Friday, March 26, 2021

Focus Paralane: Shimano WH-RS770 Wheelset and GP5000 Tires

The new Focus Paralane all-weather road bike will need a new pair of wheels. My previous all-weather road bike was the Fabike C3, but that wheelset with Alfine 11 Di2 internal hub is not suitable for this new bike. Although the DT Swiss front wheel can be used, I would rather get a pair of front and rear wheels that matches.

What I needed is a proper road wheelset, with 12 mm E-thru axles and disc brake hubs. This was what I had, the Reynolds Assault wheelset. However, I had already sold it, which I regretted a lot. At that time, I did not plan to use it on any other bike, since I already had the new Zenith Elite wheelset from Ascent Bikes. Therefore, I decided to sell the Reynolds wheelset to free up some space at home.

If I did not sell that Reynolds wheelset, it would have been perfect for this Focus Paralane, as a used carbon wheelset for all-weather duties.

Therefore, I had to get a new pair of disc brake compatible, 12 mm E-thru wheels. I did not want to fork out over $1000 for a pair of carbon wheels, for all-weather riding. Therefore, I went for the more budget option, which is a pair of aluminium wheelset.

This Shimano RS770 wheelset is a peculiar wheelset, as the rim is made of a hybrid of carbon and aluminium. More details below.

Looks totally like a low profile lightweight carbon wheelset. I like the stealthy look of it.

It has a wavy rim shape, similar to Princeton CarbonWorks wheelset. Probably a coincidence...

The rim is actually made of aluminium, but reinforced with a layer of carbon on top. Probably only Shimano is mass producing this type of rims.

Why does Shimano use carbon reinforced aluminium rims? This actually dates back to some years ago, when carbon wheelsets for rim brakes were getting popular. At that time, road bikes were predominantly on rim brakes, therefore the braking surface is still on the rim.

Some other manufacturers have a full carbon rim, which means that the braking surface is made of carbon. This tends to have poorer brake performance and heat dissipation properties compared to conventional aluminium rims.

Shimano wanted to make carbon rims, but still retain the superior braking performance of aluminium rims. Therefore, this hybrid construction was created, so that the braking surface is still aluminium, but the rim profile can be made thinner in aluminium, and cladded with carbon fibre for strength and also appearance. Check out the Dura-Ace WH-7900 C24 wheelset to see what I mean.

Somehow, this construction has endured even to this day, on the mid-range disc brake wheelset, as shown here by WH-RS770. It is Ultegra grade, but not labelled under the Ultegra series. There is no advantage to having the aluminium braking surface on the rim, since disc brakes are used.

Black spokes and spoke nipples are used, to match the black rims.

Although the braking surface seems to be present on the rim, it is not to be used.

The wheel comes with tubeless rim tape already installed.

However, the end of the rim tape was not pressed down properly, and tends to detach. If an inner tube is used, it is not a problem. However, if a tubeless setup is used, sealant will get underneath the tape and may leak.

External rim width is 22 mm, which is old school. Nowadays external rim widths are easily 28 mm or more.

Internal rim width is old school as well, at just 17 mm. Most new road bike wheels now have a wider internal rim width of at least 19 mm, or 21 mm.

Rim height at the shallowest areas are 28 mm.

If measured at the taller areas, the rim height is 30 mm.

The hubs look nice with a shiny anodised silver finish, with black areas as well. Still using traditional cup and cone bearings, but for 12 mm E-thru axles.

Centerlock disc brake mounting, which makes installing or removing rotors so much easier compared to using 6 bolt type.

WH-RS770 is the model number of this wheelset. Bladed straight pull spokes are used.

Rear wheel has a steel freehub body, to prevent gouging caused by the steel sprockets. Adds some weight over an aluminium freehub body, but lasts much longer.

Weight of front wheel is 743 grams, heavier than the Zenith Elite but lighter than the Reynolds Assault.

Rear wheel is pretty heavy at 923 grams, due to the steel freehub body and cup-and-cone bearings.

This gives a total wheelset weight of 1666 grams, which is slightly more than the Reynolds Assault (1637 grams) and heavier than the Zenith Elite (1504 grams). Not too bad for an aluminium wheelset!

Using the same Continental GP5000 tires on this wheelset as well, for maximum speed.

GP5000 tires on the RS770 wheelset. However, a silver band can be seen at the interface between the rim and the tire.

This silver band is from the exposed aluminium at the top edge of the rim, which is not covered by the carbon fibre layer.

This silver line does not look good, as it spoils the integrated look of the wheelset and tire. Does not affect function, but it lowers the aesthetic value of this wheelset. Will do something about it later.

