Photos by Huw Evans and courtesy of American Speed Company
It’s amazing, considering the amount of time we’ll spend in it, that the interior isn’t always a top priority when putting together a hot rod. We think about the engine and driveline, the type of suspension, body and paint, even the braking system, but the interior? It’s just somewhere to park our behinds when we finally get to drive the thing. But if you’re going the extra mile for that deep paint finish, detailed frame and polished dropped front axle and Quickchange rear end, a cabin that sports ratty looking seats and/or mismatched upholstery, panels and fixtures really detracts from the finished result.
Even if you aren’t building a show car, a well-executed interior will still add that extra element to your ride, both in terms of visual appeal and comfort. Especially if you’re creating a “themed” hot rod or custom, you need to consider the types of features you’ll be using in the cabin. If you’re building a traditional style car, installing late-model Recaro seats and a sculptured center console is hardly the way to go. In the same vein, a traditional leather bench would look out of place in a high-tech, billet-laden street or show rod. If you choose an interior color which clashes with the exterior hue, it can make the car stand out for all the wrong reasons.
Another aspect to consider is the quality of materials you’ll be using. If you enjoy driving the car, you’ll want upholstery and carpet that’s durable and will last. However, most of us are on a budget, so we need to be realistic about how much we’re willing to spend on our car’s cabin and the time we have to put it together.
In this article, we take a look at some of the things you need to consider when putting together a quality hot rod interior. And lending us a hand with some useful tips are the folks at American Speed Company, a Metro Detroit-based hot rod facility.
Before even beginning the process of putting together an interior, you need to consider your ultimate objectives. “When a customer comes, in we ask them what kind of car they want to build – the features, the exterior colors – because these will have a major impact on the interior, both in terms of form and function,” says American Speed President D. Mark Trostle.
And thanks to his background in automotive design, Mark is able to visualize some ideas in sketches and illustrations. “It’s a very visual thing, conceiving a hot rod,” he says. “Sometimes a customer might have an idea for an exterior/interior color combination or even features inside the car, but when you actually render an illustration for them, it can sometimes send things in a different direction. Because the body and interior are the two aspects of the car you see most of the time, you want to make sure they work well together. For example, we have a car we’re building for a customer that’s two-tone blue and silver. He originally wanted a two-tone theme for the cabin as well, but when we showed him our suggestions of an overall blue interior with silver stitching and subtle accents, he liked the end result. We live in a visual world, and often it can be hard to grasp something until it’s placed directly in front of you.”
Patterns and Colors
Once the overall theme for the interior has been selected, it’s time to delve into more detail. “You’ve got the basic color figured out,” says Mark, “but then you need to think about patterns, and if you’re going to do more than one color, where to use accents. Headliners are also important – depending on the color and pattern of the seats, you might want the bows in the headliner to match the seats or the carpet. Also, when you use different materials – leather, vinyl, fabric and fiber – you need to think how they will work together. Let’s say you want to do a black car with a tan interior. Will a tan shifter boot and carpet work well with tan leather seats and a tan convertible top? Different textures of material can actually vary a particular shade enough that it looks out of place, so sometimes contrasting colors (like red seats with black carpeting) will work better, simply because of the type of carpet or vinyl inserts being used. Perhaps even more importantly, is the material you want to use actually readily available?”
Mark cites one example where a customer was dead set on a particular convertible top, with a distinctive pattern. “The car in question was a Speed33 – one of our steel bodied cars, painted House of Kolor FC-7 root beer metallic. The customer was insistent that we used a Sonneland Mahogany top. However the problem was that this color and material, produced by the Haartz Corporation in Germany, had been discontinued. We found that it had been used on Mercedes-Benz production cabrios, but had been out of production for a few years.
“We were able to locate enough material to upholster the top, but it was a close call. And also, when you’re looking for something that particular, you’ve also got to think about the cost. When we build a hot rod, roughly half the total cost of the entire process goes into the interior – labor and sourcing the materials – so that’s something to consider if you’re looking for a specific pattern or type of material.”
