TR 4A / 5 / 250 / 6

Replacement Frames

CH01 = TR6 thru TR250

CH02 = TR4 SRA and TR4A IRS

Weight of Finished Bare Frame is 235 lbs

For reference our 1972 TR6 model frame was weighed at 180 lbs after we removed all the rust and dirt from the interior. We really do not know what a new factory frame actually weighed but we can only guess that it was more than 180 lbs before rust removed some of its bulk.

Frame length 10 ft. 10 inches

Width at front shock towers widest point 35.5 inches

Width at rear spring/ differential mount 39.0 inches

Height (max) at front tower 14.5 inches

Height (max) at rear diff. Tower 11.0 inches

Shipping pallet dimensions for all series frames.

12 ft.long

5 ft high

3.3 ft wide

2x6 construction pallet weigh's approximately 125 lbs .



Electrostatic Powder Coating - Our preferred finish due to it's durable surface... it is an electrostatically applied plastic coating infiltrating the substrate of the metal providing a distinctive finished look. We have found this surface finish to be far superior to any painted finish. This polyester powder coating material can be repaired easily... It will not pull back significantly if welding is necessary nor will it flame up in the welding process. We have found that it can be spread with a trowel when it is hot and blended easily. To make the repair look natural, feather the area when cool with sandpaper and paint with Krylons new fusion paint. It is made to paint polyester plastics thus providing a coating like the type of powdercoat we use. Our new awareness of the qualities of this powder coat and the fact that paint and powder coat now costs about the same, has led us to drop paint from our options list. Powder coating includes sandblasting, sanding, powder primer coat and a powder finish coat in a variety of colors. Black is the most popular, but a variety of other colors are available.

Phosphoric Acid Coating - Frames that our customers would rather finish themselves are sprayed with a metal prep solution to keep the frame from surface rusting until it is sandblasted and finished. This coating forms a white powder on the surface easily removable with soap and water. It is highly recommended that the chassis be sandblasted and finished as soon as possible.

Un-Finished - As the title implies, completely unfinished


Expanding Foam - Our Preferred choice is relatively new to the market.. This foam is expanding closed cell, water proof foam which sticks like glue to all surfaces when hardened. It is not a sponge and will not absorb water. Also it does not allow anything to infiltrate the interior of the chassis. The expanding foam is forced into one end of the open tubing and allowed to ooze out of the other end to assure a complete fill. Once fully expanded the over fill is cut away and the fill holes are filled with plastic caps. This foam application does two things to the structure. First it makes for an impenetrable water seal and secondly sound dampens the frame. You may think this a minor point but in fact the frame does resonate and amplify the vibrations caused by road conditions and those passed along by the drive train. Foam filling quiets the ride appreciably. About 90% of all the frames made to date are foam filled.



Swingarm Refurbishment - RATCO will refurbish your swing arms or can supply a set of completely refurbished swing arms for your project. Refurbishment consists of stripping down the arms of all rubber parts to bare metal. The arms are then blasted down to clean metal where they can be inspected for cracks and welded as needed. The threaded studs are then inspected. If they are solid and in good condition they are left as is, if not they are replaced and a Helicoil is installed as needed. The swing arm is then powder coated and all rubber parts are replaced with new parts.

Rear Shock -in-Coil Installation - While we are refurbishing your swing arms is a perfect time to install the Rear Shock in Coil Kit. We perform all of the drilling and grinding necessary to install the kit, and since we will have all of the parts except your springs, we can install everything into the frame for you, simplifying your restoration.

Rear Tube Shock Conversion - As long as we are assembling your rear suspension, we can also install the Rear Tube Shock conversion kit to simplify your restoration.

Rear Sway Bar - Like the other options, if we are installing your rear suspension, we can install your rear Sway Bar, simplifying your restoration.

Toyota HVDA Conversion - we can weld brackets onto your frame which will allow you to install the Toyota transmission using the OEM Toyota transmission mount. For new RATCO frames this is the most secure/robust way to mount the transmission. No additional cost.


