Spaghetti Legs 

I am a fairly inexperienced wheel builder. This is my third set. First two sets were 3 cross builds and came out great. This is a 28 hole Royce hub, 2 cross to red label Mavic MA40 rim. I planned it with DB14 spokes but found a deal on XL14's, but don't think that should make a difference. Anyway, per usual, triple checked all my hub and rim measurements, used two different spoke calculators and came up with 287.3 for spoke length, so rounded up to 288. I measured and ERD of 614 for the rim which jibed with what I found online for the MA40.

So now I have laced and relaced this wheel 3 times and it's clear the spokes are too long. First time I thought maybe I didn't rotate the hub enough, but didn't make a difference after paying particular attention to this. This is my first 2 cross build. I've posted a couple of pics just for critique and to see if anyone can spot any glaring errors. I have a homemade nipple driver with a 2 mm (maybe 3 mm, can't remember) slot and all the nipples are bottomed out in this pic. Valve hole is at the top.

I happen to have a bunch of 286 mm straight gage spokes, so I'll probably try to build up using those. Any advice appreciated!

Andrew R Stewart 

A common problem is having the second flange's spokes inserted one hole off in the hub. You'll get two loge and two short spokes as you tension up. Andy

Bill Kapaun

It appears there's a bunch of caveats in the spoke calc apps I looked at for that rim.
Measure your own ERD.
Take 2 spokes and run the nipple down to the screw driver flat.
Place them opposite of each other and measure the "gap" between J bends with your caliper.
2*288 +"gap" will be ERD.
Check in 3-4 different orientations to get an average.

I can't find that hub.
What's the spoke circle diameter?

Wilfred Laurier

If all the spokes are more-or-less equally loose with the nipples bottomed out, then, yes, your spokes are too long. If you do something wrong with the lacing pattern then other weird things start happening as Andrew R Stewart said.

Drew Eckhardt 

You shouldn't have rounded up if your length calculator didn't account for stretch.

Your front and rear drive side spokes are 1.7mm longer than they should be - 0.7mm from your rounding, about 1mm from 1.5mm spoke stretch at full tension.

Spaghetti Legs 

I use the Roger Musson book as a guide. It does seem as if some spokes get more tension in the current setup than others, but none obviously short.

The diameter is 67.6 mm. I did calculate my own ERD, but used a different method. I used two spokes with nipples, rubber banded them at the bends and measured across, added 24 mm for the nipples. I’ll double check using your method. I seem to recall using that technique on my previous builds.

Not sure if my calculators have stretch built in. I used UBI and Roger Mussons.

Thanks all.

Drew Eckhardt 

There's your problem - you don't add any for nipples.

Insert spokes into opposite holes, thread nipples to target depth, measure across elbows, and add twice the spoke length as specified by the manufacture or measured from J-bend to end. Repeat at 90 degrees. If that was different, do the remaining two 45 degree increments (some new rims are a little oval shaped). Take the average. That's your ERD just like Billy suggests.

desconhecido 

I don't think that your measurement differs from that offered other than your assumption to add 12mm for each nipple. I just measured a 12mm nipple and 12mm is the overall length. But, you want to calculate so that the end of the spoke just reaches the bottom of the screwdriver flat. From the hub end of a DT 12mm nipple to the screwdriver flat is about 10.9 mm. So, I think that you are over estimating the ERD by about 2 mm. That corresponds to my measurements of similar profile rims, 610 - 611 mm. Then, the rounding up and not accounting for the spoke stretch and I think that may be why they are too long. Of course re-checking the lacing to make sure you have what you intend won't hurt.

Bill Kapaun

IF I understand correctly, the nipples ate bottomed out and you still don't have spoke tension. Are all spokes equally loose?
If just a spoke length issue, I'd expect them to be quite similar.
If an indexing issue, I'd expect 2 different "sets" of similar tension.

