Anyone who's spent time on Datsun Z forums knows the struggle. Every build thread shows off different fender flares, and yet somehow nobody bothers to explain why they went with bolt-on over weld-on (or vice versa). The whole choice starts to feel much harder than it probably should, and that's when the two sides of the debate insist that their way is the only way to go.
Most Z owners need the flares for one of two reasons - either they need more tire clearance or they're after the aggressive Japanese race car look from the 1970s. Fender flares work just fine, though the installation method does change the entire project. Some owners need to keep the ability to change their car back for a possible resale later. Others know that their Z is a lifetime keeper and would rather have the smooth, integrated look.
The bolt-on versus weld-on split in the Z community exists because each method needs very different compromises. Professional shops will quote very different prices based on the direction you choose. And depending on the tools and skills you already have, some of the options might already be off the table.
Here are the differences so you can choose the right flares for your Z!
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What You Need for Each Method
The main difference between these two options depends on the way each one actually attaches to your car.
Bolt-on flares are designed to use the existing mounting points that are already on your Z, or in some cases, you'll have to drill new holes right through the fender. Before you drill anything, though, make sure to measure everything carefully and mark each exact place where the hardware needs to go. The bolts thread directly through the body metal and the flare itself, and most kits actually have rubber gaskets that create a tight seal between the flare and your paint job.
Weld-on flares are a very different animal because they need you to cut away sections of your original fender first. Once you make those cuts, you're committed - there's no way to undo what you've done. The new flare then gets welded directly to whatever portion of your fender lip remains after the cutting. After all the welding is done, you'll still need to grind those welds smooth and then apply body filler to blend everything together until it looks smooth.
The tools needed for the two types of installation couldn't be more different either. For a bolt-on installation, you'll need a drill and some decent bits, a socket set and maybe a file to clean up any rough edges you create. Most Z owners already have these tools in their garage somewhere. Pacing yourself and not rushing through it, you're probably looking at somewhere between 4 and 8 hours for the entire job from start to finish.
Weld-on flares are a challenge because they demand legitimate metalwork skills and experience. You need a welder, cutting tools, a grinder and enough experience to make precise cuts without destroying your fenders. The average Z owner probably doesn't have this specific equipment just sitting around collecting dust. And even if you somehow do have all the right tools, the job itself takes multiple days once you factor in all the cutting, welding, grinding and then all that bodywork to finish properly.
This explains why most Z owners feel comfortable with bolt-on flares they can install themselves over a weekend. Weld-on flares usually mean you'll need to load up your car and take it to a professional body shop that has the proper ventilation systems and all the professional-grade tools needed for this heavy-duty metalwork.
How the Flares Look on Your Car
Once you have them installed, the different styles of flares do change the whole look of your car, and you want to know what you're buying before you choose one style or another.
Weld-on flares have this way of flowing right into the body lines, almost as if the factory designed them that way from day one. All the mounting points disappear completely since the whole area gets smoothed out and then painted over. The transition between the flare and the original fender is invisible. Other enthusiasts at a show might even think Datsun released a limited edition model they hadn't heard about.
Bolt-on flares are a very different animal altogether. The mounting hardware is usually visible to some degree, and there can be small gaps or spaces where the flare meets up with the original body panels. Most of them have raised edges or lips that catch the light differently than the surrounding metal does. The quality changes quite a bit based on the manufacturer and what price point you're shopping at.
Paint is actually one of the biggest considerations with either type of flares, and I see customers go back and forth on this decision all the time. With welded flares, the body shop treats the entire panel as one unit during the painting process. So the color match is going to be perfect since the shop sprays everything at the same time with the same batch of paint. Bolt-on flares present more of a challenge - some come pre-painted from the manufacturer, and others need to be painted after you buy them. In either scenario, the challenge is to match paint that was applied at very different times, maybe years apart.
Quality bolt-on flares can look so nice that plenty of owners assume they're actually welded on. MSA makes bolt-on kits that fit tight enough that experienced enthusiasts need a second look to tell that they're not permanent. Those budget options from random sellers look exactly as cheap as their price tag. The quality difference between the premium manufacturers and the budget options is really big!
The venue where your car will be displayed makes a real difference. A casual weekend at a Cars and Coffee meetup is going to be far more forgiving than a formal judged show where the judges literally examine everything.
The Cost and Time You Need
Cost is always a big factor when you're choosing between bolt-on and weld-on flare kits.
Bolt-on flare kits will run anywhere from $400 to $1,200, and the price depends on the brand you go with and what material quality you want. Weld-on flares cost about the same for the kit itself.
Professional installation costs are what will actually hurt your wallet. A quality weld-on flare installation will run you at least $1,500 to $3,000 on top of the parts, and I've seen shops charge even more for complex jobs. The labor costs are so high because the shop has to cut away sections of your existing fenders, weld the new flares into position and make everything look like it came from the factory that way. Once the welding work is finished, they still have hours of bodywork ahead - they have to smooth all the seams with filler, sand everything down, put on the primer and then apply multiple coats of paint and topcoat to match your vehicle's existing finish.
