Wheel building Q's

[D▲NDY]

Hi,

I have a few options for a new aero wheelset, need some advice on lacing though..

First option,36h rear hub laced to 18h deep carbon rims (can possibly get 18front hub 28rear hub)

Second is 18 hub laced to 28..

Are both these possible? Which would be best? Will be for track duties..
Have consulted the book of sheldon, it has Something similar, 28 rim 36 hub, which leads me to think this could work.

Thanks
Dan.

 

[D▲NDY]

Swooooshhh...

 

[hamster]

The hub and rim have to be an integral multiple. So you can lace 18H to 36 by leaving out half the 36 holes.

18H to 28 would leave some areas of the rim with lots of spokes and some with none. Now, I'm sure that you could lace it up like some of the Campag wheels, but in the real world forget it.

 

[monty dog]

18 hole rim with 24 hole hub would probably work - 2 on DS to 1 on NDS but you'd have a job working getting the spoke lengths. Can't see how you'd lace a 18 hole rim to a 28 hub though.

 

[bm0p700f]

I am sure 18 to 28 will not not work.

It is interesting reading Gerd Schraners book on wheel building. He is quite clear less spokes mean heavier rims in general for a wheel that remains true through use. I am not sure what is driving the trend for the modern trends in spokes paterns you see these days, they do look good though. Take Fulcrums (campag) wheel. The rears all use 16 spoke on the drive side and 8 radially laced spokes on the non drive side (non drive side spokes are there simply to hold the wheel up and do not contribute much to strength). Howver if you are over 85kg you are advised to check your wheels for roundness/lateral run out every month or so! To me this is pointless as I am over 85 kg (88kg) as I would have a nagging doubt in my mind are my wheels going to give up on me on a long ride.

I see nothing wrong in 32 or 36 spokes in a three cross fashion laced to a light rim and quality hubs. As the rim is far from the axle you want the rim/tube/tyre combo to be a light as possible (within reason) to reduce the moment of inertia of the wheel. The spokes whose centre of mass (half way along the spoke) contribute much less to the moment of inertia of the wheel. The acceleration of the wheel is inversly proportional to the moment of inertia of the the wheel. So lower the moment of inertia for a given torque and you increase the (angular) acceleration of the wheel.

So I would pick a light rim with 32 holes and lace it up in convential way and a wheel that will last you years without truing.

But whatever you do 18 to 28 won't work in a convential way. 18 spokes to a 26 holes hub will though.