Spokes...

[Dan81]

I'm having a wheel built up by Merlin (last time I asked the queue at Tarty was too long a wait) and they recommend DT plain guage spokes for 'heavy use'....

Tartybikes on the other hand recommend double butted spokes (so the centres flex and don't send the stress to the ends)....

...so I looked and Merlin also have DT comp spokes, which are double butted and recommended for 'freeride' ...so what's best to use for strength (DT plain guage or DT double butted)?

Help!

[psycholist]

Double butted will pretty much always outlast straight gauge spokes in a wheel. The main benefit is that the spokes in the wheel can maintain tension under load more easily.

Here's why:

A straight gauge spoke will stretch less than a double butted spoke for a given load thanks to the smaller cross section supporting the load in the thin section of the double butted spoke.

Spokes in a wheel lose tension due to loads being high enough or spoke tensions being low enough that the spoke pointing towards the ground on heavy landings etc. will become slack, offering no resistance to the spoke nipple unscrewing, leading to the wheel losing more tension.

Double butted spokes are stretched more in the wheel (If they're tightened to the same tension - if the straight gauge and butted spokes are carrying equal tensions, wheels built with either should be equally strong) therefore they require more deflection in the rim before they become slack.

Double butted spokes still fail at the bend or the first spoke thread, exactly the same as straight gauge spokes, so the change in cross section does not make them any weaker than straight gauge spokes, while they should resist loosening better.

Edited May 22, 2009 by psycholist