Kaisei Tubing

It’s no secret that we love steel bikes. Steel allows us to build the bikes we need for our adventures – bikes where every detail is optimized to the nth degree. You can imagine our concern when True Temper, one of the most important suppliers of steel tubing, decided to leave the bicycle market. Without steel tubes, especially the superlight ones that True Temper was specializing in, there wouldn’t be any more of the bikes we love.

What to do? We thought about who made the best steel tubing in the world today. There is no simple answer, but Kaisei in Japan was an obvious candidate. Kaisei is unique in that most of their tubes are used for professional racing bikes: More than 2000 Japanese Keirin riders race on steel bikes, and most are made from Kaisei tubing, which is known for its high quality.

Kaisei is an interesting company, because they are just a manufacturer, without any marketing. All they do is supply tubes to Japanese framebuilders. And since those builders work for professional racers, there is no need for fancy names and stickers. As a result, Kaisei uses Cromoly tubing. It’s the strongest and most reliable, and the thinwall tubes are heat-treated. I like that no-nonsense approach.

Kaisei tubes are rounder than most, and their walls are more uniform in their thickness. They match their spec exactly, unlike some other tubes we’ve measured. The heat treatment is uniform, and it’s designed to strengthen the tubes without making them brittle. This precision reduces the risk that a frame breaks due to defects in the tubing. For Keirin racers, this point is very important: They are not allowed to change bikes during a weekend of racing, and if their bike breaks, they are out of the races. And since they live off their prize money, this means they have no income, either.

In the past, Kaisei tubing was designed for smaller frames, since Japanese (racers and otherwise) tend to be shorter than the average westerners. The thinwall “bellies” of the tubes were relatively short, which meant that tall frames were heavier and stiffer than necessary. In addition to offering these “short” tubes, we worked with Kaisei to make “long” tubes with longer thinwall “bellies” that are optimized for taller frames. Since we commissioned the tooling for these tubes, they are available exclusively from Compass Cycles.

 

To complement the excellent Kaisei tubes, we developed a selection of framebuilding parts. They are made by Longshen in Taiwan to the highest specifications. The new Compass fork crown is a perfect fit for the Kaisei TOEI Special fork blades that we use on all our bikes. The new fork crown combines classic looks with a modern box section construction. The result is an ultralight and super strong fork crown.

The Compass bottom bracket shell is specifically designed for wide tires. The chainstay sockets angle outward a bit more (10°) to accommodate curved chainstays. This provides extra tire clearance. It’s the secret for using wide tires with road cranks. Designed for standard-diameter tubes and with enough material to carve and match your preferred lug shape, the Compass bottom bracket shell combines light weight with versatility.

These are just a few elements of our new frame tubing program. Instead of lamenting the demise of a major supplier of steel frame tubing, we worked on a replacement that is arguably even better. Now it’s easier than ever before to have your dream bike made!

Click here for detailed specs of the tubes, as well as our complete program of braze-ons and other framebuilding parts.

Photo credit: Paul Keller (Photo 4).

About Jan Heine, Editor, Bicycle Quarterly

Spirited rides that zig-zag across mountain ranges. Bicycle Quarterly magazine and its sister company, Compass Cycles, that turns our research into high-performance components for real-world riders.
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29 Responses to Kaisei Tubing

  1. zigak says:

    Will you be offering lugs for the other two clusters, seatstays, seat tube and toptube intersection and the other one on the steering tube? I know it can be done without the lugs, but still.

    • There are many lugs available, so for now, we don’t plan to offer them. The bottom bracket shell for curved stays and the superlight fork crown for “Imperial” blades are parts that you can’t get elsewhere.

    • Jacob Musha says:

      I’m sure I’m not the only one that would enjoy getting a frame built with all “Compass” tubes and lugs. You could offer a unique lug set to go with the Kaisei tubing. There are so many interesting lug designs that can be made!

      I only wish this tubing and bottom bracket shell were available when I ordered my custom frame.

      • Jacob,
        if you ordered a custom frame from a good framebuilder, you should not have any concerns about the choice of tubes. Every maker of tubes has lightweight tubing in their catalogue, and they are not better nor worse than the Kaisei tubing. While the Kaisei tubes may have a better quality control than some other makers, a good framebuilder checks the tubes for roundness and correct butt length. As crude as it may sound, at the end of the day it is just heat treaded CrMo steel and no rocket science. I am happy Compass offers an alternative for the american market (and especially happy about the fork blades), but please don’t think that this is the ultimate tubing and that you made wrong choice with your custom order.

        Happy riding!
        David

      • I second that, and I don’t think Jacob was concerned about his beautiful frame. (He brought it to the Bicycle Quarterly Un-Meeting, where we all admired it.) Kaisei tubing is nice for the builder, because they won’t have “reject” tubes. When I visit builders, they sometimes show me the bowed tubes that they have never built into a frame…

  2. David says:

    great information! are 100 kg folks appropriate candidates for this OS but lightweight tubing?

  3. Phillip Cowan says:

    Have you taken a look at Thermlx from Vari-Wall? Any opinions? Just curious on your take. It doesn’t hurt that it’s made in the US.

    • Vari-Wall are an exciting newcomer to road bike tubing. They just started offering heat-treated tubing this year. I’ve seen their tubing, and it looks very nice.

