Sapim Strong J Bend Single Butted 14|13g - 2.0|2.4mm Spokes
The Sapim Strong is the spoke for wheels that carry a load. It is single-butted: 2.3mm at the head and elbow, tapering to 2.0mm for the rest of its length, so the extra steel is exactly where a heavily loaded spoke fails, at the bend. Tandems, e-bikes, cargo bikes, heavy touring rigs and big riders on rough terrain all get a stronger wheel from it, and Sapim cold-forges it in Belgium from the same 18/8 stainless as the rest of the range.
This page covers the J-bend Sapim Strong J Bend Single Butted 14|13g - 2.0|2.4mm Spokes. These spokes leave here only inside a wheel, cut to the length the rim and hub call for; choose the rest of the build in the configurator and it ships from Georgia laced, tensioned and trued.
Design and construction
A spoke almost always breaks at the elbow, where the bend concentrates stress and where the flange hole works against it. The Strong answers that with a 2.3mm elbow, about 30% more cross-section than a 2.0mm spoke, in a head that still seats in a standard flange hole. From the elbow the spoke tapers to 2.0mm, so it uses standard 14-gauge nipples and threads and builds like any other spoke.
Sapim rolls the threads and cold-forges the head, and makes the Strong in black or silver, J-bend and straight-pull. For the heaviest e-bike duty Sapim also makes the E-Strong with a 2.6mm elbow, which we stock for cargo and fat e-bikes.
Sapim makes the Strong in lengths from about 200 to 310mm in even millimeters, and a matching E-Strong for the heaviest duty. Because the thread end is a standard 2.0mm, the Strong builds with the same nipples, the same rim and the same tools as any other spoke, so the extra strength costs nothing in compatibility.
How it rides
A Strong wheel is stiff and stays that way. On a tandem or a loaded touring bike the difference shows up as a rear wheel that does not go out of true and spokes that do not break, which is the whole point. On an e-bike it gives the drive-side spokes the margin they need under motor torque. It is a little heavier than a Race and you would not choose it for a light road wheel.
We often build the Strong on the drive side of a rear wheel with a Race on the non-drive side, which puts the strength where the tension is highest.
Tandem builders have used single-butted spokes for decades for exactly this reason, and the e-bike boom has made the Strong one of the spokes we order most: a mid-drive motor puts torque through the rear wheel that a normal spoke was never designed for, and the thick elbow of the Strong shrugs it off.
Specifications
| Gauge | 14/13G |
|---|---|
| Profile | Single-butted |
| Material | Stainless Steel |
| Spoke head | Jb14|13 |
| Finishes | silver, black |
About this listing
Version notes: J-bend, 13g straight gauge, single-butted. A J-bend spoke has the elbow formed into the head and drops through a drilled flange, which is the older and far more common pattern. It fits almost any hub, replacements can be found in any decent shop anywhere in the world, and the elbow is the part that eventually fails - which is why it is seated properly and the wheel stress-relieved before it leaves us. If your hub has drilled flanges, this is the one you want.
Sizes, fit and compatibility
The Sapim Strong J Bend Single Butted 14|13g - 2.0|2.4mm Spokes is cut to length for your build; the configurator reads the rim's ERD and the hub's flange dimensions and works out the length. J-bend Strong spokes fit any standard J-bend hub in the catalog; the 2.3mm elbow seats in a standard flange hole.
We pair Strong spokes with brass Sapim Polyax nipples, always, because the wheels it goes into are the ones that see load, salt and years of service.
Inside a Sapim spoke
Sapim has been drawing spoke wire in Belgium since 1918, and the range is built around one idea: the same wire and the same head, drawn to different middles. A Leader is 2.0 mm all the way through. A Race is 2.0 mm at the ends and 1.8 mm in the middle. A Laser takes the middle down to 1.5 mm. A CX-Ray is a Laser that has then been flat-forged into a blade, which is why it is light and aerodynamic without being a fragile spoke. Every one of them keeps a full-diameter head and thread, because those are the two places a spoke actually fails.
