Fnhon Gust: Handlebar Setup and Seatpost

Previously, the key components of the Fnhon Gust 16 inch folding bike was shown. The steel frame, steel fork and aluminium handlepost comes together as a frameset. The rest of the parts needs to be sourced individually.

With careful selection, the components that are chosen will be tailored to your specific needs. This bike is targeted to have a selection of high end components, with a full 11 speed drivetrain. At the same time, lightweight components are preferred to minimize the weight, although the frameset itself is already pretty heavy.

Carbon flat handlebars of good quality can be found cheaply on Taobao, such as the Toseek flat handlebar that I have used previously on the Bike Friday Haul-A-Day cargo bike and also the Fnhon DB11 folding bike.

For folding bikes, a handlebar width of around 560 to 580 mm is ideal. If it is too narrow, it will be harder to control the bike. If it is too wide, folding might be affected due to grip and tire interference.

In this case, a 580 mm wide Toseek carbon handlebar was selected. The center clamp portion needs to be of diameter 25.4 mm to match the handlepost clamp.

Toseek flat handlebar, 580 mm wide, weighs exactly 100 grams.

PRO grips, weigh just 81 grams, which is pretty lightweight for lock on grips.

SL-RS700 11 speed road flat handlebar shifter.

Brake levers will be Sora brake levers, which are black colour to match the rest of the bike. I forgot to take a picture of the brake levers, but you can see them later on, in pictures of the full bike.

With that, the handlebar area is settled. Choosing the seat post and saddle is easy, as it is quite standard. On a 16 inch folding bike, although the seat tube is lower than that of a 20 inch bike, the seat post length used is the same, just that it extends out further from the frame. In this case, a standard seat post will do. Instead of the most lightweight version with thin clamps, I chose the type that is slightly heavier but has a much stronger saddle clamp.

Litepro seat post, diameter 33.9 mm, length 600 mm. 

I also got an aluminium seat post shim, as I thought the frameset comes with a plastic seat post shim which does not work well.

After checking, I found that a metal seat post shim is actually included with the frameset, which is good. A good quality seat post clamp with brass bushings is also included.

Saddle is provided by my friend. The grey colour does not match the rest of the bike but that is not an issue for me.

In the next post, we will check out the new wheelset and tires, which is another key part of this bike.

Fnhon Gust: Fork and Handlepost

The Fnhon Gust frameset actually includes the handlepost as well, not just the frame and fork. This is a really good deal as I know that most framesets don't include the handlepost.

In this case, the handlepost needs to be taller than what is usually used for 20 inch folding bikes, as the fork and head tube is lower on a 16 inch bike. On 20 inch folding bikes, I like a handlepost that is relatively short, at around 29 cm in height. It can be quite hard to find.

For this 16 inch frameset, a commonly used handlepost height is either 37 cm or 40 cm. In this case I think a 40 cm handlepost might be too tall if you prefer a sporty riding style over an upright, casual style.

Long handlepost for the Fnhon Gust 16 inch frameset.

Handlepost weighs a pretty hefty 636 grams! This does not even include the compression bolt.

Height is around 37 cm when measured from the base to the center of the clamp.

Quick release lever type. OK for flat handlebars, but not tight enough to prevent rotation if you install drop bars.

Compression bolt and shim weighs 48 grams.

After installation, we shall see if the handlepost height is OK. If not, it is possible to change to a taller or shorter one, as it is just a standard handlepost. Fnhon makes many types of handleposts of various heights, clamp type and inward/outward folding type.

Next, let's take a look at the Fnhon Gust front fork. Same as the frame, it is also made of steel, so we can expect it to weigh quite a bit more than an aluminium fork. Last time, when I changed the front fork on the Dahon Boardwalk from steel to aluminium, the weight was greatly reduced from 800 grams to 440 grams.

16 inch front fork weighs 637 grams, which is heavy. A longer 20 inch aluminium fork would weigh around 200 grams less, while a full sized gravel bike carbon fork weighs around 400 grams.

The steerer tube is also steel, which contributes a lot to the weight.

Nice gold markings on the fork to match the frame. Not sure what MARTAX is.

Gold markings to indicate 4130 chromoly steel.

Possible to install either V brakes or caliper brakes. More details in future posts.

The fork is heavy as it is made of steel, although that is to align with the design intention of this frame. There are other bike models which are made of aluminium, if you prefer a more lightweight 16 inch folding bike.

Fnhon Gust: Frame

A new bike project offers the opportunity to learn new things. In this case, building a 16 inch bike up from scratch is new to me, as I have only assembled 20 inch 406 and 451 bikes previously.

