H-Mark Adjustable Ti Steering Box Assembly

H-Mark Titanium Steering Box: A masterpiece of engineering.

Advantages: Stronger, lighter, adjustable, easy to rebuild, quicker ratio.

Stronger:

• 1" diameter rack gear is larger and stronger than the 7/8" of the other models. Designed to increase strength and reliability.
• Rack width supported area of the housing is 3-7/16" providing greater support for the rack shaft. Other models are 2-15/16".
• Made with a 3/4-20 spline to interface with the steering shaft universal joint. Use 16-624 Universal Joint with this rack. All other racks use a 5/8-36 spline which wears out a lot quicker.
• All 4 bushings are custom made for us per our drawings and spec. They are made from C86300, a manganese bronze alloy, a high-strength, copper-zinc alloy known for its excellent wear resistance, corrosion resistance, and heavy-load-bearing capabilities.

Lighter:

• Despite being larger and stronger, the H-Mark Ti Steering Box is lighter thanks to the 6AL4V high grade Titanium Rack and Pinion gears: lightweight and strong! This box weighs 2.175 pounds which is .288 pounds (132 grams) lighter than the 16-500 Axle mount rack box and a lot lighter than any frame mounted box.

Adjustable:

• The pinion gear is housed in an eccentric mount, enabling precise adjustment of backlash (the clearance between the rack and pinion gears) to ensure optimal performance and feedback to the driver. As the system wears, this adjustable design allows the play to be easily eliminated. To adjust, simply loosen the three titanium 1/4-20 flanged hex head screws and rotate the mechanism to achieve the desired fit.

Quicker Ratio:

• Ratio: One turn of steering wheel = 6.15" of rack travel. Our other axle mounted racks are one turn of steering wheel = 4.8" of rack travel. This will make a very noticeable difference in driver feel if you don't change anything and just put this rack on. The ratio between how much the driver turns the steering wheel to how much the front wheels turn is a function of the rack box ratio and the distance from the center of the king pin to where the steering rods mount.
• We recommend if you are switching to this box from our original axle mount boxes and you like the steering ratio of your current setup, then switch to the 16-1945 3-3/4" steering arms to maintain the same feel. Or keep the 16-194 3" arms on for a quicker ratio, this means you will move your hands less for the same amount of front tire steering movement.

Here is a chart showing the different ratio racks, the different length steering arms, and the corresponding degrees of front tire turning you will get with 1/2 turn of steering wheel input. More degrees of movement equal a quicker turning ratio

Some drivers like the 16-194 for wingless racing, and the 16-1945 for winged racing.


Other specifications:

• 4-1/2" of travel stroke (more than the 4-1/8" of our other racks)
• Distance from rack centerline to mounting holes is 3/4"
• Distance from center line of the pinion gear to the mounting holes is 1-15/16"
• 200 Grams lighter than our other rack boxes
• End Clevises are made for 7/16" rod ends.
• 1-3/4" center to center distance on the 3/8" mounting bolt holes. Fits all of our rack box axle clamps
• To remove the two rack bushings in the event of damage, simply tap out the two roll pins that retain the busing in place and they will slide out.
• Tighten the 3/8" mounting bolts to 20-22 foot-pounds and use thread locker.
• 11-1/4" Center of center of the steering rod mounts.
• Use only Bulldog 657 Grease when rebuilding 77-808.

Tighten the (2) 3/8" mounting bolts to 20-22 foot-pounds and use 77-795 thread locker. Tightening these bolts too much can result in the rack box not being able to steer easily.