Abbey lacing stands are back in stock and improved!
April 27, 2014 11 Comments
Crack the code to everlasting wheels.
What’s the biggest overlooked feature in wheel building? Do you use it to your benefit? I bet not, but even still, you could probably use a reminder. Hint: it’s about spokes.
Facts
#1 - The single biggest weakness for cost conscious wheels is spoke breakage (also for many high performance wheels as well).
#2 - Spokes break overwhelmingly at the elbow (hub), secondarily at the threads (rim).
#3 - Stronger spoke material, larger spoke numbers, and thicker spokes decrease a wheel’s tendency to break them.
Solution: Beefy Elbows!
Builders pick spoke brand and gauge so let’s see what is possible.
Spokes as strong at the elbow as they are at the thread is the obvious solution. Do such spokes exist? Sure. Examples: Alpine (DT), Strong (Sapim), or DH13 (Wheelsmith).
Does anyone use them these days? Nearly no one! Ask the makers.
This is ignorance at a level we can't afford. We need ways to get people on bikes (new or old), persuade them to carry their gear, add features like pedal assist motors, lights, and suspension, and spokes are breaking left and right.
How do Beefy Elbows Work?
The three models just mentioned have 13g elbows (2.3mm diameter) but are 14g (2.0mm dia) at the thread end (so compatible with all rims).
Surprise to many, 2.3mm fit hubs drilled for 2.0. How? The rolled thread of a 2.0mm spoke is 2.2mm outside diameter. Rolling a thread, like plowing dirt, creates peaks and valleys (no material removed). To accept the thread while being spoked hubs are drilled larger, generally to 2.5mm. If you use a 2.3 x 2.0 spoke, the elbow fits perfectly.
Beefy elbow spokes work with 99.9% of hubs and rims intended for standard spokes. So let’s use them!
Beefy elbow spokes cost no more than butted. A set of 32 DH13 (single butted) spokes weighs 7g per wheel (32) more than straight 14g. That’s less than the weight of one spoke and that tiny weight is at the hub where it has the smallest dynamic effect.
How Much Better Are They?
Remember that a spoke’s fatigue resistance is proportional NOT to its diameter but to its cross sectional area.
That’s a whopping 32% increase for a paltry 7g/wheel. Equivalent to adding 10 spokes to the wheel. Experience shows this one feature can nearly eliminate spoke breakage. Combine with larger tires and you have a solution for every under-built, over-used, or over-loaded wheel.
For a review of the engineering behind spoke longevity, check this nerdy post.
How to Start?
Begin using beefy elbow spokes tomorrow! Tell other builders, mechanics, and product managers at once. Convince spoke companies to NOT drop these gauges the way they dropped many 15g models. Slow sales leads to the end of any product.
Pat yourself on the back for being a wheel guru; knowing cheap tricks, clever solutions, overlooked options; and spreading the word. No flailing around blindly, you’re a confident expert. Prove it by putting beefy elbow spokes to work.
By the way, since too few spoke distributors know about beefy elbows, Wheel Fanatyk now sells Wheelsmith DH13 blanks. Cut them to size with your Morizumi or Phil machines. You are also well served by equivalent products from other spoke companies.
February 12, 2024
The killer for rear derailleur wheels is the left-right tension difference. Single-butted 13/14g spokes deal well with the extra tension on the right, but you don’t really need them on the left and there’s a reason the wheel should last even longer if you use more elastic double butted spoke on that less tight side.
The trick is to match the spoke stiffness to the tension, so that both sides have the same elongation – just like a front wheel. And how often does anyone break a front wheel spoke?
The unequal elongations when the same type of spoke is used in both sides of a dished wheel means it doesn’t take much of a bump in the road for any left spokes in the bump zone to go completely slack, while the right spokes still have tension, so that part of the rim doesn’t simply move toward the hub, it also kicks over to the right! And if you build wheels, you’ll know how far a rim can deflect sideways in response to a modest difference in left-right spoke tension. This is why rear wheels go out of true and can even collapse in a Pringle shape without being hit sideways at all, but just from running straight over a bump in the road. A bit of rim is pushed toward the hub, the left spokes attached to it go completely slack and then the still quite tight right spokes yank it over in their direction!
Please think about it and give ‘Dish-Matched Spoking’ a try. Single butted are good for high stress wheels, but are even better IMHO with double butted on the less stressed side.
