Cervelo Aspero: Tubeless Setup with Schwalbe Tire Booster

One big advantage of using wide gravel tires is the ability to run low tire pressures. With a low tire pressure, the tire can conform easily to the uneven terrain, generating good traction and improving ride comfort.

However, if you are using inner tubes, there is higher risk of getting a pinch flat when running low tire pressures. This is due to the softer tire which can bottom out easily when hitting sharp edges or landing heavily. When that happens, the inner tube will be pinched between the tire and the rim, creating the distinctive "snake bite" marks of a pinch flat.

This happened to me while riding off-road on the previous Canyon Endurace, using the 32 mm wide Panaracer GravelKing SK tires. I was not paying attention and deviated off the path, and although I managed to recover without crashing, I suffered a rear tire pinch flat when the tire bottomed out on the edge of the road. If I remember correctly, the rear tire pressure was about 38 PSI.

Therefore, when I went for even wider gravel tires on the Cervelo Aspero, I wanted to try tubeless tires as well. The WTB Venture 47 tires are tubeless ready, as with practically all decent gravel tires nowadays. With a tubeless setup, there is no inner tube to pinch, which allows low tire pressures to be run safely. This is seen on many MTB where low tire pressures and tubeless setup is commonplace.

One tricky part of tubeless tire setup is the seating of the tire beads onto the rims. As there is no inner tube to push the tire from within, a quick blast of air is needed to push the tire onto the correct inner edge of the rim. If the blast of air is not large or fast enough, air will just leak out from the gap between the tire and the rim.

The solution is to use an air compressor, or for the home mechanics, a canister to store and discharge the compressed air quickly. It is a bit like a giant CO2 inflator, just that the air pressure is lower, but with much greater volume.

There are many such air boosters on the market, specifically catered for seating tubeless tires. I made my choice based on good reviews on this Schwalbe Tire Booster. Let's see how it works and how effective it is.

Schwalbe Tire Booster

Comes with a metal tank with a hose attached, a velcro strap and the instruction manual. The velcro strap is for attaching the air tank to the vertical cylinder of a floor pump if needed.

A Presta valve at the top of the tank allows the tank to be charged, by pumping it up with a normal floor pump.

Once the air inside the tank is of sufficient pressure, you can open the valve to release a large amount of air quickly. This will seat the tire onto the rims properly.

Pump head at the end of the rubber hose can be switched between Schrader or Presta valves.

Before using the tire booster, the rim needs to be prepared. A layer of tubeless rim tape is needed to seal the rim to prevent air leakage. Nowadays if you get a new wheelset, tubeless rim tape is usually already installed. A tubeless valve is also needed, as shown below.

Tubeless valve to be used for tubeless tire setup.

A Presta tubeless valve has a removable core, so that you can push in large amounts of air quickly, and also to inject sealant into the tire.

To charge the air tank, just connect the pump head of your floor pump to the Presta valve at the top of the tire booster. Pump it until around 160 PSI, which is pretty high. This is to ensure sufficient air pressure and volume to seat the tire later.

Once the air tank is charged up, and the hose connected, get ready to turn on the valve!

First try, not successful. Some sections of the tire (top left) is not seated onto the rim. This is because I did not charge the tire booster to a sufficiently high air pressure, which is around 160 PSI.

After charging the air tank again, which is super tiring for the arms, I gave it another go. This time, the entire tire was able to seat fully on the rim.

At this point, the tire beads are already resting properly on the rim. However, if you try to pump up the tire now, you will still have air leaking from the multiple gaps between the tire and the rim. The most tiring part of seating tubeless tires with the air booster is charging the air tank up with a floor pump.

The next step is to add sealant to this tubeless tire setup, so that the sealant can plug and seal the gaps that are invariably present. If you do it correctly, it is actually not messy at all. I read many how-to-do guides and tips on tubeless tire setup, and now I'm going to try it for myself for the first time. If you have a friend who can show it to you, that would be best.

Stan's sealant, one of the best in the business. Might as well get a big bottle instead of a small one, in case I screw up.

Instructions written at the back of the bottle. As you can see, there are different methods to set it up, which mainly depends on your type of valve.

