Birdy AXS: Birdy Bike Frame and Handlepost

In the previous few posts, I have studied the stock setup of the Birdy City, followed by comparing the geometry and size, and finally dismantling the frameset. Now, I will study these individual frameset parts in more detail, by checking out the design and the weight.

Frameset parts laid out in an exploded view.

Main frame and rear triangle still attached. It is not recommended to remove the rear triangle as you will need to knock out the pivot pin.

Folded Birdy frameset is very compact, and it comes like this when shipped from the factory to the bike dealers for component assembly.

Made in Taiwan by Pacific Cycles. Note how the black plastic stopper controls the clearance between the bottom bracket shell to the rear triangle.

Rear triangle goes very close to the bottom bracket when folded. The plastic stopper needs to be adjusted to make sure there is no metal to metal contact.

Check out the 2 plastic stoppers which serve different functions. The one on the left touches the bottom bracket shell, to control the rear triangle position when folded.

The other plastic stopper shown here will get close to the seat post when it is put down, to prevent the rear triangle from swinging downwards when folded. Both can be adjusted.

Stock Birdy seat post clamp. The number 40 refers to the internal clamp diameter, which matches the external diameter of the Birdy seat tube.

Stock Birdy seat post clamp weighs 52 grams.

Stock Birdy rear suspension block weighs 39 grams. This is probably the lightest design.

Weight of Birdy main frame and rear triangle, inclusive of headset cups, RD hanger, rear pivots, rear triangle latch, and the round black plastic stoppers is 2146 grams. All other parts have been removed from the frameset.

Birdy fixed height (non-telescopic) handlepost shown here. The lack of telescopic feature means that it is lighter, but not sure how much lighter.

Steerer tube is part of this handlepost, as well as the bearing cone of the upper headset bearings.

The end of the steerer tube is cut by the factory, with the star nut inserted. See how it is done here.

Length of the steerer tube is 130 mm.

Weight of fixed height Birdy handlepost, inclusive of the steerer tube, weighs 691 grams.

After weighing the frame, I was quite surprised at the weight. My initial estimate of the main frame and rear triangle is about 1.5 kg, but it turned out to be 2.1 kg instead. My estimate was based on the weight of an aluminium mini velo frame, such as the Wheelsport Fantasy. However, it seems that my weight estimate is way off the mark, as I did not take into account the weight of the pivots and thick rear triangle.

In this case, it means that the full bike will likely weigh more than the Fnhon DB12 (8.9 kg without pedals). Hopefully the increase is not too much, so as to justify the inclusion of the suspension feature.