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5X Racing Stock Class Autocross Bump Stop Kit for Miata

Miata Bump Stops

20923093 - 5XRNA58/58
Stock/Street class SCCA Autocross rules specify the use of stock springs, but do allow shock and bump stop changes. However, the bump stops do not engage earlier than on the factory setup. Installing these 58mm tall stops are shorter than the factory NA or NB bump stops and can be used to dramatically changed handling behavior. They effectively raise the cornering spring rates and balance the car since the bump stop spring rate is now added to the main springs rate. Different bump stop stiffness front versus rear can be used to change handling behaviors while keeping your factory springs.
  • Kit includes: two 58mm RED (soft) bump stops for the front, two 58mm WHITE (medium) bump stops for the rear, four fender washers appropriate to your choice of shock, shock spacers (if needed) for your choice of shock
  • Availability: Normally in-stock
    Pricing: $80.00
    5 5 1

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    Partnering with Fat Cat Motorsports allowed us access to their proven engineering and techniques on how to custom tune your suspension by way of bump stops. When the average person thinks about suspension, they think springs, shocks, and bushings. Bumpstops are the "cushion" between the shock body and the shock mount, without them the metal shock body would come in contact with the metal shock mount during full shock compression causing damage, and a terrible ride! The factories take bumpstops into consideration, however they tune them to be used with factory shocks and springs and often use inferior materials like rubber (which is unforgiving when compressed) or lower quality MCU (micro-cell urethanes) which can't handle the thermal loads as the higher quality MCU bump stops we use. When you start customizing your suspension by replacing the shocks and springs, the factory bumpstops now become mis-matched to the rest of your suspension. Most people will try and reuse the factory bumpstops, but this will not yield optimal handling characteristics because of the now lower and shorter suspension travel plus lower bump stop quality. When you upgrade your springs and shocks to lower your car or if you simply want to improve the handling and durability of your stock suspension, bumpstops can be the "missing link" in your suspension that you never thought of!


    Shipping Information

    • Item Requires Shipping
    • 1.0 lbs.
    • W5.0000” x H5.0000” x L5.0000”

    Customer Reviews

    Comment Total Reviews (1)

    Stock ride height means less crunching
    • Currently 5/5 Stars

    Reviewed by:

    Product ownership: Less than 3 months

    Purchased from: 5X Racing

    I used this kit with a set of Koni sports and the stock springs. With this setup I have not bottomed out under normal driving conditions. With large bumps or potholes the car stays smooth though, which is great for a daily driver/ occasional autocross car.

    My biggest complaint about this was the documentation to go with it. They came with a piece of paper leading back to this site, but it was harder than necessary to find any information, and I don't think the information I found was for this kit in particular. It would have been easier if they had either included a printout or even shown a picture of them in position on this page as an additional product image.

    Delivery was fantastic though, they were in my hands within 48 hours of placing the order. I would definitely buy these again.

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