BMX Racing History · Chapter 5 · Legend Bike Co

Redline: The Brand That Invented the Modern Race Bike

Here's how fast it happened. A motorcycle frame builder named Linn Kastan drove past a bike shop in Northridge, California, one afternoon in 1974. He stopped. Went in. Thirty minutes of conversation later he was already working out the world's first tubular chromoly BMX fork in his head. He had it sketched by the time he got back to the shop. Built by the next morning. And by the end of that week every serious racer in the San Fernando Valley wanted one. That's not a slow build. That's a brand catching fire.

That fork started Redline. And it was nowhere near the last thing they got right.

A Christmas Gift That Changed the Sport

Kastan came out of motorcycles. In November 1970 he partnered with a professional flat-track racer, Mike Konle, and started Redline Racing Frames in Northridge. They built custom chromoly motorcycle frames and swingarms — heli-arc welded, made to a standard the racing crowd actually trusted. Six people, one single-car garage, and growing fast.

In 1973 he built a bicycle frame for his son Curt as a Christmas gift. Same 4130 chromoly tubing he was already running through the motorcycle shop. The thing sat hidden in the backseat of his truck for weeks. A friend talked him into showing it to Bob Hansing, who ran Shimano USA. So one morning Kastan drove past the Shimano offices in Sun Valley on an errand, went in on a whim, and Hansing pointed him at Jim Emerson, who owned Pedalars West in Northridge — the shop at the dead center of the Valley BMX scene.

Emerson liked the frame. But what he actually told Kastan was that the sport didn't need another frame. It needed a better fork. The forged steel forks on every BMX bike out there were snapping constantly. Kids were getting hurt. Nothing on the market could hold up to what these racers were doing on a track.

"As much as he liked the frame, what they really needed was a better fork because the forged fork that was on all of the early bikes was not strong enough for what these kids were doing. As I was driving back to my shop, I came up with an idea; I decided to make the fork from chromoly tubing, and I actually made a couple that same afternoon." — Linn Kastan

He showed up the next morning with a finished fork. Emerson bolted it onto a bike, racers beat on it, and Emerson called back with the verdict. Make more. A lot more.

February 1974, Redline's first tubular chromoly BMX forks went into production. They sold instantly. Nothing else out there came close on strength or weight — it wasn't a contest. The Squareback frame, which was really Kastan's original Christmas frame cleaned up for production, followed later that year.

Byron Friday and the Test Bench

You can't build products without a kid who'll break them on purpose. Redline found theirs through Jim Emerson, who introduced Kastan to a local racer named Byron Friday. Friday was fast, but the real value was that he was sharp enough mechanically to tell you exactly what failed and why. He rode to the Redline factory from Van Nuys every single day — fifteen miles through alleys and backyards — and put whatever Kastan was building through everything a track could do to it.

"I was talented on a bike, and very capable mechanically. Jim Emerson at Pedelars West bike shop suggested to Linn Kastan that I might be a good fit for Redline as their product tester... My role was mainly to give Linn advice on where the opportunities for new products were and to test them. I also ended up working the tube bender, chop saw and helping out with anything else that was happening in production. Linn found it useful to have a BMX racer showing up every day — someone who was passionate about product development — and I was at least partially the catalyst and motivation for Linn to spend time drafting blueprints and designing the Redline Pro-Line series of products." — Byron Friday

That loop — rider finds the failure, engineer fixes it, rider breaks the fix, do it again — was how every big Redline product got built. The fork led to the Squareback. The Squareback showed the next weak point. The next weak point became the next product. By the late 1970s they'd chewed through just about every component on the bike that way.

The Squareback and the Magazine That Made It Famous

The Squareback went into production in late 1974, just a handful at a time. At $85 for frame and fork it was steep — about what a complete Schwinn Sting-Ray ran. So it sat. The price kept it out of most kids' hands, and sales crawled for a while.

Then Bob Osborn launched Bicycle Motocross Action in December 1976. The very first issue ran a review of Redline's chromoly fork in the New Products section. Osborn, the editor and publisher, didn't hedge a word:

"Here they are folks, the Daddy of them all; Red Line chromoly, tubular forks. What can I say about them that you don't already know? They're expensive (a shade over 30 bucks), and they're tough (4130 tubing, heat-treated stem). They're beautiful, and they work." — Bob Osborn, BMX Action debut issue, December 1976

That put Redline in front of every serious BMX household in the country, all at once. By 1978 Kastan had built roughly 10,800 Squareback frames out of the Chatsworth shop over about three and a half years. And BMX Action had become the sport's bible — with Redline sitting there as the gold standard for gear.

David Clinton — the first NBA National No. 1 Amateur — put it about as plainly as anyone could:

"BMX forks were constantly breaking and Linn was the guy that essentially solved that problem. In the early 1970s, BMX was about jumping and racing on downhill tracks up in the mountains and the Redline chromoly fork was a game-changing invention because it was both strong and light. And Linn applied the same high standards to the design and production of everything he produced. The Squareback frames, the Redline V-Handlebars, the Proline stem, and the chromoly Flight Cranks were all best-in-class products. Redline set the standard for reliability and functionality, and the industry followed their lead." — David Clinton

The Proline, the MX-II, and the Complete Race Line

In 1977 Kastan and Konle split. Konle went off to run Champion Racing on the motorcycle side. Kastan went all-in on BMX. By 1978 the Redline catalog had turned into a full race line — two new chromoly frames, the MX-II and the Proline, which was the company's first dedicated Team Model, plus V-bars, a stem, seat clamp, and seat post. The Squareback had been one great product. The 1978 lineup was a brand.