Which leads to our next subject: the quality of the material used. “Leather is a popular material for upholstery in hot rods,” says American Speed’s General Manager Kevin McLoughlin. “Properly maintained, a quality leather will outlast cloth fabric by many years and continue to look good. It also has a timeless quality that most fabrics simply can’t match.” But where do you start? “There are a number different grades, or ‘grains,’ available,” says Kevin. “The higher the grain, the better the quality, but the question is: how much are you willing to spend?”
Companies like Spinneybeck Enterprises Inc., based in Getzville, New York, can prove to be an excellent resource when it comes to selecting leather upholstery for use in automotive applications. Spinneybeck, whose name represents a combination of the old English word for wood bark (in which tannin is derived for use in leather making) and the Norse word for stream (since water is also an integral part in the leather making process), has grown from fairly humble origins to become one of the world’s leaders in supplying leather upholstery for automotive applications.
“We have had good success with Spinneybeck,” says Kevin. “Through multiple different samples you can select the color and texture that’s right for you – everything from simple grains like ‘Alaska’ to Embossed, Perforated or even Leather Weave. It’s also good quality, and a lot of it is priced at between $10 and $12 per square foot.”
Spinneybeck was one of the first companies to introduce Italian leather – full grain aniline dyed hides – to North America for design use some three decades ago. It represented a major step forward, especially compared to the leathers that were being offered in American-built cars of the time.
“There’s a sizeable difference between American and European sourced hides,” says Kevin. “Generally, cows in North America are fed differently and tend to be more exposed to barbed wire because of the type of pens used to house them. This affects the texture of their skin and hence the hide, just like your own diet affects your complexion, as well as the type of work you do. If you work with heavy machinery, for example, you’re more prone to getting cuts, scrapes and scars than working in an office. On a cow’s hide, the scars that result from contact with other cows and barbed wire will result in blemishes in the leather.”
So while you might think you’ll be saving money by purchasing lower quality leather, it’s often a penny wise and pound foolish approach. When the hide is cut, trimmed and mounted over the seat frame and foam, it’s often only then that flaws in the leather will truly reveal themselves. “We had a particular car that had a front bench seat,” says Kevin. “When the leather was heated and stretched over the seat, a major flaw appeared, right in the middle of the lower cushion. When you’re doing an interior, you’ll probably have 140 hours of labor in the process, but the better the leather you use, the better the result, because the fixed overhead cost [labor] will be the same regardless.
“European leathers tend to be “purer” than American ones, but they cost more. Let’s say you choose a full-grain leather that costs around $12 a square foot, something like Spinneybeck’s Espana. By the time you’ve trimmed the whole car – even a fairly small machine like 1932-34 Ford – you’re looking at a minimum of $5000, and closer to $8000 for a good quality result if you factor in labor costs from a reputable trim specialist.” But of course in the world of hot rodding, you can always spend more.
“To get a pure, unmolested hide, which one of our customers insisted we use on his car, it ended up costing approximately $17.50 a square foot. By the time we had trimmed it and completed the interior for the car, including the seat, door panels and inserts, the total cost was in the region of $17,000, and that’s in a car with no back seat or headliner. Full grain, top quality leather will last a lifetime, but at the end of the day, you need think long and hard about whether you can justify the cost.”
Choosing a Trim Shop
Once you’ve decided on the color and material, you then need to select a specialist who knows how to properly work with it. “There’s a great deal of difference between a trimmer and an upholsterer,” says Kevin. “A trim specialist will be able to cut, stretch and stitch the material in the right way. Most upholstery shops will simply use pre-cut material, such as fabric or vinyl, and simply drape it over the seat or door panels and secure it.”
At American Speed, Scott Clampit heads up the dedicated trim department and has many years’ experience trimming and fitting interiors. “A good trim specialist is able to actually sculpt the material he’s working with,” says Kevin. “In Scott’s case, he sews pull strings into the leather, which he then brings through the foam and to the back of the seat itself. By doing so, he’s able to adjust the tension on the leather hide he’s working with, so it can be sculpted – actually making the leather conform to the shape of the foam and the seat frame.”