As this 16 inch frameset is new to me, there will be inevitable mistakes made during the assembly, such as finding out that some parts don't match, or a wrong specification is used. Nevertheless, I am confident of solving these problems using the experience that I have from building up many different bikes previously. 

What we have here is a 16 inch Fnhon Gust frameset, which is an interesting frame. First of all, it has a unique geometry, with a large chainstay and no distinct seatstay. Instead, it has a couple of braces in place to reinforce the joint between the chainstay and the seat tube.

This is a steel frame, which means that it is likely to be heavier than an equivalent aluminium frameset, but of course also tougher. My one and only steel frame was the Dahon Boardwalk, which started me on the bike modification route. It is not ideal to make a lightweight bike using a steel frameset, as it is usually heavier than an aluminium frameset. However, for this project the priority is not to minimize the weight.

Let's take a closer look at the frame and see what makes it so special.

Black frame with gold accents! Reminds me of the Dahon Boardwalk with lots of gold bling.

Frameset comes with seatpost clamp and seatpost shim included.

Steel head tube. Looks pretty round to me, unlike the Crius AEV20 which I worked on previously.

Uses a standard Litepro headset. Black is the chosen colour here, although gold would work well too.

Headset bearing cups pressed in with a proper headset press. No difficulty here.

There are metallic flakes mixed into the paint, which looks amazing! Looks similar to the metallic look seen on the Cervelo Aspero frameset.

Fnhon logo embossed on the headtube in an attractive gold colour.

The model name is also painted onto the frame in a shiny gold font.

More details about the frame painted at the back of the seat tube. This gives the frame a really attractive classic look.

Gold plated folding lever? Not sure if it is real gold plating or not.

Gold bands painted on the chainstays as well.

Rear derailleur dropout is welded to the frame, instead of being a separate piece. As it is made of steel, it can be bent back to straight without cracking.

Lots of cable guides at the bottom of the frame, which is good for cable routing flexibility.

More cable guides!

Frame (inclusive of headset bearing races) is 2417 grams.

A pair of the headset bearing races that are pressed into the headtube weighs 16 grams.

The frame weight, excluding any headset parts, but inclusive of seat post clamp and seat post shim is 2401 grams, which is the same as the larger 20 inch Dahon MuEX aluminium frame. I think it is a good weight for a steel folding frame, since it is equivalent to that of an aluminium frame.

I was really impressed with the gold accents on this Fnhon Gust frame, as it really stands out from the black paint. This bike is not for my use, but I am helping to build it up for a friend. I think this is a really attractive 16 inch frameset!

Cervelo Aspero: Sunrace RX1 11-36T Cassette

On the Cervelo Aspero, the gravel setup has a 11-34T Ultegra-grade cassette on the wheelset. The sprocket sizes on the 11-34T 11 speed cassette are 11-13-15-17-19-21-23-25-27-30-34. When I'm riding gravel, I usually use the smaller 34T inner chainring for lower gearing. Due to cross chain issues, I cannot use the top gear (11T) on the rear cassette. Of course, I can shift to the larger chain ring for higher gearing, but this is usually not necessary.

This means that my gravel gearing is from 27 to 70.6 gear inches (shown below), which is not quite high enough. When I need to go faster, I will need to use the large chain ring. The low gear is good, although I will sometimes wish for an even lower gear when climbing on off-road terrain.

There are effectively 16 non-overlapping gears on this setup, biased towards the small chain ring for gravel riding.

I was thinking of getting a cassette with an even larger sprocket, for even lower gearing. For Shimano cassettes, the next step up would be an 11-40T cassette, which is too big a jump. The rear derailleur also will not be able to reach both the 40T sprocket and 30T sprocket on the gravel and road setup respectively, as I tested earlier.

Then, I came across this Sunrace CSRX1 cassette which is marketed as a gravel cassette, with a 11-36T gear ratio. I had previously used a Sunrace cassette on the MTB, and it worked pretty well. Therefore I was willing to give it a try as I think the quality should be quite decent. There is also another important advantage over the 11-34T cassette which I will reveal later.

Disassembled view of the Sunrace CSRX1 11-36T cassette!

Largest two sprockets are 32T and 36T, mounted on an aluminium spider.

Next three sprockets are 21T, 24T and 28T, also mounted on an aluminium spider.

Remaining gears are all individual sprockets from 11T to 19T.

Large spider with 32T-36T sprockets weighs 127 grams

Small spider with 21T-24T-28T sprockets weighs 119 grams

There are two bright red aluminium spacers which weigh 5 grams in total.

