American Classic RD2218 Rims

[LloydP]

Has anyone seen/held these at all? As best I can tell they're not the same as found in any of their wheelsets. I'd prefer actual experience--I can make up all the conjecture and so-on I like on the basis of a few images and a cross-section!
I was considering getting some new wheels this year and had pretty much settled on something with the Pacenti SL23s, but these looked like a potential alternative.

[pam]

I think the only information about this rim on the whole world wide web is one builder's opinion in this thread:
http://forums.roadbikereview.com/wheels ... 16125.html
One other user on that forum also posted a picture of their cross bike running these rims.

These seem like they would be an upgrade all around from Kinlin XR19W and the only sub-400g alternative to Stan's Alpha 340 which have thin brake surfaces and don't hold tires securely.

[LloydP]

Interesting. As you say, that makes them sound like a decent alternative. The lower profile works for me aesthetically, so now I'll have to see if I can find some!

[prowheelbuilder]

We have built about 20 pairs of them since they have been released. They are better than the Stans Alpha 340's as they are torsionally stiffer. The only down side to them are the lack of a welded seam. For there weight I give them a thumbs up. However they will not be a super durable rim and they will give you a fair amount of vertical compliance which is great for rough surfaces but not great for high corner power scenarios such as Crits. I would not recommend building them with a super light spoke such as a CX Rays unless you are 160lbs or less and would not put a rider over 200lbs on them. Hope this helps.

[pam]

Thanks, that is helpful. Compliance is good for what I want, I'm not racing, and the extra tire volume for no weight over a XR19W should be nice. I realized these are almost exactly the same dimensions as the Mavic A119 rims I have on my touring bike, just ~375g instead of 540g.

[prowheelbuilder]

Just to be clear, these are not in any way good for touring. Would not want to see you stranded in BFE .

[pam]

I thought about clarifying that but decided against it previously. I'm definitely not touring on these, hopefully putting them on my light fixed gear build in the gallery.

[prowheelbuilder]

All the better as the rear wheel will be built more symmetrically helping to add the torsional rigidity.

[LloydP]

Sounds alright as I'm a shade under 150lbs. How would you compare them to the Velocity A23?

[prowheelbuilder]

Although the A23 may be a bit stiffer both vertically and laterally I prefer the tubeless profile of the AC 2218 and the 2218 is much lighter (by about 60 grams per rim which is roughly equal to 18 lbs per climbing mile in moment of inertia weight). Both are not that great when it comes to the seem as both are not welded. I am not as concerned about strength but more concerned about the seem shifting (which typically occurs during the stress relieving process). Its more of a pet peeve than a serious concern.
So my conclusion is if it were between those two rims I would pick the A23 for daily use and the 2218 for a great climbing wheelset or rough rough road wheel set (given your 150lb weight).

[WMW]

http://amplewritings.blogspot.com/2013/ ... eless.html

Note he says it was a NDS spoke. Since it is triplet laced I'd expect the NDS side to be most highly stressed (lateral forces) and the angle is extreme. Ideally a triplet rim should have an asymetric inner wall.

It also appears to have a small bead lip like the 340, so I suspect it will suffer from the same issue of some tires not hanging on very well.

[prowheelbuilder]

Have yet to see this happen with any of our builds using the 2218 rims. However it is very important that they not be built over 120 kgf.

[WMW]

Have yet to see this happen with any of our builds using the 2218 rims. However it is very important that they not be built over 120 kgf.

That one was built by AC. And it was a NDS spoke on a triplet, which surely wasn't too highly tensioned.

Lowering tension doesn't prevent fatigue on aluminum, but it can make it last long enough that you don't care.

How much does tension drop with a tire installed? On the 340s it's a lot.

[pam]

The rim pictured is ~310 instead of 390g and 21 instead of 18mm deep, meaning thinner walls. The user also says they had trouble bringing the spokes back up to tension once the tires were mounted but never says what tension is, leaving the possibility of user error. AC claims they use the same tensions for all spokes in a triplet wheel, meaning the spoke that cracked the rim should have been at full DS tensions statically, but potentially seeing higher tension than the DS in use from lateral forces on only 8 spokes.

AC is the only one crazy enough to make ~300g rims and there are few people crazy enough to use them for everyday wheels.

[WMW]

I have a set of early 340 rims that actually weighed 336g and 349g. 20f, 24r CXRays. Old Alchemy hubs that are ~20g heavier than the ACs. They weight 1185g... 1197 with Stan's tape. Versus the authors 1258g with tape. So let's call it about 70g heavier rims (pair). Which puts them at 377g each... roughly. Maybe the new ones are a little thicker at the spoke which would be nice.

And he increased the tension only to try to compensate for the large drop in tension with tires mounted, to keep the spokes from working loose. I'm not a big fan of tubeless rim design, especially with light rims. Tension always varies a lot depending on the tire that is mounted.

Rims like that are best for light riders anyway, and triplet needs a pretty strong and stiff rim to work well. I think it would be better with normal lacing and more spokes.