CH-01 / CH-02 Frame

CH-01 / CH-02 with Ford 302 V8 Modifications

CH-01 / CH-02 Mods for Jaguar Diff

Powder Coating

Phosphoric Acid Coating

Foam Fill


Swing Arm Refurbishment

RATCO Supplied Arms

Customer Supplied Arms

Richard Good Adjustable Swing Arm Brackets

SICK-01 w/Monroe Sensatrac Shocks Installed

SICK-02 w/Monroe Gas Charged Shocks

TCBK-01 Brackets only

TCBK-02 w/Monroe Sensatrac Shocks

TCBK-03 w/Monroe Gas Charged Shocks



$500 Additional




$300 (required for all shipped frames)

$450 Refurbishment only $475 Installed

$350 Refurbishment only $375 Installed

$129 Installed

$280 Kit Only $500 Installed

$250 Kit Only $500 Installed

$150 Kit Only $175 Installed

$200 Kit Only $225 Installed

$250 Kit Only $275 Installed

Front Suspension

Actual part color is black

Front Tube Shock Conversion Kit

This kit replaces the standard lower shock mount brackets, the ones that look like dog bones, with new brackets. The new brackets allow the use of the Sensatrac shock absorbers, which has pin type ends. Orientation of the new bracket is essential in the operation of the system and specifically the shock absorber. This kit is recommended as a complement to either of our rear shock conversion kits.


FSK-01 Front Tube Shock Conversion Kit

FSK-02 Front Tube Shock Conversion Kit

$165 (includes Monroe Sensa-track Shocks)

$135 (includes Monroe Gas Charged Shocks)

Rear Suspension

Rear Tube Shock Conversion Kit


Our research as to whether these kits actually cause the failure of the differential cross member at the frame rail, has concluded and the results say that it indeed speeds up a process that will eventually happen anyway. Our response to this is first to design a better system and second to be prudent. We recommend carefully inspecting the weld areas at the crossmember to rail interface and after finding them to be sound and solid, then install this kit. The improvement over lever shocks is worth the risk. If that sounds irresponsible let me say that the failure (possibly) caused by this performance improvement is never catastrophic or life threatening. It is however a major inconvenience. It is never our intention to put anyone in harms way. We have done the research and testing that has led us to design a product we believe is best for this application..

We designed the system to help deter the failure by making the structure out of steel that will flex with the force of heavy shock loads. All of our competitors brackets are made of 1/4 inch material. Ours is made of 3/16 material. This thinner material and the design of the bracket itself, actually flexes under load. It is our belief that if the bracket flexes it will take most (if not all) of the stress from the cross member to rail weldments. Our testing has shown this to be true. We have used this system for over ten years without failure on many cars belonging to friends and customers. If your frame is in good shape and you have checked the areas in question for structural integrity, then we recommend this product and know that you will see a great improvement in ride performance.


Actual part color is black


(all IRS Cars)

TCBK-01 Tube Shock Conversion for IRS

TCBK-02 Tube Shock Conversion for IRS

TCBK-03 Tube Shock Conversion for IRS

(TR4A w/o Distance Piece)

TCBK-07 Tube Shock Conversion for SRA

TCBK-08 Tube Shock Conversion Kit SRA

(TR4A w/ Distance Piece)

TCBK-09 Tube Shock Conversion Kit SRA

TCBK-10 Tube Shock Conversion Kit SRA

$150 Brackets Only

$200 Brackets W/ Monroe Shocks

$250 With Monroe Gas Charged Shocks

$265 Brackets Only

$325 Brackets W/ Monroe Shocks

$265 Brackets Only

$325 Brackets W/ Monroe Shocks

Rear Shock in Coil Kit

Actual part color is black

For All Triumph TR series IRS Cars

Now you can have the best rear suspension system for your Triumph. Race proven shock in coil technology places the spring and shock on the same rotational plane, decreases the sprung weight and neatens up the entire area as a bonus. This kit is essentially the same system as supplied with our new frames but it incorporates the necessary hardware to convert your stock spring and shock arrangement to coil-overs. It contains everything that you need and comes with complete instructions.

The conversion from stock to coil-overs requires a degree of mechanical ability. Some of the tasks you will need to accomplish are:

  1. Removing your old shocks, springs and swingarms.

  2. Drilling four holes in the swingarm base for the lower shock mounting plate. You will use the mounting plate as a drilling template.

