Frequently Asked Questions
Answers About Impact Derby Products
Find the answers to some of our customer’s most common questions below. If you don’t see an answer to your question here, please reach out through our Contact page and we’ll be happy to help!
What is the purpose of the curved trailing arms?
The curved lower trailing arms are intended to be used with rear ends that have the heavy-duty coil/leaf type lower mounts installed. The curved design gives additional clearance between the trailing arm and the lower mount. If you don’t have this style of lower mount on your rear end you can use the standard straight trailing arms.
Are the curved lower trailing arms longer than a straight arm for a specific application?
No, the bolt hole to bolt hole length of the curved arms are the same length as the straight arms for each application.
Can the watts conversion trailing arms be used on a regular Ford?
Our watts conversion trailing arms are shorter than a factory Ford trailing arm in order to compensate for the length of the watts conversion brackets and package tray differences. They are also shortened to pull the rear end forward about an inch for better tire clearance. For these reasons, they will not fit the ’97 and older Ford cars.
Can I purchase tie rods with different ends on each end?
Of course! You can set up the tie rod any way you like, big pin on one end, hiem joint on the other, small pin and big pin, etc. Please contact us directly to place a custom order so we can configure your set how you need them.
Do you sell axles for Ford 9 inch?
Yes, we can put together an axle package for almost any rear end. We can provide just the axle shafts all the way up to a full package with a built third member, axles, and housing ends. Contact us directly to place a custom order for this.
Can I get 40 spline axles for my 10 bolt or Ford 8.8?
Unfortunately no. The case for these rear ends physically limits the axle size to 35 spline. 40 spline setups are available for the 14 bolt, Ford 9 inch with the proper components, and the Dana 60.
Do your pinion brakes come with everything you need?
Yes! The 14 bolt and 9-inch pinion brakes include the yoke, rotor, loaded caliper, brake hose with fittings, bracket, and hardware. The 10 bolt kit includes the same with the exception of the yoke. The 10 bolt kit uses a yoke spacer to work with the factory 71-76 GM round flange yoke.
Can you ship rear ends?
Yes! We ship several rear ends via LTL freight a year. We recommend you have somewhere to ship this to that has a forklift or a dock so it is as affordable as possible. Freight can range from $400-$1,000 depending on your location and the ever-changing fuel prices.
Which watts conversion kit do I need for my rear end?
We offer two basic types of watts conversion kits. One kit is intended to be used with GM 10 bolt/12 bolt rear ends with the factory cast upper ears. The other kit is intended to be used with any rear end that has been jigged off of a Ford frame and suspension mounting points. If you have ever put a 10 bolt in a 97 and older ford you know it is a little tricky to get the trailing arms in without a little binding. Having two types of conversion kits takes care of this.
I want to purchase a rear end. What is the wait time and how do I pay?
All of our rear ends are custom configured to fit your specific needs and are built to order. Lead time can vary between one month to three months depending on parts availability and workload. Builds are completed in the order they are received. If you have a show in mind you need the rear end for, please communicate that upfront to make sure we can meet your needs. Rear ends require a 50% deposit upfront to get a place in the build line. Flexible payment options are available but the balance is due within 30 days of completion.
What types of rear ends do you build?
We try to focus our efforts on rear-end combinations that fit a wide range of needs and budgets without sacrificing durability and availability. These include GM 10 Bolt, GM 14 Bolt, Dana 60, Ford 9 inch, and Ford 8.8. Sticking within these options allows for a reliable assembly that can go from mild to wild. All of the rear ends we build are converted to aftermarket bolt-in type semi-floating axle shafts.
