Home | About Chris | My Bikes |Tandem Tests | Tandem Tips | Rides and Races |Team|Sponsors | Pro pics | Links

Fork failures are the single most dangerous failure which can occur on a bicycle, so read on:

HELP. Because I was flooded with requests and suspect more are coming, I'll simply post this and hope earlier respondents can do without my drawings.

For those who missed yesterday's posting, tandem forks with 1" steering tubes are not as safe as they should be--every year a few of these snap without warning. Because inspections of the steering tube require fork removal (and even then you might not spot an impending failure), there are only two ways to protect yourself. First, very expensive, buy a new fork with a pressed-in sleeve. Second, use the instructions below to build your own retrofit sleeve. The parts cost less than $5, the installation takes 15-30 minutes, and the weight is about 3 ounces.

Do you need it? Unless your builder already installed a sleeve, the answer is yes. How can you tell if your builder installed a sleeve? Remove the front wheel and use a flashlight to look for a sleeve in the lower 2-4" of the steering tube. If you own a Santana you won't need to look--a pressed-in sleeve was a standard feature of prototype #1 and included on every Santana with a 1-inch steerer built since.

In a reply to my earlier posting someone suggested a butted tube would be superior to a sleeve. Actually, virtually all steering tubes are butted, but only to a single-bike spec (the butt is too thin and too short). Santana has a stronger tandem-spec butt plus a sleeve. The advantage of a soft-steel sleeve is that a defect in the steerer can't propagate into the sleeve.

Here are instructions on how to reinforce a steerer without a sleeve:

Tools:
Besides the normal small wrenches, you'll need a vice, hacksaw and electric drill with 6mm (or 1/4") drill-bit

Materials:
A four-inch length of 7/8" OD steel tubing (or the "quill" from an old 7/8" steel stem), plus a 6mm nut and bolt long enough to fit through the fork crown (the same bolt you'd use to install a front rack or fender).

Overview:
Once you find the short piece of tubing, you're halfway done--you won't even have to remove the fork or adjust the headset! You also don't need to worry about neatness--except for the bolt through the front fork crown, the finished job is invisible.

Instructions:

1. Put the tube in a vice and, with the hacksaw, cut a pair of length-wise slits extending 2.5 of the 4 inches. These slits will allow the sleeve to compress enough to be hammered into the butted section of your tandem's steering tube.
2. Remove the front handlebar stem from the steering tube.
3. If your tandem already has a bolt through the crown (or a bolt-on front brake), you'll need to remove it.
4. With the slit-end down and the slits aligned to sides (instead of front and back), insert the sleeve where the stem was.
5. Hammer the sleeve into the steerer until the bottom of the sleeve is even with the bottom of the fork crown and/or steerer.
6. Using the hole(s) in your fork-crown as a drill-guide, drill a 6mm hole through the inserted sleeve and steerer.
7. Install the nut and bolt.
8. Re-insert the stem. The front stem of a tandem should be extra-tight.

c/o Steve Lesse
santanainc@aol.com