SRAM Torpedo Fixed / Free Hub – On Test
The SRAM Torpedo hub is unique, and one of the more exciting test items to come into my hands in some time. Freewheel or fixed – this hub switches with a few turns of a screw making it the first such hub to do so since the long lost ACS Freetrack. This switcheroo does come with a weight penalty – the hub is listed at about 480g, though honestly the weight difference between the Torpedo and a conventional flip/flop fixed/free hub with cog and freewheel attached is minimal.
Spaced at 130mm, the hub is truly meant for road and ‘cross bikes though squeezing a mountain frame 5mm or stretching a track frame 10mm is really no big deal as long as they’re steel and not heirloom quality frames with delicate bottom bracket lugwork. Cogs are available in either 1/8″ or 3/32″ width and 16/17/18t with a 46mm chainline or 19/20/21t with a 49.5mm chainline for maximum crankset compatibility. The 32h hub builds up with no dish and is available in a few different colors – silver, green, gold, purple and blue. Drilled 15mm cap nuts keep the wheel in place, though first look says you may want to use a chain tug to keep things secure since the nut is not serrated. And keep a small flat blade screwdriver handy to perform the magic with, conveniently my Leatherman has a blade that fits just right…
The real deal about the hub is that fixed to freewheel conversion, accomplished with roughly 8 turns of the recessed screw head pictured. In freewheel mode it has a confidence inspiring audible click of freewheel pawls slipping across the teeth with very little drag, just as it should. It feels exactly the same as any quality freewheel. Lock it down to fixed and it is silent, though the cog does experience some backlash or “play” back and forth. It is noticeable in the pedals – I’d estimated it to be a few degrees (less than 10) at the cog. More than a loose chain on a conventional fixed hub allows. First impressions based on a very brief ride to the Post Office and back is that the backlash is there and not going away, but not as much of a problem as I thought it would be on the workstand. In fact, after just a bit of pedaling my mind adjusted to it and while the feeling did not go away I wasn’t cursing myself down the street either. Skidding felt normal, though who knows what it may be doing to the internals. SRAM likely doesn’t want me to open it up and find out how it works, but curiosity is calling and something tells me I’ll see the guts of the Torpedo before long.
The Torpedo hub certainly adds complexity to a fixed drivetrain, but for someone who likes to coast sometimes and not others this is an interesting niche product. Time will tell how it works over the long haul, we’ll keep you informed as we tick off the miles.