One-arm forks on bikes

Factual Questions
1

I was gazing at the super-expensive bikes at the local bike shop and noticed that some have one-arm forks in the front. I vaguely recall hearing that some motorcycles have that as well. It looks cool, but is there any advantage at all? Since eliminating one arm would put a huge force on the other, you’d have to make it pretty strong, and I don’t think you would save any weight.

2

Oops, I meant to post that on GQ - could the moderator move or delete it?

3

Since the original post is a question requiring a factual answer, not a Straight Dope column, this thread is leaving the Comments on Cecil’s Columns forum and going to visit my colleague manhattan in the General Questions forum, at the original poster’s request.

moderator, Comments on Cecil’s Columns

[Edited by Arnold Winkelried on 09-11-2000 at 11:53 AM]

4

The theoretical purpose of the one arm fork is that traditional forks will torque unevenly, causing loss of traction, and/or energy. The weight savings is greater with one beefy fork as opposed to two moderate forks. I’ve test rode both types, and really couldn’t tell the difference. I didn’t get a chance to do any downhill bombing on them, which is where I think you would really notice performance differences.

5
      • The actual purpopse of one-armed forks is to separate you from as much of your money as possible until Taiwanese factories get their tooling up and running and you see one-armed fork bikes at Wal-Mart for $200.
  • The other day I was wandering through and saw that they had a Mongoose mountain bike priced ~$450 that had a front disk brake. - I think about three years ago you had to pay ~$350 just for a disk-brake kit (the brake itself and a special front hub to build your wheel around). - MC
6

You may be able to concoct good reasons for one-arm, but the real reason is to show off design prowess. It creates confidence in the market place. Period.

7

Thanks for the response. Do you mean that the two forks may bend by different amounts, putting stress on the axle? I supposed that makes some sense, though there is always a stress on a cantilevered axle, isn’t there?

Anyway, yes I did suspect that it’s mostly for showing off. I was curious because one Dutch recumbent bike I was looking into had this feature, but I decided against this bike for other reasons anyway.

8

Yes, and causing the tire to lose traction as the opposing fork arm allows the tire to basically slide away from the force exerted on it.

9

Another reason is to reduce drag around the front wheel. No idea how effective they are at doing this