Monday, March 11, 2013

A Century Later: PIAS Scarab Prototype

First of all, I'd like to set things straight. This is not just a bicycle I've built, this is also a bicycle I designed from the ground up. I might be biased, so let's not consider this as a "true" review. I put this under the "A Century Later" category because this article sums up all the experiences I have after more than 160 (total) kilometers. Now move along.

You might have seen all the build possibilities on the PIAS Scarab, and this is one of them. I decided to built it as a all-weather roadbike so I can put it under testing on any weather conditions. That, and because of all the bicycles I have in my stable, this is the only one that can be fitted with full-shroud fenders.
The Scarab will be available in three sizes and two colour schemes. This is the 53cm frame, with the colour scheme that will not make it to the production line. It was based on Woof Jakarta's Fixed Fest 2012 poster scheme, but the manufacturer simply can't catch up with the exact colour that we want.

The frame features neat TIG welding throughout. It wouldn't fell on the lightweight category, but it's not as heavy as a tank either. The frame is using double-butted 4130 chromoly tubing, that soaks up road (or lack thereof) surface bumps nicely.

The moment the frame arrived at our shop I immediately dive through my old parts bin. Only the brifters and fenders are bought new, the rest are old stuffs I had laying around my storage. The Scarab is using 1 1/8" threadless steerer tube, so any 1 1/8" threadless headset will work. The drivetrain is a mix between Shimano 105 5700 rear derailer, 11-28T cassette and brifters mated to old Shimano Dura Ace 7410 crankset (with 48/39T BBB chainrings) and newer 7700 front derailer.
The production frame will be built without brazed-on tab for the front derailer, but we will include an adaptor clamp with each frame. If you want to use clamp-on derailer, the clamp band diameter is 28,6mm. By the way, the seatpost size is 27,2mm.

One of the difficulties of building one of the first disc brake-equipped dropbar bikes in Indonesia is to find the mechanical disc brake caliper that would work with the brifters. Standard mountain bike/long cable pull calipers will give poor performance if mated to dropbar brifters or short cable pull brake levers. After previously running Avid BB5 Road calipers, I switched to Shimano BR-R505 caliper not too long ago and I can say they give decent braking performance. Plus, I already have Shimano XT BR-M775 brakes on my mountain bike so I don't have to stock different brakepads.
For the production run we'll be working with bicycle component distributors to provide mechanical disc brake calipers that will work with dropbar levers. And if you want to run hydraulic disc brakes on this frame, as long as you want to spent a little time threading the hose through the continuous brake cable mounts, we've got you sorted.

The fenders are another story. We found inexpensive metal fenders but the struts are not adjustable, so we bend the front struts and aim them at the rack eyelets. We have to drill another set of holes on the rear fender to make them sit nicely. As for the wheels, this build is using Velocity Aerohead rims laced to Shimano XT hubs and shod with 28mm Panaracer Pasela tires.
This frame is built with adjustable chainstay length so you can adjust the chain tension if you choose to run single chain and cog without the need of separate tensioner. I currently set the chainstay length at 442mm to see how it goes under the guise as a touring bike. It may not be as agile as my road bike, but the extra length provides better vibration absorbment.
Few things will be altered for the production run. We will add front brake cable mounts on the fork leg, revise the seat cluster area for better weatherproofing, and tweak the chainstay length.


  1. Om, berikut review pias scarab versi saya