WGD

I've done most of my own work over the years but I stayed away from building wheels. I finally decided to try my hand at it and I'm trying to build a reasonably bullet-proof touring wheelset for a 1984 Univega Specialissima. Right now, I'm doing the front wheel. My components are:

Shimano 105 HB-1050 hubs (NOS).
Flange dia: 38mm
Flange offset: 35mm (both sides)

Velocity Atlas 700c, 36H eyeleted rims (new)
ERD: 605mm
Offset: None

DT Swiss Competition spokes, butted 2.0/1.8/2.0; DT Swiss 14mm chromed brass nipples
Spoke length: 294mm

I'm using 3x lacing.

Here's my problem. The wheel is laced up. I started out using Jobst Brandt's book but I thought I had screwed it up, so I took it apart before I tensioned anything and went to Sheldon Brown's site. I laced it up again and I have the same problem. The spokes seem to be too long. I tried several different calculators and got virtually the same result: between 293 and 294 mm. Following the directions from both sources, I threaded the nipples on a few turns. They seemed really loose, so I tightened them until the spoke threads were just at the bottoms of the nipple sleeves. Still loose. In many cases, the nipple heads still protruded from the inner wall of the rim. Finally, I turned all nipples until the ends of the spokes reached the bottom of the slots in the nipple heads. Some if the spokes have seated but there's no tension and some of the heads still stand proud of their seats. I'm a bit leery of proceeding. What am I doing wrong? I've measured the spokes and the length is correct (at least as far as the online calculators are concerned). When I thread a nipple onto a spare spoke, it bottoms out before the end of the spoke rises above the head of the nipple, so I have very little length to spare for tensioning/truing. Should I just give it up and order shorter spokes or am I missing something?

Note: One of the many sites I checked for specs on the rims gave the diameter as 605 (603). Does this mean the 605 ERD published in about a million places (including Velocity's website) is wrong?

Bill Kapaun

IF you only crossed 2, you'd be about 5mm too long on all spokes.
IF it seems only alternating spokes are too long, your indexing is off by 1 hole on the 2nd set. Note the the holes are offset from each other on the opposite flanges as in the attached pic

WGD

On the first attempt, I was 2 high, then 2 low (alternating). That's why I re-did it. Now, they're mostly even, just apparently too long.

FTB

Assuming that the wheel is laced correctly as you believe, I am almost certain that the mfg supplied ERD is incorrect. mfg supplied ERD are always off due to being measured incorrectly or wear on machinery. My nemesis rims I just built up some track wheels on are said to be 611mm yet as widely known, they are larger and measure at 618mm...
I am unsure how velocity measures ERD but too often mfg will measure the distance from the two spoke holes from the inside of the circle instead of from where the two nipple heads set on the outside of the circle if that makes sense.
This is the case with many chinese carbon rims but perhaps velocity too?

Measure it yourself from 4 different places in the rim and avg them.
The difference is (hopefully) >2mm

Edit: unpopular opinion but if your spokes are too long (by only a handful of mm) you can still build the wheel. In fact, the wheel should be more durable than if the spoke threads ended up at the end of the nipple slots only. I believe fanatik did an article on this. I always go for the larger of the size spoke I need instead of the other way around like sheldon etc (e.g. 297.2 --> 298mm)
I wouldn't do this if your spokes are tooooo long though.

daverup 

You could try measuring the rim to get another estimate for the ERD using the Sheldon Brown method,
https://www.sheldonbrown.com/spoke-length.html

Dan Burkhart 

I always measure because as you say, manufacturers data is frequently unreliable. I have found Velocity rims to be more accurate with the ERD in recent times than they were a few years ago though. I have several Atlas rims in the shop right now and I have verified them all to 605mm.
I would agree with the part about not worrying too much about spokes that are a bit too long. Ric Hjertberg's article on this stands conventional understanding on its head, and the many wheels I have come through here for repair with more spoke sticking out of the nipple than many would be comfortable with demonstrates to me that Ric has it right.
There seems to be lots of hand wringing on these forums about spoke threads bottoming out in the nipple before full tension is achieved, but my experience shows this is less of a problem than many think.

grizzly59

Can you post a picture of the inside of your rim showing the nipples and spoke ends? I'm baffled as to why the folks who actually make the rim can't post an accurate ERD. If you can figure out a shop that builds wheels with your rims, give them a call and ask what spoke length they use. Your hubs are going to be common dimensions.

WGD

I suspect this is what I need to do. If Velocity's published ERD is wrong, that could be why I found the (603) remark on the net. I'll try to measure it directly tomorrow. Unfortunately, now I can't find the site where I saw that.

I took a some pictures but I can't get one that really shows the problem. Basically, I have all the nipples bottomed out but there is still some slack in the spokes.

Retro Grouch 

Where is the first spoke crossing relative to the hub flange?

Jicafold

I have always used the calculator on the Pro Wheelbuilder site and it never did me wrong. Consider using that site. I follow lacing instructions on Sheldon Brown

https://www.prowheelbuilder.com/spokelengthcalculator

mack_turtle

This has happened to me as well, because I trusted the manufacturer ERD. In my case, it was a WTB rim. Always double check the ERD!