Actual tire width is about 27 mm, when mounted on this wheel with 17 mm internal rim width. In comparison, actual tire width is 28.5 mm when mounted on internal rim width of 21 mm.

Added the Dura-Ace RT900 rotors as well. Now it looks fast!

Comparing the RS770 wheelset with the Zenith Elite wheelset, both with 28 mm GP5000 tires. Rim height is obviously different. The silver line on the RS770 wheelset stands out too much, unfortunately.

For pure academic purposes, I installed the previous Continenal Grand Prix 4 Season tires on this new rim as well.

Using Continental Grand Prix 4 Season 28 mm tires on different internal rim widths:
20 mm rim --> 31.8 mm actual tire width
18 mm rim --> 30.8 mm actual tire width
17 mm rim --> 30.8 mm actual tire width

As you can see, the previous generation of Continental tires are generally oversized, even when mounted on narrow rims. The new generation (GP5000) is more true to size.

Later on, after the wheelset is installed on the full bike, I will be able to evaluate the ride quality of this RS770 wheelset with GP5000 tires.

Friday, March 19, 2021

Lezyne Sport Gravel Floor Drive vs Steel Floor Drive

Just when you thought you already had everything gravel related, such as a gravel bike, gravel drivetrain, gravel tires, gravel shoes, etc, here comes another item.

This time, it is a gravel specific floor pump. The first time I heard of a gravel specific floor pump, I was quite amused, as the normal floor pump for road bikes works for gravel tires in any case.

However, once I started reading more about gravel floor pumps, it seems to make sense. For example, 28 mm road bike tires only need about 80-100 PSI, but the usual floor pumps go up to 220 PSI, which is way beyond what is required.

As such, the pressure gauge has all the numbers squeezed closely to fit in up to 220 PSI of range, but only about 100 PSI is needed. The pictures below will show you what I mean.

Let's do a comparison between my trusty Lezyne Steel Floor Drive, vs the new Lezyne Sport Gravel Floor Drive (gravel floor pump in short).

Lezyne Sport Gravel Floor Drive, with a maximum pressure rating of 100 PSI.

Instead of having a Presta/Schrader reversible pump head, it has a special head where one side threads onto the outside of the valve. More details below.

Side by side comparison, with the new gravel pump shown on the right.

Gravel floor pump is slightly taller, otherwise they look pretty similar.

Both pumps have a wooden handle, which is nice. However, the gravel pump's handle has been dyed black.

Both barrels are steel, but the gravel pump barrel has a slightly larger diameter and has a matte finishing.

The base area looks quite different, although they are both of the tripod design.

The gravel dial is huge! Also, since the gravel dial reads to a maximum of 100 PSI, it is much easier to fine tune the air pressure.

Steel Floor Drive dial: Max of 220 PSI, with lines at every 5 PSI interval
Gravel Floor Drive dial: Max of 100 PSI, with lines at every 1 PSI interval

Ever since I used 28 mm wide Continental GP4000/GP5000 tires, the maximum tire pressure that I needed was 90 PSI, but usually 80 PSI is enough. Therefore, this gravel pump is able to satisfy my tire pressure requirements.

With the indicator intervals of just 1 PSI, I can adjust the tire pressure accurately for gravel tires, where my usual tire pressure range is 25 to 35 PSI. For low pressure tires, a pressure difference of just a few PSI can be felt. Previously on the Steel Floor Drive, tire pressure control was vague, but now I can set it to within 1 PSI accuracy if I want.

Gravel pump uses a fibre reinforced resin base, instead of a steel base.

The resin base is big and strong with reinforcing ribs, but still not as stiff or stable as a steel base.

I wanted a steel base for a floor pump, as it makes the pump more stable due to the heavier base. There is no need to get a floor pump that is lightweight, as a heavier one is actually better for stability. However, it seems that Lezyne is gradually changing their pump base design to use resin material, which I believe is due to lower cost.

Steel floor drive weighs exactly 1600 grams.

Gravel floor drive is a bit lighter at 1521 grams.

There is no meaning to get a lightweight floor pump, unlike a portable pump where a lighter pump adds less weight to the bike. In this case, a heavier floor pump is actually preferred, but not available.

Moving on, let's compare the pump heads.

Red ABS 2 pump head from the steel floor drive, vs the black ABS 1 Pro pump head from the gravel floor drive.

I don't think I ever did a review for the Lezyne Steel Floor Drive, so I shall elaborate a bit more on the pump head. A few years ago, Lezyne came out with this new ABS 2 pump head, where instead of screwing the pump head onto the valve, you slide a sleeve on the outside of the pump head. After sliding the sleeve, you turn it slightly to secure the airtight seal.

