by Brad Mathison
The theory behind the Boyesen FlexGrip is based on the simple fact that most riders suffer arm pump, blisters and wrist injuries more on their left side because of the stationary grip. The Boyesen FlexGrip offers a small degree of movement, or "flex", through a pair of molded elastomer inserts.
When I first received it I was a little skeptical. Most people are not used to their left grip moving, and it does look just like a throttle for the left side. In fact it requires a throttle-side handgrip (24mm). It has been tested for almost three years now and, in its final stage of evolution, is ready for public sale.
Installation was a breeze. It comes with three sets of elastomer inserts (soft, medium and hard), a pair of Renthal medium compound grips, and some basic instructions. After installing two inserts and gluing the Renthal grips on, it slides over the bar and tightens with two screws (just like the throttle housing). Although on some handlebars, like Renthal, you have to file & sand the knurling off the left side.
I have had the FlexGrip on my RM125 for about six months now. When I first installed it on my bike, it was a little strange being able to twist the clutch side grip. But I had already forgotten it was even there by the time I was 20ft down the track. I still use medium inserts for both front and back, although a lot of people prefer the hard compound elastomer on the forward side. It did help with arm pump, and the blister situation on my left hand is much better.
In early November I had a little 5th gear "get off", breaking ribs and dislocating a shoulder. The bike came out even worse, among other things it bent the bars down about three or four inches and stripped the left-hand side clean. After finding the FlexGrip lying in the woods it was cleaned up, greased and put back on a new set of bars. From this little test it seems to be very durable. I've also noticed the left side grip doesn’t get punched through when you drop the bike because of the housing. No need to cap your bars with a nickel any more!
You will have to order your grips from Boyesen or buy double sets because it requires that you use two throttle-sized grips. Boyesen does supply all of the Renthal flavors to fit. I wouldn’t ride without one now. My recommendation to anyone that suffers from arm-pump: give the FlexGrip a try.
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