Wednesday, July 22, 2020

Cervelo Aspero: WTB Venture 47 650B Gravel Tires

As you already know, I like gravel riding, as it allows me to explore unpaved roads anytime I come across them. Previously I have tried the 700C x 32 mm Panaracer GravelKing SK tires on the Canyon Endurace, followed by the 650B x 43 mm version on the Cervelo Aspero gravel bike.

The GravelKing SK tires are nice and fast rolling, even on the roads. On light gravel trails they are fantastic as they roll really well. However, they tend to lose grip when cornering fast on loose surfaces. The result is a sliding rear end that can feel disconcerting if you are not expecting it or ready for it. This is due to the absence of raised side knobs on the tires. 

Also, the 650B x 43 mm tires were true to size, measuring 43 mm on the Hunt 650B Adventure Carbon Disc wheelset. I had purposely chosen the smaller 43 mm version, as I was expecting it to get wider once installed on the 24 mm wide Hunt rims. Since it didn't expand as I expected, I was not maximizing the tire clearance on the Cervelo Aspero frame. I would have gotten the wider 48 mm version if I knew it would be true to size.

So, I have two main reasons to change the gravel tires. The first being that the GravelKing SK does not corner as well as I like, while the second reason is because it is not maximizing the tire width available on the Aspero frame.

The Aspero frame has a maximum frame clearance of 57 mm when using 650B tires. With a recommended 4 mm clearance on either side of the tire, the maximum 650B tire width allowed is 49 mm.

After reading many tire reviews, it seems that the WTB Venture 47 650B tires may just be the tire that I am looking for. Let's take a closer look at these tires.

WTB Venture 47 650B tires. Of course I must get the brown sidewall version for the gravel look.

WTB calls 650B tires as Road Plus tires. The highlight are the rows of outer knobs for extra grip during cornering.

Tightly packed centreline for fast rolling, with lots of soft flexible ribs for grip on rough surfaces, and large side knobs for cornering traction.

Due to some quirk of manufacturing, they are labeled as 44-584 tires, which is different from the 47 mm tires that they are advertised as.

These tires are heavy! At 550 grams, they are 300 grams more than a typical 28 mm wide road bike tire. This is due to having much more rubber and width on the tire.

When mounted on the wheels, this is the actual tire profile. Ideally, only the centreline portion will touch the road when riding on smooth paved surfaces.

Lots of flexible ribs for extra grip on loose and uneven terrain.

Actual tire width is just over 47 mm when measured across the knobs. This leaves about 5 mm of tire clearance on either side of the tires.

If you measure without the knobs, it is about 45 mm wide.

WTB + Hunt! Tire height is a lot taller than the shallow Hunt rims.

Venture 47 650B Road Plus is the model of this WTB tire.

Both tires installed onto the Hunt wheelset. With inner tubes for now.

Looking good! Very gravel-like appearance.

Front wheel weighs a massive 1538 grams, inclusive of wheel, tire, inner tube and rotor.

Rear wheel weighs exactly 2 kg, including the wheel, tire, tube, rotor and also the 11-34T cassette.

As you can see, having a gravel wheelset with wide gravel tires is heavy, mainly due to the heavier tires and larger inner tube required. Any weight savings from a smaller 650B wheelset is totally cancelled out by the tire weight. On the other hand, a MTB tire weighs even more, so a gravel tire that weighs 550 grams seems lightweight in comparison.

6 mm side clearance between the front tire and the front fork. Lots of clearance in the radial direction too.

Lots of clearance at the rear seat stays as well.

Another view of the tire clearance at the rear seat stays.

5 mm tire clearance at the chain stay area, which is the area on the frame that has the smallest clearance. I'm very comfortable with this amount of clearance.

View of the rear wheel with WTB Venture 47 650B tires.

Here is how the whole bike looks with the wider and more aggressive Venture 47 tires!

View from the drivetrain side. I really like how the change of wheelset totally transforms the bike's character.

The tires in its natural habitat! Works super well on loose gravel and sand as seen here.

With these new tires, I am able to corner faster with more confidence, as the pronounced side knobs are effective in providing traction during cornering.

A downside of having lots of flexible ribs is that lots of small stones are collected between the ribs. Doesn't bother me too much, as they tend to fall out on their own after some riding.

Full list of component weights, updated with these WTB Venture 47 tires.

Cervelo Aspero in road bike setup is 7.6 kg without pedals, which is decent but not really lightweight. My personal benchmark is still the Canyon Endurace, which weighs just 7 kg without pedals. When converted to the gravel setup, it adds almost 700 grams, due to the heavier tires, inner tubes and cassette.

Cervelo Aspero road setup without pedals: 7.6 kg

Cervelo Aspero road setup with pedals: 8.0 kg

Cervelo Aspero gravel setup without pedals: 8.3 kg

Cervelo Aspero gravel setup with pedals: 8.7 kg

The gravel setup is now approximately 200 grams more than the previous setup with 43 mm wide GravelKing SK tires. I guess it is the price to pay for wider tires that weigh even more.

On the other hand, the off-road capabilities have been greatly enhanced. With wider tires, I can run even lower tire pressure, which enhances off-road grip. The taller side knobs of the Venture 47 tires also improves the cornering traction. In fact, this gravel setup should have no problem tackling mild MTB trails, such as Track 15 or some stretches of the Bukit Timah MTB trail.


  1. Given the WTB tires support tubeless, what is your thinking behind running inner tubes, especially when bike weight seems such an important factor to your build.

    1. Later on I changed the tires to using tubeless, just haven't written about it yet.
      There is some weight savings by changing from inner tubes to sealant.
      The main aim is to improve ride quality and be able to run even lower tire pressures without getting pinch flats, although the weight savings is a nice side benefit.

  2. what tire pressure are you running with those tires?

    1. For actual off road riding, about 25 front and 30 rear. For gravel, about 5 PSI more at 30 front and 35 rear. For road, about 35 front and 40 rear.

  3. hi thanks for this blog, i'm looking for similar wheel size and tire, whats the height of the tire when inflated? is it about the same as the width? thanks

    1. Check out this other post showing the wheel diameter.


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