      What I like about Kaisei is their experience. There are tens of thousands of frames with Kaisei tubing that have been raced hard for decades by Keirin professionals. We already know that Kaisei’s tubes are reliable, and that their heat treatment doesn’t make the tubes too brittle. I am excited about the new sizes, because it means that we now have tubes optimized for taller frames as well as shorter ones.

      Overall, it’s good to have more choices in tubing. New makers entering the field gives me confidence that steel bikes have a great future ahead of them.

  4. That bottom bracket is a big breakthrough for lugged frames. I need to figure out a jig to make a subtle bend in the chainstays to take advantage of them. I’ll be out to French Fender Day, so I can ask Peter Weigle how he does it!

    • I’ve seen four builders bend the chainstays four different ways: At TOEI, they clamp one end and just bend it – this was shown in Bicycle Quarterly 52. Jean Desbois at René Herse used a similar method, but with heat to make the bending easier and smoother. Mark Nobilette had a curved mandrel that he pushed against the stay in a vise. Hahn Rossman made a set of mandrels that shaped the entire tube at once – just put the chainstay inside, clamp it all in a vise, and presto! Unfortunately, his mandrel was designed for skinnier True Temper chainstays, so it doesn’t work for the slightly larger (and stiffer) Kaisei chainstays – where it puts the bend too far back, where it doesn’t match the widest point of 650B tires. (It would be great for 26″.) We are working on a new mandrel for 650B – in the future, we plan to offer curved chainstays ready-to-go.

  5. correomartell@gmail.com says:

    Will you carry Kaisei tubes in .9-.6-.9 or .8-.5.-.8 in standard sizes? 017 is good, but 019 and 022 are still very useful.

  6. Bob C says:

    Did Peter Weigle use this tubes for the bike that was entered in the Concours?

    • He used some Kaisei tubes. Most of the custom-drawn tubes weren’t ready yet… The Concours de Machines really was an exercise for us to think about what we need in our program to make these bikes. Only part of the results were used on the actual bike. You’ll see the rest coming online in the future.

  7. G says:

    Can I ask what you would suggest for complementary forks for disc brake applications with a Kaisei-tubed frame?

    • Disc brakes require stiffer forks, so I wouldn’t recommend the “TOEI Special” blades without careful testing. The “Continental” blades should work fine, if the fork is designed and built with care. Of course, you can also use ready-made carbon forks with a frame built from Kaisei tubing.

      • Tom says:

        I was surprised that, according to the technical specs, the “Continental” fork blades have a smaller diameter at the tips (12 OD, 10 ID) than the “TOEI Special” blades (13 OD, 11 ID). Because that dimension is most critical to resisting the forces of a disc brake and rotor, it would seem that the “Continental” blades would be even less suitable for that application than the “TOEI Special” blades.

        It seems that a somewhat larger OD might be needed for disc brake applications; unless, perhaps, the fork with Kasei blades was to be built with unraked, straight blades. As Nova states in the description of their disc road fork blades, “No more problems with flex or bending at the bottom of the blade- the 17mm diameter solved the problem.”

        Thanks for offering the tubing, fork blades, and other specialized framebuilding parts, and also for working with Kaisei to accommodate the needs of tall riders!

        -tom

      • The tip of the “Continental” blades is smaller, but they taper more quickly, so where the disc tab attaches, they are much thicker than the “TOEI Special” blades. However, I’d discuss fork blades for disc brakes with your builder. Your idea of a straight, unraked blade for a disc brake makes a lot of sense. We’ve been thinking along the same lines. The fork Hahn built for his Ex-Bontrager used straight blades. With a traditional raked fork, you put a lot of stress at the end of the curve. This is a good place, because it’s far from any heat-affected area. But once you add a disc tab, you stiffen the lower section of the blade (which concentrates even more stress here), and the brazing will affect the tubing. It seems better to use a straight blade without that stress concentration…

  8. Jörn says:

    Hi Jan,
    will there be tubes for (really) tall guys at some point? A seat tube in the longer than 600mm? Thank you!

  9. Timothy Nielsen says:

    How does one pronounce ‘Kaisei’?

  10. Goff V says:

    I’ve been waiting for this announcement. I briefly had an Ebisu that was built with Kaisei tubing and it distinctly rode very nice. I’m in line for my second FitzCyclez custom frame and this might be the tubing for it. Jan, just want to confirm the superlight standard diameter set is ok for tig welding?
    PS nice riding with you at the UnMeeting, what a blast that gravel route was (especially the paved downhill)
    Goff in PDX

    • The Kaisei tubing isn’t air-hardened, so it’s not specifically designed for TIG-welding. It really depends on your builder – in the 1930s, Reyhand gas-welded Reynolds 531 frames, and I’ve never heard of one break… Ask the builder whether they think the tubing will work with the way they make their frames.

  11. john hawrylak says:

    Congratulations on the Kaisei tubing, it must have been a big investment on your part.
    I noticed the DT on your “Mule” bike (BQ #54) is OS 0.35mm wall thickness and is thinner than the “Mule” tube set you sell, DT is OS 0.5mm wall.
    Can you explain why the tubeset is thicker wall??
    Did you determine a thicker wall DT was required from using your “Mule”??

    • The Mule’s extremely thinwall down tube has a lot of dents… For most riders, a slightly more dent-resistant tube is desirable, which is why our 31.8 mm tubes are 0.7-0.5-0.7. To compensate, our “long” tubes have longer unbutted thinwall “bellies”, so the overall flex characteristics are similar.

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