ZTR Iron Cross for road tubeless?

A few days ago I got a little bit obsessed with finding out what this rim is (apologize for crap photos)-

I did suggest that I could be a 700cc/29er version of the ZTR Olympic rim which they didn't make-

But now they do make them! -

"The new ZTR Iron Cross rim combines a stiff 17.5mm rim depth, a 20mm wide internal cavity, and our ultra-low-profile Bead Socket Technology (BST) sidewalls to virtually eliminate pinch flats under some of the lowest tire pressures you can run. At 385 grams a rim, the ZTR Iron Cross disc rim will make your next cyclocross disc wheel build considerably lighter but able to handle all the punishment you can dish out. The new ZTR Iron Cross disc rims are designed only for use with cyclocross tubeless tires and traditional cyclocross clinchers.

Black anodized finish for disc brake use only.

Fully tubeless compatible with our of 21mm yellow tape and 35mm or 44mm valve stems.

Size 700c x 23.2mm
Color Black
Hole # 32
Brakes Disc Brake Only
Weight 385g
ISO 622 x 20
ERD 600
Tape Width 21mm"

Personally I think they look perfect for fixed road usage, especially going tubeless with the 25mm Hutchinson Intensive Tubeless tyre for an ultra light weight, puncture resistant, and auto sealing wheels. It would also have the benefits of using wider rims on normal tyres giving better grip and feeling more like a tubular.

But, as they say in their specs, it's only for use with cyclo-cross tyres.
Now forgive my ignorance on this point, but aren't cyclo-cross tyres essentially just beefed up road or touring tyres with knobs on?!! (or slimmed down MTB 29er XC tyres)
What is to stop these being laced up and used with a road tyre?

I'm honestly asking for advice, explanations, educated guesses, and constructive criticism here, so if you do know something about cyclo-cross tyres that makes them different, or can help me work out if they're a feasible road combo, please put your 2pence in.

The advantages? -
Rim weight - 385g
Tyre weight - 320g
NO inner tube
Better grip and cornering ability
Minor (if any) aerodynamic advantage from small V section

Disadvantages? -
Er.... being too light and not carrying speed so well...?
Possible problems with smaller road tyres "burping" under heavy cornering?

In essence they have got a good XC rim, cut out braking surface to make it lighter AND stronger, and did it 700cc diameter.
WIN!! :D

all good, except cx tyres are larger than road tyres and run at lower pressure

the worry will be that using road tyres at road pressure the tyre may blow off or the rim not survive

however i am just a about to use a set of stans 29er rims for a cx bike (because the iron cross were not available) and there is a similar caveat about how high a pressure the rims can take when using inner tubes rather than tubeless

with inner tubes you can have a slightly higher pressure as the tub will help seat the bead of the tyre onto the rim, but the rims are not specifically designed for full road pressures

James- Are you using the ZTR Crests?

Out of interest, what is the consensus of opinion on pressure for cyclo-cross duties?

'Cause the beauty of running tubeless is that you can run lower pressures safely and I would be thinking about 60psi for road.

But I agree with you on the smaller tyres might not working out, maybe a 28mm...

What size cross tyres are you using?

i have yet to build the new bike

using a hope hoops/crest wheelset, will use 32mm tyres, probably start out with 60psi front 70 rear, but this is above stans suggested limits

interestingly stans are now saying that you can use a tyre and tube at the maximum rated pressure for the tyre with the crest rim

http://messageboard.notubes.com/viewtopic.php?f=1&t=3329

Ah ha! Thanks James!

The Iron Cross rim is 1mm thinner than a crest, and from their diagrams, appears to have just as thick, if not thicker, rim walls than the Crest 29ers.

I cannot see why this wouldn't work, after all, a tyre bead is a tyre bead, the tubeless systems might fit the bead a bit better, but the bead shouldn't be any different from cyclocross to road, and if you can use a standard non-tubeless cyclo-cross tyre on the Iron Cross, then you should get a tubeless road tyre on.

