A reinforced head end where a straight-pull spoke leaves the flange.
- Stiff and stays that way on tandems and loaded touring bikes
- Gives drive-side spokes margin under e-bike motor torque
- Single-butted down to 2.0mm, with standard 14 gauge nipples and threads
- Cold-forged in Belgium
Sapim Strong Straight Pull 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 end, tapering to 2.0mm for the rest of its length, so the extra steel is where a heavily loaded spoke fails. 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.
This page covers the straight-pull Sapim Strong Straight Pull Single Butted 14|13g - 2.0|2.4mm Spokes, the version with no elbow for straight-pull hubs, where the 2.3mm head end reinforces the spoke where it leaves the flange. To have them cut to length and built into a wheel, choose your rim, hub and nipples in the configurator and the wheel ships from Georgia laced, tensioned and trued by hand.
Why the straight-pull Strong is different
- Thick where it leaves the hub. The extra steel sits at the head end, where the spoke meets the flange. The rest of the spoke runs at 2.0mm.
- Aimed at heavy work. Sapim names cargo bikes and demanding conditions as what the Strong is for.
- Normal at the rim. The thread end is 2.0mm, so it takes the same 14-gauge nipples as the other spokes we build with.
- Straight-pull hubs only. It will not go into a drilled flange. The J-bend Strong is the one for those hubs, on its own listing.
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 head end, about 30% more cross-section than a 2.0mm spoke, and this version has no elbow at all. From the head end the spoke tapers to 2.0mm, so it uses standard 14-gauge nipples and threads and builds like any other spoke.
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 head end of the Strong takes it.
Specifications
| Gauge | 14/13G |
|---|---|
| Profile | Single-butted |
| Material | Stainless Steel |
| Spoke head | Sp14|13 |
| Finishes | silver, black |
Which version this is
What this listing covers: the 13g straight gauge Strong in the straight-pull pattern, single-butted. A straight-pull spoke has no elbow: it leaves the hub in a straight line and the flange holds the head directly. That removes the bend that J-bend spokes break at, and it keeps the spoke loaded purely in tension. It only fits hubs built for it, and it is not interchangeable with J-bend - so check the hub before ordering, because a straight-pull spoke will not go into a drilled flange at all.
Sizes, fit and compatibility
The Sapim Strong Straight Pull 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 straight-pull flange dimensions and works out the length. Straight-pull Strong spokes fit straight-pull hubs only; pick a straight-pull hub and the configurator offers them for e-bike and heavy-duty builds.
We pair straight-pull Strong spokes with brass Sapim Polyax nipples, always.
Sapim spokes, and how we choose them
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
ProWheelBuilder's part is picking the right spoke for the wheel and lacing it, and we will tell you honestly which one we would use.
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.
Strong Straight Pull Single Butted 14|13g - 2.0|2.4mm Spokes questions
Will this straight-pull spoke fit my hub?
Only if the hub was built for straight-pull spokes - the flange holds the head directly and there is no drilled hole for an elbow to sit in. It is not a preference, it is a fit: a straight-pull spoke cannot be made to work in a J-bend flange. Check the hub, or send us the make and model and we will tell you which pattern it takes. The same Strong is listed separately in J-bend.
Strong or Race?
Strong for tandems, e-bikes, cargo bikes, loaded touring and heavy riders; Race for everything else. The Strong's thicker head end 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, but the hub has to be a straight-pull hub.
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? Email info@prowheelbuilder.com (fastest) or leave a voicemail on 470-253-0929 — you will be talking to the people who build the wheels.
