Which gauge spoke to use

Njineer

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Aug 3, 2018
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Hey everyone I’m shopping for spokes to replace my wheels. I’ve bought shimano a 5lb Alfine 8 speed and a dynamo hub. The bike I got came with Sturmey Archer wheels. That come with 12 gauge steel spokes. I’m learning about spokes in the process. 2.3mm is 16 or 15 gauge is not sure but I believe a spoke advertised at 2.0 is a 14 gauge spoke. Then there’s single double and triple budded titanium or steel. I weigh about 180 and that’s my bike weighs about 80lbs. I just called and asked for the weight of this https://www.bikeberry.com/motorized-bicycles-diy/motorized-4-stroke-26-motor-ready-bicycle-w-2-4l-in-frame-gas-tank-diy.html bike it’s not the same but it should be close to what mine is. So that’s about 260 give or take another 15 to 20lbs for the 5lb Shimano Alfine 8 speed and all lights and accessories the dynamo hub is going to need a rectifier and I just score on a cane crake thud buster. So I believe I’m looking at around 270-275lbs. What material, gauge and number of “buds” would y’all recommend I buy.

 


Frankenstein

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Jun 24, 2016
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5,078
12 if you want to use a (stock) rag joint, for direct hub mounting and jackshafts you can use simple 15g without worrying, spokes are ridiculously strong otherwise when laced correctly, they would rather rip out of the rim instead of actually breaking in two.

The correct term is butts, not buds, I would completely skip butted spokes as they mainly provide a weight and air resistance reduction compared to single gauge spokes, you don't need either when the engine is doing the brute work and you aren't even racing (yet.)

It won't matter what size spoke you use when you crash or slam potholes, they will get out of adjustment during those type of things regardless. I can tell you if you invest in 12g they will be the last spokes that wheel will ever need, you'll wreck the rim and hub before they get a chance to snap. I would not exceed the size for the rims, and if they came with 12 then I would use 12s again because the beds (holes) for the nipples will be sized for a 12g spoke nipple, using smaller gauge will make for a semi-loose fit.

As the diameter of the spoke gets larger (like 2.3mm vs 2mm) the gauge number will get lower, 12g spokes are thicker than 14g, 14 is thicker than 15 and 16.

I would look at the maths for something like upping the crosses when lacing, that might be possible to do so you can just reuse the old spokes. By that I mean do a 4 cross instead of 3, or vice versa, if it were me I'd even try to find used wheels, eventually you come across the right length, usually for so cheap it's not even funny.
 

Frankenstein

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That’s great thanks a lot. I won’t mess with butts and just get straight spokes. This Alfine 8 hub on the website it says spike size 13/14. Does that mean I can only use 13 or 14? https://bike.shimano.com/en-EU/product/component/alfine-s7000s700/SG-S7001-8.html
That means the holes are meant to take between 13 and 14g without putting too much stress on the spoke elbow, using something smaller will put undue stress on that joint because the spoke just can't sit firmly in the middle of the bed on the hub, it just doesn't distribute the force evenly over that head and forces it to bend out which weakens it (and you'll have to adjust the spokes more while they stretch out, but that's just more uneven stress.)

What it really means is you should only use one of the 2 to help ensure you don't break a spoke, you can use very small brass washers on spokes that are undersized to help prevent that problem if you choose to go smaller.
This dynamo hub I got just says 14
But since you said 14 gauge would be smaller than 12 gauge. Than could the hub spoke holes be drilled out? Maybe that’s a common practice I haven’t learned about. Lol this is the first wheel I’ve had built like this. I’m not doing the work myself I’m actually looking for a shop near me that can do it. https://bike.shimano.com/en-EU/product/component/shimano/DH-3D37-QR.html
14 is smaller than 12 yes, and I am sure it can be drilled out, but I'm not sure if it's a smart thing to do. I have punched holes in a hub to take larger spokes by putting a standard punch with a tapered shaft that got bigger to match the handle diameter, basically I just used it to swedge the holes larger, that just means I hit it with a hammer until the wedge shape of the punch expanded the hole a bit, once it was bit enough to take the new spoke I stopped. I choose swedging because it is low risk to create points that could lead to stress fractures, drilling can leave sharp edges and nicks can make stress risers that could crack a hub flange. I've drilled rims before without problems, only steel however.

It is not common practice to modify hub by drilling, it's probably vehemently advised against by just about everyone, including me, the flange on a hub is usually bare minimum, most material will be like that on a bicycle, the idea is to cut weight (and costs) down as much as possible so there isn't a lot of play in those parts, it's how it is.

You should just pick up the largest matching gauge for the hub you use, generally speaking you won't need to maintain wheel true as often and you risk least damage to both hub and rim since the larger the spoke the more surface area the tension is spread across on both parts. You don't need to worry about weight and air resistance when you have a motor and in reality the motor will be harder on smaller spokes just because that's how it works, getting heavier spokes will benefit motored bikes out of nature.
 

Njineer

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Aug 3, 2018
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I really appreciate all your input I really do. If I’ve explained my self clearly and I understand you clearly. I would say with your help I understand that the largest spoke size I can use on either hub that I mentioned purchasing is 13 gauge. Also I’ve learned that I can achieve at least one gauge larger size spoke in the hub by lightly working the spoke hole with a light mallet and tapered punch. Which of the two options would you go for?
 

Frankenstein

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Jun 24, 2016
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5,078
I really appreciate all your input I really do. If I’ve explained my self clearly and I understand you clearly. I would say with your help I understand that the largest spoke size I can use on either hub that I mentioned purchasing is 13 gauge. Also I’ve learned that I can achieve at least one gauge larger size spoke in the hub by lightly working the spoke hole with a light mallet and tapered punch. Which of the two options would you go for?
Well if you want to use the same rim (and that rim is 12g) then I'd maybe punch the hub, especially if I had the right length 12g spokes on hand already. If not and I had to order it then I'd just likely stick to 13 after checking the fit on the rim (smaller might be ok, and may be favorable if the cross count is higher as the angle of the spokes out the rim will be greater, tightly bedded nipples don't want to rest at an angle as much and cause a bend in the spoke.)

If you are using the old wheel rim and spokes I would try to see which hub had the closest flange diameter to what you have now, if you pick one with a similar size then the old spokes should do the job. Are you doing a rag joint or plan to use a direct hub mount?
 

Frankenstein

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I used a punch like this.
mayhew-punches-nail-setter-sets-89052-64_1000.jpg


And I laid the hub over a vice (orange) while punching to support it to prevent bending the flange, 2 fair smacks (like enough to really make your finger hurt but not break or fracture it) with a normal 16oz hammer did it for me, basically test the water to see how much you need to open it for the spoke, it's not going to be much, it only needs to clear the threads on the end as they are physically larger in diameter than the spoke. A couple were only just big enough that I couldn't push it through from the inside (to bring the spoke to the outside of the hub, half of them are that way) but I could twist it and it would sort of thread through, I don't think that's a great idea but I only have so much patience so I dealt with it.
Note080418_1.jpg
 
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