Legend Bike Co. — Founders & Builders of BMX

Linn Kastan

Co-founder of Redline Engineering. Builder of the first tubular chromoly BMX fork. USA BMX Hall of Fame, 1985.

Linn Kastan did not set out to change bicycles. He set out to build a Christmas present for his son. The bicycle he welded together in late 1973, out of the same 4130 chromoly tubing his Chatsworth, California shop was using for flat-track motorcycle frames, ended up being one of the most consequential bikes in the history of the sport. Almost everything that followed in BMX — chromoly forks, double-clamp stems, three-piece tubular cranks, purpose-built race frames — runs back through him.

Before BMX: Redline Racing Frames, 1970

Redline Racing Frames was founded in November 1970 in Chatsworth, California by Kastan and motorcycle racer Mike Konle. Kastan was the heli-arc welder and frame designer; Konle was the speedway and flat-track rider with the machining background. Their first product line had nothing to do with bicycles — they built lightweight 4130 chromoly motorcycle frames and swingarms for TT and flat-track racers, and within a few years were doing prototype motocross work for Honda R&D and Kawasaki out of their San Fernando Valley shop. By the early 1970s Redline had a staff of about six and a reputation as the custom shop ambitious riders went to.

That motorcycle background matters. It is the reason the first Redline BMX parts looked the way they did, were welded the way they were, and held together the way they did. Kastan was not learning frame craft on the kids' bicycles. He was bringing motorcycle-grade craft to them.

The Christmas bicycle, 1973

In late 1973 Kastan welded a small chromoly frame as a Christmas gift for his son Curt, using leftover motorcycle tubing. He hid it in the back of his pickup so the kid would not find it. After Christmas, word got back to Bob Hansing, the president of Shimano USA, who asked to see it. Kastan happened to drive past Shimano's Sun Valley office one day, walked in, and showed Hansing the bike. Hansing sent him up the valley to Jim Emerson at Pedalers West in Northridge — the bike shop where the early San Fernando Valley BMX kids hung out.

Emerson liked the frame but told Kastan the real problem was the forks. The forged Ashtabula-style forks on every BMX bike of the day were breaking. Kastan drove home thinking about it. By the end of that same day he had welded up the first prototype Redline tubular chromoly BMX fork. He brought it back the next morning. Emerson bolted it to a bike, a kid jumped it off roofs and starter shacks that night, and the fork held.

"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. I went back to show him the next morning, and at first glance, he thought they were built from solid bar and would be way too heavy. But he fitted them to a bike, and they put them to the test, and I guess it went pretty well because he called me and told me that I would be making a lot more."
— Linn Kastan, VintageBMX interview

February 1974: the chromoly fork

The first production pairs of Redline tubular chromoly forks were going out the door of the Chatsworth shop in February 1974. Frank Numeroski, a parts distributor from the Bay Area, walked in and offered to buy every fork Kastan could build. Joel Davis at West Coast Cycle followed with a thousand-piece order — the biggest Redline had ever taken. Bob Osborn, writing in the debut issue of Bicycle Motocross Action in December 1976, called them simply "the Daddy of them all."

1974: the Squareback frame

Late in 1974 Redline started building its first complete BMX frame — the Squareback, named for its rectangular-section lower chainstay with the dropout cut into the tip. The frame numbers started at 100. Kastan kept the ledgers. He told VintageBMX that from November 1974 to March 1978 Redline built 10,500 frames. The Squareback was the first production all-chromoly BMX frame to ship in volume.

It is the Squareback — not the MX-II — that the historical record points to as Redline's true 1974 first frame. The MX-II and the ProLine arrived a few years later, in the 1978 Redline catalog. The often-repeated line that "the 1974 Redline MX-II is the first purpose-built BMX bike" telescopes the timeline a bit; the more accurate version is that Redline shipped the first chromoly BMX fork in February 1974 and the first chromoly BMX frame, the Squareback, later that same year.

The Konle split and full ownership, 1977-1978

By the mid-1970s the partnership had two different futures pulling at it. Konle wanted to stay in the motorcycle business. Kastan was being pulled deeper into bicycles. In 1977 Kastan and Konle agreed to part ways. Kastan took full ownership of Redline. Konle kept Champion Racing and the motorcycle side.

The ProLine series and Byron Friday

From 1976 onward Kastan had a teenage BMX racer from Van Nuys named Byron Friday riding his bike fifteen miles each way to the Northridge shop, working the tube bender and the chop saw, and breaking parts. Friday was Redline's in-house test rider — the rider Kastan handed every new fork, every new stem, every new bar, every new crank to first.

