BikePGH Message Board Archive

Spoke Length, does it really matter that much?

I have decided to try my hand at wheel building and am just getting started on my research. The books make a huge deal about spoke lengths, being accurate to the millimeter. In particular that the drive side and non-drive side of the rear wheel have spoke lengths that differ.

When I use the online spoke calculators I find that the spoke lengths differ for the sides by about 1mm. Over the last year I have replaced several spokes on different wheels and the depth of the hole where the nipples sit are at least 5mm. So with 5mm of gap between the top of the nipple and the inner tube, whats the big deal about calculating spoke length down to the last mm?

Any thoughts, this seams to be making this harder for no reason. I measured the spoken lengths on one of my rear wheels, which is properly dished, and the spoke lengths are the same on both side (Albeit the spoke tension varies between drive and non-drive side).

eppi

2011-07-31 02:08:40

You need that "5mm of gap" to properly true the wheel. If your spokes are too long or too short and you try to balance the wheel you may find some of your spokes don't reach or are too long. This depends on your lacing pattern and hub flanges and rim depth and on depending on how complex you make it. At least that's been my experience. Also, depending on your lacing pattern, you may need 3 or 4 different lengths of spokes. It's a pretty involved process, but I came up with some cool patterns in my early 20s. I was into the "fashion wheel" fad like 10 years back. If you want to build the easiest wheel, you can straight-lace one. But those are extremely weak and usually used for racing.

humblesage

2011-07-31 03:19:41

Oh, and spokes stretch a little... Forgot that point.

humblesage

2011-07-31 03:21:08

The short answer: Yes.

Longer one: You can get away with about 2mm length difference than what the spoke calculator tells you. Most spoke brands only make them in 2mm gaps of length anyway, so it's not like you can buy 278 and 279mm spokes, more like 278 and 280. I normally fudge on the side of minimizing the spoke length differences across the wheel so I can buy in bulk, but for differences of more than 3mm between lengths from the spoke calculator I'll purchase different length spokes.

bradq

2011-07-31 08:22:00

^ What he said.

For alloy nipples it is very important to have the spoke length right on. You want the spoke to come almost all the way through the nipple or the nipple will break in half. For brass nipples it does not matter that much.

jwright

2011-07-31 13:04:49

Thanks folks. For the record, I am going with brass nipples and a 3 cross pattern. Spoke calculator tells me 291.6 and 292.9. I will probably build these this fall. Once I save up the $ for all the parts.

eppi

2011-07-31 15:21:26

your observation for the difference in spoke length on each side is only because of your rim, hub and dish combination. there are others where it will differ much more drastically (offset rim, etc)

dmtroyer

2011-07-31 15:30:11

I heard it isn't the length that matters. It is how you use them.

stefb

2011-07-31 20:00:01

Also, if spokes are long enough so that the edge of the nipple screws down much past the end of the threads, you also run the risk of stripping the nipple since not all the threads are fully engaged.

But you probably can get away with a single spoke length for that wheel.

johnwheffner

2011-07-31 23:47:49

Guys with short spokes also drive a Corvette

greasefoot

2011-08-01 00:53:02

You could go with 292 or 293 for the entire wheel. I would get 293's if you can.

jwright

2011-08-01 11:53:55