Steelman54 

The Brandt book works, so no issue there. I agree with others here, the spokes are most likely too long as the published ERD is probably a mm or 2 too large. I recently did a pair of Mavic open pros for a friend. He talked to a well known internet bike site and they made the recommendation on length for 3 cross. They were about 2 mm too long.

Geepig

I find that on your first attempt it helps if you have another similar wheel already with the target spoke pattern - so that you can refer to it. As I specialise in a particular brand of 24" wheeled bike, I already had several suitable wheels lying around with check to check my work.

cjenrick

get some shorter spoke,

3alarmer 

...just out of curiosity, at what point in the lacing process are you making the judgement call that the spokes are too long ?
Have you already made the hub twist, and laced up the third and fourth sets of spokes ? If so, then I have no advice. If not, that would be one answer.

Also, as already mentioned, if you get the number of crosses wrong, this will produce a similar result to what you are describing.

cbrstar

I think a thread like this needs pics! It's possible you did a 2x instead of a 3x etc. You also can't always go with the "factory" ERD because it might be calculated with a different sized nipples.

3alarmer 

...the only reason I'm asking, is because if you go with the old right triangle/trig function method of calculating spoke lengths, your spoke length (the hypotenuse of the triangle), is in direct relation (and constrained by) the squares of the other two sides (one of which is half the erd of your rim, the other the length along the hub from center point to flange.)

You mention that your spokes seem to be "too long", but I get the feeling, given your bottoming out description, that they are very much too long.

I have not run the calculation, but you can do it yourself. Run your spoke calc app using the shorter erd figure and see what you get. From what I recall from doing these wheel builds and spoke calculations, I'm uncertain that a difference of 2mm in the rim erd would result in such an overlong spoke, (in the world of a Pythagorean, at least).

dabac

ERD can be tricky. The last rims I built up used the surface that the nipple rests against as the ERD. While in build descriptions it’s common to give the ERD as the diameter where you want the spoke to end. Back when I used Spocalc, there was a piece about ”add 4 mm to Mavic official numbers”.

WGD

All spokes are laced and I've checked the crossing pattern several times. The spokes are bottomed out in the nipples and I still have little or no tension.

3alarmer 

...have you rechecked all your measurements ? The hub flange diameter, for example.
It would be helpful if you could post a photo of your lacing pattern as well.

I do try to get my spoke calc inputs as close as I can, but if I'm in a hurry, I just use the manufacturer's ERD.
A 2mm difference in ERD gets cut in half to 1mm in calculating the spoke length.

I'm still dubious that his is the only thing going on in your problem, but you are the only one present and on site.
I am unable to identify exactly what it is, over the internet and without the hub and wheel in front of me.

oldbobcat

Your measurements are plausible and I've never known Velocity's specs to be inaccurate. I ran your numbers through the QBP calculator and got the same length.

I refuse to offer advice before I see a photo of this wheel.

mack_turtle

photos or nothing!

is is possible that the spokes you're using are longer than you think? can you measure one to make sure it's the length you think it is?

desconhecido 

With your problem, it looks like you are using numbers in a spoke length calculator that will give you a useable spoke length. Probably, the ERD of 605 is close enough, but measuring ERD is a good thing to do. Park tool has a page describing a good method for doing this.https://www.parktool.com/blog/calvin...e-rim-diameter

When lacing, there are only a couple things that you need to be very careful about. First is making sure that the first spoke inserted will go into a proper hole with respect to the valve hole so that when the hub is wound up there will be easy access to the valve stem. Also, it's important to match the spokes on each flange to the proper holes as the holes in the rim are not exactly in the middle but are offset slightly towards each flange. Then, you insert the other matching eight spokes on that flange side.

Next, you have to insert the mirror image spokes on the other flange and you must make sure that when the hub gets wound up that the spokes will be in the proper holes on the flange and on the rim. Refer to Bill Kapaun's photo above. When you have determined the flange hole and rim hole for the first spoke on the second flange (10th spoke overall) insert it, screw a nipple on it, and test wind it. Make sure that the spoke is offset in the flange correctly. If you choose the offset in the wrong direction, trouble will ensue.

The third thing is getting your crossing spokes correct. For three cross, a spoke that leaves the hub in a clockwise direction will cross the first, third, and fifth spokes on the same flange, counted clockwise.

There are plenty of descriptions of how to successfully lace a wheel. Brandt's method, which is what I used to learn how to lace a wheel, and Sheldon's method will both lead you to success if followed carefully.

As a wag I'm going to suggest that your spoke length should work. If you are right that your crossings are correct, it seems likely that you may have chosen the wrong offset hole in the hub when you insert the 10th-18th spokes. But, it's just a guess.

Bill Kapaun

IF you laced 2X instead of 3X, your spokes would be about 5mm too long.
Going from 3X to 4X would use about 6mm more spoke length.
Why not just add a cross and see what happens.

trailangel

Pictures!...?? Where are the pictures?