Cannondale Topstone Carbon Force eTap AXS: Checkpoint – by MG
The Cannondale Topstone Carbon has been one of the most talked about new gravel bikes for 2020. For more than two months, we’ve been testing a top-spec Topstone Carbon Force eTap AXS, riding enough miles on it to nearly wear out the rear tire. Here’s the latest update on our experience with this groundbreaking new gravel bike.
Get caught up on our earlier posts with specifications and available models of the Cannondale Topstone Carbon:
- Cannondale Topstone Carbon Force eTap AXS: Getting Rolling
- Gravel Grinder News: Cannondale Goes Big with New Topstone Carbon
From the first revolution of the pedals, it’s easy to feel the speed Cannondale has engineered into the Topstone Carbon chassis. Compared to the other carbon and alloy bikes I’m currently testing, the Topstone Carbon accelerates with an urgency that’s unmatched in my stable. Everyone I’ve let ride the bike has come back with the same feeling. It’s fast.
The Topstone Carbon takes every (meager) watt of energy I have and makes the most of it, thanks to the stiffness Cannondale engineered into the massive downtube and chainstays. When combined with engineered flex in the seat tube, top tube and seat stays, and the Kingpin pivot atop the seat stays, the frame effectively isolates the rider from the typical jarring and abuse a rider would take on an ultra-stiff frame.
The Topstone Carbon is stiff where it needs to be for drivetrain efficiency and stable handling, yet flexible in other parts of the frame to achieve the desired ride quality.
Does Kingpin Work?
Yes it does, but it doesn’t feel like any other ‘suspension’ bike you’ve ridden. The Kingpin suspension splits the travel between the saddle and the rear axle, so you don’t get any unexpected suspension movement under power. There’s no power loss due to bounce or sag, and the bike feels very normal over smaller bumps. It feels smooth, but you don’t get a sense that there’s overt movement going on as you pedal.
When traversing larger bumps or extended sections of washboard, the Kingpin suspension becomes more apparent as it actively works to mute the vibration reaching the rider. The suspension effect is more apparent when seated than when standing, which makes sense given some of the travel comes at the saddle, through flex in the seat tube, top tube and seatpost.
Some readers have asked how much effect Cannondale’s SAVE seatpost has on the ride quality of the Topstone Carbon. The SAVE post is widely regarded as one of the smoothest riding rigid posts around, so to find the answer, I swapped it out for a rigid alloy post from PRO Bike Gear, and went for a ride.
What I found was interesting. With the alloy post installed, the Topstone Carbon took on a slightly firmer ride quality, but also felt like it activated the Kingpin suspension on smaller bumps more than with the SAVE post installed. I suspect the reason is because the less rigid SAVE post is absorbing more of the chatter before activating the Kingpin suspension. The stiffer alloy post doesn’t flex as readily, so it more quickly puts energy into the Kingpin suspension on smaller bumps and vibrations. As a result, the Kingpin suspension was easier to feel working with the alloy post.
Bottom line: the ride quality is simply different with the SAVE post than it is with the alloy post – not better or worse. The bike rides great regardless of seatpost, but I actually prefer the more direct ride the alloy post offers. To me, that’s proof that Kingpin really works.
Getting a Handle
Cannondale reduced the bottom bracket drop on Topstone Carbon frames relative to its alloy models, one of which we tested and loved earlier in 2019. Initially, I thought this might be a problem, as I typically prefer the handling of bikes with a lower bottom bracket.
For reference, the large Topstone Carbon I’m testing has 61mm of BB drop, compared to 75mm of drop on the same size alloy Topstone. That means at the same saddle height, the rider sits 14mm higher on a Topstone Carbon than on the alloy bike – not an insignificant amount.
Ultimately, my concerns were unfounded. While I can definitely feel that I sit higher up on the Topstone Carbon than I do on other bikes, once rolling, the sensation mostly disappears. It’s replaced by a capable, precise feel, and plenty of confidence and cornering traction. The slightly higher BB height also gives me the ability to rip through our local singletrack on the way out and/or home from gravel rides without fear of clipping a pedal in corners.
For those considering the Topstone Carbon to pull double duty as a gravel and cyclocross bike, the higher bottom bracket could be a difference maker. You can easily pedal through corners that’d trip up a bike with 75mm of BB drop. It’s also a good deal for folks who want to run 650b wheels on the bike.
The 71.2-degree head tube angle isn’t particularly aggressive, but with 55mm of offset in the fork, steering from center is quick, light and easy to control. The geometry makes the bike capable in corners, but for those used to bikes with more aggressive head tube angles and less fork offset, it might take some time to acclimate to the different feel as you lean in. It likes to be told what to do with a confident hand. I’m a big fan of the Topstone Carbon’s handling feel, but for some it might be more of an acquired taste.
