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Kingpin Suspension, SmartSense Radar: The Topstone Carbon 1 RLE Has the Goods, Rides it All

Cannondale has a long history of doing things differently, sometimes in ways that seem odd at the time. It refused to use anything but round tubes for a while when road bikes were going aero. They have a left-side only suspension fork, cleverly dubbed the "Lefty." The brand even made its own motorcycle back in the early 2000s.

Cannondale Topstone Carbon 1 RLE(Photo/Seiji Ishii)
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So, when the Topstone Carbon 1 RLE hit my door, I wasn’t surprised that the bike struck me as odd. First, there is rear suspension but no front suspension. I thought that would feel weird. And the top tube, seat tube, and chainstays have strangely shaped tubes. Finally, the SmartSense gadgetry seemed superfluous.

But after 4 months of testing around my local gravel, dirt, and rough country roads, I started seeing and feeling the logic. The bike proved comfortable and was a Swiss Army Knife for backroads riding.

In short: The Cannondale Topstone Carbon 1 RLE (Radar, Lights, and Electronic Drivetrain) was a rural back road and gravel generalist. It could handle hard riding to prepare for gravel events, commute to the coffee shop in town, or take on bags without complaint. And it could do it all with an added level of comfort thanks to the Kingpin suspension. But there were notable quirks.

Cannondale Topstone Carbon 1 RLE


  • Frame material Carbon
  • Fork Cannondale Topstone Carbon
  • Components SRAM Force eTap AXS
  • Wheels 700c Cannondale Hollowgram G-SL 27 Carbon
  • Sizes XS, S, M, L, XL


  • Kingpin rear suspension attenuates bigger hits
  • SmartSense enhances safety
  • No real weight penalty for features
  • Double chainring


  • SmartSense integration limits flexibility
  • Front end steering could be slow for some

Cannondale Topstone Carbon 1 RLE: Review

Kingpin Rear Suspension

Cannondale Kingpin rear suspension
The Kingpin allows the seat stays to pivot on the seat tube; (photo/Seiji Ishii)

Dropped seat stays, including those on Cannondale’s road frames, are known to improve vertical compliance through seat tube flexion. When the rear wheel hits something, lowered seat stays bend the seat tube forward, and the saddle moves back and down. The Cannondale Kingpin suspension system accentuates these movements in a relatively simple way.

Cannondale put a thru-axle and bushings in the seat tube to join it to the seat stays. This junction pivots, allowing freer movement as the seat tube flexes. The brand combines this with purposeful and visibly obvious top tube, chain stay, and seat tube shaping, forming “leaf springs” by reducing certain dimensions to enhance flexing.

Cannondale claims about 30 mm of travel at the seat and 10 mm of travel at the rear wheel. This latter claim is important. It means that the suspension still works when the rider stands and can help with rear wheel traction.

How Did the Topstone Carbon 1 RLE Feel on Dirt?

Cannondale Topstone Carbon 1 RLE
The chain stays, top tube, and seat tube have “leaf spring” profiling; (photo/Seiji Ishii)

First off, the effect of the Kingpin system wasn’t immediately apparent. Cannondale outfits the Carbon 1 RLE with their flexy SAVE seat post and 40c tubeless tires, which I felt absorbed most of the chatter of the limestone lodged in my local hardpacked dirt roads. I normally run 28 psi in the rear and 26 psi in the front for tires of this width.

When I hit larger edges or potholes, I could feel the Kingpin in action. The sharpness of rear wheel impacts was noticeably attenuated. The effect wasn’t in the realm of a rear shock, but it was much more than I could ever attribute to the most vertically compliant carbon frames I’ve ridden.

Cannondale Topstone Carbon 1 RLE rear end
The Kingpin rear suspension system was vertically compliant but maintained a snappy, efficient feel; (photo/Seiji Ishii)

This might not be enough for some, but having a cush rear end usually means dealing with less than efficient power transfer or the lack of the snappy feeling desired for high-performance riding. The Topstone Carbon 1 RLE excelled in keeping the feeling of power transfer and snappiness intact. I attributed some of this to the stout front triangle tube diameters and junctions, especially around the bottom bracket. I was sure the 420mm chain stay length helped, too.

One day, I chose a route with significant chip-seal mileage connecting the dirt roads I wanted to ride. Wanting more road efficiency, I increased my tire pressures to 32 psi in the rear and 30 in the front. I assumed the bike would feel harsher and more skittish on gravel. And in the front, it was.

But at the bike’s rear, the Kingpin system felt more active, and I didn’t feel the difference nearly as much as I did in the front. So, in a way, the Kingpin made more of a difference with higher rear tire pressure.