The Proline was the frame every serious pro wanted. Clean lines, purpose-built geometry, chromoly all the way through. So when Stu Thomsen — who'd spent 1977 to 1979 racing for SE Racing — came over to the Redline factory team in 1980, the Proline was what he raced. He'd go on to be the most visible rider in the sport, and Redline the most visible brand standing behind him.

The Flight Crank

The other thing Redline built that nobody could touch was the crank. Everything else on the market in the mid-1970s was either a crude one-piece steel unit or a pretty alloy three-piece that bent the first time you looked at it hard. Kastan started chasing a real fix in late 1975, and it took him four years of iteration to nail it.

The whole thing came down to the arm. He started with teardrop aero tubing, switched to rectangular chromoly tube, then heated the arms to 1,600 degrees so the air sealed inside expanded and bulged the tube out — giving him width right where he needed it. Then a two-piece splined chromoly spindle, a bolt-on sprocket, sealed bearings. Stronger than anything else you could buy, and once he figured out the production, consistent too.

The Redline Flight Crank hit production around 1979–80. First tubular chromoly 3-piece crank in BMX, and it became the standard pro crank for years. At $160 for the crankset plus $21 for a sprocket it was no bargain — but every pro who raced for real ran one. Brian Lewis, the guy on the cover of that debut BMX Action issue shot at the Pipeline Skatepark in Upland, was on Redline. The Flight Crank showed up on pro parts lists the same way the chromoly fork had hit shop orders six years before. Fast, and total.

The Factory Team

The golden run of the Redline factory team went from roughly 1978 to 1985. Three riders defined it.

Stu Thomsen came over from SE Racing in 1980 already the most accomplished rider in the sport. People called him the Babe Ruth of BMX, and it fit — physical dominance plus week-in week-out consistency. At 6'2" and 200 pounds he was bigger than most of the field and he used every bit of it. His Redline years, 1980 to 1983, were the peak of his career. The Proline II came out in 1982, and honestly Thomsen's results in BMX Plus and BMX Action were the ad. He left for Huffy in 1984.

Greg Hill won the first IBMXF BMX World Championship in 1982 in Dayton, Ohio — the race that kicked off international BMX. He was on Redline gear through key parts of his career and one of the top national pros all through the early 1980s.

R.L. Osborn — Bob Osborn's son — was already riding tricks at the magazine's Pit test facility in Torrance when he picked up factory support. He rode for the BMX Action Freestyle Team alongside Bob Haro, and his Redline deal ran that whole stretch. He had real input on the RL-20II — the Redline freestyle frame that carried his initials. When the Redline deal wrapped up, he went and started his own company: BULLY Bikes.

Into Freestyle and Beyond

By 1982 Redline had the whole racing lineup covered — the Proline II, the MX-III, the PL-20, and the PL-24, their first 24-inch cruiser. In 1983 they pushed into freestyle with the RL-20 Prostyler. It didn't take off right away. But by 1985, with the RL-20 II, Redline had a real foot in both sides of the sport.

1985 was probably the high-water mark of the Kastan era. Deep product line, strong team, and a reputation for quality and engineering that he'd spent a decade building, all peaking at once. Then over the next three years the ground started moving — mountain biking was pulling kids off BMX bikes, inventory was stacking up across the whole industry, the boom was running out of air. In 1988 Kastan sold Redline to Seattle Bike Supply and the company packed up for Kent, Washington.

Kastan didn't sit still. After the sale he launched a new BMX brand under his own name — Kastan — and kept right on building.

After the Sale

Under Seattle Bike Supply, Redline kept making BMX bikes and branched out. First mountain bike in 1989, road bikes in the early 1990s, a switch to a pink, white, and black color scheme before going back to the original red, black, and white in 1993. Accell Group bought SBS in 2006. Regent LP picked up Redline from Accell in 2019 and runs the brand today.

The BMX line never really went away. The Proline name came back. The Flight Crank turned into a collector's piece. And the Squareback — in reproduction and tribute form — is one of the most chased-after vintage BMX frames anywhere in the world. Linn Kastan's name is on every one of those original parts. Even when it isn't printed on them.

"Linn applied the same high standards to the design and production of everything he produced. Redline set the standard for reliability and functionality, and the industry followed their lead." — David Clinton, first NBA National No. 1 Amateur

Timeline

• 1970 Linn Kastan and Mike Konle found Redline Racing Frames in Northridge, California, building motorcycle frames and swingarms from 4130 chromoly.
• 1973 Kastan builds a chromoly bicycle frame as a Christmas gift for his son Curt. A chance visit to Pedalars West bike shop sets the direction for everything that follows.
• 1974 First tubular chromoly BMX fork goes into production in February. The Squareback frame enters production in small quantities. Byron Friday becomes Redline's test rider.
• 1975 Initial prototypes for the Flight Crank developed.
• 1976 Squareback production ramps up. BMX Action debut issue runs the "Daddy of them all" review of Redline's chromoly fork.
• 1977 Kastan and Konle separate. Kastan takes full ownership and goes all-in on BMX. Proline developed.
• 1978 Full product catalog: MX-II, Proline, V-bars, stem, seat post, seat clamp. Kastan establishes overseas manufacturing in Japan.
• 1979–80 Flight Crank goes into production. Stu Thomsen joins the factory team from SE Racing.
• 1982 Proline II introduced. PL-24 (first 24" cruiser) released. Greg Hill wins the first IBMXF BMX World Championship.
• 1983 RL-20 Prostyler launched — Redline's first freestyle-specific frame.
• 1984 Stu Thomsen leaves for Huffy. RL-20 II gains traction in the freestyle market.
• 1985 Peak of the Kastan-era Redline lineup.
• 1988 Kastan sells Redline to Seattle Bike Supply. Company relocates to Kent, Washington.
• 2006 Seattle Bike Supply acquired by Accell Group.
• 2019 Regent LP acquires Redline from Accell.