Together with the bottle of sealant, I got the Stan's sealant injector as well, which is basically a syringe that screws onto the valve.

The syringe injector should make it much easier and less messy to inject sealant into the tire.

However, I found that the Stan's injector does not screw on properly to the valve at all. I tried with a few different valves, and they all had the same problem. I think there is a problem with the screw thread on the injector.

Luckily I had not started with the sealant, so I could put away everything and continue another day, until I got a properly working injector syringe.

I came across this sealant injector by KOM Cycling, which is slightly different. Check out the details below.

Sealant injector by KOM Cycling, which works differently from most other sealant injectors.

Contents of the KOM Cycling sealant injector. There is even a valve for controlling the sealant flow if needed.

What's different is the rigid tube shown on the left side, which is narrow enough to go INSIDE the valve, instead of around the outside. This allows sealant to be injected AND also removed if needed.

Usage method is pretty much standard, which is to suck up sealant from the bottle first. The metered syringe makes it easy to measure the amount of sealant that is required.

Now, insert the syringe through the valve, so that the sealant is dispensed directly into the tire, bypassing the valve area. This is supposed to reduce the chance of the valve clogging up.

I never liked this kind of valve core tool, as you can only engage the valve core at 180 degrees apart, which means the spokes always gets in the way when tightening or loosening the valve core.

This smaller valve core tool works much better, as you can spin it around easily. Remove the valve core so that the rigid tube of the syringe can be inserted.

For this tire width of 47 mm, a sealant volume of 60 to 90 ml is recommended.

Insert the tip of the rigid tube into the open valve, and inject the sealant!

As the rigid tube goes through the valve, the sealant does not cling to the inside surface of the valve. Injecting the sealant was easy and mess-free with this tool from KOM Cycling.

If you ever want to remove sealant from the tire, this tool makes it possible, as the rigid tube can reach all the way to the bottom of the tire, and suck out the remaining sealant. It can also be used to measure the amount of sealant remaining, and top up just the necessary amount.

This sealant injector from KOM Cycling is highly recommended, if you want to set up tubeless tires with sealant easily and without mess.

A side benefit of using sealant instead of inner tubes is some weight savings. Each of the Schwalbe SV21 inner tubes for wide 650B tires weigh 200 grams. If you substitute it for a tubeless valve (< 10 grams each) and 60 ml of sealant, you can save around 130 grams per wheel. In other words, a tubeless setup is lighter and more puncture resistant (small holes are sealed automatically), although setup might be more troublesome.

Take note of the additional 500 grams of weight for the gravel setup, compared to the road setup.

The table above shows the weight of my Cervelo Aspero, with the WTB Venture 47 tires set up tubeless. The weight difference from the road wheelset has been reduced from almost 700 grams more, to just 500 grams more. A weight loss of 200 grams by converting to tubeless.

I was pleased to note that this tubeless conversion worked successfully, without making a mess with tire sealant. With the correct tools, tubeless setup is actually pretty easy.

The ride quality with the tubeless setup is instantly noticeable, with it being more plush compared to using inner tubes. At the same tire pressure (eg. 30 PSI), the tubeless setup is definitely softer. I guess the tire deforms more readily without the extra layer of inner tube inside. I have heard that rolling efficiency with a tubeless setup is better, which will be a good bonus as well.

Cervelo Aspero: 700C vs 650B Wheel Size Comparison - Part 2

In the previous post about the Cervelo Aspero, I introduced my new gravel tire, the WTB Venture 47 650B Road Plus. Being a wider tire than the previous Panaracer Gravelking SK 650B x 43 mm tire, there are some differences in size and dimensions.

Let's start with the wheel size comparison between the Venture 47 tire and the GravelKing SK tire. A wider tire is usually taller in profile as well, so I would expect the Venture 47 to have an overall tire diameter that is slightly larger than the 43 mm wide GravelKing SK.

Both tires will be mounted on the Hunt 650B Adventure Carbon Disc wheelset, which has an internal rim width of 24 mm. This is pretty much the standard rim width (in first half of year 2020) for gravel wheelsets.

