Chinese Carbon, Disc Specific Rims?

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dvincere
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by dvincere

Are there any Chinese carbon disc specific rims out there? Particularly for CX. I'm actually interested in both tubular and clincher varieties, too.

It seems silly to buy a rim with a brake track when it's not needed and it seems potentially destructive to buy a rim that may not be built for the forces being applied at the spoke holes due to the disc brakes.

Any thoughts? Can one use a 29" MTB rim for this?

eric
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by eric

You can use 29er rims. But see http://twentynineinches.com/2009/01/15/ ... -29er-rim/
Light-bicycle has some disc CF 29er rims that a bunch of people on mtbr are using.

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MajorMantra
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by MajorMantra

...although some people claim it's not always quite that simple: http://paolocoppo.drupalgardens.com/con ... ake-matter

(I haven't tried though, and it may only be a problem with tubeless specific rims, I'm not sure.)

I'm also interested in answers to the OP's question. There are certainly already Chinese carbon 29er wheels. There are also plenty of matte black road options (Farsports etc.) with fairly unobtrusive brake tracks.

eric
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by eric

One other problem I just though of is inflation pressure limits. 29er rims often have low limits like 45psi or even lower. Perhaps not a problem for CX but 45 psi would not be good for road use.

bm0p700f
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by bm0p700f

No carbon disc specific rims for CX yet, which is a shame. The MTB rims I think will be a comprimise to far unless you are running CX tyres and riding off road then low pressure is all you want.

Gunjira
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by Gunjira

I think you can custom order light bicycle rims without brake track. Gonna do so myself with their tubeless road rims.

allardklijnstra
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by allardklijnstra

I think you can buy track rims wich have more spoke holes but they are generally tubular only. They shouldn't have a brake surface tho.

pushstart
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by pushstart

Yes, my LB U45 rims have no brake track. I didn't know to ask; I just told the rims were for disc-brake wheels and they spec'd them without brake tracks in the invoice. I imagine these would work well for cx (I am using them for road).

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bm0p700f
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by bm0p700f

No brake track does not mean the rim has been designed as disc specific. There should be a big weight saving for a disc specific rim. I doubt these rims show a weight saving so to me they are not properly disc specific.

pushstart
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by pushstart

No need to quote above

They are not disc specific, in design, sure. I believe Enve makes a road disc specific rim? In any event, I think the weight savings remain to be proven. There are plenty of disc-specific alloy rims and they don't seem to be saving any significant weight.

HillRPete
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by HillRPete

Oh there are lots of very light aluminium MTB rims for disc-only use, but probably the lower max pressure (than road rims) also allows to save material, in addition to not needing a brake track.

NovemberDave
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by NovemberDave

Weight savings for disc-specific road-pressure-capable clincher rims will likely prove not to be very big. At say 100 psi, the rim structure is working harder in its "tire attachment" role than it is in its brake track role. Bead hook depths can be lowered to alleviate this, but wider rims need structure to support their shapes. Add full, no limits road tubeless capacity to them and you might do as well as being at net even with a current rim-brake rim.

pushstart
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by pushstart

wassertreter wrote:Oh there are lots of very light aluminium MTB rims for disc-only use, but probably the lower max pressure (than road rims) also allows to save material, in addition to not needing a brake track.


So there are also lots of very light road rims with brake tracks. It is hard to find apples-to-apples comparisons, but e.g. Stans Alpha 340 rims (rim-brake) weigh 10g less than Iron Cross (disc-only, a little wider but also shallower). That is just one mfr, obviously, and not a great comparison but it suggests that any savings will be in the handful of grams. I would love to be wrong, of course.

Beancouter
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by Beancouter

I have used farsports 38mm cx on my bike. Whilst the moulding looks like it has a brake track, I don't believe it can be used for braking. The composition certainly looks different to the similar rims on my non disc road bike
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bm0p700f
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by bm0p700f

Well Ryde have a 25mm deep alloy climcher disc only rim that weighs 337g. So there is a weight saving for proper disc specific rims. This rim has an internal width of 15mm, can hold 1200N spoke tension and will take tyres inflated to 120 psi. So proven it is it is just no one has done it for carbon yet.

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