Thursday, 29 September 2016

Tech Talk: Cannondale Slate

Cannondale Slate

Once upon a time there were mountain bikes, road bikes and in between a little category called cyclo-cross bikes. If you wanted to ride on the road, you’d buy a road bike, if you fancied thrashing through the woods you’d pick an MTB and if you wanted to take your road bike off road, you were either very optimistic or a total idiot, depending on your point of view. But now, the spectrum is considerably fuller and the gaps between different bike genres have faded away. One of the most obvious examples of that is the Cannondale Slate.

Cannondale’s goal with the Slate was to create a bike that was fun to ride. Not fun to race, or shred, or tour but fun to ride almost anywhere. The idea was a fast-rolling, drop-bar bike that offered comfort and control over a variety of surfaces.

The Frame

Flattened chainstay

The frame is a 6069 Smartformed, TIG-welded aluminum tubing with Cannondale’s signature smooth-finish welds. The company makes use of a variety of mechanical processes and double-pass welding to create the Slate then it uses heat-treatment to maximise the strength and durability of the frame. The Slate frame makes use of Cannondale’s latest BB30A bottom bracket design, a 27.2mm seatpost diameter, and a 142 x 12mm rear thru-axle that threads into a replaceable rear derailleur hanger. Internal routing is provided for the brake and gear cables and is compatible with electronic groupsets. The tubes have flowing shapes with radically vertically flattened chain and seatstays allowing slight flex vertically, constituting the SAVE system for the rear end

Lefty Oliver

You need a few special parts with that fork

Most important to the Slate is the Lefty Oliver fork, a new road specific single sided 30mm travel dual crown suspension fork designed specifically for the Slate. It is air adjustable, with pressure recommendations on a chart printed on the fork leg in case you forget. There is essentially no sag, so that simplifies things as well. The fork has damping control and an easy lockout for climbing, with a blow off platform that will open the valve should you have a hard hit when locked out. The lockout is definitely firmer than the mountain bike Lefty when locked out and features a a carbon body with an aluminum stanchion.

Lefty Oliver Fork
The Oliver fork demands a variety of proprietary parts, starting with the front hub. The front axle is forged as part of the lower leg assembly and the front hub bearings are pressed into place each time the wheel is bolted on. There is no quick-release mechanism for the wheel, but then, there’s no need to remove the wheel to replace the tyre and/or tube.

The Oliver has a proprietary dual-crown and steerer design with a precise-fit that demands a specific head tube length, oversized headset bearings, and a unique stem diameter. The steerer is installed from the bottom-up like a giant pin and is secured by clamps in each crown. There is no adjustment for bearing pre-load so the stem simply slides on top of the upper crown with just 12.5mm of spacers for height adjustment. The unique diameter of the steerer means that the only stems that can be used with the Oliver are those made by Cannondale.


Fork: A bicycle fork is the part of a bicycle that holds the front wheel. A fork typically consists of two blades which are joined at the top by a fork crown. Above the crown, a steerer tube attaches the fork to the bicycle and the handlebars (via a stem) allowing the user to steer the bicycle. The steerer tube of the fork interfaces with the frame via bearings called a headset mounted in the head tube. At the bottom of the fork, dropouts hold the wheel. Usually, either the axle is bolted to the fork, or a skewer passes through a hollow axle, clamping the axle to the fork.

BB30BB30 is a new bottom bracket standard for bicycles. It requires a completely different shell than a standard bottom bracket, one that can fit a press in style bearing. BB30 stands for Bottom Bracket w/ a 30mm spindle. BB30 was originally developed by Cannondale, but left as "Open Source" so anyone could develop off of it.

Chainstay: The tube connect BB house with rear drop out

Seatstay: The tube connect seattube with rear drop out

Thru Axle: TA resemble large pins that pass through holes in the frame and forks tips to secure the wheels. There are no slots in the dropouts so a TA must be removed completely to release the wheel. TA typically thread into the frame or fork tip and have a quick-release lever to assist with tensioning the axle.

Stem: The stem is the component on a bicycle that connects the handlebars to the steerer tube of the bicycle fork. Sometimes called a goose neck,[1] a stem's design belongs to either a quill or threadless system, and each system is compatible with respective headset and fork designs.

Headset: The headset is the set of components on a bicycle that provides a rotatable interface between the bicycle fork and the head tube of the bicycle frame. The tube through which the steerer of the fork passes is called the head tube. A typical headset consists of two cups that are pressed into the top and bottom of the headtube. Inside the two cups are bearings which provide a low friction contact between the bearing cup and the steerer.

Dual Crown: The base of the fork steerer tube, in this case Lefty had a 2 crown like a sportbike fork suspension.


Ride On!

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