Sunday, July 25, 2021

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.


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.

Friday, July 23, 2021

Focus Paralane: Wide Gear Range with Sunrace RX1 Cassette

After I installed the Wolf Tooth Roadlink DM onto the Dura-Ace rear derailleur, the capability of the rear derailleur has theoretically increased. It should now be able to work on larger cassettes, beyond the recommended 30T largest sprocket.

I plan to install the Sunrace RX1 11-36T cassette onto the Focus Paralane, to increase the gear range for better climbing. This cassette comes from the Cervelo Aspero gravel bike, where I used it for gravel riding.

The previous cassette is 11-32T, which is good but I still need one more lower gear for steeper slopes. For 11 speeds, I believe this is the widest cassette that I can go, before the gear steps get too big for comfortable road riding. Remember, this Focus Paralane will also be my primary road bike, as I have installed all my best road bike components on it.

With the rear derailleur modified, the next step is to install this 11-36T cassette and see if it all works well together.

To recap, this 11-36T cassette from Sunrace weighs 351 grams. Not so lightweight, but still acceptable.

A 1.85 mm spacer is needed behind this cassette, as I will be using it on a 11 speed freehub body.

The red coloured lock ring and cassette spiders are the trademark of Sunrace cassettes.

Sunrace cassette installed on the Ascent Zenith Elite carbon wheelset! This wheelset and tires are probably one of the fastest available.

Here is how it looks at the lowest gear, with the rear derailleur fully stretched.

I purposely used a slightly shorter chain to provide higher chain tension, which will reduce chain slap when in the smaller sprockets. In this case, the rear derailleur cage is not over-stretched, so it is OK.

B-tension of the rear derailleur is adjusted to minimize the distance between the guide pulley and the 36T sprocket.

Still plenty of bolt length available on the B-tension screw, as this Roadlink can actually support up to 11-42T cassettes.

Chain position set in the middle of the cassette.

I used a cable tie to fix the Di2 wire to the Roadlink, so that there is no stray wire that can catch on objects.

With this Wolf Tooth Roadlink DM, the Dura-Ace rear derailleur can be used on the 11-36T cassette.

A front single drivetrain provides a clean setup and works for me, as long as you choose your gear ratio and gear range carefully.

After extensive testing, I am happy to report that this wider range 11-36T cassette works well for me. I get to keep all the high gears for relatively fast road riding, and yet I gain one additional low gear for climbing steeper slopes. I lose the 14T that was on the 11-32T cassette, but the jump from 15T to 13T is not an issue.

New gear range with 11-36T cassette

Shifting across all gears is good, except for the most outward gear, which is when I shift from the 12T to the 11T sprocket. For this shift, if I maintain high chain tension while shifting, it will not shift smoothly outwards to the 11T. Instead, the chain will remain on the 12T sprocket, while the rear derailleur has already moved to the 11T position. This leads to chain rubbing sound, until I perform the shift again.

To solve this, I need to reduce the chain tension by pedaling softly for a split second, during this outward shift. This will allow the chain to shift outwards from the 12T to the 11T smoothly with no delay. Most likely this issue is due to the larger distance between the rear derailleur guide pulley and the 11T sprocket, as the whole rear derailleur has been moved downwards due to the Roadlink.

I expect that this problem will become more severe if an even larger cassette is used, such as 11-40T or 11-42T cassette. Therefore, if there is a need for a larger cassette, just change to a MTB or gravel rear derailleur instead, like the Deore XT or GRX versions.

Other than this issue, there are no other shifting problems with this cassette and rear derailleur. Seems that this Roadlink is actually pretty useful and not just a gimmick.

Sunday, July 18, 2021

Focus Paralane: Wolf Tooth Roadlink DM

In the previous post, where I wrote about the full road bike setup on the Focus Paralane, I was still using the Ultegra R8000 11-32T cassette. It is a good cassette with a nice range, when used with a front double crankset. However, with a front single crankset, the gear range is too limited for a broad range of riding conditions.

I had chosen the 40T Stone chain ring to get a good gear range of 34 - 98 gear inches. This makes it well suited to my commuting purposes, but it does mean that the low gear is a bit high for some slopes, such as the steeper ones at Mount Faber or Lorong Sesuai. I'm not a strong rider, so I need all the lower gearing I can get.

While converting the Cervelo Aspero to a front single gravel bike, I realized that the 11-36T Sunrace RX1 cassette is now available, as I have already changed to the 11-42T cassette on the Aspero. This means that I can use the wider range 11-36T cassette on the Paralane, to replace the current 11-32T cassette.

As mentioned, the Sunrace 11-36T cassette has close gear steps of 11T-12T-13T at the top end of the cassette, which is necessary for road riding. If I use this cassette, I will retain the same top gears, but gain one more lower gear, as the 36T sprocket will provide a lower gearing than the current 32T sprocket.

Problem is, the Dura-Ace R9150 Di2 rear derailleur can only be used with 11-30T cassettes, as per recommendations. I was already pushing it beyond the recommended range by using it with the 11-32T cassette. I am quite sure the Dura-Ace rear derailleur cannot be used up to the larger 36T sprocket due to poor shifting performance.

One way is to change to the GRX RD-RX815 Di2 rear derailleur, which is rated up to 34T sprockets. I have also used it with the 11-36T sprocket with no major issues. 

However, I decided to try something different first. I have read about third-party components that can allow your rear derailleur to be used with larger sprockets. They work by positioning your rear derailleur lower down, so that it can reach the larger sprockets. Shifting performance at the smallest sprockets may be affected due to the increased distance from the guide pulley.

Wolf Tooth Roadlink Direct Mount (DM).

Very clear explanation on how it works. Apparently can be used even for 11-42T cassettes!

It is just a longer adapter for the rear derailleur, that will position the rear derailleur lower down.

There are a few different versions of Roadlink or Goatlink, be sure to get the correct type.

Rear side of the Roadlink.

A quick comparison shows that this Roadlink is longer than the stock adapter on the rear derailleur.

The bolt on the rear derailleur needs to be removed, to replace the adapter. A bit similar to converting the rear derailleur from DATT to Direct Mount, but simpler.

Roadlink at the top, Dura-Ace adapter at the bottom.

Different stopper designs, hope it works well!

Roadlink has a hole pitch of over 37 mm...

...while the stock adapter has a hole pitch of just 26 mm. A significant difference.

Roadlink weighs 20 grams...

...while the stock adapter is lighter at just 12 grams.

Dura-Ace rear derailleur with the new Roadlink installed! Looks pretty long.

Weight is slightly increased to 205 grams.

Fits well on the bike. I'm excited to see how well it works with this little modification.

Installation was not difficult, what is unclear is whether this will work well or not. I have to install the 11-36T Sunrace cassette, and see if this modified Dura-Ace rear derailleur can shift properly on that cassette. If it does not work well, my backup plan is to change the rear derailleur to the GRX RD-RX815 that has been proven to work. That will add some weight as the GRX rear derailleur weighs more at 287 grams, although it does come with the clutch mechanism.