Demo Derby/Demolition Derby Tire Spine Run-Flat InsertFor common Demo Derby tire sizes. These podium proven, trail tested and military used inserts are your solution to flat tires taking you out of the event Single insert pricing Lubrication for installation provided with new insert purchase Inserts are size specific and should be purchased based on your desired tire size. If you don't see your insert size please contact us for availability Tire Spines are a run flat insert that installs inside your

The Ultra 4 Legal Tire Spine greatly increases sidewall strength

For common Demo Derby tire sizes

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

but recommended for individuals without a shop

You also have the option to have a tool/bolt pocket cut out of them for some easy to reach storage for those lug nuts

you are agreeing to use at your own risk

*Used for wheel sizes up to 15"

We fully understand this may not fit everyone's unique wants and needs

every track is different

Due to website shipping calculation limitations

This option will be enabled when inventory is out of stock

and then added an additional accessory storage pocket that is 3+"x9