The right tire size makes a huge difference in how your Datsun 240Z looks and runs. When you choose the right size, you might improve the way your car feels on the road, help it corner better, and give it that classic look everyone appreciates. You'll also avoid problems where the tires rub against the fenders or suspension parts. It's not too hard to figure out - you just need to know a few basic tire measurements and think about what matters most to you when you drive.
New tires could be one of the best upgrades you can make for your 240Z. The factory put some pretty skinny tires on these cars back in the day. I'll tell you about what came on the car from the factory, why moving to 15 - or 16-inch wheels makes sense, why wheel offset matters, and how to balance comfort and performance. Each choice you make changes how your Z feels on the road. You might want it to feel like it did in the 1970s, or you might want it to handle more like a modern sports car.
The perfect tire setup for your Z will give your car that just-right stance while still keeping the feel that makes these cars so popular. You'll want to match your tire choice with how you actually use the car and what you like about driving it.
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What Are The Original Tire Sizes?
When the Datsun 240Z first came out of the factory, it had what looked like pretty small wheels compared to what we see now. The 240Z originally had 175 HR 14 tires on 14x4.5J steel rims. Some later models sometimes came with a bit wider 195/70R14 tires. These skinny tires with tall sidewalls gave the Z a look that you'd expect from sports cars back in those days.
When you drive on these original tires, it might feel different compared to modern ones. The skinnier contact patch didn't give you as much grip when taking corners. The taller sidewalls also moved around more during hard driving. But this old-style setup wasn't all bad - your ride was more comfortable over bumpy roads and the car felt more forgiving when you pushed it to its limits.
It's fairly hard to find exact matches for these old sizes because tire makers no longer produce these old-fashioned sizes. You might have to check some specialty stores or consider similar modern sizes instead. Z owners have often found that 175/70R14 is a great replacement for the original 175 HR 14 tires.
If keeping your Z like it was when it left the factory matters most to you, it's worth putting in the time to find the right tires. People who love these cars say the Z just looks right with the original tire sizes. The way the fenders match up with the tires creates that classic 70s sports car look, which is why some owners go out of their way to stick to factory specs.
The thin 4.5-inch wheel width seems almost funny compared to the wide wheels we see on modern cars built for speed. Cars built for speed now usually have wheels that are twice as wide. Those skinny wheels helped make the Z feel light and nimble on the road, and they also allowed you to use less gas and put less strain on your steering parts.
Some of the early 240Zs actually came with even skinnier 165 HR 14 tires, which gave a more old-school driving feel. Later models came with wider 5 or 5.5-inch rims paired with 195/70R14 tires to give you better control of the road.
Are 15 Or 16 Inches Tires Better?
When you choose to use 15" or 16" wheels, it opens up more options for your 240Z. You'll have many more choices for performance tires with these larger sizes. The stock 14" wheels no longer give you the options you need, especially with how tire technology has changed. Z owners have found that 15x7 wheels work well for driving.
They fit without having to make major changes to your car and give you a good mix of performance and a comfortable ride. You'll need to start looking at the offset numbers, though, with something between +15 and +25mm usually working best for these cars. They let you use tires with shorter sidewalls, which helps your car handle better when you're taking corners fast. These larger wheels also allow for bigger brake upgrades if you want to improve your stopping power.
Z fans say that 205/50R15 tires give them plenty of grip without any rubbing problems. Some like to go wider with 225/50R15 tires for the best possible traction. But you might need to roll your fenders for these to fit. Most drivers think this extra work is worth it for the added performance they get.
Your Z will look different with larger wheels. The car sits with a more aggressive stance that catches people's attention when you drive by or show up at car meets. You should also think about weight when picking new wheels. Some 15" options are fairly lightweight, which helps your Z feel quick and responsive.
Heavier wheels might make the car feel more stable. But they can also make your steering feel less sharp than before. If you're watching your budget, 15" wheels are probably your best bet because they're easy to find from different businesses and won't cost you too much.
The 16" wheels usually cost more and might need extra work to fit right. The tires available play a big part in choosing wheel sizes for older cars like the Z. You'll find decent performance tires in both 15" and 16" sizes these days. But quality 14" performance tires are harder to find each year, which is enough reason for owners to switch to larger wheels.
What About Offset And Fitment?
When choosing tires for your Datsun 240Z, you need to keep in mind the offset, wheel width, and wheel-well space at the same time. The stock offset for the 240Z wheels was between 0 mm and +15 mm, which helped the wheels fit just right in the car's small wheel wells. A zero offset is a good starting point when you're trying to determine the wheel fitment because it means the wheel sits right in the middle of the wheel well. That makes things easier for most Z owners who don't want to change their fenders.
Z owners can make mistakes when using wheel setups that are too aggressive. A negative offset pushes your wheels outward toward the fenders, which might look nice but can cause serious rubbing problems. A positive offset pulls the wheels inward and can sometimes hit parts of your suspension.
The stock Z came with 195/70R14 tires when it was new, and most owners now like to use 15x7 or 16x7 inch wheels because they provide better tire options. These sizes usually fit without requiring changes to your car's body. Width is a big part of these cars, and you can usually fit 205-225mm wide tires under the stock fenders. If you try to go wider than this, you'll probably run into rubbing problems, and your tire options will become even more limited if you have already lowered your car.
