Sapim Stainless Flat Round Nipple Washer
The Sapim stainless flat round washer is the simplest of Sapim's nipple washers: a flat stainless disc that sits between the nipple head and the rim bed on eyeletless rims that already have a countersunk spoke hole, spreading the nipple's load over a wider area of aluminum or carbon without changing the nipple's seat. It is the washer for rims whose countersink already gives a Polyax nipple room to tilt and that only need protection against the nipple head deforming the bed. This page covers the Sapim Stainless Flat Round Nipple Washer.
We sell Sapim washers only as part of a wheel we build. Choose your rim, hub and spokes in the configurator and the wheel ships from Georgia laced, tensioned and trued by hand.
Design and construction
An eyeleted rim spreads nipple load through a stainless insert; an eyeletless rim, which is most modern rims, puts the nipple head straight onto the rim bed, and under 120 kgf of tension a nipple head can deform an aluminum bed or crack a carbon one over time. A washer spreads that load. The HM concave round washer has a spherical dish that matches the Polyax seat, so the nipple can tilt and the spoke runs straight; the concave oval washer does the same on rims with oval holes or strongly angled drilling; the flat round washer spreads load on rims that already have a countersink. All three are stainless steel, and Sapim sizes them to the 14-gauge Polyax.
How it rides
You will never feel a washer, but a wheel built with the right washer on an eyeletless rim holds tension longer and does not develop the cracked or bulged spoke holes that end a rim's life. The flat washer is the one for rims that have the countersink and need only the load spreading.
Sizes, fit and compatibility
The Sapim Stainless Flat Round Nipple Washer fits the 14-gauge Sapim Polyax nipple and any eyeletless rim with a standard spoke hole; the configurator fits the washer automatically on rims that need it and skips it on eyeleted rims and rims that ship with their own washers.
Building it at ProWheelBuilder
Sapim makes the flat round washers; ProWheelBuilder is an independent wheel builder in Georgia, not the manufacturer. The build is the same every time: measured ERD, spokes cut to the half millimeter, staged tensioning with a gauge, stress relief, a final true, and tubeless tape and a valve on request.
The configurator shows only hubs and spokes that match the flat round washers drilling, strikes through combinations that are not made, and prices the wheel live.
Building it well
Spoke count is worth a sentence. A modern rim on a modern hub does not need 36 spokes to be strong, but it does need enough spokes for the rider and the riding: 28 for most road and cross-country wheels, 32 for trail, gravel with a load, heavier riders and e-bikes, 36 for touring and tandems. The configurator recommends from your weight and bike type, and we will talk you out of a count that does not suit the rim.
One more thing
Rims are measured before they are built. We check the ERD of every rim with a gauge rather than trusting the catalog number, because two rims from the same box can differ by a millimeter and a spoke cut to the wrong length either bottoms out in the nipple or runs out of thread. It is the least glamorous part of building a wheel and the one that decides whether the wheel stays true.
And another
A word on tubeless. Every tubeless-ready rim we sell leaves the shop taped and with a valve fitted if you ask for it, and we tape to the rim maker's recommended width rather than whatever is on the bench, because a tape that is a few millimeters too narrow is the most common cause of a slow leak. Add sealant, seat the tire and ride.
Warranty
Manufacturer's warranty. Sapim Nipples warrants this product against defects in materials and workmanship. The duration, conditions and claim process are set by Sapim Nipples and can change without notice, so ask us and we will confirm the current terms before you buy.
ProWheelBuilder. Any wheel we build on this part carries ProWheelBuilder's one-year warranty in addition to the manufacturer's. Broken spokes are replaced for a year whatever the cause, and all wheel-side labor is included - truing, re-tensioning, rebuilding. Where the maker covers a failed rim or hub we handle that claim for you; where they decline, an eligible replacement comes at 25% off current retail. The customer covers shipping in both directions. Components supplied by the customer are not covered.
Full terms are on our Policies & Warranty page.
Stainless Flat Round Nipple Washer questions
Which spokes and nipples suit the flat round washers?
For most riders a double-butted spoke such as Sapim Race or DT Competition with brass nipples; lighter riders can go to Sapim Laser or CX-Ray. The configurator recommends a gauge and count for the flat round washers from your bike type and weight.
Does my rim need washers?
Eyeletless aluminum and carbon rims without their own washer system, yes; eyeleted rims and rims that ship with washers such as DT Swiss PHR, no. The configurator decides for the rim you choose.
HM concave, concave oval or flat round?
HM concave round for most eyeletless rims with a Polyax nipple; concave oval for oval or strongly angled holes; flat round for rims with a countersink that only need load spreading.
Do washers change spoke length?
Slightly; a washer adds about a millimeter under the nipple, which we account for when we cut spokes.
Are the washers stainless?
Yes, stainless steel, so they do not corrode against an aluminum rim.
Do you ship this on its own?
Yes. Accessories and tools ship on their own; wheel components are built into wheels here.
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.
