Modern Jeep Bumper Design
Bumper to Bumper – Modern Jeep Bumper Design
By Justin Banner
You read and hear about so many different types and designs of bumpers, but what do they all mean? What is a stubby-width bumper? Why might I need a winch plate? What is the difference between a stinger bar and a prerunner bar? We’ll answer those and more in this bumper design article.
After tires, wheels, and suspension, the front bumper is probably the next thing most Jeep owners look to change on their Wrangler or even any other off-roading SUV. If you’re new to this, you’re probably wondering why the stock bumper isn’t good enough on these vehicles. Jeeps are “trail rated” and made for going off-road, right? Well, yes and no.
Stock Jeep Bumper Limitations
What you must remember is that the factory stock bumper of any Jeep is designed to fit within a set criterion of the vehicle’s design. This is especially true with Jeeps made to meet CAFE standards on fuel economy and emissions requirements. It also must meet Jeep’s own crash requirements as bumpers for SUVs and trucks aren’t regulated like cars are.
For example, if you look at the JL’s bumper, you’ll see that it has features that better enclose the front tires from air it pushes through on the front end. The cap just past the corners of the front bumper force air to flow around the wheel well to improve aerodynamics for fuel economy. A stock JL front bumper also features a skirt on the bottom side to prevent air from hitting the radiator area and, again, force air to go around it and under the chassis.
These requirements force a bumper to be designed with compromises and not for ultimate off-road travel. Jeep has done the best job it can but it’s not made for hardcore crawling.
Where the Aftermarket Comes In
Knowing that, the aftermarket for Jeep bumpers has helped increase the clearances of nearly their entire product line. With that done, though they have created a large swath of options for the Jeep owner and the differences might be confusing for those who aren’t familiar with off-roading.
So, let’s run through the different types of bumpers and the options you have when checking out new designs for your Jeep.
There are three different widths for Jeeps that most of the aftermarket industry recognizes: full-width, mid-width, and stubby-width. What we’re defining doesn’t really have a true, accepted definition, though. There isn’t a set measurement for any of those widths, but there are accepted ideas and practices when it comes to them.
A full-width bumper is designed to be the same width as the OEM bumper. At the very least, it spans the width of the OEM Jeep fender flares. This offers the same impact protection as the stock Jeep bumper but, depending on design, can hinder boulder and obstacle clearance for the front tires.
This is perfect for those of you who live in states that require bumpers to cover the front tires or meet the same width as the OE Jeep design. Not every state requires that, so be sure to confirm that you need to before buying.
This is a very loose definition, but most mid-width bumpers cover up to the middle of the original Jeep flares on Wranglers. They can be a little shorter or longer than that, but this width bumper does not cover the entire width of the stock Wrangler from OE flare to OE flare.
This is a great way to get extra boulder and obstacle clearance while retaining some sort of impact protection for your front tires. This may also allow you to skirt some state laws with bumper width requirements. Again, check with your inspector or local laws before committing to this width bumper.
Some mid-width (and full-width) bumpers can also allow you to get your fog lights out wider than stock on JKs and JLs, too. So there is an advantage there as well.
Some would argue that these are nothing more than bars or formed plates the cover the original bumper mounts, but stubby-width bumpers are usually no wider than those mounts. Some go a tiny bit wider, reaching the same width as the grille but don’t go further than that. Any wider and it should be considered a mid-width. Again, it’s not a defined width here, but the accepted idea is that the width isn’t much wider than the grille shell and should be smaller.
These bumpers offer maximum boulder and obstacle clearance, but at the cost of providing zero tire impact protection. For hardcore crawling and rock racing, you need this width of bumper as that is the only way to get full front tire clearance.
That does mean that states that have bumper width requirements a stubby bumper isn’t going to be legal. If you’re also worried about tire contact as you drive, that’s another “no” to buying a stubby-width bumper. If neither are your concern, then there isn’t much stopping you from buying one if you want it.
There are a few recognized types of bars available for most bumpers, too. Most of them have a function beyond looking like your favorite off-road racing rig or crawler, too.
A prerunner bar spans the width of the front grille in most cases, but can be wider if it or its auxiliary tubes don’t interfere with the front lights. Well, in most cases anyway as, much like bumper width, these design criteria aren’t set in stone with actual numbers. Just ideas and practices.
The focus of a functional prerunner bar is to add impact protection for the grille and winch. The bar will usually jut out just past the bumper’s face or will be very close to it. Instead of that tree or rock impacting the winch, the bar takes the hit first and reduces or prevents it from taking the hit.
Yes, there are prerunner bars that are simply there for looks but they can also function as light bar mounts in some cases. They may even include mounting tabs just for that. These bars are usually made of tube but can also be constructed from steel plate, both in functional and show designs.
Stinger bars are a specialty of the rock crawling scene and provide a function when designed properly. When it’s designed to work, a stinger can prevent you from rolling forward onto the roof of your Jeep on a steep decline. The bar will prevent the it from over-rotation, past its center of gravity to make sure your Jeep will remain on its wheels and not on its lid.
This is on top of grille and winch protection, just like the prerunner bar.
You’ll likely to see several options to get built into your bumper to spec it out how you like. If you’re a regular trail driver, you’ll want to make sure that a winch plate is included or if its integral to the bumper you are wanting to buy.
A winch mounting plate is designed to hold your winch to your bumper, putting it high enough so that the line can clear the bumper and can usually come with a fairlead mount. Most are designed to bolt on to your Wrangler much like how your bumper attaches, using the same bolts and some times even utilizing the swaybar’s front chassis bolt on older platforms.