When you lower your Z, it looks great. But you get less space for tires. Z owners often figure out the problem the hard way after putting in coilovers since tires that fit well at normal height suddenly start rubbing on every bump in the road.
Your wheel bearings can wear out too early if you use the wrong offset, which changes how much weight your bearings have to manage and can lead to an expensive problem that many don't consider until it has already happened. Some Z fans use wheel spacers to achieve the fit they want. They must be installed properly because cheap spacers can cause dangerous vibrations or even break while you're driving.
To find the best tire setup, you usually have to do some testing to get it right. Z owners like to keep track of what works and what doesn't and they enjoy sharing what they have learned at car shows and in online communities.
Comfort vs Performance
Tire sidewall height changes how your Datsun 240Z feels on the road. With taller sidewalls, you'll get a much smoother ride on rough roads. They're better at soaking up bumps, hitting a pothole, or driving over bad pavement. If you use your car for commuting to work or taking long drives, you might like this extra comfort.
Shorter sidewalls make your Z handle more like a real sports car. The steering feels quicker and more connected to the road. You'll also find that you can take corners with better grip and confidence. People who take their cars to track days on weekends usually choose these tires because they want that extra bit of performance.
Back when your 240Z was new, it came with 175/70R14 tires, which were a middle-ground choice. They gave a great combination of comfort and handling for that time. Z owners switch to something like 195/60R14 or 205/60R14 to get better grip. These sizes still give you decent ride quality.
You might want to look at something like 225/50R15 if you're more into pushing your car harder. These wider tires with lower sidewalls stick to the road better. Keep in mind that they'll make your normal driving much rougher because you'll feel every little bump and crack in the road through your seat.
The width of your wheels also matters when you're picking tire sizes. Wider wheels let you put wider tires on your Z and sometimes require you to change your fenders a bit to make everything fit. It can be extra work. But many people think it's worth it for the better cornering grip.
Remember that changing your tire size can throw off your speedometer readings. It's best to keep the diameter close to what the car originally came with so your speedometer stays accurate and your gearing works as it should. Some Z owners like to use a staggered setup on their cars, which means putting wider tires on the back wheels than on the front. It helps you get better traction when you step on the gas. However, the downside is that it might change how your car behaves in some situations.
Don't Forget About Speedometer Calibration
When you install tires that are a different size than those originally on your car, it can change how your speedometer works, too. This happens because bigger tires take more time to complete a rotation than smaller ones. Your speedometer doesn't know that you made this change, so it shows your speed based on the size of the original tires.
If you go with tires that have a bigger diameter, your car will actually be moving faster than what shows up on your speedometer, which means you could be driving at 70 mph even though your gauge only says 65 mph. It works the other way too because smaller tires will make your speedometer read higher than your speed.
This problem also affects your odometer, which tracks how many miles you have driven. When it doesn't give the right numbers, it can throw off your car maintenance timing and even affect your car's value when you want to sell it later. Many 240Z owners don't know that their readings are off by 5-10% until they check against a GPS or look at highway mile markers.
The nice thing is that you can fix this problem pretty easily. The 240Z has a mechanical speedometer that works because of a gear inside the transmission. You can buy speedometer correction gears made specifically for the 240Z from places that sell parts for these cars. These gears come with different numbers of teeth to match the tires you've put on. To find the right gear, you'll need to solve an easy math problem based on how big your new tires are.
Putting in the new gear takes about an hour in your garage if you have the right tools. You'll need to remove the speedometer cable from the transmission and install the new drive gear. Many 240Z owners do this job on their own without any fancy tools.
While you're waiting to fix your speedometer, you might want to use a GPS speedometer app on your phone as a backup because it can give you an accurate reading no matter what size your tires are. I know someone with a 240Z who found out he had been driving 8 mph faster than what his gauge showed for years!
Build Your Dream Car
When you look at the options, from those factory 14" wheels to the newer 15" and 16" setups, you'll find that each choice has its own nice points. Some Z owners want that true 1970s look with wheels that match the era. But others enjoy better handling and a larger selection of new tires. What matters most is that you feel happy every time you get behind the wheel.
Think about the time when you took a corner in your Z and felt well connected to the road. Remember that feeling when everything just works together - how the car sits, how it grips and how it responds to you. That's the sweet find we're all trying to achieve.
Maybe you've kept something close to the first 175 HR 14 tires, or maybe you've switched to something more modern like a 205/60R15 or even a 215/55R16. The thing that counts is how it makes your car feel when you drive it. Keep in mind that bigger tires might throw off your speedometer readings a bit. But most of the time, the better handling is probably worth that small issue.
There's quite a bit more to making your Z drive and look its best than just picking the right tires. We at Skillard love how much care goes into fixing up and improving these cars, and we've worked for years to create custom parts just for classic Z cars, from the early 240Z to the 260Z and 280Z models. Our parts not only improve your car's performance but also keep the great look that makes these Japanese classics special.
You can take your Z-car to the next level with our help. We have all kinds of parts, from aluminum door cards to bumpers, center consoles, and spoilers, all made to fit perfectly with the smooth lines of your Datsun. I still remember how I felt the first time I put new wheels on my own Z and then stepped back to see how they changed the overall look and feel of the car. You can feel that same excitement, too! Visit Skillard.com to check out all our Z-car parts and find what you need to bring your car dreams to life.
