Help re:Spoke Length (and margin of error)

richa

Hi, I am looking to buy some spare spokes. These will be taken to stage races so that if I need a running repair after a stage then I have a suitable spoke handy.

The spokes are DT Competition Straightpull Spokes with a range (AFAIK) from 304, 305, 306 to 307mm.

Do I need to 'stock' spares in all lengths, or can one make do with slightly shorter/longer spokes?

What is an acceptable margin-of-error? 3mm ok?
Is it better to be longer or shorter?
What size spokes would you recommend taking as spares?

NB These spokes are very difficult to source, will probably have to be bought in packs of 10 @ £18, so it would cost £72 to take all 4 sizes.

Many thanks,
Rich

rrsodl

RichA wrote:

Hi, I am looking to buy some spare spokes. These will be taken to stage races so that if I need a running repair after a stage then I have a suitable spoke handy.

The spokes are DT Competition Straightpull Spokes with a range (AFAIK) from 304, 305, 306 to 307mm.

Do I need to 'stock' spares in all lengths, or can one make do with slightly shorter/longer spokes?

What is an acceptable margin-of-error? 3mm ok?
Is it better to be longer or shorter?
What size spokes would you recommend taking as spares?

NB These spokes are very difficult to source, will probably have to be bought in packs of 10 @ £18, so it would cost £72 to take all 4 sizes.

Many thanks,
Rich

A well built wheel should not break spokes. Spokes break due to metal fatigue which can be prevented by stress relieving the spokes.

You would need one length for the front wheel and two lengths for the rear wheel. Sometimes the difference between the two spoke sizes is small

say your spoke length calculator gives 287.9 DS and 286.1 NDS then you could safely get away with a 287 for either side. So, I suggest you measure one spoke from each side of the rear wheel and if the difference is not more than 2mm you could get something that works for either side. There are people that allow for spoke stretching and round down to 2 or even 3mm from the size given by spoke length calculators but I'm not sure it's a good idea, maybe I'd try it if I didn't have another option.

You can also consider that wheels that break spokes they tend to break spokes on the NDS (RHS) and gamble with spokes for the NDS only.

richa

Thanks. A sticker on the rim says 305/306 front, 307/305 rear.

This is on a 29" XC Mtb so whilst I hope not to break a spoke, I want to be covered.

I might just get a bunch of 305mm and hope that will do???