The type of foam used also has an impact on the type of stitching you can use for seat coverings (see sidebar). “You need to choose a type of foam that will help achieve the finished result you’re looking for,” says Kevin. “Structural foam used for seats can have an effect on both the stitching and also how it supports you when you sit on the seat. For example, if you’re going to be using a tuck ’n roll stitching technique for the seat cover, you’ll need thinner foam for threading the stitches. For an end bolster you’ll need thicker foam, which provides more support. Generally, pleating foam (or pink foam), which is used on most automotive seats, comes in ½-inch, ¼-inch and 1/8-inch thickness.”
Comfort and Ergonomics
“A lot of people don’t realize it, but interior comfort is hugely important,” says D. Mark Trostle. “How the seat is sprung will affect your posture – the springs in the seat frame act as suspension for your body. Some of the early frames we had shipped in were actually too ‘tall’ because the bottom springs were too long, which affected height and posture. Today, Scott [Clampit] is able to re-spring the seats to individual customer requirements.” This brings up another interesting factor when it comes to hot rod interiors: comfort and ergonomics.
“Think about it,” says Mark. “Not only do you want the interior to look the part, but you want it to function well too. And really the only way you can achieve that is by taking measurements and actually sitting in it before you start to put it all together.” On one particular car, a turnkey in-house build done by American Speed for a big, tall customer, several sessions were focused on getting the ergonomics just right so he could drive it.
“We ended up shortening the steering column and actually sinking the floor to gain height inside the car,” relates Mark. “And when you have to make modifications like that, it can affect other aspects of the car such as clearance for the frame rails, transmission tunnel, exhaust system. So the person who is going to drive the car should sit in it and mock up the interior before the car is assembled, so you know where any alterations have to be made.”
But what about hot rods that will have more than one regular driver, people of opposite stature – one who is big and tall, the other who is short and thin? “It’s a question of measuring the dimensions of those different drivers,” says Mark. “That then allows you to tailor the seat, steering column, pedals and other features accordingly. At American Speed, because of our ties to the OE side of the automotive industry, we’re able to engineer features such as power adjustable seats to accommodate different drivers and occupants for every car we build, or provide suggestions to customers who want to complete their projects at home.”
Another aspect of comfort is sound deadening. Reducing road and wind noise is important for the OEMs, so why not apply the same approach to your hot rod? Not only does it help make the car more pleasurable to drive, it also acts as a good cushion for feeding wires through the car and out of sight. “A material like peel and stick Dynamat allows you to provide the sound and heat insulation you need, especially if you’ve got a big cube engine and loud exhaust system,” says Kevin McLoughlin. “On top of that you can then lay jute, a type of recycled carpet that acts as a cushion between the floor of the car and the carpeting itself. By cutting holes in the jute, you’ve got space for the wires to run without resulting in rattles. Not everybody uses jute these days, but it just adds to the overall refinement of the car once it’s finished. And when doing any interior work, laying down the sound deadening is one of the very first things you should tackle.”
Beyond insulation, seat springs and interior configuration, the type of materials used for the panels and carpet is important, as are fittings and fixtures – items like door handles, locks, window cranks, instruments and interior controls, as even the smallest item can make or break the look and functionality of an interior.
“The type of material you actually use for things like the door and kick panels can make a huge difference on the overall look and feel of the interior,” says Kevin McLoughlin. “And it’s something that often doesn’t get a great deal of attention. Luan, which is simply quarter inch paper shaving glued to pressboard, is cheap and popularly used, but it isn’t very durable as a basis for interior panels. It absorbs a lot of moisture and eventually will separate from the surface material like fabric or leather, eventually causing the material to discolor and tear. Think of all those sagging headliners you find in older cars.”
As a result, Kevin suggests using ABS (Acrylonitrile Butadiene Styrene) a type of thermoplastic, often used in industrial pipes. ABS is somewhat flexible and highly durable, with a strong resistance to heat. It can also be fairly easily formed into different shapes, which makes it a good choice for interior panels on custom cars and hot rods.