WTB Venture 47 on the left, GravelKing SK 43 on the right. The shade of brown on the sidewall is different.

The Venture 47 which is at the back is slightly larger in diameter.

This is due to the taller tire profile of the Venture 47, which can be seen by comparing the axle height difference as well.

Close up look at the different tire tread profile. Venture 47 on the left has nice big lugs at the side for good cornering traction.

Width difference of 47 mm vs 43 mm is noticeable as well.

In short, the wider Venture 47 tire is also larger in diameter as well. This is actually a good thing, we I found that the 43 mm wide GravelKing SK was a bit undersized in terms of tire diameter, compared to standard 700C tires.

Another comparison to be done is with the standard road setup wheelset, which has Continental GP4000 28 mm tires mounted on the Reynolds Assault Limited Edition carbon wheelset. Apparently a 700C x 28 mm tire should have roughly the same tire diameter as a 650B x 47 mm tire.

I think the calculations may have been something like this, where the rim diameter is added to the tire width/height to get the overall diameter. Not sure how accurate or true this is.

700C x 28 = 622 + 28 + 28 = 678 mm

650B x 47 = 584 + 47 + 47 = 678 mm

584 mm and 622 mm are the ETRTO rim diameter of 650B and 700C rims respectively.

Road wheelset vs new gravel wheelset

Road wheelset shown at the back is still larger than the 650B gravel wheelset.

Tire tread pattern is totally different!

Huge difference in tire width as well. Actual tire width of the road tire on the left is 32 mm, vs 47 mm on the right.

Here are some numerical data of the actual measured tire diameters, with the different tires and different wheelsets.

Continental GP4000 700C x 28 (actual 32 mm): 695 mm diameter
Panaracer GravelKing SK 650B x 43: 677 mm diameter
WTB Venture 47 650B x 47: 681 mm diameter

There is still a 14 mm diameter difference (7 mm radial difference) between the road wheelset and the gravel wheelset (with Venture 47 tires), which is a noticeable amount. I would say that instead of the gravel tires being undersized, it is the GP4000 tires being oversized, as the actual width is 32 mm instead of the rated 28 mm.

I suspect that this older generation of GP4000 tires were designed on narrower 15-17 mm wide road rims, so when installed on the wider 21 mm Reynolds wheelset, the actual tire width balloons out from 28 mm to 32 mm.

As a result, the BB to ground clearance is also affected by the different tire diameters.

BB to ground distance for GP4000 700C x 28 (actual 32 mm): 268 mm
BB to ground distance for GravelKing SK (650B x 43): 259 mm
BB to ground distance for Venture 47 (650B x 47): 261 mm

7 mm less ground clearance for the Venture 47 gravel wheelset, compared to the GP4000 road wheelset.

No wonder it is confusing for consumers to select the correct tire and wheels, as the actual width and actual diameter can vary so much, depending on your combination of tire and rim which is practically infinite.

Wahoo Kickr Core: Usage

Carrying on from the first part of the Wahoo Kick Core introduction, this post will show the direct drive smart bike trainer in more detail.

In the first part, the bike trainer was assembled, but the cassette has not been installed yet. The axle adapters also need to be selected and installed, in order to mount the bike. Let's see how this is done.

Without any adapter in place. This recessed area will hold the selected axle adapter.

With the 12 mm thru axle adapter installed, for 142 mm width. If this adapter is reversed, it will be for 148 mm width, which is for boost type MTB.

On the other side, the 12 mm thru axle adapter is installed. This same adapter is used regardless of whether the bike OLD is 142 or 148 mm.

With the cassette installed! I selected a Shimano 105 CS-R7000 11-28T 11 speed cassette, as it is cheaper and does not wear out as quickly as a titanium Dura-Ace cassette. Any additional weight is irrelevant on the bike trainer.

View of the bike trainer with the cassette installed.

When plugged in, the indicator lights will turn on. This bike trainer can connect via ANT+ or Bluetooth.

Comparing the axle height from the ground, between the bike trainer and the actual bike. I'm surprised to find that the actual height of the bike trainer is slightly lower than the actual bike!