Theoretically, this makes attaching and detaching a pump head faster than screwing it on and off. Plus, it has an added benefit of preventing the valve core from being unscrewed from the valve during pump head removal. This can happen if the valve core was not tight enough, while the pump head is attached too tightly.

Practically, this works well if there is plenty of spoke clearance around the valve, as both hands are needed to hold and slide the sleeve onto the valve. Sometimes it can be quite tight, making it difficult to attach or remove the pump head. I always find it difficult to attach this pump head to the valve which is on the wheelset of the Bike Friday Haul-A-Day, due to the high spoke count and small rim diameter.

Also, this ABS 2 pump head depresses the valve core continuously on the Presta valve, meaning that if you press the pressure release button at the side, it will let out ALL the air in the tube, instead of only the air inside the pump hose. On previous pumps with ABS 1 pump head, pressing this button releases only the air in the pump hose, making it easier to unscrew the pump head.

ABS 2 pump head, with an external sleeve that you slide down to tighten the pump head onto the valve.

Converting to Schrader is easy. Just slide down the sleeve first, BEFORE screwing it onto the Schrader head. This is one advantage over traditional screw type pump heads where it needs to be removed and inverted.

ABS 2 Pump Head
1) Quick to attach and release, given sufficient spoke clearance
2) Easy to switch between Presta and Schrader
3) Does not loosen valve cores

1) Needs more spoke clearance around valve
2) Can be difficult to attach on some valves
3) Bleed button releases all the air from the inner tube, instead of just the pump hose
4) Sleeve can be slippery, making it difficult to slide on, especially if it is tight
5) Does not work on valves that are too short as there is nowhere for the internal rubber ring to grip
6) Pump head needs to be detached quickly to prevent air leakage during removal
7) Makes a loud popping noise during pump head removal

The ABS 2 pump head has been discontinued, probably due to having too many disadvantages compared to advantages. Lezyne claims that it is discontinued due to having too many internal moving parts to work reliably.

Now, the new Lezyne pumps are equipped with an updated version of the original ABS 1 pump head, which is called ABS 1 Pro. It is the screw on type of pump head, which may have the tendency to loosen valve cores if they are not tightened properly.

ABS 1 Pro pump head on the gravel floor drive.

Pump head is detachable and reversible.

On one end of the pump head, it is the familiar Presta thread, which threads onto the valve core. On the other end, instead of a Schrader head, it has a M6 x 0.8 mm screw thread, which is the thread size on the OUTSIDE of the Presta valve.

On the Presta valve, there are two threads. The smaller one on the valve core, and the larger M6 x 0.8 mm thread at the bottom.

The purpose and idea of having this M6 x 0.8 mm thread is to allow the pump head to be screwed onto the Presta valve, with the valve core removed. This way, there is no valve core restricting the airflow through the valve.

On tubeless wheels, the Presta valve is just a valve attached to the rim hole, with no inner tube. Theoretically, with the valve core removed, and the M6 x 0.8 mm pump head side attached, it is possible to inflate and seat the tubeless tires, without the use of an air compressor or compressed air tank. I have not had a chance to test this out, but if this works, then there is no need to use my Schwalbe Tire Booster to seat tubeless tires any more.

Other pump heads that are included: The needle head for balls, and the yellow plastic head for balloons and other stuff.

Without a Schrader adapter, this also means that the gravel pump is not able to pump up inner tubes with Schrader valves, if you only have the stock pump head. In my case, it is not necessary, as all my bikes are using Presta valves.

However, I do have extra Lezyne pump heads (ABS 1), which is the usual Presta/Schrader reversible pump head. That fits nicely onto this Lezyne gravel pump as well, if I ever need to connect it to a Schrader valve.

Lezyne ABS 1 pump head, with a reversible Presta/Schrader design.

The internal profile depresses the recessed pin in the Schrader valve, which works differently from Presta valves.

Here is a nice summary showing the history of the different pump heads used by Lezyne. Ultimately the ABS 2 pump head used on my Steel Floor Drive has been discontinued, so only the ABS 1 Pro pump head (screw type) are now available.

Favourite Features of the Gravel Floor Drive:
1) Large dial with indicator lines at 1 PSI intervals, makes it easy to fine tune the air pressure for gravel tires.
2) ABS 1 Pro pump head is still preferred over the ABS 2 design, as it is easier to use.

I don't miss the extra pressure range of the old steel floor drive, as I don't need to pump over 100 PSI (except when I was using the narrow Schwalbe One 23-451 tires, where 120 PSI was recommended).

