19 January 2009

bikefix Exclusive Review: Alpha Q Prolite stem

Gosh, doesn't this stem look familiar? One of the advantages of going to 31.8 stems and bars on all of my bikes (mountain and road) has been the ability to swap stems between bikes to find the perfect position on each. Unfortunately, it turns out that three out of the four bikes in my garage feel great with the same stem length. On deciding this, I went to the shops in search of a lightweight threadless stem that was mountain-approved and not too expensive. Last spring I wrote about Ibis/Origin8's Propulsion stem. From a little-known distributor's house brand and appearing on Ibis' mountain and road bikes, the Propulsion came in at ~120g and was plenty stiff enough for single speed use and really wide 'bars.

Well, it looks like Alpha Q have been talking to the same guys in Taiwan. For $45 at my local bike shop, the company's Prolite stem bears a striking resemblance to the Ibis/Origin8 twins, though with a couple of very minor changes. The face place hardware has been changed slightly and the hardware torque spec's increased from 5Nm to 6. The stem's advertised weight is down to 105g (in the 110mm length)- which may or may not be an actual change. To my eyes, they're otherwise identical. A cross-section on the company's website shows added material running down the length of the stem at 3:00 and 9:00, allegedly to improve torsional stiffness while retaining vertical compliance (though the Prolite is far from flexy). In fact, it's both stiffer and lighter than the $225 Deda Mag00 on my road bike (which, in all honesty, should probably be retired).

If a company can afford the tooling investment, forging components from aluminum is one of the lightest, strongest and most economical ways to make a bike part- which is why you don't see CNC'd-from-billet parts from Shimano or Campagnolo. Forging aligns the material's grain structure with the ultimate shape of the part and shot peening (as appears to have been done here) work hardens the surface and helps to prevent cracks from forming. The twin 2-bolt clamps (which may or may not skirt Easton's long-standing prohibition on using 4-bolt stems with carbon bars) are very nicely shaped for light weight and stiffness and, thanks in part to the larger surface area of the 31.8mm diameter bar/stem interface, hold bars firmly without the need for excessive fastener torque.

As with a lightweight component at any price, it would be wise to observe all torque specifications when installing or adjusting the Prolite stem. I would complain about the easy-to-damage button head hardware on the the steerer clamp, but they should be more than adequate for the specified 6Nm torque and should be slightly more knee-friendly than sturdier socket head cap screws (as on the face plates) would be. Available from distributors QBP and BTI, the Alpha Q Prolite should be more readily available to your local shop than the Origin8 or the Ibis, which is an added bonus. With apologies to Keith Bontrager, the Prolite looks to be strong, light and cheap. It looks you can have all three after all.



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