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PostPosted: Sat Nov 30, 2013 4:57 pm 
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Location: Ruidoso, NM
petepeterson wrote:
For the record the enve 25 rims are 35gr heavier not 200. You'll be fine.


All the big carbon rim manufacturers (with substantial R&D budgets) have tried to make rims that light... and they don't anymore. Does that indicate anything to you?

It would take a lot of faith to believe that an obscure Chinese company has done it better. They may be ok for light use, but no way are they robust general use rims.

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PostPosted: Sat Nov 30, 2013 6:30 pm 
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kavitator wrote:
I think ENVE has a reason to add weight on their rims - less overheated brake tracks-specially on low profile rims - less mass less cooling
Please explain further how overheating brake tracks is an issue with tubular rims/tires?


WMW wrote:
All the big carbon rim manufacturers (with substantial R&D budgets) have tried to make rims that light... and they don't anymore. Does that indicate anything to you?

It would take a lot of faith to believe that an obscure Chinese company has done it better. They may be ok for light use, but no way are they robust general use rims.


I don't disagree with you WMW. Whomever manufactured these rims is likely pushing the limits but it's worth considering what the degree of risk is with a weight difference of 10%? If they have 85 - 90% of the structural integrity of enve's would that make them unsafe? What I was more reacting to were erroneous comments (comparing them to clinchers or claiming they are 200gr lighter than anything else for example) dismissing them as dangerous because they happen to be lighter than enve and from china. It's not black and white.


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Posted: Sat Nov 30, 2013 6:30 pm 


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PostPosted: Sat Nov 30, 2013 7:13 pm 
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Overheating - very easy and fast. Specially with lower price rims where epoxy and all structure is less advanced than high end rims (enve, zipp, gigantex, hed...)
And with wrong brake pads you destroy rim very quick at 20% descend on full braking

for 50,60mm and deeper this is not so much problem becouse of large surface cooling is much better

not only cheap rims has this problem-also much more expinsive low profile (lightweigh, easton, ffwd, specialized roval...)

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PostPosted: Mon Dec 02, 2013 6:15 pm 
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:shock: :? 8) http://www.ebay.com/itm/Dimple-surface-full-Carbon-fiber-Road-bike-TT-bicycle-wheels-58mm-Clincher-/121225860208?pt=US_Wheels_Wheelsets&hash=item1c399fd470

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PostPosted: Tue Dec 03, 2013 4:06 am 
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Hi all,

Just wondering if anyone has tried the carbon rims from Light Bicycle http://www.light-bicycle.com/700C-carbon-road-clincher-U-shaped-45mm-rim-tubeless-ready.html#.Up1JINIW2So. Looking at building these as my first carbon wheelset. I'm around 82Kg and would use these for crits and general riding on flat to undulating terrain. Thinking of front 20 h radial and rear 24 2x DS/NDS with double butted spokes most likely DT comps or even Phil Wood as can get them cut locally. These would be laced to novatec hubs.

I currently ride kinlin xr270 front 24 2x and rear 28 2x and happy how these turned out, wondering if the carbon set will be the same stiffness or stiffer.


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PostPosted: Tue Dec 03, 2013 5:11 pm 
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Did you even look a few threads down and read the open mold wide aero thread?

viewtopic.php?f=113&t=103936


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PostPosted: Tue Dec 03, 2013 8:33 pm 
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Yes I did and there wasn't anything on the above mentioned rim.

Sent from my XT905 using Tapatalk


Re-edit- Apologies, I didn't get to page 38 of the above mentioned thread :oops: . Admin feel free to delete thread.


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PostPosted: Wed Dec 04, 2013 2:37 pm 
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I think everyone has spent to much time looking at the weight of deep profile carbon clinchers. Those 230g 20mm tubulars are similar to many 20mm rims out there. I have a set of similar planet X hoops. Now with two seasons of cross and one season of road racing on them. They have held up very well.


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PostPosted: Wed Dec 04, 2013 4:14 pm 
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Overheating has only been an issue and mentioned by anyone regarding in relation to carbon clincehers. Never heard of tubulars overheating, just the natural of the design.

With that said, my Zipp 303 FCs tubulars had excellent braking, I don't do big long descent, overheating in Florida doesn't exist. So it means nothing to me personally and would never be an issue and moot point from my perspective.

My HongFu 40mm Aero brakes fine, but the braking, with same pads/brakes, is not as robust as the Zipps. They definitely have the braking surface/R&D done very well and that is proven IMO. The HOngFu still stops fine, you have to squeeze a bit harder on the brakes, and it slows. Never an issue and concern for me personally in my terrain and environment of riding/racing.

Not sure how many people are doing 20% descents for extended periods. If that is an issue for some people, then some common sense says you should be running tubulars or aluminum rims from now on.

