Quiring Cycles

In the late 1880s, the best bicycle frames were  fabricated out of steel  as skilled artisans joined the tubes together by brazing them over an open hearth.   Constructing frames predominately out of steel still continued for over 100 years, but along the way the quality of the steel alloy tubing improved and so did the method of joining this steel.   During that time, frames got lighter and stronger and, respectfully, the ride quality of steel frames improved too.  

While it seems that most bike frames are made of other types of materials these days, steel frames have still seen advancements.    One such example is the recently released stainless steel tubing called XCr, made by the famed Columbus tubing manufacturer of Milan, Italy.

At Quiring Cycles, LLC, Scott has taken to the challenge of making several of these frames over the last few years.    He speaks very highly of the quality of the XCr stainless tubing and also notes the extraordinary skill needed to make a frame from it.  His personal road bike that he loves to ride is made from XCr.

While attending the NAHBS in both Richmond, VA and Austin, TX, Quiring has had a chance to speak with Mauro Mondonico, the Sales Manager for Columbus, about the unique characteristics of the XCr stainless.  It turns out that XCr is made from a solid billet bar of stainless steel, and it is drawn out into a tube continuously until it reaches its final impressively thin walls. For example, the top tube in mm has a butted .6/.4/.6  profile wall thickness, which is comparable to the upper ranges of other super-steel tubesets by Columbus and Dedacciai (another Italian tubing maker).    The downtube has a remarkably thin wall of .65/.4/.65 mm, and other areas reach a wall in the weld zone as thin as .5 mm. 

One might ask the question, if it is so thin, how does it stay together?  The secret is in the incredible tensile strength of the XCr material, which is around 200,000 psi.  Or, in other words, it is 500% more than the tensile strength of typical aluminum alloys, and a little more than 60% stronger in tensile strength when compared with 3/2.5 titanium in a cold-worked-stress-relieved state.   

Despite thin walls to save weight, XCr's larger than normal sized seattube, top tube and downtube contribute to the frame's balanced stiffness and liveliness.  What we mean by oversized is a 31.5 mm diameter top tube and seattube, and a 38 mm diameter downtube.     

What does all this above info mean? Since XCr does not rust, it does not need paint (paint adds weight). And, since XCr has super thin butted walls, it rivals aluminum and titanium frames  in weight.   Yet, the XCr has the classic "feel of steel" for all-day comfort, a desired trait by many cyclists.

Due to the thin tubing, careful construction of an XCr frame must be taken into consideration since stainless is very hard to miter and to weld.   Fortunately for Quiring, part of his TIG welding instruction many years ago at Grand Rapids Community College included the joining of stainless.   Generally speaking, Quiring says, during the welding phase, stainless has a relatively high coefficient of thermal expansion and a low rate of thermal conductivity when compared to welding conventional carbon steel tubing.  What this means is that the heat needed to TIG weld the material must be precisely directed and the miters must be very tight so there is minimal gaps to fill.  Furthermore, an inert welding environment is key to join stainless because it will help prevent the metal's carbide precipitation effect that happens during the molten stage.   Lastly, careful consideration in weld sequence should be carried out so the frame comes out straight.

In terms of visual appearance of a weld, XCr is thin so the weld bead width will be very small.  Also, a light copper color in the weld bead is desired when the raw weld is viewed.   A darker burnt color in the weld bead is a sign that this joint may have gotten a little too hot and, as a result, the latter may not be as strong.  As with other steel tubing, XCr only receives one pass around with the TIG torch at each joint, so it must be done right the first time!

The above photos show our tight tube miters and the weld zone in a raw state as an indication of what we believe are desired traits and techniques used in constructing an XCr frame. 

This frame is for a long-time customer in Maryland, and will be used as a performance-oriented machine with fatter road tires, a CX fork, and canti brakes.  So when he wants to hit a few dirt roads, he can do that too! 

As centuries have passed, cyclists have taken to their steel frames, but today's steel frames are much lighter and more fine- tuned when compared to the bicycles of yesteryears.  Imagine that feeling as your ride begins and you pedal effortlessly down an endless winding road, and you can imagine the feel of a high-quality Quiring built XCr stainless frame. 

--Posted by Peekster