Aluminium lock ring weighs 5 grams

Entire cassette weighs 351 grams, which is 14 grams more than the 11-34T cassette, and a huge 145 grams more than the Dura-Ace 11-30T cassette.

One interesting detail is the small stamped circle just above the larger spline, to help identify and orientate the sprocket during assembly to the freehub body.

I was not sure if I needed to use a 1.85 mm spacer behind the cassette, as I could not find any documentation online. If the CSRX1 cassette is designed for road hubs only, a 1.85 mm spacer is not required.

However, if the CSRX1 cassette is designed for older 8/9/10 speed hubs, then a 1.85 mm spacer will be necessary. Only way to find out is to try it out!

Without the 1.85 mm spacer, the 11T sprocket barely protrudes above the freehub body. When I tightened the lock ring, it will bottom out on the freehub body, leaving the sprockets still loose.

After adding the 1.85 mm spacer, there is more clearance for the lock ring to tighten properly.

In conclusion, this Sunrace CSRX1 11-36T cassette is designed based on 8/9/10 speed freehub body length. It can be fitted on older hubs without any spacer. However, since I am installing it on the new 11 speed road ready Hunt 650B Adventure Carbon Disc wheelset, an additional 1.85 mm spacer is necessary. 

11T to 36T sprockets all visible! The quality of the nickel plating looks good.

The bright red anodised aluminium spider can be considered an iconic feature of Sunrace cassettes.

Overall view of the gravel wheelset with the new cassette and Venture 47 650B tires!

Distance between the guide pulley and the largest 36T sprocket is set to the minimum possible.

When the gravel wheelset is changed to the road wheelset, with 11-30T cassette, the distance will become larger. Shown here is still the 36T sprocket.

How it looks when the chain is on the largest 36T sprocket

Gravel drivetrain!

Backpedaling in the 36T sprocket may cause chain drop, so avoid this.

The GRX RD-RX815 Di2 rear derailleur has been adjusted to accommodate both 11-36T cassette and 11-30T cassette, which is a pretty big difference. It is able to shift properly across all gears, in both inward and outward directions, for both cassettes. This is very impressive, to have such a robust rear derailleur that can cater to a large difference in cassette sizes, without adjustment between cassette swaps.

Sometimes the shifting is slightly delayed on the 11-30T cassette, but shifting is always successful, so it is acceptable. Considering that the rear derailleur was adjusted for the 11-36T cassette, I can accept this slight issue on the 11-30T cassette. Otherwise, the shifting performance of this Sunrace CSRX1 cassette is no problem at all.

The first advantage of this CSRX1 cassette is to have a slightly lower gear with the 36T sprocket, compared to the previous 34T low sprocket. As shown below, the lowest gear is now 25.5 gear inches instead of 27 gear inches. Not much, but good to have anyway.

With the 11-36T cassette, there are 15 distinct gears. Note and compare the lowest and highest gear when using the smaller chainring, against the previous table which shows the 11-34T cassette.

The second and more beneficial difference is the higher gear ratio that I get when using this new 11-36T cassette. Previously, the HG800 11-34T cassette has gear steps of 11-13-15-17-19..., while this CSRX1 cassette has gear steps of 11-12-13-15-17...

Note the presence of the 12T sprocket on the Sunrace cassette, which avoids the big gear ratio change compared to shifting from 13T to 11T directly.

As mentioned earlier, when I am in the smaller chain ring, I can use all the gears except the top gear (11T). Previously, on the 11-34T cassette, the second-top gear is the 13T sprocket. Now, on the 11-36T cassette, the second-top gear is the 12T sprocket.

Gravel range on HG800 11-34T cassette: 27 - 70.6 gear inches

Gravel range on RX1 11-36T cassette: 25.5 - 76.5 gear inches

The gearing effect of this new cassette is a slightly lower low gear, and a higher high gear, which means a wider gear range, spread over 10 speeds. This is for pure gravel riding, when I only use the small 34T inner chain ring. The new top gear ratio of 76.5 gear inches is enough even for fast gravel riding, which means that I can stay in the small inner chain ring almost 100% of the time.

Updated bike specifications, with the Sunrace CSRX1 11-36T cassette.

Overall bike weight is still about the same. In road bike mode, 7.4 kg without pedals. In gravel bike mode, add 700 grams, to be 8.1 kg without pedals.

I am happy with this change, as I have expanded the usable gear range, with no discernable downsides, except for a very slight weight increase and a slightly slower shifting performance.