This is just a sliver of the info from our TECH INDEX (LINK).
Our team has the experience to get you the right dies for the correct OD (outside diameter)with your tubing bender. Here is a few guidelines based on what you’re doing:
(rock bouncers, buggies, exo cages, in cab cages, Jeeps, Toyotas, etc): Go with a 1.75 (1 3/4) OD tube die. You will be using .120 wall, and it will look best on a 6″ CLR (bend radius) die, but can be done on a 4.5 CLR with more deformation.
1.625 (1 5/8) x .083 is the tubing most of the NHRA specs are based on, but you will have to get your rulebook to determine all the sizes you need. For example, the 25.3 SFI also uses 3/4″, 1″, 1 1/8″, 1 1/4″, and 1 1/2″. Get a 6.0 CLR for all sizes that you buy over 1.25 OD to be able to bend to the thin wall tubing used. Remember that the rule books list minimum wall thickness and minimum diameter, you can always go bigger and thicker and pass an inspection, which can allow you to buy fewer dies to complete a project. The NHRA handbook covers cars 8.50 second ET (elapsed time) in the 1/4 mile and slower, and that is free from NHRA online. Faster cars are covered by the SFI foundation, and the specs are not free (you can purchase them from SFI).
SCCA/NASA/autocross/rallycross/Pro Touring/Road Racing cages:
SCCA/NASA specs vary widely based on racing class and car weight, with 1.625 (1 5/8″) OD tubing being the most common. Some cars are allowed 1.5 (1 1/2) OD, and some require 1.75 (1 3/4) OD. The specs are available on the SCCA and NASA web pages for free. Follow the same CLR guidelines as NHRA/SFI above.
(Ultra4, Trophy Trucks, Baja 500/1000, other racing series): Go to the SCORE web page for more info. As of 6/5/17, cars over 4400 lbs race wieght has to use 2.00″ OD tubing and .120″ wall minimum for the primary cage structure. We only offer 2 inch dies on a 6 inch radius, which will bend .120″ wall.
Sand Cars :
(sand rails, dune buggies, etc): These are not generally regulated in any way. We have a calculator for tubing that can help you compare materials, and keep in mind this is your safety on the line. Light is fast, and light and fast can be dangerous. These projects vary from lightweight VW powered machines to 1000+ horsepower LS powered cars. On the small side for lighter and slower projects, 1.5 x .095 may be enough (use a 1.5 OD x 6 CLR die). On heavier and faster projects, 1.75 x .095 is a good material to consider (1.75 OD x 6 CLR die). Save weight on shorter support tubes by buying a second and third die, dropping 1/4″ and 1/2″ off your primary tube size. Recommended dies are 1.5 OD x 6 CLR, 1.25 x 4.5 CLR, and 1.0 x 3.5 CLR.
Side by Sides, SXS, RZR, etc:
We recommend using the same OD that was stock on your side by side so that the cage can use all the bolt on stuff that came with it (mirrors, belt mounts, fire extinguisher, lights, etc). This is 1.75 OD for nearly all side by sides, with the exception of the Can-Am Maverick, which is 2.0 OD. We recommend a 6.0 CLR die for both of these materials. Popular support size is 1.25 OD and we recommend a 4.5 CLR die for this application.
If your build is street or recreational, we recommend 1.75 OD for cars over 3500 lbs, 1.625 (1 5/8″) for cars over 3000-3499 lbs, and 1.50 OD tubing for cars under 3000 lbs. We are not liable for decisions you make on your build. This is just a guideline to help you learn. Wall thicknesses vary, and are common in .120 and .095, and sometimes include .083 (.083 is usually 4130 alloy). Please keep in mind that cages and helmets usually go together, and you will want to pay attention to how far you’re putting metal from the driver’s head and how you plan to prevent a head injury if the driver will not always be wearing a helmet.
JEEP Wrangler (TJ/LJ/JK):
Most of our customers use 1.75x.120 wall, your choice on a 4.5 or 6.0 CLR die. The OEM cage on the TJ/LJ is 2.125 (2 1/8″) OD. Jeep used this large OD in an attempt to compensate for the severe lack of tubing and triangulation present on the stock cage, as well as all the unsupported bends. The stock roll cage is woefully inadequate in many offroad rollover situations, but can be heavily reinforced/reconstucted to be safe if done right.
1 1/4″ schedule 40 pipe is the most common material, in steel, stainless, or aluminum. This comfortable size meets construction codes in most areas and is very inexpensive. You can use a 4.5 or 6.0 CLR die. This material is 1.66 OD.
Sport boats have wake towers built out of 1.50 pipe (1.90 material… pipe, not tube) most of the time. Aluminum is the material of choice. Get yourself a 1.90 x 6 CLR die from our range of pipe dies, and get pressure rollers or UHMW pressure dies so you can bend aluminum. Fishing boats and other pleasure boats frequently have rocket launchers, fishing pole racks, bimini and bikini tops, T tops, etc. These can be made out of anything, but 1 1/4 aluminum pipe is the most common, since it is affordable and won’t rust. That material is 1.66 OD and is best bent on a 6.0 CLR die. Yachts are a little more common to use stainless over aluminum, usually 316L alloy. Pick a big radius for your die when bending stainless (the biggest we sell for your OD). Engine room and bow railings and other railings for human safety and comfort are commonly made from 1.25 OD .065 wall tubing, which bends beautifully on our 1.25 OD x 6 CLR die. 1 inch .065 is used on these craft as well, and it bends great on our 1.0 OD x 4.5 CLR die.