  3. Attaching the upper shock mounting plate to the frame with the hardware provided.

  4. Reattaching the swingarm/shock/spring to the frame.

  5. Compressing the spring to attach the assembly to the spring tower. This is easily done with a floor jack.

This procedure is performed twice. Once for each swingarm and is easier than it might sound.

The conversion should take about 3 hours once you understand the procedure. If you have ever replaced your springs,then you know how to do half of the job already.

You get the following material with the kit;

  1. Upper and lower shock mounting hardware for the swingarm and the frame attachments

  2. Two Monroe Sensatrac shock absorbers or optional stiffer gas charged shocks with hardware.

  3. Two sets of rubber spring seats.

  4. All hardware necessary

Monroe shocks are recommended because this particular model fits in the coil spring and has the correct length and compression dimensions. Unfortunately for some, we have not found a performance shock that works well in this situation.

This system is perfect for normal street use and at the same time excels at those times when you want the best cornering performance. Sensatrac shocks have variable valving and change their compliance based on road conditions. When the road is harsh they soften and when the road is smooth they stiffen. The gas charged shock is stiff all the time and is a good choice for those who want better cornering stability during autocross or flat track.. Add a set of our front and rear matched sway bars and you’re ready to rock and roll.


SICK-01 Rear Shock in Coil Kit (2pcs) $280 Monroe Sensatracs Shocks

SICK-02 Rear Shock in Coil Kit (2pcs) $250 Monroe Gas Charged Shocks

SICK-02 Inst Rear Shock in Coil Kit (2pcs) $500 Monroe Gas Charged Shocks (Installed)

Note: Let us know if you are using shorter springs as we have a modified kit for this application


These replacement springs are standard height and rate as original.


FSSK-01 Front Spring Kit (TR6/250/4A) 2pcs

RSSK-01 Rear Spring Kit (TR6/250/4A) 2pcs

RSSK-01 Inst Rear Spring Kit (TR6/250/4A) 2pcs

$150 Standard Rate and Height

$160 Standard Rate and Height

$185 Standard Rate and Height (Installed)

Refurbished Swing Arms

Swingarm Refurbishment - RATCO will refurbish your swing arms or can supply a set of completely refurbished swing arms for your project. Refurbishment consists of stripping down the arms of all rubber parts to bare metal. The arms are then blasted down to clean metal where they can be inspected for cracks and welded as needed. The threaded studs are then inspected. If they are solid and in good condition they are left as is, if not they are replaced and a Helicoil is installed as needed. The swing arm is then powder coated and all rubber parts are replaced with new parts.

TR6 Swing Arm with Replacement Rubber Parts

TR4A Swing Arm with Replacement Parts

TR4A Swing Arm, un-refurbished


Refurbished TR4A Swing Arm Set

Refurbished TR6 Swing Arm Set

Un-Refurbished TR4A Swing Arm Set

$450 pr

$450 pr

$100 pr

TR4A-SRA Forward Leaf Spring Bracket

Some TR4's and all TR4A's with Solid Rear Axle require these brackets to attach the forward end of the spring to the chassis. Customers converting an IRS TR4A to a solid Rear Axle will require a pair of these hard to find items.


FLSB-01 Forward Leaf Spring Bracket 2pcs


Distance Piece

The Distance piece was used in some later TR4's and all TR4A's. They are not available from any other source we are aware of. This replacement is made from 11ga steel rather than cast aluminum as the original was. The product shown is the replacement for Stanpart 137634 and 137635 (right and left handed parts), These were used on TR4's after CS23383. We also have Stanpart 14227 which has the tab centralized so there is no right or left handed part, we believe these were used on all TR4A's. These were Please let us know which one you need,


Distance Piece (TR4 / 4A) pair


Sway Bars

For All Thriumph TR Series 4A(IRS), 5, 250, 6 (not available for CH03 series, TR2-3)


Front sway bars are also available and ours can be used alone without the rear bar or can be used in conjunction with the rear bar. Our front bars are reproductions of the stock bar in 4140 chrome molly steel, mandrel bent in 7/8 inch diameter. They match the rear bar and when used together are designed to provide neutral steering without inducing under steer or over steer. These are powder coated and come with all the necessary mounting hardware.