A Matter of Balance
Balance from front to rear is an area where the Topstone Carbon could improve. While the fork is by no means harsh, there is a definite difference in the feel of bumps through the front and rear wheels.
I mostly remedied this by installing a larger 45c version of the WTB Riddler tires that are spec’ed on the bike. While the larger tire won’t fit in the rear of the Topstone Carbon frame, the fork passes the tire with at least 5mm of clearance everywhere.
The Hollowgram Si carbon handlebar flexes a bit more than normal bars, but in terms of overall impact absorption, the rear end is doing more to smooth the ride. It’s by no means a deal killer, rather, it’s an opportunity to make future iterations of a great bike even better.
I’d love to try the Topstone Carbon with a Lauf Grit SL fork, but the internal routing of the bike’s front brake line makes such a swap a much more time intensive endeavor than if the hose was externally routed.
How’s the Spec?
The 2×12-speed SRAM Force eTap AXS group is overall very good. With a 1:1 low gear (33:33t) and a 46:10t tall gear, the Topstone Carbon is geared well for the gravel I typically ride.
Shifting is solid and dependable, if a bit noisier than an equivalent Shimano drivetrain. Front shifts to the big chainring and rear shifts to smaller cogs (both taller/harder gears) are two areas where Shimano still holds a slight lead in shift quality. SRAM has virtually leveled the playing field with Shimano in terms of shifting to easier gears, both front and rear.
One issue I have with SRAM’s new eTap AXS road groups is the Flat-Top chain. While I’ve had no problems with the function or durability of the chain to-date, the fact that I can’t replace it with any other chain in a pinch is hard for me to get my head around. The chain also isn’t compatible with all chain tools, and requires a special quick-connector link as well. If you’re a one bike household, that might not be an issue. That said, if you’re like me and have a dozen bikes in your basement, having one bike that needs a special chain and tools is more of a problem.
Cannondale’s Hollowgram 22 wheels feature 22mm tall, 25mm wide (internal) tubeless-ready carbon rims, with 24 butted spokes in the front (laced in a 2:1 pattern) and 28 spokes in the rear (laced 3-cross). Overall, the wheels have stayed true and round with just one minor round of truing after about 200 miles of riding.
I didn’t weigh the wheelset, but they feel very light in hand and spin up and roll very nicely. The rear HG hub has proven DT Swiss internals as well, so it should be solid for a good long time.
To date, I haven’t had any weird creaks from the Kingpin pivot or press fit bottom bracket, though I’ve heard reports of other riders suffering a different fate with their Topstone Carbon bikes. I’ll update this in my At the Finish review, but for now, all is quiet on the Topstone Carbon home front.
Ai For Bikes
One of the more polarizing features of the Topstone Carbon frame is Cannondale’s proprietary Ai offset frame design. Ai offsets the entire drivetrain out (to the right) by about 6mm. This allows them to run 15mm shorter chainstays than on alloy Topstone models, with little sacrifice to tire clearance.
That said, tire clearance on the Topstone Carbon frame isn’t particularly generous by modern standards. You can fit a true 40c (measured) tire in the chainstays, but anything larger will be problematic in anything but dry conditions. While Cannondale claims 40c clearance on the fork as well, I’ve been running that big 45c WTB Riddler with room to spare.
The Ai offset design centers the rim by re-dishing the rear wheel to the left/non-drive side. Obviously the Hollowgram 22 wheels on the Topstone Carbon are built around this different dish. Some aftermarket wheels will also be able to be re-dished to fit into a Topstone Carbon frame, but some will not.
For someone (like me) who has several gravel and/or road bikes in their quiver, the offset frame limits the ability to swap wheels among bikes. For some, this may be a deal breaker, but I suspect most Cannondale aficionados won’t be fazed. After all, the company has used the Ai offset design for several years in a number of their most popular models including the F-Si MTB hardtail and Super X ‘cross racing bike.
The Verdict for Now
Cannondale has another winner on its hands in the Topstone Carbon. For open minded gravel cyclists not encumbered by traditional expectations, it can be a one way ticket to gravel nirvana. If it were a car, it’d be more of a Ferrari than a Cadillac, so its greatest appeal will be with racers and those with a need for speed. That said, the Topstone Carbon is versatile enough that I wouldn’t hesitate to throw on a frame, seatpost and handlebar bag for a quick bike camping trip. It’s fast, but it’s no one-trick pony.
We’ll wrap up our Topstone Carbon Force eTap AXS review with our At the Finish post in a couple weeks. In the meantime, head over to Cannondale.com to learn more about each of Cannondale’s alloy and carbon Topstone models.