Monday, October 21, 2013

Cannondale Slice versus Slice RS

For the past two years I have trained countless hours, raced ten half Ironmans, six Ironmans and multiple shorter races on both the Cannondale Slice and the Cannondale Slice RS. I love both of these bikes for different reasons. This post will explain what I believe are the main differences as well as what I wish was different on these bikes.

A little background on my two bike setups:
  • Slice High Mod frame with Dura Ace Di2
  • Slice RS with Ultegra Di2
Both bikes have Rotor 155 cranks (yes, I actually do use a 155s and yes, they make them that short), Profile Design Aeria bars and Profile Design ABS Carbon Brake Levers.

Cannondale Slice


When I was first fit on the Slice the biggest problem we had was getting the bars lower. For most age group athletes, my fit is aggressive and most athletes would not have this problem. I've had a couple people test ride my bike and they always come back saying "The cockpit is too low for me."

We solved the problem of getting me lower thanks to Profile's Aris stem, which can be inverted. When I pack the bike in the box to go race the breakdown process is fairly simple and involves removing the bolts for the bars.

Cannondale manufactures the Slice frame so it can be internally cabled. However, the cables for Dura Ace Di2 are wider than the standard cables and therefore my Di2 cable runs beneath the frame, and my brake cable runs inside the frame. You can see the hole (which I capped) for the internal cabling of a standard shifting cable right above the "C".

Di2 Battery Mount.

Di2 Adjustment Switch is attached right near my stem.

Front brake is a standard (non-hidden) brake with release to open and close the brakes.

Rear brake is the same setup as the front.

Front derailer.

Rear derailer.

Frame has space for a single water bottle cage. I have added a cage between my aero bars as well. When I race Ironman I also add a single cage behind the seat.

Seatpost is aero and the bolt for tightening it is easy to access - which translates to it being easy to use a torque wrench to properly tighten it. However, when shipping the bike it's important not to lose this collar, otherwise you can't tighten the seat.

The things I love about my Slice....
  • It's light - really light. Climbing on this bike is amazing. However, when it's super windy I get blown around more.
  • Because I have Dura Ace Di2 on this bike I can shift in both aero position or while climbing. I would always choose this option for technical courses such as Alcatraz.
  • The brakes although not as aerodynamic, are super simple and easy to use. If something goes wrong in a race and my wheel starts rubbing, I can reach down and open up the brake.
The things I wish I could change...
  • 2 Water bottle cages on the frame would be nice.
  • Internal cable routing for my Di2 would make the bike look better, but it probably would not function differently.

 Cannondale Slice RS

The Cannondale Slice RS has a completely different front end that requires no use of a stem. On this bike we were actually able to get my setup lower in the front (which is what I wanted), and in the end, the RS fits me better than the Slice.

The bike comes with multiple pieces that can be used to make the front end shorter or longer. Although this bike is a bit different to pack up when I ship it to races, I actually prefer dismantling the front end on the RS, because when I put it back together it is simple to line the handle bars up properly since there is no stem involved.

All my brake cables and Di2 cables are internally routed. The Di2 Adjustment Switch is attached to the cable for my rear brake. We added barrel adjusters to each of the brake cables to make it easier to adjust the brakes while racing if needed, or when changing out training wheels for wider race wheels.

The Di2 battery sits right beneath the crank on the frame. I prefer this mount to the one on my Slice, as it is a bit more hidden and out of the way.

Hidden front brakes.

Front brakes looking from the back. I don't have many complaints about these brakes - they work and using the barrel adjustment that we added to the cables, I have no trouble getting them set properly.

Hidden rear brakes.

Side view of the rear brakes. When these brakes are set up properly they work really well (In the past I have ridden bikes where I swear that the "aero" rear brake was simply for show and stopping power was non-existant.) However, on the RS when I change from training wheels to race wheels I almost always need to readjust the cable. The barrel adjustment we added is not enough. The rear brake is probably the single part on this bike I have been most frustrated with. When it's set up - it is perfect. But changing wheels inevitably leaves me frustrated - either with centering the brakes or getting them wide enough. I learned a while ago how to fix the brakes if needed, but most of the time I let my mechanic deal with this and just don't touch it. Everyone is happier when I do this.

Front derailer. Same water bottle cage setup on this bike - one cage on the frame. I added another between the bars and when I race Ironman I add one behind the seat.

Rear derailer.

Seat post on the Slice RS is much smaller than on the Slice. Rather than a collar that goes around the seat post, there is a small piece that sits between the post and the frame (again, a piece that can't be lost when shipping the bike). I actually like this setup better, as it seems more secure to me. However, because of the location of the screw when I tighten the bolt I can't use a torque wrench. This scares my overly-careful-with-carbon-overtightening self. However, I have had no issues under- or over-tightening it.

The things I love about my Slice RS....
  • When I ride this bike compared to the Slice I feel that it transfers power better. It feels more solid than the Slice and when I really put the hammer down, the bike is quick to respond. Additionally, because the bike feels more solid, when it is super windy I tend to stay the course better rather than blowing around the road.
  • I tested both the Slice and the Slice RS for aerodynamics and the RS came out on top. This is probably partly because I am positioned lower on this bike, but also because the bike is simply more aerodynamic. Less effort to go faster adds up over 112 miles.
The things I wish I could change...
  • 2 Water bottle cages on the frame would be nice.
  • Adjusting the rear brake is still sometimes a headache for me.
  • Because I have Ultegra Di2 rather than Dura Ace Di2, I only have electronic shifting on the aero bars. Not exactly a tragedy, but once you've also had it on the bullhorns it is slightly sad to not have this option for shifting.
  • Going off looks alone (they are completely functional) the front cables going from the bars to the frame still look a little odd to me.
So if I had to choose only one of these Cannondale bikes, which one would I ride? Hands down the Cannondale Slice RS. If you have specific questions about either of my bike setups feel free to email me.

4 comments:

ONEHOURIRONMAN said...

Dang
I need to write Santa Claus early this year..

Mr. Calves said...

Your bikes don't look like mine at all. Where is all the rust and 3 year old dried Gatorade? Very confused here.

Alex Khokhlov said...

Thank you for a detailed review. In the process of switching from Slice 5 to RS

nathan ong said...

not sure if you still have the cannondale RS, btu would it be possible to see the brake cable routing through the headtube? my email is nathanong87@gmail.com . i'd really appreciate it as im trying to find a good option for the slice RS

-Nathan