MMG: Custom bent stays

Every Monday, we’ll take a closer look at a detail of our handbuilt bike frames to help give some insight into what makes a Myth a truly custom bike. This is our Monday’s Magnifying Glass series, and you can find a new one every week here on the blog.

_MG_3597As a framebuilder, there are lots of tube options available to build bikes with. When it comes to seatstays and chainstays, there are some pre-bent options available that can fill our needs. However, these pre-bent options can be limiting, and often times the builder will have to design a bike around a tube instead of designing the tube around the bike. This is especially true with mountain bikes, and with the current style of short chainstays. So it was important to me early on to be able to bend and form my own tubing so I wasn’t limited by the few available options.

Almost all of our seatstays start out as long lengths of 4130 Chro-Moly aircraft tubing. They’re cut to length, then they have a cone hot formed onto one end, (I’ll do another MMG about that later) then they’re bent to suit the bike they’re going on, and finally they’re mitered to fit the frame. Starting with raw aircraft tubing is almost like starting with a blank canvas, and any vision we have for the stays can be accomplished through bending, forming, and creative mitering.


One of the biggest parts of this process is tube bending. Tube bending is a science in it’s own right, and bending thin walled tubing for bikes requires a completely different set of tooling than most commercially-available tube benders offer. If you don’t want to be limited in the types of bends you can do, the only option is to make your own tooling.

We employ this hobo to bend our tubes

Our bender was made in-house, and so were all of the dies it uses for different size tubes, and different bend radii. It was designed specifically to bend thin wall tubing, and also to be able to create bends with extreme accuracy, to about two tenths of a degree of bend angle. All this allows us to create the bends we need quickly, and be able to make two of the exact same bend, important when making pairs of things like seatstays or chainstays.

MG_3589.jpgSometimes a design does call for a variation on a stock tube, such as an oval chainstay. If this is the case, often times we need to modify the original chainstay slightly by either increasing one of the bends, or forming part of the oval for more tire or chainring clearance. We have several forming dies made for this purpose that go in the arbor press and can be pushed down onto the stay in a controlled manner to create the formation we’re going for.

All of these things add up to something a very important. A bike design process that isn’t dictated by off-the-shelf tubing, or constrained by requiring other companies to bend our tubes. We do everything in house, and when a client wants something that isn’t available elsewhere, we’re able to create it right here in the shop.

And that’s part of what makes a Myth a truly custom bike. Check back next week for our next Monday’s Magnifying Glass where we’ll look an another detail of our handbuilt bikes.


Leave a Reply