“Not only can ABS be designed to tailor-fit the interior contours of your car,” says Kevin, “but it also provides a solid backing for attaching material, whether it’s fabric, vinyl or even leather. Today, soft texture interior panels dominate the OE side of the auto business, but it’s simple to replicate on your hot rod too.” ABS panels not only work well for the doors and kick panels, but also in areas such as the trunk. “You can use ABS panels in all sorts of places because you can form them into different shapes and sizes, everything from trunk lid insert panels to spare tire covers. A good idea is to also wrap the ends of the panel, including the surface material. This puts sharp edges out of sight and just adds to the finished result.”
Once the sound deadening and jute has been put down, you’ll need to select a rug that’s in keeping with the rest of the interior, not only in color, but also in quality and texture. “The material, threads and binding are all important,” says Kevin. “Most older cars – those manufactured from the 1950s through the early 1970s – generally used an 80/20 loop pile carpet, so named because it was made with an 80 percent rayon and 20 percent nylon mix. Some cars, especially in the 1950s and early 1960s, used what was called Tuxedo Loop, 80/20 with small flecks of black, for a more up-market look. If you’re building a traditional style car, this is probably the kind of carpet you’ll want to use. Most modern cars use 100 percent nylon plush carpet which looks out of place on a vintage car, be it a hot rod, custom or stock appearing classic.
“On a hot rod, because of its very nature, you’ll generally need to have a carpet that’s custom fit – pre-molded rugs like those found on OE vehicles generally won’t work.” And because that means using rolls of carpeting which are usually sold by the yard (often anywhere from around $30-$50 a yard), it will have to be trimmed and cut to fit the car, and holes for items like shifter boots, parking brakes, foot pedals, and seat and seat belt mounts will all have to be considered. “That’s where a good quality trim specialist again comes in handy,” says Kevin. “If you’re going to install three point seat belts, for example, you’ll need to make provisions in the carpet, where the belt brackets bolt to the floor. A good trimmer will be able to do that.”
As for fittings, fasteners, handles and other details, both Kevin and Mark suggest that you pick a specific style and stick to it. “You’ve got to be consistent throughout the interior,” says Mark. “If you use a different style of handle for the window and door cranks, it’ll look clumsy.” Adding items like color-coordinated push pins is a great idea to cover exposed panel screws. “If you’ve got screws holding the panel in place, then adding push pins is a great way to achieve a neat final look – they’re cheap and can change the look of the interior, plus when you need to access the panel, they can be easily pulled off again. They’re just another small aspect that can make the difference between a good interior and one that’s outstanding.”
Acknowledgements: Special thanks to D. Mark Trostle and Kevin J. McLoughlin for their assistance with this article.
American Speed Company www.americanspeedcompany.com 734-451-1141
Dynamic Control (Dynamat) www.dynamat.com 513-860-5094
When it comes to actually stitching upholstery, especially for a traditional look in your hot rod, there are a number of different techniques that can be used. Two of the most common are American and European deck stitching. Both look similar and use a joining stitch on the back side of the upholstery, with a flap folded over to separate the seams. However, on American Deck stitching, the surface stitch is threaded farther away from the edge of the flap. There’s also a double deck stitch, which uses a joining stitch on the back surface of the upholstery, but has two stitches on the surface side. It’s usually done with a twin needle, rather than a single needle, which helps provide better alignment and spacing of the stitches for a neater, more uniform look all the way along the join.
Also requiring the use of a twin needle is the so-called “baseball” stitch. This is usually hand sewn, but the angle of the stitches requires the skills of an experienced craftsman to pull the thread through the material to give it that signature diagonal or baseball look.
Finally, there’s the French seam, which is essentially a double deck stitch on either side of a butt joint. There’s a main joining stitch on the back side of the upholstery, while on the surface are two stitches, one on the outside of an individual flap where the seams meet or “butt” against each other. French seams are commonly found on items such as leather-wrapped steering wheels where different hides are joined together.