The bars are 4140 chrome molly steel and are mandrel bent to our specifications. They come with all the hardware and end links sets. These 3/4 inch diameter bars and all the hardware are powder coated for lasting durability.

Actual Part Color is Black/Gray Hammertone


If you are converting to the coil over shock system, then you might want to look into fitting a rear sway bar to your new frame. This sway bar is custom made for us by a premier sway bar manufacturer and is fabricated to fit our frames ONLY if a coil over shock system is used. The coil over system frees the mounting hole normally used by the lever shock on the swing arm. That mounting point is now used for the end link attachment of the sway bar. The bar rides up and over the differential along the spring tower cross member and is held in place by brackets and bushings at two locations.

The bars are 4140 chrome molly steel and are mandrel bent to our specifications. They come with all the hardware and end links sets. These 3/4 inch diameter bars and all the hardware are powder coated for lasting durability.

Actual Part Color is Black/Gray Hammertone


RSBK-3/4-01 Rear Sway Bar (for RATCO Frame)

RSBK-3/4-02 Inst Rear Sway Bar (for STOCK Frame)

RSBK-3/4-02 Rear Sway Bar (for STOCK Frame)

FSBK-7/8 Front Sway Bar (not installed)

$225 3/4" Diameter (8690)

$250 3/4" Diameter (8690) (Installed)

$250 3/4" Diameter (8690)

$250 7/8" Diameter (8567)

Transmission Bracket Kits

We have been noticing lately that customers are putting cars together from parts collected from various sources. In some cases pre-72 transmissions are being put into post 73 frames and vice versa. To help make things simpler, we are offering weld-in brackets to convert your frame to match the transmission you are installing. These are the same brackets we use on the RATCO Frames, but they have been modified slightly to fit between the inboard flanges on the factory frames.

Pre 73 Transmission Bracket

Allows you to install an early transmission in a later frame.

Welding Required

Price $150

Post 72 Transmission Bracket

Allows you to install a late transmission in an early frame.

Welding Required

Price $200

HVDA Bracket

Adapts a Toyota transmission to Post 72 Frame. More robust than the adapter hardware provided with the conversion kits.

Bolt-in, no welding

Price $200

Throttle Linkage Kit

For all Triumphs TR2/3/4/5/6 with:

Dual Strombergs

Dual SU's

Dual or triple Webers, DGV or DCOE

Triple Strombergs

Triple SU's


If you are using any of the above mentioned carburetor setups with either the stock, Pierce Cannon or Goodparts manifolds, then these kits will make your life so much simpler. It eliminates the bell crank system used in the stock carburetor setups and replaces it with a modern, infinitely adjustable, aircraft quality, push pull cable system.

RATCO's approach is to simplify the entire connection between the accelerator pedal and the throttle connection at the carburetor with a cable instead of a bellcrank. In the process we have eliminated that cumbersome bellcrank linkage and have added adjustability which allows foot pedal height adjustment, full open throttle settings and free play adjustment. All this adds up to a smoother and more accurate linkage for the street rider and track racer alike.

This system replaces the bell crank assembly at the carburetor with a push/pull aircraft cable assembly connected to the lever at the passenger side firewall and a simple bracket at the carburetor. Now Weber owners can get full throttle acceleration, which was impossible with the stock linkage. Installers get to choose the location of the carburetor bracket, which is most convenient for them and all users get smooth accurate response to pedal pressure.

All hardware needed is included and complete instructions come with the kit or can be downloaded from this web site. All parts are powder coated and all hardware is nickel-plated. Installation takes about 1 hour and requires drilling holes in the firewall to mount the bracket.

Additional Information here:


TLK-01 Throttle Linkage Kit (TR4/4A/6/250)

TLK-02 Throttle Linkage Kit (TR4/4A/6/250)

$120 For all with Standard Manifold, Dual or Triple Stromberg, SU or Weber DGV

$120 For Weber DCOE Carbs with Cannon Manifolds only.

Emergency Hood Release Kit

You may not have experienced it yet, and we hope you never do, but one day you're going to pull the hood release handle and you're going to feel the cable slip from it's clamp, or snap entirely. Due to the fact that the locking mechanism is located on the firewall, it is all but impossible to reach. This simple and inexpensive kit allows you to have a secondary method of opening the hood in case of such an emergency. Many of our customers tell us they like it so much they often use it instead of the original. It is also more convenient because it is accessible from the passenger side which is where the secondary latch is located, so it saves some walking around the car.