"A young kid from the local area named Byron Friday came to work for me. It was Byron that kept us aware of what was happening in the BMX scene because he was riding on these makeshift tracks they were building out in the San Fernando mountains. He became our chief product tester through the years when we were developing some of the first Redline products. The process was quite basic — we would make a part, or improve on one we had already developed, fit it onto Byron's bike and see how long it would take for him to break it."
— Linn Kastan

Out of that loop came the products that defined BMX for a decade. The double-clamp stem (around 1975-76, born out of Friday snapping Ashtabula stems). The V Bars — a chromoly handlebar with a bent crossbar that Kastan said gave the bar enough spring to stop snapping at the weld. The ProLine frame and fork, with their five-inch head tube; the first ProLine was built in March 1978. The MX-II frame. The Microline mini-class frame. By the late 1970s, every red-blooded BMX kid in America wanted Redline V Bars and a ProLine stem on the front of whatever they were racing.

The Flight Cranks, 1980

Kastan started thinking about a three-piece chromoly BMX crank in late 1976. It took him roughly three years to get the geometry, the tubing, the spindle splines, and the bearing setup right. The first arms were teardrop aero tubing; the next were rectangular 1" x 1/2" tube; then a heat-expanded rectangular tube. By the time the Redline 401 Series Flight Cranks went into production in January 1980 — tapered tubular arms, splined two-piece chromoly spindle, packaged with their own T-handle Allen wrenches — Kastan had killed off the one-piece BMX crank.

The Flight Cranks became, in his words, Redline's best product ever. The current Flight Crank platform is licensed to Supercross BMX by Regent today.

Going overseas, 1979

In April 1979 Kastan flew to Kobe, Japan, and stayed two months, training six young welders at Kawamura Cycles how to TIG-weld. There were no machines there; Kastan shipped six welders over and set them up in a room about the size of a double garage in Kawamura's office building. That tiny room produced Redline complete bicycles for years.

The race team and the freestyle turn

The first real Redline factory team came together around 1978, and went on tour with the ABA in 1979. The line-up that turned Redline into a household name on a race track — Stu Thomsen, Greg Hill, David Clinton, and later additions — followed. Thomsen and Hill won everything. They were also, in Kastan's understated phrasing, "a couple of brats" to work with — though Hill ran into him at a Phoenix race years later and apologized.

In 1983 Bob Osborn handed off his magazine-affiliated freestyle team — R.L. Osborn and Bob Haro had been riding it — and Kastan picked it up. The RL-20 Prostyler frameset, then the RL-20 II in 1985, made Redline a freestyle brand as well as a race brand.

1985: USA BMX Hall of Fame

The American Bicycle Association inducted Linn Kastan into what is now the USA BMX Hall of Fame in 1985, in the Industry category. The HOF citation names him plainly as the founder of Redline Bicycles and walks through the fork, the double-clamp stem, the V Bars, the Squareback, the Flight Cranks, and the RL-20 II — and credits Kastan with eliminating heavy steel BMX parts more or less by himself.

The sale, Kastan Engineering, and after

Redline went to its top distributor, Seattle Bike Supply, in 1988, and moved north to Kent, Washington. (Seattle Bike Supply was later bought by Accell in 2006; Accell sold Redline on to Regent in 2019.) Kastan waited out the non-compete and, in 1989, launched Kastan Engineering. The company produced alloy Kastan frames and the single-bladed Strut fork.

More recently, Kastan has gone back to the part of his work that earned him the Hall of Fame plaque. Through Redline Vintage BMX and a licensing arrangement that lets him use the Redline mark, he has reissued the Flight Cranks, the V Bars, the seats, the stems, and — in batches — the RL-20 II Prostyler frameset itself. He still keeps the original Chatsworth ledgers, with every Squareback frame number and the bike shop it shipped to.

Why he matters

Several brands in this history can claim a single first. Redline, under Kastan, can claim a stack of them: the first production tubular chromoly BMX fork (1974), the first production chromoly BMX frame (Squareback, 1974), one of the first double-clamp BMX stems (mid-1970s), the V Bars, the ProLine series, and the first tubular three-piece chromoly BMX cranks (Flight Cranks, 1980). He did it from a motorcycle shop, with motorcycle tooling, motorcycle welding, and one teenager from Van Nuys breaking everything until it stopped breaking. The rest of the industry spent the next decade catching up.

Sources

USA BMX Hall of Fame — Linn Kastan (1985, Industry) at usabmx.com/about/hall-of-fame/868. Linn Kastan interview, originally conducted by Bill Curtin for VintageBMX (2002), republished at BMX Products USA. Redline Vintage BMX — Redline History (run by Linn Kastan). Wikipedia — Redline (bicycle brand). BMX Society community threads on the Redline ledger and the modern Redline by Kastan licensing arrangement. oldschoolmags.com — Kastan frame & fork bike test, BMX Plus! March 1989. BMX Museum reference — Kastan Interview. FatBMX — Preserving BMX History Episode 61, Byron 'TGI' Friday.