Sign up for email updates from State Fair Park - Home of the Yakima Valley SunDome & Central Washington State Fair

Buy Tickets

Demolition Derby

Date: Sept 25, 2021
Time: 5:00 PM
Watch as cars smash, crash, and dash until there is only one left standing! The Demolition Derby at the Central Washington State Fair will be featured on three days!

Demo Derby - Saturday, September 25 @ 5pm
Truck Demolition Derby - Sunday, September 26 @ 2pm
Hornet 4-Cylinder Demolition Derby - Sunday, October 3 @ 2pm

Demolition Derby is FREE with Fair admission!
1 of 1


No Imperials 1973 and Prior.
No frame swaps of any kind on any car.
No shaping or heat treating frames on any car.
No sheetmetal swaps.
No Car can be all Black. 51% of your car needs to be a color other than Black or White.
Once you pass tech you are not permitted to alter or change anything on your car.
Every car must have a working seat belt. Lap and shoulder!
Top 5 cars from the main will be re inspected before payouts.
No 03 and newer Fords.

Topic #1: Bumper Mounting

The frame may be shortened from the front of the car in order to hard nose the bumper to frame and mounting bracket.

You can not shorten any more than the frontmost core support mount. If you remove or alter this mount you will not run.

Due to caddies debatable location of core support mount...every caddy needs to have 17" of frame rail in front of the spring pocket. Y can be closed and welded.

On unibody cars,(sui, Cordoba, etc.) you may not shorten the car in any way.

Bumpers may be stuffed or home made. Max diameter is 6"x6" with no more that a 6" point spread out over 36". No sharp points.

Minimum bumper height is 12" to the bottom of the bumper and max is 22" to the bottom of the bumper.

Rear bumpers must be stock to car or a 4x4 box no wider than factory and no thicker than 1/4 wall. The factory brackets may be welded to the frame and welded to the bumper. Or you may use a 12" long 4" wide by 3/8" thick plate to mount rear bumper. It can not be more than 12"
back from the bumper. Rear frame may not be shortened.

Option #1
The car is allowed the factory brackets or shocks that came on the car.

The original location. No stretching or relocating brackets. All bumper brackets welded to frame, bumper hard-nosed to frame and bracket.

Option #2
You may use up to a 4"x16" by 3/8" thick flat bar to mount the bumper. NO MORE THAN 12" inches can be welded to the frame. Bracket may not be any further back then 12" from the front of the frame.


It cannot be cut or manipulated in order to further brace the frame.

The flat bar will be bent into the shape of an L and welded to the bumper. This can be welded to the top, bottom, or the sides of the frame - not inside the frame.

lf you use this option all other stock brackets must be removed.

On Shock style GM cars the pocket is part of the frame but the shock must be removed.

Frame Welding

You may weld the factory Seams firewall forward only! This is considered any factory seam on frame material, including the crossmember Seams and whatnot. You may NOT weld any part of any suspension or body other than what is stated in the welding of A arms portion in the rules.

Y frame cars may close the Y and weld it shut but no added metal will be allowed. lf you add metal, you will cut open the Y completely!

You may weld the crush box.

You may tilt at the box / firewall with no added metal.

Every car is allowed a 22" rear hump plate. 1/4" thick max. Must not span the arch. Must only be welded to outside edges of the hump plate on the outside of the frame rail. Must be centered on the hump. No plug welding. Must be a 3/8" hole drilled to show thickness.

Topic #2: Body Bolts and Mounts

You may replace all body bolts with no bigger than a (1) 5/8" bolt with (2) no bigger than 3" washer on the top side of the floor pan and (1) washer up inside the frame. The washer and bolt must remain up inside the frame and the washer cannot exceed 2" inside the frame.

If you choose to remove factory bushings, you must have a 1" THICK spacer NO MORE THAN 3" IN DIAMETER to replace the bushing.

NO welding the body to the frame.
Core support spacers cannot be any bigger than 3x3 and no longer than 6" max.

You may use (2) 1" all tread thru core support.
You are allowed one 1" nut with a 3" washer on the bottom of frame.
You are allowed one 1" nut with a 3" washer on top of the frame.
You are allowed one 1" nut with a 6" plate and 3" washer on top of the hood.
No other bolts, nuts, washers or any other means of securing allowed.
If you choose to weld the all thread to the side of frame it must be located vertical at the core support and maximum of 4" of weld to the frame only.
You cannot weld all thread to the core support!
If you choose weld you lose the nuts and washers on top and bottom of the frame.

You may use (2) 1" all thread in the trunk thru the frame. or this may be welded with 4" of weld to the side of the frame only.
If bolted through the frame:
You are allowed one 1" nut and one 3" washer on bottom of frame.
You are allowed one 1" nut and one 3" washer on top of the frame.
You are allowed one 1" nut and a 6" plate and a 3" washer on top of trunk deck.
No other nuts, bolts, washers, or any other ways of securing.

