Cannondale CAAD5 slammed: Rim brakes and alloy frames aren't dead!

This is the thinking behind the wheel build

Aims & objectives

• Weight reduction, but not weight weenie territory. I want something reasonably durable
  
• Less affected by crosswinds, the 808’s are too deep for me
  
• Wider internal width and tubeless compatibility
  
  

Lacing pattern:
I love the classic look of rim brake wheels, low spoke counts and radial fronts, kind of the pinnacle of lightweight racing wheels before discs came along. So want to build in this vein. One of the issues though that you started to see at the end of this era was that the advent of 11sp cassettes meant you ended up with a lot of dish (and therefore spoke tension difference) between drive side and non-drive side spokes. This was more of an issue with 130mm spaced rim brake rear wheels which can work out with the NDS spokes being around 40-50% of the DS spokes, the result being higher likelihood of loose NDS spokes over time. This is less of an issue with 135/142mm spaced wheels which can sit around 55-65% difference.

So down the rabbit hole I went and there are only a few ways to improve this situation, asymmetric rims which have an offset bed or to go with 2:1 spoke lacing. Asymmetric rims are not typically available with carbon rims so they are automatically ruled out. This left me with 2:1 lacing, for those who don’t know it involves having double the amount of spokes on the drive side compared to the non-drive side, this has the effect of giving you much more even tension. In this case 130mm spacing with a 24h rear wheel (16:8 DS to NDS spokes) it would be about 80% which is pretty good. Also I wanted to try it for the challenge and it looks cool

Looks like this

However the spoke length calculation is not particularly straightforward, especially on the drive side spokes. As effectively there are 16 drive side spokes (like half a 32 spoke) but you are trying to fit it into a 24 hole rim and not evenly spaced…. So anyone who wants to know more about this read here:
https://spokecalc.io/two-to-one-lacing-pattern.php

You have to apply a correction factor basically to the crossing number, I chose to go with 2 cross on the rear drive side as it meant a very close spoke length DS/NDS and also slightly shorter spokes, they are almost near tangential in any case.

Front wheel lacing is just plain old radial, symmetrical so nothing really to talk about here

Front Hub:

Bitex RAF13 20h Radial lacing. Bitex has quite a lot of front hubs with most builds going with the RAF 12 (bigger bearings more durable and heavier) or the RAF10 (tiny bearings 688 x4 of them) for weight weenie builds. I found the RAF13 on Aliexpress, as it has the more aero narrower flange width of the RAF10 but with 2x 699 bearings. Marginally heavier, similar aero but probably less bearing drag as there are half of them.

Rear Hub:

Bitex RAR9 rear 24h (2:1 lacing). This is the lightest hub that Bitex makes for rim brakes, at <200g, great value and has a good reputation. Bearings are not weird uncommon ones as it uses the standard 6802 x 4.

Rims:
Light Bicycle AR56mm, graphene brake tracks. 20h front, and 24h rear (drilled for 2:1 lacing). I found the old Zipp 808’s too deep for general riding, having nearly crashed once or twice due to a cross wind. Also due to their vintage they were not tubeless compatible and were a narrow 16mm internally, 25mm GP5000’s measured 23mm on these. I decided on the AR56 as they are still quite light but decently deep and won’t catch too much wind.
Profile

Spokes & Nipples:
Sapim CX-Ray black & Sapim double square brass nipples. These nipples are longer on the inside which gives it more thread purchase on the spokes and also has the advantage of being able to be fully tensioned from the inside of the rim. I don’t particularly like alloy nipples as I don’t think the weight saving is worth the reducing in durability, strength and resistance to corrosion. CX-Rays don’t need much explanation, they are the gold standard and managed to get them for not too much £££