Spoke Lengths - What to order?

[Caerus]

Just had confirmation from the wheel builder, he assures me that he is correct. Thanks for all the help

[kosmonooit]

Problem is if they are too long the nipples run out of thread and start twisting the spokes / mangling the inside thread.

[Caerus]

Strange one, I have now got a reply back from Stans No Tubes

 

"Our recommend lengths are here http://www.notubes.com/literature/Stans_hub_spoke_chart_2012.pdf

We use 260 & 262 for this build when we build it."

 

There is now a 2mm discrepency between Stans and my wheelbuilder( 262 & 264)

 

Who is right and who is wrong?

[splat]

Do the spoke calculators/Wheel builders take into account the stretch factor on the Revolution spokes?

[Minion]

Do the spoke calculators/Wheel builders take into account the stretch factor on the Revolution spokes?

Usually not. That's one of the reasons you need to round the spoke lengths down and even subtract a millimetre or two (I was wrong in my earlier post where I said to add length).

[Caerus]

So I just called Maverick Cycles who have a champion wheelbuilder there, and according to him, I will need 260mm & 262mm, same as Stan's No Tubes measurements. I asked about the "stretch" of the Revolution spokes and he said it makes no difference for any measurements.

 

So any suggestions? The Maverick guys built my first custom wheelset and not had any issues in over two years.

[Caerus]

So I get a reply from CRC now,

 

 

Thank you for your e-mail. To lace front and rear Hope Pro 2 Hubs to 26" 32h NoTubes ZTR Crest rims you will need 264mm and 262mm spoke lengths, this is based on a 3cross spoke lacing pattern using 14mm nipple lengths.

The configuration is as per below:

Front Disc side - 262mm

Front Drive side - 264mm

Rear Disc side - 264mm

Rear Drive side - 262mm

 

Kind Regards,

 

This is now the same as the first wheelbuilder. Would it be the nipple lengths that are causing the differences perhaps?

[b-rad]

also try the DT Swiss Spoke Length Calculator.

[Swift01]

The ERD on the Stans web site for most of their rims are wrong. JB measured mine for my ZTR Alpine rims and it was different to what was printed on the rim and website. Nearly all the rims were wrong. That could be why the DT swiss calculator is different to the wheel builder

[Johan Bornman]

You omitted one vital piece of information - the number of spokes in the wheel. You allude to 36, but the extra four could be spares....or not.

 

The Stans tech department is manned by dimwits. Don't expect an intelligent answer from them. If you go onto their support forum you'll see me ask their techies straight, exact questions and I get answers that don't relate to the question at all.

 

Stans' big problem is that they don't know what an ERD measurement is. ERD, or Effective Rim Diameter, is an imaginary point inside the rim (to the same on the opposite end) where the spokes should end. You can't see this pointand therefore can't measure it with a ruler or tape measure. You have to use a special tool.

 

Stan's don't have one so they guess. Not one of their stickers on any of their rims is accurate. Not one.

 

The best example is their Flow 29er rim where the claimed ERD is off by something like 100mm. Perhaps Ricky Bobby can post us a photo of the sticker on his rims and you'll see. An ERD that's off by 100mm will give you a spoke length error of just more than 50mm.

 

Spoke measurement is a bit of a scientific art. The scientific part is that you start off with the formula for a line in space - see http://en.wikibooks.org/wiki/Calculus/Lines_and_Planes_in_Space - and then we apply some art to it to modify it.

 

If you use the pure line in space length, then the spokes end up too long. This is because they stretch as they are tensioned and, the rim compresses.

 

Therefore we have to round down. By how much? That's the question that experience will teach you.

 

As a rule of thumb - on a large wheel built with Revolution/Lasesr spokes (thin 15mm spokes), you can round down by up to 3mm. On a small wheel (26") by up to 2mm.

 

On a large wheel with 1.8m spokes, by up to 2.5mm and on a small wheel with the same spokes, up to 2mm.

 

Nipple length NEVER compensates for poor spoke calculations.

 

The problem with online spoke calculators (and Stans' stupid guesswork) is that you never know whether you are presented with the aboslute length or rounded-down length.

 

A conscientious wheelbuilder won't allow a non-rounded down spoke to go into his wheels. This just complicates repair work later on.