Cervelo Aspero: Revised Wheelset and Component Specifications

Finally, I think I have nailed down my ideal tire selection for the Cervelo Aspero, for both road and gravel configurations.

For fast road riding, I will use the Ascent Bikes Zenith Elite, which is a lightweight carbon wheelset with a 50 mm rim height. Paired with fast rolling Continental GP5000 tires, it rides really well!

As for gravel grinding, the wide and comfortable WTB Venture 47 650B tires are used, on a lightweight Hunt 650B Adventure Carbon Disc wheelset. The large air volume offers great suspension and traction on rough and loose off-road surfaces.

Both wheelsets and tires are different from what I initially started with, as I had to experiment to find out what works and what does not.

Initially, during the previous wheelset comparison (Part 2), I found that the 650B tire diameter (WTB Venture 47) was quite a bit smaller than the 700C tire diameter (GP4000). This was different from what I expected, as I have read that the tire diameter of a 700C x 28 mm tire should be similar to a 650B x 47 mm tire. 

I thought that maybe there was a mistake, as there was no way for a wide and tall 650B tire to make up for the difference in rim diameter (622 vs 584 mm, for 700C and 650B respectively).

However, after trying the new GP5000 tires, I found that it was due to the oversized GP4000 tires, which actually made the tire diameter of the road wheelset too big. The 650B tire and wheelset was actually the correct size, not too small.

Therefore, now I have the chance to compare the tire diameter of all three wheelsets.

1) GP4000 tire on Reynolds Assault wheelset (21 mm internal rim width).

2) GP5000 tire on Ascent Bikes Zenith Elite wheelset (17 mm internal rim width).

3) Venture 47 tire on Hunt 650B Adventure Carbon Disc wheelset (24 mm internal rim width).

I will leave out the Panaracer GravelKing SK 650B x 43 mm tire from this comparison, to make it less confusing. If you wish to know more about that, can check out Part 1 of the wheelset comparison.

GP4000 tire on Reynolds Assault wheelset, tire diameter is 695 mm.

GP5000 tire on Zenith Elite wheelset, tire diameter is 686 mm. This is 9 mm smaller than the previous road wheelset.

Venture 47 650B tire on Hunt 650B wheelset, tire diameter is 681 mm. This is 5 mm smaller than the GP5000 wheelset, instead of 14 mm smaller than the GP4000 wheelset.

From this, we can conclude that the GP4000 tires create an oversized tire diameter. Based on Continental's own estimates, a 700C x 28 mm tire should have a standard tire diameter of 686 mm. This is spot on when the GP5000 28 mm tire is mounted on the Zenith Elite wheelset.

Therefore, the final conclusion is that the GP5000 wheelset and Venture 47 wheelset have a tire diameter difference of just 5 mm, which is quite acceptable. The difference in BB height or ground clearance would be half the tire diameter difference, which is negligible to me. I think this is the ideal situation, where the BB clearance, toe overlap clearance and also trail is consistent across these two wheelsets.

Zenith Elite road wheelset with GP5000 tires. All black with high profile rims.

Road vs gravel wheelset. Very different look and capabilities, to suit different riding modes.

Road wheelset has high profile rims and a short tire sidewall, while the gravel wheelset is completely opposite, with a low profile rim and a tall tire sidewall.

Axle height comparison shows them to be almost the same, with the road wheelset just slightly higher up.

Tire diameter is almost the same, as shown from this picture.

Tire width is very different! 27.5 mm vs 47 mm, almost a 20 mm difference in width, and many times difference in air volume.

Gravel front wheel (including tire, sealant, rotor) is 1449 grams.

The road front wheel is almost 300 grams less at just 1163 grams.

Gravel rear wheel is 1895 grams, including tire, sealant, rotor and 11-34T cassette.

The road rear wheel is 380 grams less, at just 1515 grams with 11-30T cassette.

Full and final (maybe not) Cervelo Aspero specifications

Overall weight of the road bike setup without pedals is just 7.4 kg, which is a very nice weight for a hydraulic disc brake road bike.

When converted to the gravel setup, the heavier wheelset adds almost 700 grams to the bike weight, giving a gravel mode bike weight of 8.1 kg without pedals.

Due to the slightly different hub dimensions, the rear disc brake rotor will rub slightly on the brake pad for one of the wheels. The solution is to add a Centerlock rotor shim on the rear hub that has the rotor in a more inward position. The idea is to push out the rotor slightly, so that it is in the same position as on the other rear hub.

Centerlock rotor shim installed on the Zenith Elite rear hub. The shim is 0.25 mm thick.

The shim is sandwiched between the rotor and the hub, pushing the rotor position more outwards.

After adding the shim, the rotor position between the road and gravel wheelsets are almost the same, which makes it possible to adjust the brake caliper, so that the wheelset swap is seamless with no brake pad rubbing on either wheelset.

Finally, some pictures of the Cervelo Aspero, in road and gravel modes!

Looks 100% like a road bike, with the high profile carbon wheelset.

The Ascent Bikes Zenith Elite wheelset rolls really well and suits this bike nicely.

WTB Venture 47 tires on the Hunt 650B wheelset makes this a true gravel bike, capable of tackling all but the most technical terrains.

I used it like a MTB, riding on actual MTB trails. Not the best bike for the job, but it was a lot of fun!

At this point, I would say that quite a fair bit of time was spent choosing and testing the different wheelsets and tires, and I am happy to finally find a combination that I like. Just by swapping wheelsets, the Cervelo Aspero transforms from a pure road bike to a great gravel bike that can take on gravel and light trails with ease.

Is there any other bike that can handle this road and gravel mode transformation as seamlessly? Maybe there is, but I bet the paintwork is not as unique and beautiful as the Teal on this Aspero!