In all, I am happy with the Lezyne Sport Gravel Floor Drive, with the major advantage being the large pressure gauge and more precise tire pressure adjustment.

Saturday, March 13, 2021

Cervelo Aspero: Trail Mixer Positions

Right from the start, when I first got my Cervelo Aspero, I have been using the Trail Mixer in the rearward position. This increases the trail which enhances the stability of the bike.

While swapping around with different wheelsets, I encountered some problems with the alignment of the Trail Mixer. It is very difficult to get a good alignment, due to some part interference and hole misalignment issues. You can read all about the details in this blog post.

That was the reason why I did not switch the Trail Mixer to the forward position to try, as it was so difficult and time consuming to set the Trail Mixer properly, once it is loosened.

Recently, I managed to get a customized jig made, which will help with the alignment of the Trail Mixer. More details to be shared below.

Before that, let's check out the existing Trail Mixer position, which is in the rearward position.

Trail Mixer in rearward position. Note that a special brake adapter is needed to push out the brake caliper, to match the rearward axle position.

Another look at the Trail Mixer, and also the special brake adapter by Cervelo.

Some Aspero owners report that they do not have the special brake adapter, which means that they can only use the Trail Mixer in the forward position.

Now, I will be switching the Trail Mixer to the forward position, and see what is the difference in riding feeling compared to the rearward position.

If using the Trail Mixer in the forward position, the standard brake adapter that comes with the brake caliper will be used. Here is how it looks side by side.

The problem I faced with the Trail Mixer is that when I tighten the 2 small bolts at the side, it will cause the Trail Mixer to move during tightening, causing it to be misaligned. As the hole tolerances are tight, even a small misalignment will prevent the hub axle hole and Trail Mixer hole from lining up properly. The result is that the thru axle is unable to be inserted smoothly and fully.

I needed to be able to tighten the 2 small bolts, when the hub axle is aligned in the dropouts. However, the hub itself is big and will prevent the 2 small bolts from being tightened.

What I need is to be able to tighten the bolt, with the hub placed into the dropouts. This will ensure perfect alignment. However, there is no space to tighten the bolt in this condition.

The solution that I have is to use a dummy axle, which will simulate a hub axle in terms of dimensions but not the size. Then, I will be able to tighten the 2 small bolts with the dummy axle installed, ensuring perfect alignment.

Dummy axle with internal diameter of 12 mm and external diameter of 19 mm. Length is 100 mm.

Designed to fit the standard 12 mm thru axle with very small clearance.

Dummy axle placed into the dropouts, with the 2 small bolts of the Trail Mixer loosened.

Insert and tighten the 12 mm thru axle, so that it compresses the dummy axle. This ensures perfect alignment of all the holes. The Trail Mixer is free to move slightly for self-alignment, as the 2 small bolts are not tightened yet.

Then, tighten the 2 small bolts to lock in the position of the Trail Mixer.

This solution works really well! With the dummy axle ensuring perfect hole alignment during tightening of the 2 small bolts, there is no more issue with thru axle insertion. Finally I can say that I have solved the annoying Trail Mixer issue permanently.

Trail Mixer in the forward position for less trail, and standard brake adapter in use.

Bringing the bike out for test riding, with the Trail Mixer in the forward position.

Looking good on gravel!

I did some test riding on both the road wheelset and gravel wheelset, and compared the riding feeling. It is hard to quantify the differences between forward and rearward Trail Mixer position, but it is clear enough that the difference can be felt.

Trail Mixer position with Road Wheelset
Rearward: Stable at high speed, able to ride without hands. Slightly sluggish in turning.
Forward: Tends to be more twitchy, but highly maneuverable. Behaves like a normal road bike.

Trail Mixer position with Gravel Wheelset
Rearward: Good stability when rolling down off-road slopes. However, difficult to execute sharper turns on tight switchbacks.
Forward: Needs more attention during high speed descents as it is less stable. However, great for making sharper slow speed turns over rough terrain.

As you can see, the differences are pretty much what I expected, from a difference in trail of about 5 mm. The difference is not day vs night, but it is enough to be felt. The side benefit is slightly more toe clearance due to the front wheel being located 5 mm further forward.

Note that both wheelsets are similar in size, especially since the 650B wheelset has 47 mm wide WTB tires. If a larger 700C x 40 mm wheelset is used, it will have a different feeling as well.

My preference is for the forward position of the Trail Mixer, as it gives the bike a more lively feeling. I like the ability to make sharper turns at low speed, making it good for more technical terrain. It also feels more like a road bike with the sharper handling.

If you have not compared the differences, I suggest you give it a try, and see which is better for you. It depends a lot on your riding style and riding terrain as well.