I admired the simplicity and relative effectiveness of Cannondale’s Kingpin approach and definitely felt it improved comfort and efficiency on dirt roads. But to have those advantages at the rear of the bike and not the front felt strange and somewhat wasteful of such a novel system.

I strongly felt that at least some front-end damping would have made the bike feel more balanced and efficient. But Cannondale does offer a version with a Lefty front suspension fork.

Cannondale Topstone Carbon 1 RLE front end
The flat, wide top of the FSA carbon handlebars proved comfortable in the rough; (photo/Seiji Ishii)

The frame geometry complimented the “soft tail” functionality and usability well. The slightly slacker head tube angle and larger trail number kept the bike feeling stable on fast hardpacked straights that were littered with rain ruts. But the bike still maintained enough front-end responsiveness to not require directed efforts when closing radius turns snuck up on me.

I could tell sharper directional changes were slower than my gravel race bikes if I focused on the front-end characteristics. But on the Topstone Carbon 1 RLE, I thought the added stability fit the bike well due to its wide swath of ability.

The chosen components at touchpoints added to the overall chatter damping of the bike. The Fizik Terra Argo X3 saddle felt too soft initially, but after a few rides, I appreciated the poshness on rough terrain. And the FSA K-Wing AGX Carbon’s wide flat top was super comfortable on the roughest dirt roads.

SRAM Force double chainring
Double chainrings are increasingly rare on gravel bikes; (photo/Seiji Ishii)

I greatly appreciated the double chainring on this bike. It seems like all the newer gravel bikes are 1x, but I always feel like I need in-between gears. And the SRAM Force AXS e-Tap 43/30 chainrings and 10-36 12-speed rear cluster had me smiling from the first mile. I loved being back on a double.

The bike, with all that it entails, didn’t inherit a weight penalty. At 19 pounds, 7 ounces, the large-size tester, as delivered with SmartSense and set up tubeless (no pedals or bottle cages), is within the ballpark for a light gravel bike.

What’s Up With the SmartSense?

Cannondale SmartSense rear radar unit
The SmartSense rear-facing radar unit; (photo/Seiji Ishii)

The Topstone Carbon 1 RLE comes with SmartSense, which expands on the functionality of the Garmin Varia radar systems (and it’s also made by Garmin). A seat-mounted radar and tail light, bar-mounted visual traffic indicator, and headlight are all hard-wired to a battery at the bottom of the downtube.

Just like the Garmin Varia units, Cannondale’s SmartSense provides audible and visual cues to the traffic approaching from the rear. The bar-mounted indicator shows the relative distance and speed of the approaching cars, and the radar system can communicate with Garmin head units and smartphones.

SmartSense adds reactive lighting that adapts to increase visibility to approaching vehicles. The tail light also acts like a brake light, reacting when the bike slows. Additionally, the lights adjust to ambient light, aiding visibility and vision as conditions change.

Cannondale Topstone Carbon 1 RLE front end
SmartSense lighting is reactive to light conditions, approaching traffic, and bike speed; (photo/Seiji Ishii)

I use and like the Garmin Varia system on other bikes, more so in rural areas than urban ones. In the city, my head is on a swivel by default, and I assume there is a car behind me. I appreciate the Vario most when I’m zoning out on country roads with little traffic. The warning of cars when I don’t expect them is much more valuable to me. So, I felt the same about the SmartSense radar system and felt it greatly improved safety out in the sticks.

The full integration of the Cannondale SmartSense didn’t win me over, though. The hardwired system meant I had no choice but to run all the components unless I wanted to go through some hassles. Also, the rear radar unit and tail light made seat bags unviable. I would have appreciated being able to quickly remove parts of the system to save weight or space for bags. And sometimes, I didn’t want to run any part of the system.

Final Words on the Cannondale Topstone Carbon 1 RLE

Overall, I felt that the Topstone 1 RLE was a jack of all dirt road trades. It fared well as a comfortable straight-up gravel or all-road bike. It was a great high-end commuter. And with multiple bottle, fender, bag, and rack mounting options, it would make a super capable bikepacking rig. All this with the benefit of Kingpin in the back and the added safety of SmartSense.

Sure, you could find a better, more specific bike for each of these rural cycling disciplines. And the bike had a few idiosyncrasies. But if I had to choose one bike for anything I might encounter or desire to do in and around my rural Texas home base, the Topstone Carbon 1 RLE would be in the running.

At an MSRP of $7,850, the Cannondale Topstone Carbon 1 RLE definitely sits at the high end of gravel or all road bikes. But it’s a Swiss Army Knife for rural riding, which made it a super handy and fun quiver of one.

a cyclist resting on a guardrail

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