Topic #3: Suspension

Any rear Diff out of a car or pick up. 8 lug max DANA 60 and 14 bolt.
You may brace the housing. No Dual rear tires.
No axel savers and this includes home made versions.
Bracing may not reinforce the structure of the car at any point.
You may clamp shocks or place filler blocks in coil springs to adjust height.
You may chain the humps with 3/8 chain in two locations. The chain can wrap around the frame with one wrap. It may not be welded to the frame. It may not be bolted through the frame.

You may weld the upper A arms down with a 3"x4" strap 1/4" thick front and rear of the upper A arms only.

No leaf spring conversions.

Max 9 leaf pack. Main leaf being on top and others below with a 2" stagger down.

You may not move the shackle mount for the springs in your car. They must mount in original location.
You may have 3 clamps added per spring pack.

Trailing arms may be modified. You may fully stuff the trailing arms as long as they began as a factory set from a car in the class.

For 98-02 Ford products You may use watts link type brackets to install rear end in your car.

If the bracket is welded to the frame it has to be limited to 4" of weld surface on side of the frame for each bracket. This means you can have a 4"x4" plate welded to the frame .The material must not exceed 3/16 material and not to exceed 4"x4" welded surface to the frame.

All other factory brackets must be removed off the frame.

Pinion Brakes are allowed.

Aftermarket tie rods are allowed. Must be factory style rod end. You may reinforce factory tie rods. No heim joints allowed!

Aftermarket ball joint with weld in sleeves are allowed. The sleeve can not be longer/deeper than 3".

Spindles, A arms, and other steering components must be stock for the class you are running. You may not move the suspension location. This includes all the creative ways to bolt and secure hubs to the spindle. Must be only the stock method.

12" total length of loose 5/16 chain or 1/4 cable per side to support front suspension.

Topic #4: Body Welding

No body panel rust repair!!!!!
Floor rust may be patched in the pan area with same thickness as original and cannot overlap existing metal more than 1". You cannot patch any part of rocker panel inner or outer.

You can use filler up to 3 inch wide and no thicker than 1/4"'.
Hoods must be open or oft for inspection.
Hoods can not be welded shut.
Hoods may have eight points of contact.
Hinges are not counted as points.

No welding of any kind on hinges or inner seams! If you weld hinges to brace sheet metal you will cut out the hinges not just cut the weld! And you will cut inner seams fully so day light can be seen!

No larger than 1" bolts for points of contact with no bigger than 6" plates.

These points of contact are sheet metal to sheet metal and the allthread is to be no longer than 12".

Point of contact is either a bolt and 6" plate 3/16" thick, a six inch angle iron pair with two 3/8 bolts.

Trunks can be welded shut solid with 3" strapping 1/4 thick. Door seams can be welded solid (outside only) 3" strapping by 1/4 thick.
There is to be no welding the body to the frame in any location (no inner fenders, body mounts, etc.).

You are allowed to have two straps from hood/core support to bumper and trunk lid to bumper. These straps are to be no thicker than 1/4"
and no wider than 3". They cannot be connected by more than 3" on either end to bumper and front core support/trunk deck. They are not
allowed to be longer than 36".

Only factory seams may be welded, i.e. if you tuck the trunk you cannot weld the lid to the floor of the trunk as it is not a factory seam.

Both driver and passenger front doors can be skinned with up ta 1/4" material. The skin can not go more than 2" outside the opening of the
front door.

Topic #5: Tires / Wheels

Any pneumatic tire is allowed. No solid.

Full centers are allowed.

Bead protectors are allowed.

Stem protectors are allowed.

You may weld wheel seams with one pass.

Bead Locks are not allowed.

Topic #6: Engine / Trans Mounting

Any motor transmission combo is allowed with the following rules applied.

NO transmission brace of any kind.

Lower cradles with pulley protectors max 1/2" material. They must bolt in factory location or very close to it.

Pulley protectors can exceed more than 1" past pulley.

No halo on engine.

You may have a 6x6 by 1/z " mounting pad when mounting the motor if needed. This plate is meant to mount a motor not to strengthen the frame! Plate may weld to engine cradle only and at no point is it allowed to touch or weld to the frame!

If welding your cradle in you are allowed 8" of weld per side. Must weld to crossmember and not to the frame in any location.

No Distributor protectors at all.

No skid plates.

No aftermarket steel trans or engine pans.

No Mid plate.

If running valve cover protectors or coil protectors on the back of your heads you must cut the firewall out directly behind these protectors so
they do not strengthen the firewall in any way!

NO factory cradle swaps.

Steel and aluminum Bells and steel tails are allowed.

Homemade cross members are allowed with a max material size of 2"x2"- 1/4" wall.

You may weld this to the frame only. You may use (2) 6" long piece of 2x2 angle 1/4" thick one on each frame rail to mount your crossmember
to the frame.

