Spokes advice please

[Daddybus]

D'evenin all... I've got a 26 x 13/8" dynohub front wheel that I want to put into a 26 x 11/4" rim. Question is can I re-use the spokes? I know there is a 7mm? overall difference in wheel DIAMETER but would there enough tolerance in the radius length- I suspect probably no but has anyone tried?

 

[Spoked Wheels]

If the rims ERD are very similar then you have a very good chance that you can re-use the spokes. Why don't you find out the new rim ERD, measure the hub dimensions and enter the data on a spoke length calculator.

 

[e-rider]

D'evenin all... I've got a 26 x 13/8" dynohub front wheel that I want to put into a 26 x 11/4" rim. Question is can I re-use the spokes? I know there is a 7mm? overall difference in wheel DIAMETER but would there enough tolerance in the radius length- I suspect probably no but has anyone tried?

you need new spokes

 

[Daddybus]

Sorry ...ERD? ...I'm just going on tyre wall size 590 old wheel 597 new wheel. Cheers tho I'll have a look for a spoke calculator.

 

[Smurfy]

You need to measure the rims (I don't recommend relying on ERD databases). Many people, including myself, have made an ERD measurement tool using two spokes, two nipples, and a steel rule. For maximum accuracy, cut the spokes and file the ends square, rather than trying to measure between two spoke ends. For even greater accuracy, measure every pair of spoke holes and average the measurements (rims are rarely perfectly round).

See link for ERD measurement.
https://leonard.io/edd/howtomeasure

 

[Yellow Saddle]

You will need new spokes for two reasons. 1) They will be the wrong length for the new configuration. 2) If you do a spoke swap you have to make very sure that each spoke is in exactly the right L/R orientation as before otherwise you risk premature breakage.

 

[Smurfy]

By the way, you may find different spoke length calculators give slightly different results. This doesn't mean they are wrong, it just means they are based on slightly different assumptions or that ERD has been defined slightly differently.

My favourite is spocalc.xls by Damon Rinard, not least because it is Excel based, so you can save calcs for later reference. Be aware that Sapim's online spoke length calculator has slightly different convention for defining ERD, so avoid unless you understand the difference.

 

[Daddybus]

Wow ... Might need some time to get my head round it all!- cheers then

 

[Daddybus]

So if the general consensus is that its not possible to use the old ones...to avoid all the maths... !!! Could I just remove the old ones, measure, add 3.5mm for the extra radius, then order the closest available to?

 

[Yellow Saddle]

Just measure the hub and rim and I'll do the math for you. Do you know how to take the measurements?

 

[Daddybus]

@Yellow Saddle cheers I'll let you know...