An Experiment In Front End Geometry: Fork #2

Continuing on from the radical Blackbuck fork, I went to the “other end” of the spectrum and installed a Bontrager Race X Lite Switchblade Fork

Blackbuck and Switchblade fork
The Switchblade is a carbon/aluminum composite fork that sports “traditional” dimensions. With this fork installed on the Blackbuck we get the following numbers to chew on:

Head Angle: 72.3 degrees
Axle to Crown: 465mm
Offset: 38mm
Wheelbase: 42.5″
Bottom Bracket Drop Range(EBB): 55mm-65mm
Approximate Trail*: 84mm

Changes Made: The necessary changes made to accomodate my saddle to bottom bracket relationship and my saddle to bar relationship were as follows:
-Moved saddle forward approximately 20mm.
-Removed several spacers from the previous set up.
-Changed to a 20mm longer stem and one with a bit of rise to keep the bars the same distance from the ground as before. (The fork had a shorter cut to the steer tube.)

Handling Characteristics: This is probably what a lot of folks would have considered a “baseline” set up. The “old” offset, locked in by 26″er geometry, was what a lot of 29″ers had in the begginings of the 29″er era. It is also the reason a lot of folks said 29″ers were slow handling. Thus the new crop of longer offset forks that are available today.

The Blackbuck nearly threw me for a loop with the Switchblade on the front. The bike now required far more input to steer than I had gotten used to with the longer offset forks. However; in another example of mountain biker adaptability, I reigned it in within a few minutes, and by the end of the first ride I was comfortable with the forks geometry quirks.

The bike definitely was better in slow speed maneuvers and it did require a bit more body english and turning of the handlebars to get through corners. If you are a fan of dancing with your bike and love the prospect of wearing out head set bearings, this is the set up for you. I found that the combination of the offset and axle to crown height made the Blackbuck seem more “wheelie happy” and it wanted to have its front end weighted on climbs to avoid popping the front end up. Standing climbing was a bit calmer on the single speed, especially the mad grunting, almost-to-a-dead-stop climbs. The longer offset set ups were a bit more of a handful in those situations.

A Note On The Forks Ride: This fork was also reviewed on Twenty Nine Inches before, so again, please use the Search box at the upper right for more. I’ll just say that on the Blackbuck the Switchblade was another good, abeit very different pairing. I think the offset would favor longer, high speed descending. If your trails tend to be this way, you might give the Switchblade a look.

Final Thoughts: I have no trouble figuring out this combination, but I will say that over a long ride, for me, all the sawing at the bars and body english maneuverings get tiresome. I am predisposed to a bike that takes a bit less effort to pilot around tight single track. (Maybe I’m lazy?)That said, this combination was still a lot of fun to ride and because things seemed to happen a bit slower, or in a more stable way, I felt better about some trail sections than I had with the other forks. Was it too slow? That is a topic that is also debatable. It certainly didn’t handle quite like a NORBA XC racer machine, but then again, should a 29″er handle that way? Should there be a shorter offset suspension fork in the future for 29″ers? That may be a topic for another post. All I can say is that this combination was totally rideable yet not quite my cup of tea.

*The trail charts I used all gave slightly different answers and of course, your tire selection will also affect the trail figure slightly. Take my trail figures with a grain of salt. Your mileage may vary!


No Responses to “An Experiment In Front End Geometry: Fork #2”

  1. Cloxxki Says:

    72d HTA, 38-39mm offset, that was called 29″ specific geometry for quite a few years.
    My buddy has an On-One Scandal setup with alu Switchblade. Very content with it, even if I prefer a quicker handling rig on our twisties. He calls it steering precision though, and I can only concur, it’s precise this way. I suppose he’s o lazy handlebar janker, uses a really wide 15d bar even.

  2. Glenn Says:

    Sounds similar to the 2005-07 Fishers with the Reba – of which I ride. Most of the time it is great, but those 180 degree switchbacks are a PITA!!!! And the wheelie effect, yikes, it’s the worst on uphill switchbacks, where sometimes I think I am riding a unicycle.

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