The crossmember must only be in contact with the body or tailshaft . It may not connect to or touch at any time the bell housing.

No part of the cradle or bell may be within 4" of the frame or suspension including torsion bars.

The transmission crossmember is in no way allowed to be tied into the ears, wings on a 74 and older Cadillac. In no way means in no way. If
at any point during the event the ears come in contact with the crossmember you will be disqualified! Creative rubber spacers or what not will not help you get through tech. This includes in the repair section. No 9 wire or repair plates may connect to the ears after the heat!

Topic #7: Cages

Dash bars and rear cross bars are mandatory. Max of 6" material.

Uprights are mandatory max of 6" material
There also must be door bars on each side of the car. A minimum of 6 inch material is to be used, but not to exceed 12 inches wide and 3 inches thick. The dash bar to rear seat crossbar can be no longer that 65".

The cage gas tank protector must be 4" off all rear sheet metal at beginning of the show.
Cage must be 6" off the firewall and 8" from rear humps.

If using exterior door bars they must not go into or cover any portion of the front of rear wheel wells.

You are allowed to weld 4 down bars from the cage to the frame. The bars need to go straight down vertical not angled. If you run your down bars in
an angled fashion you will remove them and will not be allowed to run down bars at all! They can be located from the front door seam back and no
further back than 8" in front of the rear inner wheel well. Max size is 3" material.

Cages on wagons must not extend back any further that the front side of the inner wheel wells. This includes the gas tank protector.

The Halo Bar/Roll bar may not be connected to the window bars in any way.

Topic #8: Window Bars / Screen

Window bar is mandatory in the front. Material must be at least one inch and not exceed 2" material. The max length is 36". The window bars can be no further apart then 24" and remain in the opening of the window front and rear. No attachment to fenders etc. You may have up to two in front and two in the rear window. The two in the rear must be mounted in front of the top trunk seam. You may have a 4x4 plate 1/4" thick to mount the window bars to the roof and sheet metal front and rear!

Topic #9: Coolers

Radiator must remain in original location. NOT CLOSE TO STOCK BUT IN STOCK LOCATION!!!!
Transmission coolers may be used, but must be fastened in a safe container and strapped or bolted down.
High pressure line must be used. No fuel line for the transmission! No oil coolers allowed.

Topic #10: Battery

You may use up to two batteries as long as they are fastened and covered for safety.

Topic #11: Fuel Cell

The factory tanks must be removed from the vehicle. A replacement tank is to be mounted inside the vehicle and the max capacity is 10 gallons. The tank must be securely fastened. NO plastic tanks! Fuel lines must be double clamped. Fuel must be gasoline. No exotic fuels such as alcohol, methanol, e 85 etc.

Topic #12: Sheetmetal Bolting and Pre-Bending

You may have bolts with a 3/8 inch max for bolting sheet metal together.(i.e. Fenders, hood bracing).


Fenders 8 each.

You may crease the front fenders and the rear quarters.
The trunk may be tucked.
The trunk and speaker tray can have a 6" dish.
No welding the body to the frame in any location.
You are allowed 4 locations of 9 wire, 4 wraps max. Must be behind the drivers seat. Must not go to or around cage or drivetrain. After your heat you will be allowed 4 more spots of 4 wraps anywhere on car as long as it still does not connect to cage or running gear.

Frame Repair

After your heat you will be allowed to weld on 6 - 4"x7" by 1/4" thick plates for repair.

These plates may be welded to the frame anywhere on the car, but frame ONLY.

No suspension or sheetmetal connections. If in question, please ask. The mad dogs will have 2 added to use anywhere on the frame of their

They cannot be installed inside the frame.

They cannot tie into other structure such as the ears/wings on caddies or to brace cradles and bells etc.

The plates must be 1" apart from weld to weld.

The repair plates may touch the bumper and A arm plates and existing bumper brackets.

All repair plates must be provided by yourselves and they must have a 3/8" inspection hole drilled in or a 3/B" section left unwelded.

Promoter reserves the right to make judgment calls on all builds. Do not weld or add anything unless stated in this set of rules otherwise you will probably have to cut or leave it on the trailer.

Drivers only in inspection lines! If your pit guys or anyone else decides it is a good idea to argue with techs while you are being inspected you
will be DQed!! We will not tolerate this issue again!

TEAM DRIVING: I am a realist. I know friends and families will run together. I will say though if you draw three of you and it comes down
to three on one I ask that you at least mix it up a little as to not ruin the show. I know you all understand what I am asking so please help
the crowd enjoy what they are paying to see.

All payouts are subject to video review. In example if there is an issue such as someone feels they were in fourth and I have them in fifth, I will go back and watch the video to make sure before I pay out. It is the most fair way to make sure people get the money they earned.

If you have questions, call Jeff @ 509.480.9112.

Back to
Buy Tickets!