Cannondale's Topstone Lefty is the most advanced gravel bike to date and may be the brand's segment-defining new product.

Front suspension on Cannondale gravel frames is nothing new. Slate brought Cannondale's Lefty fork into the realm of gravel and tarmac riding a few years ago, but this top-stone is a more integrated design. The most significant advance is the addition of suspension on the rear end of the bike.

The Topstone Lefty combines Oliver's single-sided suspension fork with Cannondale's kingpin rear suspension system to provide 30mm of terrain absorption at both wheels, gravel bike that can comfortably travel between road and trail, and with its flex stay design and seat tube pivot, the Kingpin does much of that.

Compared to Slate's Lefty, the new damper adds 60% more rebound range to Oliver's suspension action, which should improve front wheel control over high frequency bumps at speed.

Gentle gravel road descents and urban manhole covers have little effect on the Topstone Oliver. It has a blow-off valve system that keeps the suspension active when needed, even when the forks are locked out.

Cannondale's Oliver forks also feature stop-lock brake mounts. This accommodates flat-mount calipers, minimizes weight, and makes it very easy to remove the front wheel when needed.

In addition to the 30 mm active suspension, the Top Stone is equipped with substantial tires to further enhance traction and ride comfort over the entire terrain range. Two versions are available: a 700c wheel version with a rigid carbon fork and a 650b wheel version with the new Lefty Olivar.

In all sizes except the XS Topstone, the head angle is 71.2 degrees, promoting quicker steering response and a stronger climbing position from the front center of the frame. The seat tube is 27.2mm and can be fitted with an aftermarket dropper post for Topstone riders who get a lot of mileage out of forested singletrack.

Another feature that indicates that Cannondale product planners see the Topstone as a true all-terrain travel bike is the minimalist chain guide. Its function is to prevent the chain from falling off when rolling at speed over roots and rocks.

Cannondale's Topstone 1 uses SRAM's Eagle XO1 eTap AXS 12-speed drivetrain and disc brakes that clamp 160mm rotors. The rims are made of carbon fiber with a 23mm inner diameter from Cannondale's Hollowgram series.This premium Topstone is priced at £6,599.

Combined with a Shimano GRX 11-speed drivetrain and brakes, the Topstone 3 uses WTB aluminum rims instead of carbon. Priced at £3,399. Cannondale's Topstone Lefty is available in sizes XS, S, M, L, and XL.