I am not 100% set on the alphas, especially with kinlin rims available also from the BHS at a significant savings over the alphas. Superlight hubs, xr200s, Sapim lasers or DT revs, 20/28h, yes? That is a lightweight, inexpensive build.

It isn't 19/40... it's 17.25 and 38.25. You could have ~2mm more on the DS with S and still not hit the derailleur. Does it matter? An extra 2mm on the DS while maintaining the same tension ratio would result in ~20% increase in lateral wheel stiffness. Or you could keep lateral stiffness the same and make the NDS tension higher, which would increase the capability of the wheel for radial loads. Since this is an Alpha 340 thread... the lightest aluminum clincher you can get... then yes... it matters. You can compensate by adding more spokes, but that isn't an optimal (ie low weight, low aero drag) solution. Most of the people on this forum are pushing the envelope and "little" differences like 20% aren't trivial.

Rear wheels on modern road bikes are a big compromise... especially with Campy. All that dish and high spoke tension ratio comes with a cost in wheel strength and weight.

I'm pretty set on the 340s. I'm looking to use BHS hubs. I'm 150lbs and sprinting is my strength. Here's my proposed build. The front I'm pretty set on. It's the rear that I have more questions on.

Front build
BHS UL Front 20H, Radial, Sapim Laser, Alloy nipples

Rear options
BHS SL Rear 24H, 2x both sides, Sapim Laser, Alloy nipples
BHS SL Rear 24H (16:8), 3x DS, radial NDS, Sapim Laser, Alloy nipples

Please critique, so if you think I should use slightly thicker spokes or brass nipples, or some other lacing pattern, let me know. Nothing has been ordered. I just plan to use A340s with BHS hubs. I can even change the hole drillings if you think the proposed builds aren't sufficient.

Thanks.

Unless these wheels are only to be used for hillclimb races they're too light. You need more spokes or a stiffer rim to make a durable wheel.

Even with an XR270, 20 lasers and a BHS UL front (with its narrow flanges) make for a somewhat flexy wheel. It doesn't bother me but I'm a 142 lb climber. With a low profile rim like a stans 340 I would only use it on hillclimbs and would not be railing the descent. Under me your proposed rear wheel would be breaking spokes within a few weeks. The 340s have a low tension limit, they tend to detension when the tire's inflated (especially with tubeless), and the BHS SL211 rear hub has a somewhat large tension difference between DS and NDS. All that means that the NDS spokes will be going slack as the rim flexes. Ping, ping.

Maybe you're extra easy on wheels and never stand on climbs.

For some reason I have no issues with 18f and 24r, 170 lbs... railing the descents and standing on the climbs... but that is with Alchemy hubs.

I ride 340's. American classic hubs, revolution spokes . They weigh 1182 grms .I weigh around 13 stone and have had no issues. I did have some premium r sys and also some topolinos, all very good wheels, but a set of hand built wheels are hard to beat in my experience. Jon at Just riding along in sheffield uk built mine. The guy really knows his stuff.

this table http://www.notubes.com/literature/ztr_rim_specifications.pdf suggests 125 KGF for spoke tension on the road rims. and mine are good and tense.

also suggests nipple washers, which I never noticed before, and I've just finished building mine up. so my choices are - ride them & see what happens - or start all over again.

a few typos on their site - says to use 21mm tape instead of 12mm.

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dangerous curves ahead

Hey guys,

Recently my 340 set has been giving me troubles more often. They seem to get out of true and have a crazy horizontal and vertical hop. One of my mechanics had to spend 3 hours on the set. They are built such as: 340 rims, CX-RAY, Alloy Nips, to Alchemy hubs 20/24 Radial/2x both sides. I have been seeing some comments being made that Stan's does not like the use of CX-ray spokes? Is this a contributing factor on why they get out of true so fast or is it the amount of tension that is needed?

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2012 Izalco Pro 2.0*Re-Grouped*

Mine never go out of true... with CX-Rays.

Are you sure you haven't done something to put a permanent kink in the rim? If the rim isn't straight and round, it need to be replaced.

I think they are assuming that the washers will keep the spoke holes from cracking, but when I tried them, they apparently pressed on the rim sidewalls. I'm not sold on it being a good idea. I'd like to hear what others have experienced.

I have been using 340 rim/ cx rays and BHS 16:8 triplett hubs for 2000km with no issues. I am 74kg and the roads are fairly rough here. The triplett lacing evened out the tensions nicely.

what was your lacing? 3x DS and radial NDS?



since there isn't an eyelet, the washers serve the purpose and help distribute the load. i don't know where you got your washers from, but mine came from stan's directly and they fit nicely into my first A340 build.

I got the washers from Stan's also. Definitely distorted the rim more than without.

Looking to build up stans 340 on white industry h2/h3 hubs, both 32 hole. Going with either sapim laser or race, was leaning towards laser all around, with race on rds, everything laced 3x. I weigh 190 or less

I spoke to palligap the U.K distributor for STaan's about the use of washer on alpha 340's and they said the rim had ben redesigned so they were no longer needed. Not to sure from seeing there documents or from rruff's observation if Palligap are misinformed or not. Maybe rruff's observation lend support to Palligaps asertion and the document is old and out of date or simply incorrect.

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www.thecycleclinic.co.uk