Put a wider wheel and a bigger tire on almost any truck and two things happen immediately. The tire sticks out past the bodywork, and the first wet gravel road coats the side of your vehicle in a stripe of mud and stone chips. The second one is the reason flares exist. The first one is the reason they are sometimes required.
Flares get discussed as a styling part. They are, but they are also the fix for a real problem created by the wheel and tire decision you already made.
Why the problem appears
Two changes push a tire outboard:
- Wheel offset. A lower or negative offset wheel moves the tire outward. This is the big one, and it is why two people running the same tire size can have completely different coverage. Our guide to wheel offset and backspacing covers the mechanics.
- Tire width. A wider tire grows in both directions from the wheel centerline, so half the extra width goes outboard.
Add a lift and the fender opening moves up relative to the tire, exposing more of the tire's shoulder to view and more of the world to spray.
What flares actually do
- Cover the tread. They put bodywork over the part of the tire that throws water, mud, and stones.
- Protect paint. The stripe of chips along the lower doors and rear quarter comes from an uncovered front tire. Flares plus mud flaps largely eliminate it.
- Add clearance. Cut-out and high-clearance flares raise the effective opening so a taller tire can cycle without contacting sheet metal.
- Satisfy coverage rules. Many jurisdictions require the tire tread to be covered by bodywork when viewed from above, or within some distance of vertical. Rules vary widely by state, province, and country. Worth checking your local regulation rather than assuming, because enforcement varies as much as the rules do.
The main types
OE-style replacement
Match the original opening shape, add an inch or so of coverage. Clean look, easy install, minimal extra clearance. Good if your tires are only slightly wider than stock.
Pocket and bolt-on style
Wider coverage with visible hardware, usually bolting to existing fender holes or requiring a few new ones. The common choice for a truck on a modest lift and a wider wheel.
Extended and high-clearance
Cut higher into the fender arch as well as wider. These are the ones that actually buy you tire clearance rather than just coverage. Most require trimming the fender, which is a one-way decision. Common on rigs running noticeably oversize tires.
Tube fenders
Maximum clearance, minimum coverage. For dedicated trail rigs. Almost never street-legal for coverage requirements, and they leave the tire fully exposed.
Materials and how they age
- Textured ABS or TPO. The common factory-style material. Holds up well, hides scratches, does not need paint. UV fades it over years; a plastic restorer brings it back.
- Smooth paintable ABS. Looks best when painted to match, shows every scuff, and a rock strike takes paint off in a way textured plastic does not.
- Steel or aluminum. Used on high-clearance and tube-style setups. Durable, heavier, and they transmit impact into the mounting points rather than flexing.
- Flexible urethane. Bounces back from contact with trees rather than cracking. A good choice for tight-trail rigs.
The mistakes people make
Buying flares to fix rubbing
Flares do not stop most rubbing. Rubbing usually happens at full steering lock against the inner liner, the frame, or the sway bar mount, or at full compression against the top of the wheel well. That is all inboard and upward, where a flare does nothing. Only high-clearance flares that involve trimming the arch address the compression case.
If you are rubbing, diagnose where before you buy anything. Cycle the suspension, turn lock to lock, and look for the witness marks.
Ignoring what happens when you trim
Cutting a fender exposes bare metal. If you do not seal and paint the cut edge, it will rust, and it will rust from the inside where you cannot see it. Prime and paint every cut edge, same day.
Drilling without checking what is behind
Wiring for side markers, washer lines, and in some vehicles airbag sensors run inside fenders. Pull the liner and look before a drill bit goes through.
Forgetting the liner
Removing a fender liner to gain clearance is common and it works, but the liner was keeping water and salt out of a cavity that traps both. If you remove it, plan on rinsing that area out regularly or you are trading clearance for rust.
Skipping mud flaps
Flares reduce spray. Flaps stop it. If the reason you are doing this is paint protection, flaps behind the front tires do more than the flare itself. They also make you considerably less unpopular with the vehicle behind you on gravel.
Installation notes
- Test fit before removing any factory trim, and lay out where every fastener lands.
- Clean the mounting surface thoroughly if any part is adhesive-backed, and install above the minimum temperature the adhesive specifies. Cold adhesive does not bond and the flare falls off in a month.
- Use the supplied gaskets or foam strips. They are there to keep water from sitting between the flare and the paint, which is a rust starter.
- If trimming, mark with tape, cut conservatively, then test fit and cut again. You cannot put it back.
- Seal and paint all cut edges before final assembly.
- Retorque and check for rattles after a few hundred miles.
Getting the order right
Choose wheels and tires first, fit them, drive the truck, find out where it actually rubs and how much coverage you are missing. Then buy flares to solve the specific problem. Buying flares first and hoping the tire fits underneath is how people end up with a set that is either pointless or not enough.
Start with wheels and tires to settle the fitment question, then look at body parts for flares and trim. If the tire size you are chasing needs more room than a flare can give you, that is a suspension conversation.