Thursday, November 12, 2009

FSA V Drive MegaExo Crankset Review

Bought this for a Trek hardtail replacement frame that I have been using for a wet weather commuter.  Since I now have a new dedicated commuter, I'm slowly changing the frame back to a mountain machine.  I thought this would be a good choice because a) I'm a new fan of external bottom-brackets and b) it was pretty cheap.  The chainrings look pretty nice - pins and ramps abound.  The cranks are pretty lightweight - hope they are durable, since I have read some mixed reviews about their strength.

The bottom bracket cups went on pretty smoothly.  I had a "BB7000" model, which has a plastic "sleeve" between the two cups that the spindle goes through.  While this is cheesy, I'm pretty sure that it is largely irrelevant to the operation of the cranks (many external BBs doesn't have a "sleeve" at all).  The cups only require a Park BBT-9 tool to install, which works on Shimano and Campy external BBs - obviously someone screwed up since it does not require a proprietary tool (although FSA does have it's own version of the tool).  The crank  comes with a Torx wrench for the chainring bolts, in case you don't have one (and if so, might as well suck it up and get some - they are the future).

The only confusing part about mounting the cranks is that there appears to be several sizes of the BB and you need to know which one to use to determine how many spacers you need to install.  I never saw anything about different BB sizes when I bought the thing, so I'm not sure what the deal is there.  The one I have was supposed to be used for BB-mounted derailleurs, which I don't have.  I ended up guessing that the derailluer mount was about the size of one spacer and acted accordingly - I, of course, backed it up with caliper measurements.  The problem was that the chainline was off when after I installed, so I had to remove at put the spacer on the left-side cup (I initially put it on the right, since that is where a BB-mounted FD would have been installed).  Chainline was perfect after that.  FSA really needs to work on their installation instructions regarding spacers, BB size, and chainline.  By the way - one of the o-rings already came installed on the spindle.  This was a little confusing, since the instructions say there are two, but there is only one loose one (for the left side).

The spindle does not inspire as much confidence as my Campy cranks.  In my opinion, the hirth joint on the Campys appears much more stable than than the FSA - which is basically just secured to the left-side crank by a fixing bolt and two opposing 5MM bolts on the crank arms.  There are splines on the spindle that match up to the crank, but they are fairly shallow.  I'll see how this works out - I can imagine potential slippage due to a lot of touque, but only time will tell (might just be paranoid).  Once installed, the resistance on the cranks was way more than a normal, adjusted BB, but about the same as my external Campy BB when I first installed it (it loosened up after 500 miles, or so, but still has more resistance than a conventional BB).

As far as their operation, they are nice and stiff compared to the Shimano sealed BB I had on there before.  No creaking when riding and the bearings are loosening up (but don't think they will ever be as loose as a conventional BB).  The chainrings shift very smoothly.  So far, so good.  I'll update of there are any problems.

1 comment:

Francisco Rodriguez Casal said...


I have some issues with this crankset. I need some info:
What size is your bottom bracket shell? 68cm? 73cm?
How many spacers (and where) you install?

How many space left between the spindle and the left crank outer?