People are using 23mm tyres on 23mm rims, so I see no problem with 25mm tyres fitted to 24mm rims!

join the stans forum and go and ask some questions

the great thing is that employees of the company chip in on a regular basis

it was interesting to see that they now reckon the rims can take a full pressure tyre and tube combo, that had been my one minor concern about using the crests as a road/offroad rim

i am now even more excited about the commuto x bike

Yeah, I know what you mean!

If this works out right, these will build up into a shockingly light commuter/city bike.

And they've already said the Crest 29er can be used for the road at full pressure, so then the Iron Cross, which uses the same technology, but in a different design, should work equally well too!

I'll check out what they say on the forum.

interesting to note that the crest is a few grams lighter, but the iron cross is a deeper profile rim, so will actually probably have a lower rotating mass, as more of the weight is closer to the hub

i assume you are planning on using these for a brakless skidder bike

^ Yes, do think the tubeless might not work for a rear, but as I want it for the front, not an issue.

^^ The Crest has the shoulders the Iron Cross lacks, which make it marginally more aerodynamic, but more importantly, should make the nipple bed area stronger.

james, angel, should I go crests or iron cross then?
cross seemed like a better option but after your problems AngelD i can reconsider
low flange hubs, that wont be a very heavy riding
road only, 23 or sometimes 25c

i am no expert, my crests are fucking bombproof, there was half a brick in the middle of the road that i hit in excess of 20mph and the wheels are fine (but am using 32 mm tyres)

possibly if you are using narrower tyres the iron cross may make more sense

Tbh, I don't think you'll get a 23c tyre to work on either rim. I know the Iron Cross rim on a 25c will work ok as long as there is enough clearance to allow for a little flex, mine was just too damn tight.

I was just about to build up a pair of wheels with these rims: http://bor-germany.de/en/product/46-bor-333xmd-29er-355-g
but reading this thread made me nerveous about the pressure limits.
I plan to use these mostly on road with 30c-32c tyres, what pressure should I aim for? Do you think the rims will hold up for it?

TYRE PRESSURES:
Tire Diameter: 1.75’’ to 2.35’’
1.75/1.8: 2.2 bar - 3.5 bar (32psi - 50psi)
2.0/2.1: 2.0 bar - 3.2 bar (29PSI - 45psi)
2.25/2.35: 1.8 bar - 2.9 bar (26psi - 42psi)

So it looks like their implying the rims will be able to take at least 50psi. Are you going to want any more than 60psi on 32mm tyres?

If you search on line there's a calculator for working out your ideal tyre pressure based on your weight and tyre combo.

the ztr people said that when used with road clincher max inflated should be as advised on the tyres

Any more information than what they did say they could be ever say you are?

;)

So it looks like their implying the rims will be able to take at least 50psi. Are you going to want any more than 60psi on 32mm tyres?

If you search on line there's a calculator for working out your ideal tyre pressure based on your weight and tyre combo.

I'm just a bit unsure that I can extend the chart below min tyre width.
but I guess it would go something like this:

TYRE PRESSURES:
Tire Diameter: 1.75’’ to 2.35’’

1.25/1.5 (38psi - 65)
1.5/1.75 (35psi - 56)
1.75/1.8: 2.2 bar - 3.5 bar (32psi - 50psi)
2.0/2.1: 2.0 bar - 3.2 bar (29PSI - 45psi)
2.25/2.35: 1.8 bar - 2.9 bar (26psi - 42psi)

the ztr people said that when used with road clincher max inflated should be as advised on the tyres

but these are not ztr and at 355g might be a bit more fragile.

The last question is still: will I die if I try this?

Any more information than what they did say they could be ever say you are?

trying to understand this sentence gives me headache!

Does anyone have any experience running ZTR Iron Cross or Crest with 28c tire and tube 60+ PSI?

Get the pacenti road disc rims as they are fine for road tubeless pressures

Thanks but I'm not really looking for road tubeless.

I want a wheelset to ride tubeless cyclocross in the winter (I race) and on the road with tubes in the summer (I don't race on the road).

Pacenti are heavier than Stans notubes.

I think the Grail would be perfect for you, rather than the more race focused Iron Cross.

http://www.notubes.com/Grail-C158.aspx