Another common term when discussing hot rod and custom car interiors is “tuck ’n roll,” but what exactly is it? Essentially, tuck ’n roll is a stitching technique in which pleats of upholstery are sewn onto the back of the seat foam and then doubled over and sewn again, resulting in a “hidden” stitch on the surface. On most 1950s and 1960s Detroit cars, tuck ’n roll inserts were used in conjunction with areas of flat material, usually vinyl, with piping used to separate the solid and tuck ’n roll sections of the seats, which were often finished in contrasting colors. When hot rodders first started adopting this trend for their cars, they would often uses pieces of newspaper stuffed into the foam to give the pleats a more defined look before stitching them. Today, you can actually buy pre-cut rolls of tuck ’n roll upholstery, while modern pleating foam makes the job easier. Nevertheless, proper tuck ’n roll still requires patience and skill to execute properly, which is why, if you want that period look, you need to seek out a reputable trim specialist who can perform the work.
When you’re putting together a hot rod, the interior should play a prominent part in the plan. On this somewhat traditional looking 1933 Ford roadster, the interior color has been color-matched with steel wheels, resulting in a subtle yet eye-catching car.
A more modern look, though still based on a 1933 Ford, shows what a difference a change in exterior color, interior hue and wheels and tires can do for the look of a car. When choosing an interior color, it’s important to make sure that it complements the paint.
Sometimes, color contrast can work well on a hot rod interior. This one has red seats and traditional style door panels, but note how the black carpet and dash work well as a contrasting color, especially because they’re the same color as the bodywork on this Deuce roadster.
Before you even begin your project, it’s a good idea to visualize what the finished product will look like. That applies whether it’s the interior or any other aspect of the car. This rendering, done by American Speed Company, shows how the proposed colors for the car’s interior, convertible top and wheels will work with the chosen exterior paint color.
When developing an idea for the interior, not only is the color important, so is the pattern you’ll be using. This sketch for a Ford 5-window coupe clearly shows an early-1960s style influence with traditional style tuck ’n roll upholstery for the door panels and seat.
While still at the concept stage, it’s also a good idea to illustrate any features you want to incorporate in the car – including a retractable armrest, or maybe even cup holders, as these are aspects that will need to be integrated into the upholstery plan.
Once the design for the interior has been visualized, along with the color, the next stage is selecting the right material to use for trimming. Spinnerbeck has carved out a name by offering good quality leather hides in many different shades and textures for automobile interiors. The leathers shown in these samples cost, on average, $10-$12 per foot.
Another important aspect to consider is comfort, including the seat frame, which is the backbone of the interior. Depending on the requirements, the seat frame will sometimes have to be re-sprung to accommodate taller or heavier drivers.
Along with the frame, choosing the right backing foam for the seat is crucial for driver comfort. Foam adds structural integrity – the thicker the foam, the more bolstering it helps provide. Thinner foam is often used for the main part of the seat for comfort, while thicker material is fitted to side and end bolsters to keep the driver planted in place.
When choosing material for your interior, you need to be aware of what’s available and what you can afford. Some fine European leathers can run to more than $20 per square foot, and if you’ve got more than 140 hours in the car on the interior alone, the cost can quickly add up.
Even if budgeting isn’t of primary concern, you have to make sure that the different textures of interior upholstery actually work with the chosen exterior color of the car. Note the carpet and vinyl shifter boot samples seen here that will be used on a car painted House of Kolor Root Beer Metallic.
Once you’ve selected materials and colors, it’s time to start putting your interior together. One aspect to consider is adequate sound deadening, especially if you’re running a lusty V-8 with a fairly loud exhaust. Dynamat is self-adhesive material with a tar-like backing that provides good noise and heat insulation.
Other points of consideration when it comes to details can also include the trunk. Here, jute (recycled carpeting) has been added, while ABS (Acrylonitrile Butadiene Styrene) plastic panels that hide the fender metal work are being test fitted.
Jute is primarily used in original equipment vehicles, but it is also a good choice for hot rods. It provides a suspension for the carpet and not only helps eliminate squeaks and rattles but also acts as a good casing for under-floor wiring.
Today, the choices for carpeting in your hot rod are almost limitless. Traditional carpet found in most 1950s-1960s American cars and many original hot rods was called 80/20 Loop, namely because it contained 80 percent rayon fibers and 20 percent nylon. If you’re building a traditional style car today, it’s still the way to go. Most modern automotive carpet is made from 100 percent nylon and can be had in a wide variety of colors and textures, as seen here.
