Cervelo Aspero: Road vs Gravel Setup

As you already know by now, my Cervelo Aspero is a dual use bike, which means that it can be both a road bike and a gravel bike. This only requires a wheelset swap, as already demonstrated successfully on the Canyon Endurace.

Although the Cervelo Aspero is designed as a fast gravel bike, there is no reason why it cannot be a good road bike as well. All it needs is a fast set of high profile carbon road wheels and smooth rolling road tires. The frame geometry is very similar to that of an endurance road bike, which means it is not too upright for fast rides. Even though the frameset is quite a bit heavier than the Canyon Endurace, it is acceptable as it is not meant to be a pure climbing bike.

The road wheelset is the same old Reynolds Assault Limited Edition Disc wheelset that came stock with the Canyon Endurace, with Continental GP4000 28 mm wide tires. The actual tire width is about 32 mm due to the wide 21 mm internal rim width. This is a good wheelset that I like very much.

On the other hand, the gravel wheelset that I will use on the Aspero is the new Hunt 650B Adventure Carbon Disc wheelset, with 43 mm wide Panaracer GravelKing SK tires. Although the previous DT Swiss G 1800 gravel wheelset was good, it is for 700C tires, which is not what I want on the Aspero. Instead, I want to take maximum advantage of the big tire clearance on the Aspero, which is why I will use 650B wheels and wide tires.

As shown below, the road wheelset and gravel wheelset are different, which means that I do not need to compromise a single wheelset and tire to fit both road and gravel riding. The road wheelset can be optimized for fast road riding, while the gravel wheelset will be optimized for comfort and traction during off-road riding.

650B wheels are visibly smaller than the 700C wheels. The taller 650B tire is not enough to make up for the difference in rim diameter.

Cassette and Rotor Comparison

Road wheels use a Dura-Ace 11-30T cassette and a Dura-Ace RT900 160 mm diameter disc rotor.

Gravel wheels use a HG800 11-34T cassette and a Deore XT RT800 disc rotor, also 160 mm diameter.

Front Wheel Comparison

Road front wheel, with high profile rim and road tires.

Gravel front wheel, with a smaller 650B low profile rim, but high volume gravel tires.

It is necessary to use the same size of disc brake rotors and number of speeds on the cassette, if you plan to swap wheels like this. Remember, the idea is to make it as fuss-free as possible to convert between a road and gravel bike setup, with just a wheelset change. No adjustment should be needed.

On both wheelsets, the rotor is located at almost the same position, and I was able to setup the brake calipers to accommodate that. Therefore, there is no brake rotor rubbing when swapping between these two wheelsets.


Front Fork Tire Clearance Comparison

Lots of tire clearance at the fork around the 700C road bike tire. This frame can accept up to 700Cx42 mm wide tires.

Lots of clearance radially, when using the smaller diameter 650Bx43 mm tire.

Rear Wheel Setup Comparison

Road rear wheel

Road rear wheel with 11-30T cassette, using the GRX rear derailleur.

Gravel rear wheel with 11-34T cassette, also using the same GRX rear derailleur. There is no need to adjust the rear derailleur setting after swapping wheels.

Rear Chain Stay and Seat Stay Clearance Comparison

Still plenty of tire clearance at the seat stay area, around the wide gravel tires. There will be even more clearance when the road tires are used.

Still lots of clearance around the rear road tire, along the seat tube and the chain stays.

For the gravel tire, there is more clearance with the seat tube due to the smaller tire diameter, but lesser clearance with the chain stays as the gravel tire is wider.

In the picture above, notice that the 4iiii power meter on the left side crank arm manages to clear the frame. There is actually a healthy amount of clearance with the left side chain stay. In fact, there is more clearance than on the Canyon Endurace frame (shown below).

Small clearance between the left side chain stay and the power meter, on the Canyon Endurace.

Initially I thought that the left side chain stay is pushed outwards due to the BBright construction. However, later I realized that it is actually the same as the standard press fit BB construction. At the same time, the left side chain stay also needs to be moved outwards to give wider tire clearance. In summary, the Cervelo Aspero can accommodate wide tires, and still have enough clearance for a left crank arm power meter!

Non drive side view of the road setup

Non drive side view of the gravel setup.

Drive side view of the road setup

Drive side view of the gravel setup

As you can see from the pictures, only the wheelset is changed between the road setup and the gravel setup. Visually it looks quite different, especially the tires. However, the drivetrain is almost completely the same, except for the cassette.

Due to the different tire diameter, the clearance between the bottom bracket and the ground is also different. The gravel setup has lesser ground clearance due to the smaller tire diameter.

There is a diameter difference of 16 mm between these two tires. Therefore, the radial difference is 8 mm. This 8 mm will be the difference in axle height from the ground, and also the bottom bracket distance from the ground. Tire deflection under rider's load is not accounted for in this case.

BB to ground distance for Continental GP4000 road tires (700C x 28): 268 mm
BB to ground distance for Panaracer GravelKing SK gravel tires (650B x 43): 260 mm

The ground clearance of 260 mm may seem to be too low, but it does not give me any problems. I don't encounter pedal strikes when leaning over on gravel or on smooth tarmac. This is likely helped by my usage of 165 mm crank arms, which are 5 mm shorter than the more common 170 mm crank arm length.