At a San Diego bike shop I saw a machine that is purported to take the tension out of a wheel while it's being built so that the tension won't be released when you first start to ride it.

Description: Machine is larger than a wheel and it has hydraulics that stress the wheel to relieve tension in spokes.

I'd like to find out more about this machine, but I couldn't find the name of it in order to google it. What is this machine called? Links to manufacturers?

  • 1
    Just a note: Absent such a machine, a knowledgeable wheel builder will place the partially trued wheel flat on a hard surface (but maybe with a block of wood under the hub) and press down hard on the rim with both hands at 180 degree opposite positions while the hub rests on the surface. Move hands around the rim, pressing on different points, then flip the wheel and do the same thing again. After that true the wheel a bit and then repeat the stressing procedure. Commented Jul 19, 2011 at 11:04

2 Answers 2


I can't find a current reference or photo, but we used to have one at my previous shop. If I remember correctly it was manufactured by J.A. Stein, but that may be wrong. It was a professionally made copy of a popular homemade wheel building tool.

It was called a Stress Relief Box. It consisted of a 6 inch deep box, about 3 inches wider than a 700c rim. There was a a hole cut just about 2" smaller than the rim in the top of the box, so that when a wheel was set on top of it, the rim was supported, but the spokes and hub were not touching anything. There were inserts to allow use with smaller wheels as well.

There was an metal arm that straddled the wheel, which looked like a taller, and wider version of the Park tool dishing tool, with a lever that allowed pressure to be safely placed on the center of the hub.

In this version, there were no hydraulics, but it would appear similar to a hydraulic press, or there could be more versions of them. There were lots of homemade ones, so there is also a possibility that it was a DIY version. I know a guy in Seattle who was working on a Arduino controlled version which was supposed to allow you to set a tension level.

The one we had worked well, and required minimal setup, although it took up space. I haven't seen one in any shop since, and I can't find a current reference, so it may be off the market.

This a very rough diagram of what it looked like:

Stress relief box

  • Yeah, thats it, looked exactly like that, thanks.
    – Ville M
    Commented Jul 20, 2011 at 20:24

The BMD "wheel stabiliser" accessory for their wheel building machine may be what you saw.

The process is known as "stress relieving" but I can't find any reference to a dedicated machine either. The wheelbuilding machines are fairly easy to find once you get through the description pages (ex Shenzhen New Canghai Machinery Co) but I couldn't find any stress releiving machines.

I found the BMD link in the search results for "bicycle wheel building machine" above by going to the manufacturer pages then looking for related machinery. On the BMD page I clicked their "products" link since it seemed likely that someone who makes the building machine would also make the stress-relieving one.

Look at this http://www.youtube.com/watch?v=MZLMFiw5OLA

Its done on a BMD machine. What you see are the mechanics of pushing on the spokes. This will set the spoke head in the flange of the hub and the nipples in the rim. Than the nipple keys that turn the nipples additionally unwind the spokes after truing. This will give a long live and stable wheel (Bob at BMD).

  • Thanks for thoughtful answer, however, I don't think this machine was part of a complete automated wheel building machine, it was just met to assist in what is called stress relieving by Jobst, also it looked more horizontal rather than vertical in your link above. Not sure, maybe this is it, but I'll leave question open for now in case somebody has couple more links.
    – Ville M
    Commented Mar 1, 2011 at 18:01

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