Cervelo Aspero installed on the bike trainer! I placed a spacer between the rear brake pads, so that the piston does not pop out if I accidentally press the brake lever with no rotor in place.

Due to some differences between the bicycle wheel freehub and the bike trainer freehub, there may be a need to adjust the rear derailleur index position when switching between the wheel and the trainer. With a Di2 rear derailleur it is easy, you just need to take note of how many clicks to adjust it. With a mechanical rear derailleur this can also be done, you just need to take note of how many clicks is needed to adjust the barrel adjuster on the rear derailleur.

When the bike is installed on the bike trainer, the RD position needs to be offset outwards for proper indexing. This will vary between bikes.

Full view of the bike on the bike trainer. A front wheel block is not necessary as the rear axle height is almost the same as the front axle height.

A direct drive bike trainer uses the same drivetrain on the bike, just with a different cassette that is on the bike trainer.

The good thing about the bike trainer is that it can be switched between different bikes easily, provided the axle requirements are standard (130/135 mm QR or 142/148 mm E thru), and the number of speeds are the same.

Therefore, it is easy to put on the Dahon MuSP folding bike as well, as it has a 11 speed drivetrain too.

1x11 speed Dahon MuSP on the Wahoo Kickr Core bike trainer. The axle adapter needs to be switched to the 130 mm QR type.

Closer view of the bike mounted on the bike trainer. The rear wheel is higher up than usual due to the different wheel sizes.

The rear axle to ground distance is measured to be about 33 cm.

Using the front wheel block and a suitable book, the front axle is propped up to roughly the same height as the rear axle. I think a difference of +/- 1 cm should be fine.

Getting ready for a ride on Zwift! Water bottles and a towel is a must, while a good fan is strongly recommended.

The Wahoo Kickr Core provides the controllable power meter and also the cadence. Heart rate is via my Samsung Galaxy watch which can transmit heart rate over Bluetooth. Both the watch and bike trainer connects to my phone.

After a good tough ride! If you don't already know, a Zwift ride is usually tougher than outdoor rides as you can't rest at all.

Check out the gradient! This is pretty much my max effort as my heart rate is already so high.

Another one of the weekly West Coast Riders virtual ride.

Other than joining others on virtual rides, it is also possible to ride structured workouts on Zwift. What it means is to choose one of the pre-determined workouts, where the power and cadence targets are set for you. You can adjust the targets according to your ability. Once done, you can use the ERG mode to control the training effort.

ERG mode is only available on a smart bike trainer, where the software can control the bike trainer to vary the resistance level. Power is basically a function of cadence and pedaling force. You can achieve the same power either by pedaling hard at a slow cadence, or pedaling lightly at a fast cadence.

What ERG mode does is to adjust the resistance such that your power output is constant. For example, if your target power is 175 watts, the bike trainer will automatically provide a certain amount of resistance in response to your cadence. Usually there is a cadence target as well, so you just need to focus on achieving the required cadence, and the resistance will be adjusted for you automatically to hit the power target. There is no need to shift gears in ERG mode.

Training in ERG mode. Note the stable power output at the bottom of the screen. And the horrible 16% gradient as well.

The only way to get such perfect power graphs is via ERG mode. It is very good for consistent training as there is a target to work towards.

So far I am loving the Wahoo Kickr Core, as it works as well as advertised. I shall list out some of the good and bad of this bike trainer.

Good:

1) Quiet. Slight whirring sound, but easily drowned out by the drivetrain sound or the fan. Much quieter than the previous Minoura LR340 bike trainer.

2) Smooth and balanced flywheel rotation, for a freewheeling effect.

3) Easy to connect to my phone and Zwift via Bluetooth.

4) ERG mode is super awesome for consistent training purposes.

5) QR and thru axle adapters makes it possible to switch bikes easily.

6) Works as both a power meter and also cadence sensor.

7) Enables riding regardless of weather.

8) Does not wear out your tire, although it still wears out your drivetrain.

Bad:

1) Heavy at 19 kg. But this is due to the heavy flywheel which is apparently necessary to replicate realistic road feel.

2) Expensive at SGD 1,399.