Bolt-on flares are a very different story for installation costs. At most, you might need some touch-up paint around the drill holes where the hardware goes through. Most owners install these themselves over a weekend with just basic tools and a bit of patience, and you'll have zero labor costs.
Time is also a big consideration between these two options. A bolt-on kit is something that you can install yourself on a Saturday afternoon if you have a few hours to spare and work at a steady pace. Weld-on flares are a very different story - your car is going to be at the body shop for at least a few weeks as they work through each step of the process. And when shops rush the job to squeeze in extra customers or meet tight deadlines, the work always looks terrible later. Ripples and uneven surfaces show up after a few months, and once you see them, they're impossible to ignore. Quality welded flares need time to get done right, and any shop that tells you otherwise is probably cutting corners.
That $600 weld-on kit can very quickly turn into a $3,600 project after you factor in all the professional labor. For the same amount of money, you could buy the absolute best bolt-on kit available and still have plenty of cash left over.
The financial equation does change if you have the skills and equipment to do the welding work yourself. Even then, you still need to account for all the materials like filler, primer, paint and topcoat, along with the few hours you'll spend on prep work and finishing. Most home garages also don't have an actual paint booth, and that makes it extremely hard to achieve a factory-quality finish.
How Your Flares Age Over Time
After a few years of ownership with either type of flares, you're going to see that they each age in their own unique patterns. Bolt-on flares get temperamental as time goes on. The hardware has a tendency to work itself loose little by little from all the vibration and regular driving - you'll need to grab a wrench and snug those bolts back down every couple of months or so. A lot of owners run into annoying squeaks and rattles that show up after the first year or two, and it's usually because those rubber gaskets have compressed down or just worn out from use.
Weld-on flares are a very different story because they actually become a permanent part of your vehicle's body. When they're installed correctly with quality welds, they won't budge or make any noise at all. The two types have their own rust challenges, though. The mounting holes on the bolt-on flares are known for becoming rust magnets whenever moisture manages to sneak behind those gaskets. Proper sealing from the very beginning is absolutely essential. Weld-on flares are beneficial in some cases because they cover up old factory seams where rust usually forms. Of course, when the welding work isn't done right, you've just created brand new places where rust can take hold.
Paint durability changes quite a bit between the two styles as well. Bolt-on flares have a bit of flex when you're driving later, and this movement can cause paint cracks along the edges after a couple of years. The weld-ons don't move at all once they're attached - the paint job usually holds up much better over time since they stay perfectly still, assuming the surface prep was done correctly in the first place.
Where you live really affects how these parts age over time. The road salt eats through weak points in either type of installation, and it doesn't take long for the damage to show. Living close to the ocean brings its own challenges - the salt air works its way into every bolt hole and does its best to corrode whatever it can find. Desert heat and winter cold are tough on materials, too, since the repeated expansion and contraction put stress on everything. Bolt-on flares usually show these effects sooner than welded ones. I check mine twice a year at a minimum - testing the bolt tightness on bolt-ons with a wrench or inspecting the welds closely to spot any stress cracks before they become a problem.
Build Your Dream Car
The choice between bolt-on versus weld-on flares depends on your situation and how you're going to use your Z. Every owner has different constraints and goals, and the right choice for your friend with the track-dedicated build probably won't match what makes sense for your everyday driver. Bolt-on flares give you options - you can swap them out, adjust your setup or go back to stock if you need to sell or want a different look down the line. Weld-on flares are permanent, and that's what some owners actually want. Once they're on, you never have to worry about them again. This works for drivers who know just what they want and push their cars hard on canyon runs or track days.
After talking to more Z owners than anyone can count at this point, the same pattern shows up again and again for the right flare setup. The process to get there almost never follows a straight line from point A to point B. The owners will usually go with bolt-on flares first as a way to test out the whole concept. After living with the bolt-ons for a few months, maybe even a full year, they've built up enough experience to know what they actually want. At that point, some owners stay with the bolt-ons because the flexibility works just right for them, and others will commit all the way and go ahead with a welded installation now that they know the precise setup they want to run. Local car meets and Z car gatherings are great for this type of homework, too. Most owners at these events are more than happy to talk about their setups and explain all the pros and cons of whichever route they went with.
The path to success with either option requires you to be brutally honest about three factors - your technical skills, the budget you're working with and what you plan on doing with the car. A bolt-on flare kit installed with patience and attention to detail will always look better than a welding job that was rushed or done poorly. The same principle works in reverse.
After you have your flares figured out and on the car, you'll probably want more modifications to pull the whole look together. At Skillard, we've made a name for ourselves with Z owners who need quality parts that are designed for the 240Z, 260Z, 280Z and the rest of the classic Datsun lineup.
We make everything from aluminum door cards and custom center consoles to some very aggressive bumpers and period-correct spoilers that just look right on these cars. What sets us apart is how we manage to respect the original design language of these cars, as we still take advantage of all the modern manufacturing techniques and materials we have access to today.
You'll find our entire catalog at Skillard.com, and it doesn't matter if you're doing a ground-up restoration or just want to add a few distinctive touches that make your Z stand out in a parking lot full of other classics - we've got what you need to get there.
