Bought the cheapest Cannondale Scalpel I could find (Scalpel 4) and transformed it; it's almost 22 pounds, including pedals, and racing ralph 2.25.
After 400 or so miles, I'd like to review it and share my project with other bikers who care about weight saving / trail-worthy bikes.
Disclaimer: pictured below is with the 27.5 wheels / only 15 miles of easy riding on that setup so far.
The frame is alu, thus has one extra pivot in the back. It’s good because it’s stronger, it’s bad because it’s a little heavier (okay, a lot heavier than the carbon frame). It feels very sturdy, and that was the most important factor.
Frame size is a medium – while the med alu frame is smaller than the med carbon frame, I really wish I had gone with a small frame (better adjustments, since I am only 5’6” with a short torso).
Drive Train (XX1):
First, let me say that this drivetrain make the entire bike the quietest bike I have ever been on. Looking closer, I am now debating about using a 30-tooth chain ring coupled with an 11-32 instead. Using a rear XX cassette and XX derailleur will save weight where it matters most. I’ll probably spin-out quicker, but that would save (maybe) ¼ pound – especially after shortening the chain. Otherwise, I have yet to drop a chain, even in the most grueling descents.
I have two sets of wheels – 29er and 27.5” – both with xx1 cassettes. Most of the time, you’ll find the 29” wheels. The 27.5 change everything about the bike; it’s very fun, very lively, but does lower the bottom bracket. It climbs like a goat though (smaller circumference) but surprisingly enough, doesn’t shave that much weight at all. Rolling resistance is nearly identical, though the smaller wheels require more “body effort” – very negligible. Meanwhile, think of this setup as 2 different bikes: quite fun.
On the east coast of the US, rocket ron tires are pretty much worthless. In the 27.5”, they are officially the worst feeling I ever had – on any bike. Instead, I found racing ralphs to be perfect in 29” and 27.5”. On the 29” wheels, I use a 2.1 in the rear and 2.25 in the front. I find this combo is light and super efficient. This option doesn’t yet exist on the 27.5 version.
I am looking for options on my stem. Since I am running a lefty, this is tricky. Currently using a 90mm stem with a -5 degree. The ideal would probably be -15 degrees… but I am not even sure when to start looking.
The bike is absolutely crazy fast (yeah, climbs like a goat even with the 29 wheels). The super technical descents are easily taken care of with the rig. Longer rides prove to be comfortable (though I could certainly tweak my front-end some to suit my short torso).
Compared to my 29er hard tail, this bike’s geometry is so much more precise and lively. The hard tail was like the first generation 29er from Cannondale (a boat), where the full suspension scalpel is so very nimble.
What I love:
Super Nimble 29er bike, super fun to ride - sort of "go anywhere / do anything bike".
What I question:
The bike's ability to carry water - certainly the worst I have seen.
Cable routing: ugly, requires tape to protect your frame.
You could buy a scalpel ultimate (11k) or scalpel 1 (7k), but in the end, you’ll spend far less if you purchase a scalpel 4 AND modify it from the ground up. The result will be a lighter bike, totally customized (and money left in your pocket for races).
I have built a scalpel 26 bike (carbon frame) with 27.5 wheels - xx all over the place. The bike was almost 19 pounds with pedals. The geometry was very different; I love saving weight, but this 29er bike (weighing almost 3 more pounds) is really remarkable.
Hope this helps.
SCALPEL 29er with 27.5" Wheels