Our kit is unique in that it uses the existing hole in the locking mechanism, rather than requiring you to drill a new hole. We always prefer to minimize permanent changes in favor of reversible changes. The installation is extremely simple and requires only a single 1/8" hole in the firewall to allow the control rod to enter the passenger compartment. Please review the photo above.


EHRK Emergency Hood Release Kit


Differential and Spring Tower Replacement Kits

The differential cross-member that you see here is the design used for the RATCO frame and it is the same design that is used on the Differential Replacement Kit for stock TR frames. Our kit allows you to replace your broken or tired differential cross-member without taking the body off the car.. The procedure requires some cutting and welding but can be easily done by the shade tree mechanic if a welder is available.. The kit includes all the hardware needed and comes with an instruction manual showing step by step procedures with detailed photo's..

A very important feature of the kit is that it includes a set of rail covers that wrap around the old frame rails and provide a substantial platform upon which to weld the new differential cross-member.. Once installed it allows the welding of new steel to new steel and the design strengthens the entire area as well.. It can be made to work with the old design lever shocks or if you want to upgrade to the tube shock conversion kit or the shock in coil kit, that can be made as well.. Tell us your preference when you place your order.

Due to required welding, repair kits are provided unpainted

Due to required welding, repair kits are provided unpainted

Due to required welding, repair kits are provided unpainted


RDCBK-01 Rear Differential Crossmember Kit

RDCBK-02 Rear Differential Crossmember Kit

RSTRK Rear Spring Tower Replacement Kit

$300 (for RATCO Shock in Coil)

$350 (for lever shocks)


Trailer Hitch Kit

A Trailer Hitch for a TR6??

Yes, we went and did it. We designed a 2" Trailer Hitch to bolt onto a TR6 with either a stock frame our our RATCO frame. We didn't go with the 2" hitch for the towing capacity, but rather for the large number of aftermarket accessories that are currently available in that size. The hitch is made of our standard 11ga steel tubing, and can be installed on any TR6 with Dual exhaust.

We don't expect the Towing capacity of a TR6 to be very great, but some of the accessories could really come in handy. How about some extra luggage? We will be designing an exhaust deflector system shortly so that the exhaust doesn't cook the food in your cooler.

Disclaimer! This trailer hitch is intended for light loads and low tongue weights.

Do not overload or attempt to pull heavy trailers.

How about a Luggage Tray or a nice flag holder for your next parade? Our flag holder is designed to work with readily available 1/2" Electrical conduit, so you can adjust the length to suit your flag, or replace it easily should it get damaged.

Or maybe a bike rack?

So, how do we know how much weight it can handle?

Meet our test dummy, Mr Wideload. His 200Lb load does not distort or bend any of the tubing, and the rear suspension does not even sink excessively. By the way, this car has springs 1" lower than normal.

Ok, so here is a bit more detail about the design and installation. The Hitch picks up four points on the car, the two rear differential mounting studs, and the two forward Bumper mounting bolts.

OEM Frame Installation

RATCO Frame Installation

Actual part color is black

The connection points at the forward bumper bolts are designed so that any downward vertical load is shared by the bolt as well as the frame flange. The RATCO frames can use the trunk cross bar, but the Stock frames were determined to be too weak to carry the load, so a new cross bar is added.

There's also a removable receiver tube for when you are not using the hitch. With the receiver tube removed, there is no change in the ground clearance, and the tube is about 1" past the edge of the valance and painted black, so it is barely noticeable.

The receiver tube is just about even with the end of the bumper, and even with the receiver tube mounted, there is no loss of ground clearance.

Here's what the complete kit looks like:

Includes all mounting hardware and Powder Coated, Welded Steel assemblies.

Disclaimer! This trailer hitch is intended for light loads and low tongue weights.

Do not overload or attempt to pull heavy trailers.

Flag Holder, works in any 2" receiver


THK-01 Trailer Hitch Kit (TR6 only)

FLAG-01 Flag Holder



Flat Towing Package

Coming Soon!

Actual parts are provided in black