Does the Titanium Hardtail Still Reign Supreme?
by Richard J. Cunningham, courtesy of Mountain Bike Action
When there were no full-suspension bikes and before Easton developed its legendary taper-butted 7005 aluminum frame tubing, the titanium hardtail was the best that money could buy. Put a lot of emphasis on the word, “money.” Titanium was difficult to obtain, nearly impossible to machine, and only the creme de la creme of TIG welders could successfully join the frames. But at close to half the weight of steel, yet comparable in strength, titanium’s lively feel and corrosion resistant properties eventually forced craftsmen to tame the unwieldy element.
It took another decade for the big brands to work out the bugs and copy the innovator’s designs. Unfortunately, it was too little, too late. Just as gray metal Ti frames were beginning to be dished out in semi-affordable numbers, aluminum suspension bikes literally wiped titanium steeds off the front pages. What a slap! The off-road world wished for affordable titanium and when it arrived, they didn’t want it anymore.
Is it really dead? The MBA test crew takes, look at five titanium hardtails, all built by the masters of the craft to discover the future of Ti, if there is one.
Talking to the masters of Ti
We asked the master builders of titanium frames to fill us in on the exotic world of space age plumbing and how it relates to modern day frame building. Here is what they had to say.
Seven Cycles’ Rob Vandermark on 3/2.5 vs. 6/4
“Titanium’s 6/4 alloy has some very favorable properties, hence the reason that Seven uses it for its dropouts. 6/4 is a great material for dropouts because of its toughness; however, this toughness makes it unattractive as a tube material. It is effectively not possible to draw 6/4 into seamless tubing. Drawing 6/4 tubing by using similar methods used for 3/2.5 alloy not only costs more, but it wears out tooling very quickly and there are limitations to the tube’s wall thickness, consistency and finish. Therefore, no mill offers seamless 6/4 tubing. What they do offer is seam welded 6/4 tubing.
“Seamed tubing is formed by rolling a sheet and automatically welding it at the joint. There are two major issues that keep Seven Cycles from choosing this method of tube manufacturing for its frames: First, the welded seam is a potential failure point. Second, the sheet that the tube is fabricated from is designed to be stressed as a sheet, not a tube. The grain structure of a 3/2.5 seamless tube is carefully drawn to optimize its strength. This is critical to fatigue life. Unfortunately, a sheet that is made into a tube offers the worst possible grain structure for fatigue life. The 6/4 tube will fail in fatigue cycling (repeated flexing) before it should. Independent tests show that 6/4 sheet does not have the fatigue life of a properly drawn 3/2.5 tube. 6/4’s strength properties are higher than 3/2.5 alloy, but this is irrelevant because catastrophic failure is not an issue with titanium frames. Fatigue failure is the key.”
Seven Cycles Sola
Unlimited Choices for the Discerning Owner
Seven has a host of tricks up its sleeve that set this bike apart from cheap imitations. Seven’s raw material is seamless, aerospace certified, straight gauge 3/2.5 titanium drawn to Seven’s specifications. Butting is done by Seven to within 0.001 inch.
The head tube is eccentrically butted for maximum strength and stiffness at the weld joint. Drop outs are CNC machined and logo engraved from 1/4 inch thick 6/4 titanium plates with machined ramps.
Final touches are 7/8 inch diameter, butted “S” seat stays; composite seat tube insert; and custom-made, CNC machined, nickel-plated aluminum seat clamp.
Seven’s Exclusive Argen custom tubing is U.S. made and Seven’s butting process allows for unlimited choices in wall thicknesses and tubing diameter. All frames are tailor made to rider specifications, with the rider’s weight, riding style and desired ride characteristics taken into account. Customers can choose any cable routing and braze-on adjustments. All this is done at no extra cost and takes no extra time.
Riding the Seven
|Numbers:||Seven chose a basic geometry for our bike: 71 -degree head tube and 73 -degree seat tube on an 18-inch frame.|
|Comfort:||The Seven was a very comfortable bike to ride. The frame was stiff where it needed to be and compliant where it mattered. We could sprint the bike and it wouldn’t shift itself out of gear, but it descended the roughest sections without rattling our bones. Compared to every other titanium bike, the Seven is nearly perfect.|
|Handling:||How do you want the bike to handle? Since Seven can make any geometry, tube thickness, tube diameter or tube length you want, you can make the bike handle exactly the way you want it to. If you aren’t sure what kind of bike would be best for you, Seven’s crack team of engineers can quiz you about your riding style and local terrain, take all your body measurements and design a frame just for you. Take advantage of Seven’s expertise and service.|
|Construction:||Workmanship is good as it gets on this titanium frame Seven takes incredible pride in its work and it shows. Frame weight is a claimed 3.23 pounds for an 18-inch frame. Seven makes 16 stock sizes from ten to 25 inches.|
|Weight:||Our complete test bike weighed 21.5 pounds.|
|Wax Nostalgic:||Seven’s feel and characteristics were reminiscent of the Merlin XLT. A great all around race and trail bike, the fully customizable Seven is a rare bike to find and own.|
Seven’s bikes are for titanium connoisseurs who know what they want. Building up your own Seven isn’t cheap, but the end result is stunning.
You simply can’t compare what you get with the Seven to budget titanium offerings.
MBA grade: A +