Question: How do I know if I need to use pedal washers? Some of my cranks have them, while others do not. From: Paul
Answer: Great question Paul. Pedal washers exist primarily to ensure a good pedal to crank arm interface, but they can also aid in dialing in your bike fit.
All SRAM cranks come with pedal washers while most cranks from other manufacturers do not. Some notable exceptions include Shimano Saint and Zee cranks. Why is this? Partly because flat pedals are the type most often found without a continuous flange on the pedal spindle. This style of pedal spindle digs into both the face of the crank arm the lead-in chamfer of the crank’s pedal threads.
So, do you need to use pedal washers on a SRAM crank with a continuous flange pedal spindle? Not really, but you may want to in order to get the Q-factor you need. Q-factor is the horizontal measurement between the two faces of the pedal seat on a given crankset. For example, this SRAM XX1 crank has a 168mm Q-factor.
Omitting the pedal washers will narrow your Q-factor by about 2mm. A narrower stance is good for riders with narrow hips. You can add more than one pedal washer to your pedals to better fit riders with wide hips or use more washers on one side than the other to compensate for body asymmetry.
The thing you have to watch out for when using more than one washer on your pedals is that you need to have enough thread engagement with the crankarm. The minimum required is 11mm. If you need to increase your q-factor more than your pedal threads will allow, some pedal brands offer longer pedal spindles like on this Shimano Dura Ace 9000E1 pedal, or you can get pedal extensions.
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