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by sqber

Friend of mine mounted a "33mm" Clement PDX on a regular 19mm rim and it measured 36mm. Physics or poor production?

mattr
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by mattr

Physics.
The ETRTO tyre width measurement doesn't account for modern increased rim widths, or reduced rim wall height (both of which make the tyre larger). As far as ETRTO are concerned, 19mm is probably still an ultra wide DH rim.
Try an old open pro (15.5mm IIRC) then it'll be the right size. Or just get something like a 31, or one of the schwalbes, who appear to actually check their tyres WRT UCI rules.

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erik$
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by erik$

Last two rides I had the Terreno Mix 31 at 21/23 psi and it worked really well. Still not able to burp the tires when mounting, bunnyhoping or cornering on firm ground.

I am using a digital Topeak gauge and I have feeling that the pressure might be a tad higher than what it shows.

wheelzqc
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by wheelzqc

I've had good success running the Terreno mix at low 20's psi.

wheelzqc
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by wheelzqc

I mounted a pair of Specialized Terra Pro (33) for a UCI race this weekend. First they passed the width test easily. They weight 407-410g each (claimed 415). Thread kind of locks like a PDX but the I think the knobs are higher. They mounted tubeless easily. Grip is obviously outstanding on grass. It didn't rain as much as expected (just a bit) so it was not a mud fest. Sidewalls feel softer than the Vittoria Terreno line, I had to adjust pressure (more pressure for similair feel). So far so good and tempted to try their dry version Tracer Pro.

Marin
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by Marin

I mounted Panaracer Crossblaster tire tubeless yesterday, no problems. They are labeled as 31mm and they are exactly 31mm wide on 19c Light Bicycle rims.

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FIJIGabe
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by FIJIGabe

ms6073 wrote:
Tue Jul 25, 2017 1:15 pm
Can't really offer much in the way of recent CX racing on tubeless as I always raced tubulars, but I am enjoying nice all-conditions riding with Schwalbe G-One Speed tires, but I would add that these are mounted on Enve M60 wheels which are 100% tubeless compatible. I make that distinction because experience with the original, non-tubeless Enve Twenty9 XC wheels yielded less than stellar results despite using 3 layers of Stan's (now use DT Swiss tubeless tape), I could not get them the tires to seal reliably, and anything less than 35-psi resulted in several flats.
Did you race this weekend at Millican? I used my PDX's and didn't have any problems with traction, at all. How was your experience with the Schwalbe's?

wheelzqc
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by wheelzqc

I've been having great races with the Terra so far. outstanding grip, more than a PDX whichh was my favorite, and rolling resistance doesn't seem too bad. I've had races where it was less muddy than expected and they perform well.

Now I have a pair of Tracer waiting for a dry race. 350-360g each ! Knobs look soft and I'm curious to test out their grip.

erik$
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Joined: Sat Nov 15, 2008 5:26 pm
Location: Veneto, Italy

by erik$

What are your rim dimensions, @wheelzqc?
The Terra range looks very promising based on your impressions.

I still haven't had any bad experiences with the 31 Mix either. They feel sturdy enough at low pressures and have not burped on me yet on grippy surfaces. Rock and root strikes to the rim are the enemies when going too low, but the same goes for tubulars, so no big difference there. Will probably crack my rim on the next outing after saying that.

wheelzqc
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by wheelzqc

IronCross 20mm. The Mix33 was probably UCI safe was well, looks like antyhing around 34mm of actual size will be ok. I did enjoy the mix but the Terra has much more grip, obviously. It would be a fair comparaison to have it up against the Tracer, but it's been raining lately. Overal both tires, Terra and Tracer, have an interesting lower weight.

erik$
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by erik$

Great, thanks! Good to have alternatives.

erik$
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by erik$

Hello everyone! Donnelly's new pdx wc was reported at 33mm on a 22mm internal rim. Does anyone have other alternatives? The new Michelin power jet and mud look very interesting, not only due to their colour. Has anyone got their hands on these?

I have been playing with inserts in my tires since late summer and have used an Anaconda gravel 30 mm in the front and a polyurethane backer rod 25 mm in the rear. Both have held up fine and I will take out the 25 mm one and replace with a 30 mm Anaconda, just to see if there is a big difference. The 30 mm was tricky to install at first, but I think I have the technique down now. Will update later on.

wpccrunner
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by wpccrunner

sqber wrote:
Wed Oct 10, 2018 7:11 pm
Friend of mine mounted a "33mm" Clement PDX on a regular 19mm rim and it measured 36mm. Physics or poor production?
I also have a pair of 33mm MXP that measure 35-37 depeding on which wheels i use. There is also a terrible wobbl in the casing of both tires. I contacted Donnelly about the issue and their response was "yes we know of it"

Not going to be getting Donnelly's in the future when i need new tires

sqber
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by sqber

Now I'm a sad owner of Clement MXP myself. Purchased one in a sort of an emergency. They mounted and sealed well, but on 19mm rim they measured 35mm. Due to the width and the fact that they felt way too slippery for my liking, I had to buy Schwalbe X-One allround and life is good again :)

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FIJIGabe
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by FIJIGabe

wpccrunner wrote:
Fri Oct 11, 2019 9:36 pm
sqber wrote:
Wed Oct 10, 2018 7:11 pm
Friend of mine mounted a "33mm" Clement PDX on a regular 19mm rim and it measured 36mm. Physics or poor production?
I also have a pair of 33mm MXP that measure 35-37 depeding on which wheels i use. There is also a terrible wobbl in the casing of both tires. I contacted Donnelly about the issue and their response was "yes we know of it"

Not going to be getting Donnelly's in the future when i need new tires
The wobble is a common problem on their MSO gravel tires. They've known about the issue for years, and haven't fixed it. Very bad QC, if you ask me.

Also, oversized CX tires is pretty common, TBH. Unless you're riding a UCI race, or a race that has very strict tire size limitations, it doesn't matter. The only tubeless tire that I've ridden that was "true to size" was my old Bontrager CX0 file treads, but those tires were decidedly "meh" (heavy, stiff casing, decent treadlife).

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