April 27, 2014 9 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.
#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.
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