agnewton

I am building a set of wheels with a pair of used, Hi Flange Normandy hubs from the mid 70s. I don't have the original spokes, but I got them off a 75 Raleigh Gran Prix, Mixte with steel rims. I am new to wheel building so I am unsure of which gauge/ diameter spoke I should buy to build the wheels. So I'd like to ask you all before I plunk down $70 for a set in the wrong size spokes.

The wheel building books say that spoke hole diameters range from 2.4-2.6 mm, but my average measurement for these hub spoke holes is 2.35 mm (N=16). That's smaller than the same measurement for two other hubs that I have (A Used Shimano, dia= 2.57 mm; and a NOS Sunshine dia= 2.54 mm); Only a NOS Campagnolo hub I have is close (2.32 mm). I have test fit 2.3 mm and 2.0 mm spokes in the hub; 2.3 mm doesn't make it through the bend and 2.0 mm doesn't seat all the way into the hole in the hub. (picture below). I don't have any smaller spokes for further test fits in the hub.

I have seen 1.8 mm diameter spokes for sale on eBay. Would those be the correct size to buy or will they pull out when tensioned? Or should I buy 2.0 mm spokes and assume that when tension is applied to the spokes they will imprint into the softer aluminum hubs and be seated properly? I weigh about 200 +/- 10 lbs. if that should be considered in the spoke size decision. Have I overthought this?

Thank you all,
Aric

Nessism

2.0/1.8/2.0 (14/15/14g) are hard to beat unless you are very concerned about weight.

agnewton

So my concern about a 2.0 mm spoke head sitting above the hub shouldn't be a problem? In the photo, nearly the whole head is sticking out.

Bill Kapaun

It'll "look better" when you have spoke tension seating things.
Sticking a 16 ga. spoke in a 2.6mm hole looks much worse.

agnewton

Ok. I kinda thought that the spokes would seat with tension applied, but I have no experience of my own to reassure me.

Thank you Nessism and Bill Kapaun .

Aric

3alarmer 

...it's not a big deal. If you are doing this for the first time, straight gauge spokes tend to have less windup than butted, so it makes it a little easier on you, and they last for quite a while, even though all the wheel books say butted spokes last longer. I have wheels I built 20 years ago with straight gauge spokes, and I still ride them.

Either the 1.8 or the 2.0 should work in your application. The 2.0, with larger diameter at the bend, will probably last longer, and will build up a slightly stiffer wheel (laterally), but you probably won't notice the difference if you pull them up to proper tension. If you're a lightweight person, like 180# and below, probably the 1.8 diameter is a better choice. Above that, you might benefit from the 2.0 spokes. The head sinking down into the countersink in the hole is not a big deal, Mostly spokes break off at the bend, not at the head itself. Stress relieve the bends to avoid a shorter life for you wheel.

agnewton

Thanks for the guidance on choosing the spoke size 3alarmer . I ordered double-butted 2.0 spokes. The spokes will probably arrive next week. My "race weight" is 190# and the extra stiffness will be good for the 11 months a year when I am not at race weight. This my first wheel build where I have taken the hub and rim measurements and calculated the spoke lengths, so there is the potential for that point of pride if I get it right.

The spoke length calculator gave a spoke tension ratio of 66% and 100% for the rear wheel NDS/ DS. Whenever I have slackened and re-tensioned a wheel or the one time I replaced a flattened rim, the final spoke tension ratios were closer to 80% and 100%, but the wheel dish was still fine. Is the calculated spoke tension ratio a ballpark number or do I need to add more tension to the spokes?

3alarmer 

.
...the calculated ratio you quote is an estimate, and depend on how much dish you put in the wheel you build. So a rear wheel with a five gear rear cluster (not much dish), will be different from one with a ten gear rear cluster (a lot more dish, to make room for the wider cluster.) The primary concern is having the wheel rim centered in the frame, equidistant between the two lock nuts that fit in the dropouts.

I rarely even know what this number is. I just use a dishing gauge to center the rim, as I gradually increase tension to the maximum recommended for the rim by the manufacturer.

hydrocarbon

agnewton
You'll be more than fine. According to Sapim, 2.35 mm for 2.0 mm spokes is the optimal size.

https://www.sapim.be/sites/default/files/checklist.pdf

agnewton

Good to hear. The estimate part makes sense. The spoke calculator doesn't ask about the cluster. My freewheel will be a 6-sp, ultra-spacing and all of my other wheels are <= 7 sp. Knowing that the tensions are an estimate and would be less for the smaller clusters settles the issue for me. As well, my spoke tension meter isn't calibrated. So relative tensions and a dish gauge are the best I can do and I do the best I can. Thank you.

agnewton

Oooohh. That *.pdf with the formula is good info. My google search wasn't specific enough to find those notes about spoke hole size and spoke diameter. Thank you.