Ultra 4 Legal Tire Spine Run-Flat Insert

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  • Regular price $325.00

Legal Run-Flat Tire Liner Insert for Ultra 4 and King of the Hammers.

All Ultra 4 / King of the Hammers Legal Tire Spines will come not to exceed 27" tall regardless of Tire Size Used.

Please tell us your wheel and tire size in the notes section at checkout.

Ultra 4 and King Of the Hammers (same rulebook) have a very unique rule as it pertains to Tire Run Flat systems.

2.18.6 States that Tire Liner type products with a OD of up to 27" are allowed. Since Tire Spines are not a Secondary Inflation Apparatus, and are a Tire Liner type product, they are allowed but cant exceed 27" OD tall. Fortunately, a 27" OD Tire Spine FULLY fits a 29" tall tire and in some cases, a 30" tall tire. Running a bigger tire? No problem! That's what this was designed for! Pictured above is it installed in a 32" Tire as well as a 35" Tire (Blue Bead lock Ring)

Tire Spine has designed an Ultra 4 & King of the Hammers specific Legal 27" Spine and has been in testing at Ultra 4 races in 2022 & 2023 with podium proven results.

  • Redcard verified and passed at 2023 Famous Reading Rumble July 28th 2023

Key Expectations:

  • Nothing is indestructible, take care of the Spines, they will take care of you
  • These are fitting a rule book, not your tire as is normally done.
  • Spine wear and tear is increased in Ultra 4 format because of #2 point above
  • The Spine can be moved from an old tire to a new tire if wear/tear condition permits
  • Expect vibration. Every wheel, every tire, every racer, every track is different. In almost all cases, vibration is very minimal to non existent, but it does, and will happen. Expect it (See point 2 above)
  • The bigger the tire you run, the gap between the tire and the spine increases. For example, on a 35" tire, if you compromise the tire it will go down nearly 4" before it ever touches the Spine to hold you up. We recommend running the smallest tire possible, for the best performance and handling when on a flat.
  • These are a legal created tool to help get you to the finish line and prevent extensive damage while running on a flat tire.
  • Tire Spine cannot control every possible scenario in every possible terrain involved with running a run flat liner inside a tire at Ultra 4. The Ultra 4 legal insert, is an absolute best effort solution for the unique Ultra 4 ruleset. Tire Spine assumes no risk and provides no warranty of any form for this Ultra 4 specific product. It's fitting a rulebook, not the tire. Like everything in racing, you are agreeing to use at your own risk.

Tire Spine currently has 2 different possible Ultra 4 Legal Spine Variants. The former 2 piece Ultra 4 Spine is being discontinued as of 10/1/2023. We highly recommend reaching out to us to help choose the best solution to fit your needs.

Solid 1 piece Spines with no cut, are not end user installable and all tires must be shipped or delivered to Tire Spine for installation.