However, there are universal options that require you to cut, drill, and modify your Jeep or its bumper to work.
Most winches up to 12,500-pounds have a four-bolt mounting pattern that fit within 10-inches wide by 5-inches long. Others, typically smaller than 12,500-pounds, fit in a 5-inches wide by 4-inches long pattern. Because there can be variety between and beyond these, you’ll always want to make sure your winch fits the pattern of your winch mount or the mount fits the pattern of your winch, whichever way you’re going.
Many bumpers offer lights as part of their package, others don’t but offer mounts to fit aftermarket or Jeep OE fog lights. If they offer lights, be sure they also come with the wiring required to use them or you’ll just have them there for show.
However, if lights aren’t optional but the bumper comes with mounts, make sure you get the right sized lights for the mounts. If it only fits a 20-inch light bar, that’s all that will fit with that mount. If it doesn’t say, consult with the manufacturer before ordering your lights or even ordering the bumper if you’re reusing yours.
Also, if you’re reusing OE Jeep fog lights, make sure which version fog light fits. Non-Rubicon fog lights were halogen bulb and have a different mount than the Rubicon LED fog lights. Some bumper manufacturers have brackets for both types, too.
D-Rings are a helpful addition to any bumper, front or rear. These provide additional winch points to pull your Jeep out of a stuck situation or can be used with a snatch-block to increase your winch’s pulling power.
They can also be used to give your winch hook a place to hang to when not in use. This prevents it from swinging around, damaging your bumper or even the hook itself.
The mounts can be fully welded to the bumpers or can come as bolt-on mounts. Either version can be just as strong but welded on D-ring mounts should be welded on both sides of the bumper for maximum strength.
Bolt-on mounts should come with bolts of grade-eight or higher rating. At the very least, if its mounted to the front of the bumper, it should have a tensile strength of 120,000-pounds since it’s used in a pull more than in shear (cut) and a yank will have higher stress than a steady pull.
If the mounts are under the bumper, it’s mounted in shear and will require an ultimate shear strength (in kilopound per square inch or ksi) of at three times your vehicle’s weight (for most Jeeps at 4,200-pounds, that will be a 1/2-inch-20 Grade 8 bolt with a 17,870-ksi ultimate shear capability). That multiplication should give you a safety margin for both the grading and material used in the fastener.
Useful, but Not Necessarily Required
For both front and rear bumpers, having a place to mount your license plate isn’t a bad thing to think about, especially if you’re not reusing the body mount on the rear of your Jeep and don’t want to use a spare tire mount. Many won’t because the majority of Jeep owners use those and don’t request a bumper-mounted license plate holder on the rear.
For the front, there are fairlead attachments that allow quick removal of the license plate when you need to use your winch. They range from strong magnets or folding brackets for Hawse fairleads to clips that hold on to roller types. So, if the bumper you want doesn’t have a license plate option and your state requires one to stay legal, you don’t have to stick it in between your dashboard and windshield (which isn’t legal in many states, either).
Skid plates for the front bumper aren’t a bad idea. Some bumpers have it as an option while others don’t for maximum front ground clearance. However, a well-designed skid plate can prevent damage to the lower portions of the frame and components that hang in that area like the sway bar and its links, pitman arm, and drag link. A lot of that can be prevented by good driving with a good spotter, too, but not everyone is Tony Pellegrino.
Which Bumper Do I Need?
To answer that, you’ll probably need to first consult your local laws to see what the width requirements are to stay street legal. For a lot of states and localities, a full-width or mid-width bumper are the narrowest you can run.
If your laws don’t have a requirement, then it’s up to what you need. If you’re not crawling hardcore then your best option is going to be a full-width or mid-width bumper. Having as much forward and rear impact protection as you can get with good boulder clearance isn’t a bad thing. While that may seem like a disadvantage, there are some very well thought out designs that allow maximum tire to boulder clearance while providing adequate tire coverage on the front of your Jeep. No, it won’t be wide open like a stubby but you’ll stay legal while still being able to traverse some harder trails.
Barring that, having a stubby width bumper is going to put your front tires right in the open. This will give your Jeep the best clearance for boulders and objects as you crawl tough, narrow trails. However, you must drive with that realization in mind. While the open clearance is an advantage, that also means any front-end contact could result in you climbing and potentially rolling over in the event of an accident. In the best case, it means you have a lot more bent up parts than you would if you had a full-width bumper.
While that may seem like we’re trying to scare some owners, yeah, we kind of are. You should be driving with more awareness anyhow. Always keep in mind that you’re driving something that’s much higher in the air with tires that have a taller, more flexible sidewall. Regardless of what bumper you have you are driving something that’s a little less stable when compared to a stock Jeep, let alone a car, and shouldn’t be driven like one. Add in that you’ve just opened up the front tires to objects and you now need to be even more aware of that fact.
That doesn’t mean fear your lifted Jeep, though. Just drive with that awareness and respect as you always should when driving something modified. It’s still your Jeep, just one that is better able to crawl over stuff.
Bumpers Are Just A Start
You should now better understand what you’re looking at when it comes to Jeep bumper design. Being able to make an informed decision on a purchase that can be nearly as expensive as your lift kit is always a positive. Just don’t forget to browse our selection of bumpers for your Jeeps so you can get the best offered in the industry. If you ever have any questions, we’re always here to help, too.