Treat it as what it is. One test, five pulls per spoke, measuring yield load on a straight pull in a machine rather than a laced wheel under a rider - and it does not capture fatigue life, which is what actually ends most spokes in service. It is also not new; it predates Snyder closing. But it is a real measurement, on real samples, by someone with nothing to sell, and it is part of why Sapim is what we reach for.
These are the spokes we build with day in, day out. We stock the whole working range in both J-bend and straight-pull, in the lengths our builds actually call for, so a wheel is not waiting on a spoke order. If you are not sure which model your build wants, tell us the rim, the hub and roughly what you weigh and we will tell you which one we would use.
An independent spoke strength test
The manufacturing detail above comes from the maker. The choice of spoke for a given build is ours, and we will explain it if you ask.
Building it at ProWheelBuilder
Sapim makes the Strong in Belgium; ProWheelBuilder is an independent wheel builder in Georgia, not the manufacturer. We cut Strong spokes from the measured ERD of the rim in hand, lace the wheel by hand, bring it up to the high tension a loaded wheel wants with a gauge, stress-relieve it and true it before it ships.
The configurator recommends the Strong automatically for tandem, cargo, e-bike and heavy-rider builds, and only shows spokes that fit the hub you choose.
The nipple matters as much as the spoke. Brass is heavier, but it does not corrode, it does not round off under a spoke wrench after five years, and it is kinder to a carbon rim bed than alloy. Alloy nipples save about 30 grams a wheel and are the right choice on a race wheel that is kept clean. We stock both in every color the configurator offers and we tell you which we would use.
Warranty
Manufacturer's warranty. Sapim Spokes warrants this product against defects in materials and workmanship. The duration, conditions and claim process are set by Sapim Spokes and can change without notice, so ask us and we will confirm the current terms before you buy.
ProWheelBuilder. If we lace this into a wheel for you, that wheel also carries ProWheelBuilder's own one-year warranty, which covers broken spokes regardless of cause and all wheel-related labor, including truing and rebuilding, for a year from purchase. Where a rim or hub is covered by its maker, we make the manufacturer's claim for you and coordinate it; where it is not, we offer an eligible replacement rim or hub at 25% off current retail. Shipping to and from us is the customer's. This cover does not extend to wheels built from components you supply yourself.
Full terms are on our Policies & Warranty page.
Strong J Bend Single Butted 14|13g - 2.0|2.4mm Spokes questions
Should I take this in J-bend or straight-pull?
Whichever your hub takes - it is decided by the hub, not by preference. A J-bend spoke drops through a drilled flange and is what the large majority of hubs use, which also makes a replacement easy to find anywhere. If your hub holds the spoke head directly with no drilling, you need the straight-pull Strong, which is a separate listing.
Strong or Race?
Strong for tandems, e-bikes, cargo bikes, loaded touring and heavy riders; Race for everything else. The Strong's thicker elbow is where the difference is.
What is the E-Strong?
A heavier version with a 2.6mm elbow for the hardest e-bike and cargo duty. Tell the configurator it is a cargo or fat e-bike and it will offer it.
Does the Strong need special nipples or hubs?
No. It uses standard 14-gauge nipples and threads, and the 2.3mm elbow fits a standard hub flange hole.
Can I mix Strong and Race spokes?
Yes, and we often do: Strong on the drive side of a rear wheel, Race on the non-drive side.
Do I choose the spoke length?
No. The configurator calculates the length from the rim's ERD and the hub's flange geometry; we cut and thread the spokes here.
Which spoke should I pick?
The configurator recommends a spoke from your bike type, rider weight and rim; a stronger spoke is offered when the build calls for it.
Not sure? Text or leave a voicemail on 470-253-0929 or email info@prowheelbuilder.com — you will be talking to the people who build the wheels.
