Sapim Stainless Concave Oval Nipple Washer
The Sapim stainless concave oval washer is the nipple washer for rims whose spoke holes are oval or drilled at a strong angle: an oval stainless washer with a spherical dish that gives a Polyax nipple its rounded seat, spreads the nipple's load over the rim bed, and sits flat in an oval hole where a round washer would rock. It is the washer we fit on rims such as the Velocity and Astral rims with heavily angled drilling. This page covers the Sapim Stainless Concave Oval 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 oval washer is the one for rims whose drilling would leave a round washer sitting crooked.
Sizes, fit and compatibility
The Sapim Stainless Concave Oval 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 concave oval washers; ProWheelBuilder is an independent wheel builder in Georgia, not the manufacturer. We measure the rim before we cut a spoke, bring the wheel up in three or four rounds with a gauge, stress-relieve it between rounds and true it last, then tape it and fit a valve if you want it tubeless.
Only compatible hubs and spokes appear in the configurator, impossible combinations are struck through rather than hidden, and the price is live.
Building it well
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.
One more thing
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.
And another
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.
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. 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.
Stainless Concave Oval Nipple Washer questions
Which spokes and nipples suit the concave oval 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 concave oval 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.
