Thursday, May 25, 2017

Java Freccia Carbon Mini Velo: Part 3 - Frame Geometry Comparison

As with any frame, the geometry is important as it affects how the bike rides and also the handling. Since I have the Java Freccia bare frame, it is a good idea to compare it with the other bikes to see the differences in geometry. The weight of the frameset components had already been checked previously.

Java Freccia carbon mini velo frameset

Overlaying the new Java frame onto the Wheelsport mini velo for comparison

I tried to line up both the front and rear axles, but the bottom bracket does not line up. The geometry seems to be quite different...

Different top tube design, although the horizontal top tube length seems to be similar

Bottom bracket for the Java frame seems to be higher up

Front axle lined up nicely, acting as a datum for comparison

Rear axle of Java frame does not match up nicely, suggesting a shorter chain stay length

Seat tube angle and location seems to be similar

Head tube of the Java frame is much higher, which should translate into more stiffness at the front end since the exposed length of the steerer tube is shorter.

Steerer tube of the Java fork ends about 40mm below that of the Wheelsport fork, which means a more aggressive riding geometry.

That concludes the frame comparison with the Wheelsport mini velo. With a shorter steerer tube, it will mean a lower handlebar height for the Java Freccia mini velo and thus a more aggressive riding posture.

Next, I also compared the frame with the Merida Scultura 5000 road bike.

Just to double check: The Wheelsport handlebar is quite a bit higher than the Merida handlebar. The Java handlebar height should thus end up pretty close to that of the Merida road bike.

Overlaying the Java Freccia frame onto the Merida Scultura 5000 road bike, using the bottom bracket area as the datum.

Top tube height is obviously lower on the mini velo frame

Steerer tube height is about the same as that of the Merida road bike. This means that the handlebar height of the Java should be close to that of the Merida.

After doing more research, I finally found some details of the Java Freccia frame dimensions. What stood out for me was the chain stay length, which is short at only 380mm! This is quite a bit shorter than the 405mm on the Merida and the 420mm on the Wheelsport.

Frame dimensions of the Java Freccia frame

The major findings from this frame comparison is the difference in head tube length with the Wheelsport frame, and also the short chain stay length. A short chain stay length usually means a more agile but also less stable ride. Nevertheless, all these numbers should only be used as a reference, as the ride quality and characteristics ultimately depends on riding the actual bike. It may or may not have a big effect on the ride at all.

Saturday, May 20, 2017

Java Freccia Carbon Mini Velo: Part 2 - Weight of Frameset Components

After taking a close look at the Java Freccia carbon mini velo frame and fork in the previous post, let us now see exactly how lightweight this frameset is.

By building the bike up from a bare frame, it makes it easy to measure all the weights exactly. The main objective of this project is to build a mini velo that is as lightweight as possible.

From some research, I have the weight comparison of some popular and more well known mini velo framesets.

Wheelsport Fantasy (aluminium frame, carbon fork): About 2.3kg
Tyrell FX (aluminum frame, carbon fork, folding): About 3.1kg
Tyrell CSI (aluminium/carbon frame, carbon fork): About 2.15kg
Tyrell PK1 (titanium frame, carbon fork): About 2.45kg

As you can see, the lightest frameset, which is the Tyrell CSI, still weighs about 2.15 kg as it is mostly aluminium with a carbon rear triangle and fork.

The Java Freccia frameset will beat all these frameset weights by a large margin, if the claimed weight on the website is to be believed.

Java Freccia claimed frameset weight: 850 grams for frame, 360 grams for fork, giving a frameset weight of only 1210 grams (1.21 kg)!

I know that these claimed weights are often overly optimistic, and are usually too good to be true. Even then, the difference with the other frame weights are so big that there will definitely be weight savings even if the actual weight is not as light as claimed.

Frame: Claimed weight is 850 grams, actual weight is 1060 grams. Quite far off, but still lightweight.

Fork: Claimed weight is 360 grams, actual weight is 412 grams. Smaller difference than the frame.

Claimed frameset weight: 1210 grams
Actual frameset weight: 1472 grams

Although the actual weight is higher, just as I expected, it is still considered a very lightweight frameset, as it is more than 800 grams lighter than the Wheelsport Fantasy mini velo frameset!

This is a significant weight saving as the frameset weight has been reduced by more than one third.

How about the weight of the other frame components, such as the headset, carbon spacer, carbon seatpost and etc?

Headset bearings, compression ring and cover. 58 grams. No headset cups required as it is integrated into the frame for weight savings.

Specifications of the headset bearings, in case anyone is interested to know.

More carbon goodies. Carbon top cap by Controltech, 27 grams.

Carbon spacer weight, 63 grams before cutting. 120mm long.

