Chainwheel Crank Spindle Hat Washer Adapter (OPC, 19mm, 20mm, 22mm, 7/8")

We carry the most complete selection of chainwheel/spider/power disc crank spindle adapter (also called "hat washers) in the world.

Please read carefully and measure your application to be sure you get the one you need. Please note that adapter "thickness" is just the portion that sit INSIDE of the chainwheel spindle hole, not the overall thickness of the adapter (we've listed that as well for chain alignment/spacing purposes).

Option "A":

• Outer diameter (inner diameter of the chainwheel spider): 23.8mm (spindle size of one piece cranks)
• For chainwheel/spider with minimum thickness of: 2.40mm
• Inner diameter (spindle size): 19mm
• Overall thickness: 4.45mm
• Adapter material: STEEL
• Imported
• NOTES: This is a very thin adapter typically used with spiders and chainwheels made from STEEL. This is also the correct adapter for our 2nd generation power discs which are thinner/lighter aluminum than our first generation ones. It adapts a steel chainwheel/spider designed for a one piece crank to be used on a 19mm three piece crank spindle.

Option "B":

• Outer diameter (inner diameter of the chainwheel/spider): 23.8mm (spindle size of one piece cranks)
• For chainwheel/spider with minimum thickness of: 3.80mm
• Inner diameter (spindle size): 19mm
• Overall thickness: 7.00mm
• Adapter material: ALUMINUM
• MADE IN USA
• NOTES: This medium thickness adapter fits our 36T and larger SNOWFLAKE chainwheels and other thin aluminum alloy chainwheels/spiders. It adapts a thin aluminum chainwheel or spider or power disc designed for a one piece crank to be used on a 19mm three piece crank spindle.

Option "C":

• Outer diameter (inner diameter of the chainwheel/spider): 23.8mm (spindle size of one piece cranks)
• For chainwheel/spider with minimum thickness of: 4.40mm thick
• Inner diameter (spindle size): 19mm
• Overall thickness: 6.50mm
• Adapter material: STEEL
• Imported
• NOTES: This thick adapter is for all aluminum alloy chainwheels, spiders and power discs made for one piece crank that are at least 4.4mm thick or thicker. This adapts an aluminum chainwheel or spider or power disc designed for a one piece crank to be used on a 19mm three piece crank spindle. This fits our Mongoose Motomag chainwheels and all Chop Saw spiders. This adapter only fits our 1st generation power discs which do not have the recess machined into them on the back side (if you're buying power disc new from us, the drop down menu option on each listing only allows you to select the correct adapter).  If your chainwheel/spider/power disc is less than 4mm thick, you should use Option "B" or if it is very thin use Option "A".

Option "D":

• Outer diameter (inner diameter of the chainwheel/spider): 23.70mm (spindle size of one piece cranks)
• For chainwheel/spider with minimum thickness of: 4.40mm
• Inner diameter (spindle size): 22mm
• Overall thickness: 6.50mm
• Adapter material: STEEL
• Imported
• NOTES: This adapts chainwheels/spiders/power discs designed for a one piece crank to be used on 22mm three piece crank spindle. This adapter is too thick to use on our 2nd generation Chop Saw power discs or our Snowflake chainwheels.

Option "E":

• Outer diameter (inner diameter of the chainwheel/spider): 22mm
• For chainwheel/spider with minimum thickness of: 4.40mm
• Inner diameter (spindle size): 19mm
• Overall thickness: 6.50mm
• Adapter material: STEEL
• Imported
• NOTES: This adapts a chainwheel designed to be used on a 22mm three piece crank spindle to be used on a 19mm three piece crank spindle.

Option "F": OUT OF STOCK INDEFINITELY

• Outer diameter (inner diameter of the chainwheel/spider): 22mm
• For chainwheel/spider with minimum thickness of: 6.30mm
• Inner diameter (spindle size): 19mm
• Overall thickness: 7.80mm
• Adapter material: STEEL
• Imported
• NOTES: This adapts a chainwheel designed to be used on a 22mm three piece crank spindle to be used on a 19mm three piece crank spindle. Notice this is for a VERY THICK chainwheel.

Option "G":

• Outer diameter (inner diameter of the chainwheel/spider): 23.70mm (spindle size of one piece cranks)
• For chainwheel/spider with minimum thickness of: 2.90mm
• Inner diameter (spindle size): 20mm
• Overall thickness: 5.00mm
• Adapter material: ALUMINUM
• MADE IN USA
• NOTES: This adapts a chainwheel designed to be used on one piece cranks to be used on a 20mm three piece crank spindle.

Option "H": OUT OF STOCK INDEFINITELY

• Outer diameter (inner diameter of the chainwheel/spider): 23.70mm (spindle size of one piece cranks)
• For chainwheel/spider with minimum thickness of: 2.80mm
• Inner diameter (spindle size): 7/8"
• Overall thickness: 4.80mm
• Adapter material: ALUMINUM
• MADE IN USA
• NOTES: This adapts a chainwheel designed to be used on one piece cranks to be used on Profile SS cranks very rare 7/8" diameter spindle.