Bespoke said:
What are the advantages of 2 cross over 3 cross if this is the case, i.e. negligible weight savings? In other words, if 3 cross is better, as fatsprintking suggests, why would anyone lace 2 cross?
Well it does make a "custom" wheel in that it is a little different. It is a little lighter and it gives you something to talk about.
In practice a rider would perhaps not notice a lot of difference for 95% of their riding between the two if they were a light weight, but you want your wheels to be able to cope with the the 5% of situations that push them to their limits and this is where the more robust wheel (3x) wins out. It just does not make sense to mess with this for the miniscule benifts of alternative lacing.
Both GM and Bustedknuckle have a lot more knowledge than me, but a low profile box section rim is still the best compromise for me for almost all my riding situations. I like ambrosio rims, for the reasons GM has outlined previously. Their reliability and toughness mean that I dont stress at all about 100 grams extra over the lightest rims. The interesting part of the equation should be the hubs (these will be the highest cost item in the build and the area where you can get 200g difference in weight- depends on how deep your pockets are), and then spoke and nipple choice.
I am big, and like sprints/power climbs. Where I train and race involves really rough roads and possible dirt. Even on my race wheels I run straight gauge 2mm spokes and brass nipples because I prioritise a stiff and solid wheel over 150-200g weight. I could perhaps get away with lighter spokes, but from a cost benefit point of view, what I have serves me really well and gives me peace of mind. You could get away with a really light wheel, but this does not mean that you should. The peace of mind and knowledge that you have a wheel that will cope with all situations is worth having
Also remember that tyre and tube choice and tyre pressure are huge factors in how a set of wheels feel. A great set of wheels can really have the edge taken off with the wrong tyres, and a great set of tyres can suffer from dodgey tubes. You have to look at the wheelset as a whole system.
Sorry thats a pretty long winded way of saying that there is not much advantage to 2x spokes and that you should be concentrating on other aspects of the custom build!!!!