Cervelo Aspero: WTB Byway 700C x 40 Tires

I have tried quite a few different wheelsets and tires for gravel riding, starting from the Canyon Endurace where I managed to squeeze in a light gravel tire to try it out. As the Canyon Endurace was not designed as a gravel bike, I could only use a Panaracer GravelKing SK 32 with an actual width of 35 mm.  I found that gravel riding is really fun, as I took the bike all around, looking for good gravel trails to try.

In the end, I changed to a Cervelo Aspero gravel bike, as I wanted to use even wider tires. With wider tires, I can use lower tire pressures, which will allow even more grip when going off-road. To maximise the tire width, I used 650B wheels and tires, which are smaller than 700C, so that I can fit in the widest tire possible in the frame. The Hunt 650B Adventure Carbon Disc Wheelset is a very good gravel wheelset, as it is lightweight and with a tight 5 degrees of hub engagement.

Now, what I have not tried is a 700C gravel wheelset with a wide tire. Of course it will not be as wide as a 650B tire, but its bigger diameter may provide better rollover capabilities, much like how a 29" MTB wheel will roll over obstacles more easily than 27.5" or 26" MTB wheels.

After doing some research, I decided to try the WTB Byway tire, which seems to be a fast rolling 700C gravel tire. I'm not planning to ride in muddy terrain, so I don't need deep knobs on the tire. The claimed width is 40 mm, but actual width may vary. Let's find out more about this tire and why I chose it.

WTB Byway, in all black as the tan sidewall version was not available.

Size is 700C x 40 mm, which is about as wide as it will fit on the Aspero. Not sure about the actual width when mounted on the rim.

Best for firmer terrain, as it does not have deep knobs for muddy rides. Also tubeless compatible as is the default for gravel tires.

Continuous rubber along the centerline for smooth rolling on tarmac, followed by fine ribs progressing to deeper shoulder knobs towards the outside of the tire. Looks awesome.

Weighs 461 grams, which is quite a bit more than the GravelKing SK 32 (317 grams), but still lighter than the 650B WTB Venture 47 (550 grams).

Putting inner tubes first to test out the ride, before going tubeless with sealant if this tire is really good. Inner tubes are quite heavy as the tires are wide.

Testing out my new tire installation tool! It really works to hook the tire bead over the rim for the last bit.

As for the 700C gravel wheelset, I used the previous DT Swiss G1800 gravel wheelset, which I first used on the Canyon Endurace. It is a bit heavy, but it will do for testing out these new tires.

New WTB Byway tires mounted on the G1800 wheelset!

Recommended internal rim width is 17 to 29 mm wide. The G1800 wheelset has an internal rim width of 24 mm so it is no problem.

Max tire pressure is 60 PSI, although it will not be necessary to use such high pressures for a gravel tire.

With the slick centre tread, rolling resistance should be good on smooth roads. The small knobs at the sides will provide some grip on light gravel.

Measures 36 mm when mounted on the rim. Narrower than the expected 40 mm.

This might provide some clue as to why the actual tire width is not 40 mm? There is a number 36 molded on the tire, not sure if it means anything.

Actual tire width settles at 37 mm after a few days. This might be a good width for fast gravel riding.

Measuring and comparing the actual tire diameter. I find this measurement method to be the most accurate.

WTB Byway 700Cx40 tire outer diameter is 698 mm.

Here is a tire diameter comparison, for the different tires that I have tried.

700C Tires

GravelKing SK 32: 699 mm

Byway 40C: 698 mm

GP4000 28C: 695 mm

GP5000 28C: 686 mm

650B Tires

GravelKing SK 43: 677 mm

Venture 47: 681 mm

As you can see, the tire diameter for the 700C Byway is about 17 mm larger than the 650B Venture 47, which means the geometry of the bike will change when switching between these two wheelsets and tires. Not sure if this difference can be felt during actual riding, it needs to be tested.

Next, I installed a cassette and disc rotors onto this 700C wheelset, so that I can swap it onto the Aspero for riding.

Since I will be using a MTB 11 speed cassette on a road freehub, I will need this 1.85 mm spacer behind the cassette.

11-42T 11 speed cassette installed on the G1800 wheelset, which is the same ratio as what is used on the 650B Venture 47 wheelset.

Using the XTR MT900 rotors on this wheelset, just to test it out.

All black rims and tires, which looks very different from the Venture 47 tires with the tan sidewalls.

Showing the other side of the wheelset with the MT900 rotors, with black cooling fins. Looks like a normal road wheelset from far.

Next step is to put this wheelset onto the Cervelo Aspero, and go for some gravel riding! I plan to ride the same routes using both the 650B wheelset and this 700C wheelset, to get a good comparison in ride feeling. The idea is to have a fast 700C wheelset for light gravel riding, and a wide 650B wheelset for more technical gravel tracks.