As this frame uses an aero shaped seatpost, the aero seatpost is also included. This also means that I cannot use the modified FSA SL-K seatpost which only weighs 206 grams.

Aero carbon seatpost that comes with the Java Freccia frameset

Aluminium plate that clamps the saddle rails onto the carbon seatpost. Quite a common design nowadays.

It even has a special rough coating on the seatpost to prevent seatpost slippage. Similar to that found on the clamping areas of carbon handlebars.

There is an aluminium insert that extends about 10cm upwards from the base of the seatpost, presumably to strengthen the seatpost without adding too much weight.

This seatpost is also quite lightweight! Only 213 grams, only slightly heavier than the modified FSA SL-K seatpost which weighs 206 grams.

Seatpost clamp design, which has two wedges at the side that pushes a third wedge against the seatpost to clamp it in place.

Seatpost clamp mechanism weighs 27 grams

It also comes with a rubber cover to prevent water entering the frame through the seatpost area

Complete assembly of the seatpost, seatpost clamp and rubber cover onto the frame. This seatpost clamp design gives a very clean look to the frame, with nothing sticking out.

As described in the previous post, the frame and fork has special mountings to accept aero type V brakes. However, since I am using standard road caliper brakes, these mountings are not required. As such, it is a good idea to block off these holes by inserting a bolt.

Aero type V brakes seen mounted at the rear of the front fork

To save a tiny little bit of weight, I decided to use nylon bolts instead of steel bolts to seal off these holes.

Nylon bolts, not for any load bearing usage. Perhaps only suitable for decorative purposes.

4 M6 mylon bolts only weigh 2 grams

Nylon bolt sealing off the holes on the fork

Same for the holes on the rear triangle of the frame

In summary, this carbon frameset saves over 800 grams over the Wheelsport mini velo frameset, which will result in a super lightweight mini velo.

The next post will show the frame geometry comparison between this new Java frame, the Wheelsport frame and also the Merida Scultura frame.

Sunday, May 14, 2017

Java Freccia Carbon Mini Velo: Part 1 - Frame & Fork

Another mini velo? While browsing Taobao, I came across this mini velo frameset that looks rather interesting. This is a carbon fiber mini velo frameset, which is quite rare as mini velo frames are mostly made of aluminium or steel. The main advantage of this carbon mini velo frameset is the weight, which is much lower than the aluminium Wheelsport Fantasy frameset that I have. The weight will be examined in a subsequent post.

My plan is to get this new carbon mini velo frameset, and transfer all the components from the Wheelsport mini velo over to it. Let's take a look at this frameset and see why I decided to get it!

No welding on the joints, as they are all molded by carbon fiber sheets

Integrated headset design to save weight. No need to press fit any headset cups, just drop the sealed bearings in.

Down tube tapers from a bladed shape at the head tube to a squarish shape at the bottom bracket for stiffness

Nice glossy finish on the frame!

Seat stays are joined to the seat tube BMC-style.

Aero shaped seat post, with hidden seat clamp wedge for a clean look

Riveted front derailleur mounting, for brazed on type FD

Press fit bottom bracket, in order to save weight. Hope it does not cause any problems...

Only part of the cabling that runs external to the frame. Two holes for RD cable and FD cable.

Special tubed portion that guides the FD inner cable from the cable guide at the bottom...

...and out from the rear of the seat tube. If designed correctly, the inner cable will not rub on the edges of the tube. This also means that water will not enter the frame through this hole as it does not lead into the frame.

Rear triangle of the frame

Aluminium rear derailleur hanger. Note the exit point on the chain stay for the RD cable.

Flared rear triangle design, 130mm OLD. Can use either road caliper brakes or the special aero V brakes.

Java Freccia carbon front fork

Even the long steerer tube is made of carbon for weight savings

Angled mount for the bottom headset bearings already molded into the carbon steerer tube. No need to press in a crown race.

100mm OLD, for 451 sized wheels

Can use either road caliper brakes or the special aero V brakes

Usually, it can be risky to buy a carbon frame from an unknown source. However, since this is a Java branded carbon frame, I am not too worried as Java is already quite an established brand in the folding bike and mini velo market. Moreover, this Java Freccia bike model is also being sold locally, which means that this is unlikely to be a frame with dubious quality.

After studying the frame and fork in greater detail, I found that the quality and design is quite good. The surface finishing is nice and glossy, with well defined edges and smooth surfaces. There are also little touches here and there which shows that some thought has gone into frame design. Generally, the build quality is quite decent, which is what I expected from Java.

In the next few posts, I will write in greater detail about building up this carbon mini velo, and what are the differences between this and the Wheelsport mini velo.