It routinely comes up in build discussions here that you're doing the same work for either a 33" or 35" tire. However, I couldn't find anything that actually quantified that statement in one place. For discussion purposes, and so we can help better educate ourselves and others, I'm proposing we do exactly that. Here's the scenario:
Assume we are building a highly capable dual purpose TJ/LJ (i.e. daily driver and solid trail rig) for either 33" or 35" tires. We're looking to maximize shock travel, belly height, and protect vulnerable areas underneath the Jeep. We also want to maintain safe handling, acceleration, and braking.
This has to be bolt on parts, so we aren't doing any custom work like shock out-boarding, raised body mounts etc. With that in mind, I took a shot at identifying the components that should be replaced, allowing for some substitutions in a couple areas.
The one area I'd argue every TJ/LJ requires some "custom work" would be to weld mini skids on the front lower control arms. However, I'll leave that off for now, along with body armor, bumpers, and a winch, at least until others chime in.
Although I tried not to put vendor solutions here, there are two exceptions noted.
With that scenario in mind, once I put everything into a spreadsheet the introduction statement becomes abundantly clear. He's my first shot at the list, so fire away and help make this something useful for those not in the know!
Assume we are building a highly capable dual purpose TJ/LJ (i.e. daily driver and solid trail rig) for either 33" or 35" tires. We're looking to maximize shock travel, belly height, and protect vulnerable areas underneath the Jeep. We also want to maintain safe handling, acceleration, and braking.
This has to be bolt on parts, so we aren't doing any custom work like shock out-boarding, raised body mounts etc. With that in mind, I took a shot at identifying the components that should be replaced, allowing for some substitutions in a couple areas.
The one area I'd argue every TJ/LJ requires some "custom work" would be to weld mini skids on the front lower control arms. However, I'll leave that off for now, along with body armor, bumpers, and a winch, at least until others chime in.
Although I tried not to put vendor solutions here, there are two exceptions noted.
With that scenario in mind, once I put everything into a spreadsheet the introduction statement becomes abundantly clear. He's my first shot at the list, so fire away and help make this something useful for those not in the know!
| This is not a list for those wanting a budget build. It is intended for those that want to optimize a build around either 33" or 35" tires. "Optimize" means build it to maximum performance, both on and off-road, using bolt-on parts.Additionally, following the recipe outlined, you'll minimize throwing away or buying parts twice, should you start out with a 33" tire in mind, but later move to a 35" tire. | ||
| Tire Size | 33" | 35" |
| Suspension | ||
| 4" Springs¹ | Yes | Yes |
| Shocks to match lift | Yes | Yes |
| Adjustable Control Arms (Short Arms)² | Yes | Yes |
| Adjustable Track Bars | Yes | Yes |
| Rear Track Bar Bracket | Yes | Yes |
| Steering | ||
| Steering Linkage - Currie³ | Yes | Yes |
| Upgraded Steering Box/Pump/Cylinder Assist | No | Yes |
| Power Steering Cooler | No | Yes |
| Drivetrain | ||
| Gears - Optimized for your transmission and tire size | Yes | Yes |
| Lockers (Selectable)⁴ | Yes | Yes |
| Front Axle Shafts⁴ | Yes | Yes |
| Rear Axle Shafts⁴ | Yes | Yes |
| Transmission Cooler and Temperature Gauge⁵ | Yes | Yes |
| Slip Yoke Eliminator (SYE)⁶ | Yes | Yes |
| Driveshafts | Yes | Yes |
| Brakes | ||
| Upgraded Brake Pads | Yes | Yes |
| Extended Brake Lines | Yes | Yes |
| Big Brake Kit (BBK)⁷ | No | No |
| Body | ||
| Body Lift (BL) | No | Yes |
| Motor Mount Lift | No | Yes |
| Armor | ||
| Gas Tank Skid (GTS)⁸ | No | Yes |
| Tummy Tuck⁹ | No | Yes |
| Gas Tank Skid | No | Yes |
| Rocker Guards | No | Yes |
| Engine Skid | No | Yes |
| Tires and Wheels | ||
| 33" Tires | Yes | No |
| 35" Tires | No | Yes |
| Wheels to match tire size¹⁰ | ||
| Miscellaneous | ||
| Tire Carrier Reinforcement¹¹ | Yes | Yes |
| Cable Shifter for Transfer Case | No | Yes |
| Differential Covers¹² | Yes | Yes |
| Caveats | ||
| ¹A 4" spring is the optimal spring for a TJ. it provides the longest possible free length, allowing for a 10" travel shock, when set up properly. | ||
| ²Double adjustable arms make fine tuning easier, but a single adjustable arm will suffice. | ||
| ³This is one of the places where a vendors product is mentioned. Reason being, although a ZJ steering upgrade can be done, they are prone to bending if you spend a significant amount of time on rocks. | ||
| ⁴30 Spline are recommended for a Dana 35 (Super 35 Kit) or Dana 30. | ||
| ⁵All automatic transmissions should have a transmission cooler and temperature gauge. | ||
| ⁶SYE is required for all 231 transfer cases. In addition to the fixed yoke, a SYE, especially on a TJ, allows for a longer rear driveshaft. In the case of the TJ, the Super Short SYE is recommended. | ||
| ⁷This one falls into the category of you'll know you need a Big Brake Kit (BBK) when you drive the Jeep on 35" tires. If you're of the mindset that stock brakes will suffice, buy wheels with the possibility of making the upgrade later in mind. | ||
| ⁸This is optional and another case where a vendor product will be used. If you purchase a Savvy GTS it can be installed in either a BL or no-BL configuration. This means that later, if you move to 35" tires, all you have to do is raise the skid up to the BL setting. | ||
| ⁹It's assumed that if you're building around a 35" tire, you're doing so to push both the rig and your abilities. In that case, the skids are considered required. For a 33" tire build, a Non-BL belly skid could be installed, to help slightly improve belly height. However, the maximum belly height that can be obtained with a "bolt-on" skid requires a BL. This means that if you buy a non-BL skid, it would be the only part you'd need to replace, besides tires, should you choose to move up to a 35" tire later. | ||
| ¹⁰Wheel size is up to the you, but be advised that 15" tire sizes are dwindling. Also, a 17" wheel would minimize buying wheels twice, offers good tire choices, and allows for BBK options later. | ||
| ¹¹Tire carrier reinforcement is required to help reduce stress on the factory tailgate spot welds and factory hinges. | ||
| ¹²Care should be taken to get covers that offer protection and minimize interference with the front track bar or GTS. |
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