For most hot rods, carpeting, usually purchased in rolls by the yard, will need to be trimmed and cut to fit. You also need to consider provisions for features like the shifter, parking brake, pedals and seat anchor points. This is where the skills of a good automotive trim specialist can come in handy.
When it comes to providing a good backing for stitching leather upholstery, pleating foam is a popular choice. It’s available in different thicknesses for different areas, including ½- and ¼-inch thickness.
Stitching upholstery like this is still a fine art, requiring patience and a firm hand. This seat insert is being stitched tuck ’n roll style. Pleats of the upholstery material are sewed onto the backing foam (seen here). They are then double sewn over to create an “invisible” stitch on the surface side.
A skilled trim specialist will be able to form seating material over the frame using strings, heat and foam. Once the desired material has been shaped, cut to fit and stitched, it can then be draped over the seat frame as a single piece.
Here you can see how the upper portion of this bench seat, foam and upholstery has been attached and secured to the frame.
Door and trim panels are one area that’s often overlooked on hot rod builds, but they shouldn’t be. Nicely trimmed piece, like this soft leather one, add a touch of class to your car’s interior and lend a decidedly OE look and quality.
A traditional style seat with tuck ’n roll and French seam stitching receives the finishing touches. Stitching can often make or break an interior.
Here’s another view of a door panel. Note the cutouts for the window and lock release cranks, and the fact that the armrest has now been installed. ABS backing provides a hard, durable surface, with a good provision for drilling holes to allow fittings.
On the flip side, this kick panel shows how the soft leather is bonded to the ABS material. Unlike luan, which is still used on many panels and car headliners, ABS provides a sturdy backing and doesn’t trap moisture, resulting in a strong and long lasting bond between the upholstery material and the plastic resin.
It’s the details that count. Note how the edge of this kick panel curves around to eliminate any unsightly sharp edges on the side of the panel. Things like this make all the difference when putting together a good quality hot rod interior.
Carpeting should be addressed, particularly around the edges where it’s been cut. Like this, it looks pretty unsightly…
…which is why small trim panels, like this scuff plate with its chrome insert, can really help. Now, doesn’t that look much better?
Soft touch is all the rage these days when it comes to factory automotive interiors. Thanks the availability of ABS and all kinds of leather and vinyl trim options, there’s absolutely no reason why you can’t apply the soft touch look to your hot rod too.
Here’s our kick panel being put into place. Note how the folded-over edge adds a touch of quality and visual appeal now that it’s installed on the car.
With the kick panel in place, it’s time to attach the main door panel. These snap grommets will allow a snug fit, while enabling the panel to be easily removed for maintenance.
Now that all the snap pins are in place, the panel is ready to be installed. Note the jute sandwiched between the ABS and leather upholstery. The cutout is for the speaker, as this car employs a killer sound system.
Here’s our door panel being installed in a 1933 Ford roadster. Thanks to the snap pins, it’s secured in a matter of seconds.
And here’s our finished panel, installed – all we’re waiting on is the door release handle. Note how the interior color and convertible top complement the exterior of the car and match the steel wheels.
If you’re planning to drive the car, you need to consider safety items, including seatbelts. When you’re putting the interior together, you need to incorporate holes for the seat belt anchors, both on the upholstery and on the carpet.
On this particular roadster, the seat belt anchors are bolted to the floor behind the seat. You’ll need to make sure the carpet is cut to accommodate them long before you install the seat and other interior fixtures.
A nicely trimmed trunk space will complement the interior. This trim panel slides over the lock mechanism and tidies up the luggage compartment.
And here’s the finished result, complete with a leather-wrapped spare tire cover. Classy.
This is another variation on the 1933 Ford trunk theme, which incorporates carpeting along with leather-backed ABS resin panels. The options for interior and luggage compartment trim are virtually limitless.
Even when it comes to steering wheels, you want to make sure that you end up with a quality choice that matches or complements the rest of the cabin. This original-style Ford banjo steering wheel is being covered in leather, with the seams joined by baseball stitching. It doesn’t get more old-school Americana than this.