Grabbing a DT 12mm nipple, there's approx. 3-3/4 turns from screw driver flat to bottomed out.
That's 1.7mm for your ref.

63rickert

It's going to happen once in a while. Measuring ERD is always a bit odd and clumsy.
Before buying new spokes also measure these spokes that aren't working. Most all spokes are now cut by vendor, not cut by manufacturer. So be sure it was not their mistake. Ya never know.

Mad Honk 

My take after looking at the pic is that Andy is right! The star pattern of the spokes should be the same on both sides of the wheel and in this wheel there are two star patterns. As for the ERD I use a steel ruler and get the inner diameter and then add 4 mm for the rim and cup depth. Seems to work fine for me. The rim appears to be an MA 40 what is the listed ERD ? JMHO, MH

Spaghetti Legs 

Well I got the wheel put together on the 4th try. I think the problem was multifactorial. First time I laced it I was off on placement of the key spoke (pics above are after 3rd lacing). I think that got me in a bad mindset compounding the other problems. I think on this third try I got really aggressive rotating the hub, thinking maybe that was the issue (Never built hub and the spokes were pretty tight) and maybe overdid it. This last try everything came together better. Spokes are still a little long but only protrude from the nipple maybe 1 mm on a few of the spokes. I appreciate all the advice and learned some lessons for the next build.

Mad Honk 

Spagetti,
E-mail me at home, or PM for the e-mail. But I have a four step process that always works and can't be messed up. Smiles, MH

Bill Kapaun

Often the problem is the 1st spoke of the 2nd set.
You can easily mark it with a felt tip.
Hub on the left is the more typical lacing when going CCW.
The "other" is used on some rims where the spoke hole exits the rim in the opposite direction desired.
(1st spoke of the 2nd set is next to the valve hole)

ign1te

U can basically make a large range of spokes "fit" a given rim and hub by making a subtle adjustment. Lace 1 side with 50% of the total spoke count for that side. Once you have done that, start lacing the otherside in a special way. Before you place the first spoke on the unlaced side, rotate the hub as much as you can. While the hub is in the rotated state, lace a spoke and put a nipple on it. What u have now is 1 side with 50% and the otherside with just 1 spoke. Different degree of rotation of hub will allow u to accomodate different size spokes. The greater the rotation, the longer the spoke can be fit.

What you are essentially doing here is manually changing the spoke-in-rim entry angle in the build. The fit will not be ideal, but it will most likely enable you to bring the wheel to tension wihtout bottoming out on the nipple.

seedsbelize 

Congrats. I also use Roger Musson as a guide. And it always works out. Though I do make mistakes at times. My most recent build took four tries to get it right. I no longer have resistance to unlacing and starting over. Wheel building is, for me, the most satisfying part of bicycle mechanics.

Bill Kapaun

I don't think it matters which method you use.

xlbs

Try X 3...that will take up the extra.

bikebikebike

Great thread
I had a similar problem on a 20" build on my first total build from scratch
with ~2mm too long after care measuring and use of multiple calculators to confirm.
I "enjoyed" working through my errors
There are lots of things you learn that are obvious to the experienced , but not things noticed by the noob, that are hard to share.
" Why are all those guys so old?"
"Because it takes time to learn."

sweeks

If the spokes are just a bit too long (maybe no more than a millimeter), it's possible to tighten the nipples beyond the point where they bottom out. This works because the stainless steel spoke is considerably harder than the brass or aluminum of the nipple, and will deform the softer metal as it inserts itself into the nipple. Of course, there still have to be enough threads left in the nipple to hold the tension, so there's a limit to how far the nipple can be "over-tightened".

rollalongnow

MA-40 should be 618.

trailangel

Mavic MA40 700 rim 613
Mavic MA40 27in. rim 618

countalmaviva 

Total noob question: Is it possible to simply grind a millimeter off the end of the spoke? Or will that result in too little thread remaining?

-Oliver Henderson