Most non-Santana tandems (including those from custom builders) are built with easier-to-weld heavy gauge tubing. No builder besides Santana has even attempted to produce a line of welded tandems with 8/5/8 cromoly---something we've been done with near-perfect success for the past 5 years.

What is 8/5/8? An 8/5/8 double butted tube is .5mm (.019") thick throughout most of its length and butted to .8mm (.031") thick at both extreme ends. The majority of tandems, including most custom tandems, are built with cheaper-to-draw and easier-to-weld 11/11/11 or 10/10/10 "aircraft" plain gauge. It is not only easier to overheat a thin tube, an original flaw in a thin tube is far more likely to propagate into a crack.

I wish I could claim our lighter frames are less likely to fail than heavier frames from other builders because our welding ability was better, but that would be impossible to prove. Besides careful craftsmanship, the real reason Santana can successfully use lighter gauges is that we have done an incredible amount of homework. In 1983 we became the first tandem builder to use an instrumented tandem test jig to carefully measure frame deflection under simulated riding conditions. In 1992 we became the first American builder (of singles or tandems) to obtain electronic strain-gauge analysis of our bicycle frames while they were being ridden. No other tandem builder has conducted either type of test.

These tests not only allow us to build frames that are stiffer without being harsher, they allow us to pinpoint the "hot spots" where more material is needed and identify areas where it is safe to reduce a frame's weight without

risking a rash of failures. In a head-to-head testing of frame efficiency (measured stiffness divided by measured weight) Santana's frames consistently outscore others by 20-90%. While many frames (singles or tandems) might be light OR stiff, a builder can't possibly combine both attributes without utilizing large diameter light-gauge double-butted tubing.

Another tandem builder recently declined to reveal their "proprietary" gauges. This is a bit like a car manufacturer refusing to discuss horsepower.

In addition to our new 8/5/8 tubeset featuring Columbus Cyclex (a super-cromoly that outperforms the best tubing we could obtain from Tange), since 1990 we have built fillet-brazed tandems with Columbus NivaCrom (a niobium-vanadium steel) in 7/4/7. Our Easton 7000-series aluminum tubing is 20/10/20 and our Ancotech tubing (a mixture of "6/4" and "2.5/3" titanium alloys) is 10/5/10. Finally, because we want our frames to endure for decades instead of years, Santana has never used heat treated steels.

What causes a tube to crack? Assuming competent design and proper use, cracks typically result from either imperfect workmanship (usually too much heat), or from an original flaw in the tube. Thus a crack at the edge of the weld usually indicates improper workmanship by the frame builder, while a crack occurring elsewhere invariably indicates a flaw that was introduced when the tube was manufactured.

While no honest tube or frame producer can claim 100% reliability, production bicycle frames with the very highest levels of performance are invariably the result of a combined effort whereby a tubing supplier and framebuilder work together to develop lighter frames that are both stiffer and more reliable. Over the years Santana has worked directly with the top engineers and metallurgists at companies such as Ishiwata (1976-83), Columbus (1982-on), Tange (1989-97), Easton (1991-on) and Ancotec (1992-on). Framebuilders besides Santana who ceaselessly work with multiple tubing suppliers to attain unprecedented levels of performance include Ritchey, Serotta and Colnago.

After reading some of the recent posts, Steve Freides wonders why anyone would want a Santana. If he, or anyone else, is worried about a cracked tube, they should find an experienced builder and specify a frame built with smaller-diameter "aircraft" tubing drawn in heavier gauges. Schwinn used this formula to build about 1500 relatively heavy, flexy and harsh-riding Paramount tandems between 1968 and 1977. While I've seen plenty of broken Paramount tandem forks, I've not yet heard so much as a rumor of a Paramount tandem with a cracked frame tube.

Concluding thoughts:

1. When reliability is deemed the sole determinant of frame performance, the Schwinn Varsity becomes the world's most desirable frame.

2. Because the "fun" of cycling and especially tandeming is rarely affected by such minutiae as metallurgy, gear ratios and tire pressures, you don't need a high performance machine or expensive equipment to enjoy yourselves. I have no argument whatsoever with couples who ride any type of tandem---even if it's a Motiv, Gitane, Huffy or home-built. People who tell you that you NEED to spend more to have fun are wrong.

3. On the other hand (if you already know you enjoy the sport), I can't think of a healthier way for couples to spend their leisure money!