November 02, 2021
Hi Ric,
Excellent article, though I’m obviously a bit late to the game.
Any thoughts on actually building with beefy elbows? The 2.3 J-bend can make hard work of bedding down the spokes along the flange. They just don’t lay down snug like a 2mm gauge.
I recently built up a touring wheel with Alpine 3s and an Shimano LX hub. Had to resort to head washers to get the spokes to set decently. Not sure if that was ultimately necessary, but it seemed to help.
November 02, 2021
Just ordered some Sapim Force spokes to build up to some Velocity Ailerons to White Industries CLD hubs. 36h rear, 32h front. Should work out to a very long lasting wheelbuild. Interested to see how the Force spokes build up.
November 02, 2021
Ric, the benefits of extra meat at the elbow end are negated by the straight-gauge nature of the spoke at the thread end. The purpose of that but at the thread end is to protect the place with the lowest diameter, which is the thread valley. The diameter there is something like 1.8mm IIRC. By having the spoke shaft at 2mm, the strain is concentrated in the thread valley, By reducing the shaft to 1.8mm or lower, the strain is concentrated on the shaft where the smooth surface provides no stress risers and thus few cracks at either end of the spoke.
I doubt the durability of a 2.3mm – 2mm spoke has been proven, whereas the durability of a 2.0mm – 1.8mm – 2.0mm spoke has.
Making it thicker at one end may make it stronger (but we already have ample strength) but reduces durability, which is what we are after.
November 02, 2021
Ric,
I’m kind of stunned at the above comments… Having personally built about 6 touring wheelsets and a TON of Ebike wheels with Mostly Alpine3s I have never had one come back with a broken spoke! Many of the E-bikes are daily transportation.
I’m not sure why any one would say differently if they haven’t at the very least used them on a build. I do still build with mostly 2.0/1.8/2.0 and think for most of my applications they are adequate, but i Never hesitate to pull out the 13/14 when someone whispers E-bike… I don’t believe any wheel is forever though. Especially under those heavy commuter situations, and I’m very curious when/if I will see one of the wheels built with Alpine3 come back with a spoke issue. Have you seen any?
Anyways, haters gonna hate… so keep posting because I really enjoy all the WF Blog posts. Thanks!
November 02, 2021
DT Super comp spokes are widely used by many wheel builders, and at ~ 86% the diameter of the DH 13, are plenty stout for many applications. Just ask the Enduro racers…. This seems like a non-issue.
November 02, 2021
Care to elaborate on that last bit? Is their patent of PSR the reason we’re not seeing reinforced elbows on light spokes from the usual three for instance?
November 02, 2021
Ric, Always enjoy your site and blogs! Thank you… With regard to spoke gauge, my personal preference for wheel longevity is 36 × 14/16 gauge. The greater spoke count over 28 or 32, requires correspondingly less tension in each spoke, which in turn places less stress on aluminum rims and hubs, and more evenly distributes “shock” loads among a greater number of spoke resulting from encounters with pot holes, curbs, rocks and the like. Regards, BikinBobS
November 02, 2021
Beg your pardon, but the statement re. reletive cost does not hold water. The DH13 spoke is only marginally less expensive (at retail cost, anyway) in comparison to the DT Supercomp. And again, the later is widely available and utilized by many wheels builders for amateur (not pro) riders.
Further, the mathematics shown above appear to be in error; 2.3 mm is not 32% greater than 2.00 mm in ‘cross section’…that term (cross-section) typically equates to diameter. So; .3 mm increase from 2.00 mm is .15 or 15%—not 32%.
No debate from me that heavier gauge spokes can produce wheels that are less likely to fail at the ‘elbow’. Only certain details in this post appear to be a bit askew.
November 02, 2021
Ric, do you have any thoughts on Pillar spoke and their PSR (big elbows) series? Seems a lot of factory built wheels tend to use Pillar so I never gave them much thought, but after a look on their site they seem to have very progressive design.
Off topic: Spent part of the morning on a Moizumi today, and man alive, what a dream! Love using great tools!!
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PeteComo
February 12, 2024
One way around is to use washers on the bent end. Quality sold/sells a version from Bossard in packs of 1000. Part number S10332170011.
And yes, it’s a wheel business.