Otherwise, it just hasn't been proven ever an issue...and we all know the internet is the place for people to post these things for others to read/know about...still haven't seen a thread on it anywhere on any forum that I recall these about "overheating" and failure issues of carbon clinchers. Plenty of myth around, and the circumstances would be specific. Not that it isn't possible, but some common sense and practicality should prevent this from happening.


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PostPosted: Thu Dec 05, 2013 2:03 pm 
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If you do steep technical descents overheating is a real hazard. I can't do some of the mountains near me with clinchers. Part of that is the shitty condition of the roads but that leads to braking and overheating.

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PostPosted: Thu Dec 05, 2013 10:56 pm 
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I disagree with that statement, it's a bit of a blanket. The biggest factor is the rider. If you're the type of rider who is fearful of descending and grips the brakes like it's your duty, then sure CCs are not for you.

But if you actually descend and use the brakes properly, they'll be fine. I'm not sure where you - gjash - live, but out here we have plenty of horrible roads with very steep descents (12-17% averages are easy to come by, off camber, rutted, changing radius, falling rocks)... and to be direct about it: overheating of the rims has NEVER been an issue.

Here's a hint: don't use latex tubes in carbon clinchers and you'll be fine. ;)

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PostPosted: Thu Dec 05, 2013 11:15 pm 
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Are latex tubes related to carbon clincher rim failures?

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PostPosted: Thu Dec 05, 2013 11:47 pm 
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There's two types of failures due to overheating:
-blowout of tire (and with that, often the sidewall)
-delamination of sidewall, which can create a 'blowout' since the tire can't hook onto a failed wall.

Blowout of tire occurs when the heat is too high, raising the pressure inside the tube, and hence a blowout - which can often damage the sidewall of the rim because pressures were exceeded. Then people instantly point to the failed rim sidewall and think "it couldn't take the heat from braking"... which isn't an entirely accurate statement. Latex doesn't take heat very well, so the temperature of the air inside the tube increases dramatically which results in too much pressure on the sidewall, and hence the blowout of both tube and rim. This will happen with both aluminum and carbon rims, but more likely with carbon as it tends to 'warm up' faster than aluminum and transfer heat rather quickly to the tube. Aluminum rims are more likely to withstand the pressure of the increased pressure, so the sidewalls of the rim are less likely to fail. Well built carbon clinchers with well designed braking surfaces not only offer better heat retention, they also offer better friction against the pads - and therefore better braking. ZIPP is a great example of this, as well as Xentis. The open mold rims though aren't as far away as one might initially think: they're remarkably decent, if not great for most confident and experienced riders.

Delamination happens when the rim is not built properly and often with poor choice of resin used in the braking surface area. It's exactly what it sounds like: the layers of laminated carbon come apart when the resin wears away/melts. The sidewall then fails because it is weakened, and the pressure of the tube which normally pushes the tire into shape and helps keep the bead hooked into the wall then come loose and you get the blowout effect. It happens rather quickly and often the tube itself will pop when in contact with the surface of the road or other, so then you get a blowout...

Before anyone goes all gonzo and screams "thems chinese open mold rims are cheap!" keep in mind delamination has been documented on Lightweights, too, and all braking surfaces - aluminum or carbon - will wear away over extensive use. An aluminum rim which has a worn down braking surface will have less grip on the pads but also allow heat to transfer to the tube (the wall is thinner), which will result in a blowout.

So in summary, two types of failures are possible that both may result in blowouts:
1. Sidewall is fine but transfers too much heat -> tube can't resist heat, increases air pressure -> tire blowouts out and often sidewall is impacted from too much pressure, also failing.
2. Sidewall can't take the heat -> delamination -> tube/tire are no longer held in place -> blowout.

Butyl tubes offer greater heat resistance. But even with the fancy wheels of ZIPP and Xentis and their high-end braking surfaces: they state NOT to use latex tubes. Subtle hint at one of the sources of all the hub-bub in the past. :wink:

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PostPosted: Fri Dec 06, 2013 12:55 am 
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prendrefeu wrote:
I disagree with that statement, it's a bit of a blanket. The biggest factor is the rider. If you're the type of rider who is fearful of descending and grips the brakes like it's your duty, then sure CCs are not for you.

But if you actually descend and use the brakes properly, they'll be fine. I'm not sure where you - gjash - live, but out here we have plenty of horrible roads with very steep descents (12-17% averages are easy to come by, off camber, rutted, changing radius, falling rocks)... and to be direct about it: overheating of the rims has NEVER been an issue.

Here's a hint: don't use latex tubes in carbon clinchers and you'll be fine. ;)


I agree good technique helps for sure. You're right on latex! Wish I got that one before I sacrificed some skin!


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PostPosted: Fri Dec 06, 2013 12:58 am 
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prendrefeu, great post. Thanks!

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Posted: Fri Dec 06, 2013 12:58 am 


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