Axle Spacers

(8 customer reviews)

$ 2.00

Our four variations of aluminum spacers allow us to fit some of the less common bike frames. Chances are, you got to this page because we sent you the link. Please choose the specific spacer that we suggested for you.

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Axle spacers allow us to fit some less common bikes. The internal diameter is for 12mm and the outer diameter is 19.9mm, to match the diameter of the axle head. The spacers are designated by their thickness. They are all the same diameter. Designed, machined and tested in the USA.

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WARNING: This product can expose you to chemicals including nickel acetate, which is known to the State of California to cause cancer. For more information, go to

Additional information


3mm Flat Spacer, 6mm Flat Spacer, 6mm Tapered Spacer, 12mm Flat Spacer, 12mm Tapered Spacer

8 reviews for Axle Spacers

  1. Michael Martin (verified owner)

    The axle I needed for my fatbike needed a spacer so the treads wouldn’t show on the outside of the thru-axle. I sent a note to the good folks at The Robert Axle Project and the pointed me to one of these spacers. Worked like a charm. Thanks!

  2. Esteban S (verified owner)

    I needed an spacer for a thru axle that is a little longer than required and this was the only good option available. Quality is great.

  3. Brenden Bernardi (verified owner)

    I needed 3mm of added space to get my direct mount disc breaks on my gravel bike to align. I had purchased the bike last year and there was something off from the start. My LBS tried to “manufacture” a solution but I’ve never been happy with their spacer solution. Not sure how I initially missed these with my hours of searching last year but I couldn’t be happier that I found exactly what I needed here. Such a simple solution to fix manufacturing issues between frames and hubs.
    The spacers I received look nicer than in the picture. Robert Axel took the time to slightly bevel the edges so the won’t scratch your frame or thru axel. My breaks are perfectly aligned and rolls smoother than the day I purchased the bike.

    If you need a spacer stop looking and purchase. If you have a 2019 Niner RLT Steel frame or bike, you NEED one of these due to the rear break mount not allowing enough movement of the caliper when adjusting. The 3mm spacer does the trick.

  4. Eggs (verified owner)

    Shipping was 3x the cost of the part .charged me $7.50 and mailed it for standard postage .

    All because the washer is proprietary for the axle in my bike

  5. Wlad Franco-Valias (verified owner)

    Very good selection of sizes to make up for the variety of different axle sizes. I needed a spacer so I could attach the dog trailer to my fat bike. Ordered a few of each size for flexibility and make up for the delivery fee. The spacers arrived in two days, in fact just as we were getting ready for a ride. We delayed the ride by 15 minutes and were able to take our dog with us. Great quality.

  6. Tuomas Kallio (verified owner)

    Good quality spacers, fits perfectly!

  7. Mark Sanders (verified owner)

    Fast and EZ website. Quality of the spacers is top notch. Quick shipping too! Two thumbs up to the whole crew!

  8. Dan J (verified owner)

    The smallest things can make the biggest difference. Customer support helped me find this product listing and it was exactly what I needed to get a perfect fit for the trailer axle I also purchased! Fast shipping, great quality, wonderful shopping experience!

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