Author Topic: triplet design  (Read 1138 times)

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Offline coachb

triplet design
« on: March 09, 2010, 04:25:05 pm »
I am looking for design of a triplet or double using recycled bicycle frames. I have a shop class wanting to create. Thanks

Offline whittierider

Re: triplet design
« Reply #1 on: March 09, 2010, 11:36:33 pm »
I wouldn't recommend it.  Tandem and triplet tubing is much bigger than single-bike tubing.  Before the likes of Bill McReady (sp?) at Santana came along and made the tandem world what it is today, one problem with early tandems was that they were much too flexy.  Our steel tandem's tubes are the size of Cannondale single-bike aluminum tubes, and the bottom tube is as wide as the BBs.

Offline scott.laughlin

Re: triplet design
« Reply #2 on: March 10, 2010, 07:32:18 pm »
I wouldn't recommend it.  Tandem and triplet tubing is much bigger than single-bike tubing.  Before the likes of Bill McReady (sp?) at Santana came along and made the tandem world what it is today, one problem with early tandems was that they were much too flexy.  Our steel tandem's tubes are the size of Cannondale single-bike aluminum tubes, and the bottom tube is as wide as the BBs.

Well said.

Anyone with the math skills tol calculate the frame stresses would agree that a tandem or triple bike is a new and different bike from the ground up.

Offline paddleboy17

Re: triplet design
« Reply #3 on: March 11, 2010, 12:27:36 pm »
Maybe this would be a good exercise to start from scratch with purchased chromoly or aluminum tubing.  This will heavy, but it will have the sidewall thicknesses to allow for TIG welding.  As has stated many times in other threads, bicycle tubing is pretty exotic stuff that cannot be welded by just any ordinary (or even accomplished) welders.

So let them build their frames.  I live in Michigan, and we have a tubing supplier here (I have a 10 foot long section of 6061 aluminum that has an OD of 2 inches in my garage that I bought from their scrap bin).  I bet there is a tubing supplier in their town too.  And there is always the Internet.

Some years back, some of my buddies built camping trailers that out perform a BOB using locally bought tubing.
Danno