Quirk Cycles | Custom Steel and Titanium Bikes Handmade in London UK by Framebuilder Rob Quirk

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SUPERCHUB - New Model

Pleased to finally be able to show the latest model to join the Quirk Cycles line-up, here is the SUPERCHUB. This one has been in development for a while and when you look closely you will see all the little details that have gone into making this. Keep on reading and I’ll show you what makes this XC Race bike so special.

Straight off the bat one of the first things most will notice is the lines of this frame, I mean, look at that rear-end! It’ll come as no surprise that this frame is making use of 3D additive manufacturing to develop a set of unique dropouts and seat cluster. These pieces have been printed in 15-5 stainless steel and apart from looking aesthetically stunning, offer many structual benefits. Not only do they weigh less than standard brazed plate dropouts, but they make a stronger part that distribute the stresses of the frame more effectively due to the continuous skin between tubes and printed parts. The system integrates the seat clamp inside the top tube for super clean lines into the stays, and SRAM’s UDH hanger is used for a readily and easily replaceable part.

The second feature that is an instant standout is the fully integrated cable routing. I know this is one of those topics that splits opinion, especially in MTB circles, but there are some key reasons why I went this way. One aspect of steel frames that I’ve never felt satisfied with are head tube and headset standards, the predicament being that the clean lines of internal bearings meant having large overly heavy head tubes. With integrated routing I could design shorter, lighter head tubes with the higher strength of internal bearings. Done right, I could even save some weight. The headtube is a straight, custom machined 54mm ID which takes an 1.5” bearing top and bottom. Usually running 20mm of spacers would look out of place on a steel bike but with this system it positively adds to the profile. The advantage of this is that the heavy steel head tube is reduced in length and lighter ABS materials take its place. Even this larger frame looks proportional and well layed out. The system is great for reduced cable snag on the outside of the frame, but the advantage of ease of cleaning shouldn’t be overlooked either, especially when you live in rainy England.

It was important to me that this bike would be light and fully built in its current form weighs in at 10.3kg, good for a steel frame with a mix of high and low-end components. The SUPERCHUB frame itself weighs in at just 2kg and with refinement of the 3D parts it’s expected this will come down another 50-100g.

When it came to the parts I really wanted to have somehting that was stand out different. Custom buuilders is where you expect to see the more unusual, less-known component manufacturers on display but even this means seeing the same ‘recipes’ used again and again, I was keen to try something different, and make something unique to Quirk. That’s when I decided to do in-house anodising. From the cranks to the valve stems I tried to anodise any component that was aluminium. The hardest part was the derailleur, which ended up being made from the body and knuckle of a Force CX derailleur as the alloys used in the Eagle GX can’t be anodised. Dues to the differences in the alloy grades the shades and consistency of the green dye changed from part to part, but I wasn’t after consistency, I was after expression and experimentation. People will give me stick for using SRAM Level T brakes but there’s something wonderful about customising cheap parts with in-house anodising and Hopp Carbon resevoir caps. One for the boy-racers.

Just as I decided that anything aluminium was to be stripped and anodised, anything carbon was to be stripped and clearcoated raw. It worked beautifully, that Enve post - just yes.

Most my riding would fall into the XC category with the occasional trail thrown in so I wanted a to design a frame that could still tackle long distance well, but with elements that would make it handle technical trails with a bit more finesse. The 68° head tube is suitably slack by todays XC standards and when paired with a 44m fork offset makes the handling lively and predictable. I’m a big fan of shorter rakes on off-road bikes as the reduced wheel flop makes the steering arc progressive and confidence inspiring. With the longer trail it also means the bike will roll well on the flat making those longer rides less fatiguing.

The chainstays sit slightly longer than most at 433mm which means this bike climbs like a champ, but to keep the ride feeling lively I’ve kept the BB high at 60mm, raising the riders centre of gravity and preventing the frame becoming overly planted. 2.4” tyres shoe this sled and fork travel is at a short but cushy 100mm for perfect float and traction. 

Custom Quirk Cycles frameset

  • Columbus 29r and Dedaccia Tubing

  • 3D printed 15-5 dropouts and seat cluster with integrated clamp

  • Rockshox SID Select SL Fork with custom paint logos

  • SRAM Eagle Groupset in-house anodised

  • Garbaruk 12 Speed Cassette with in-house anodised 50T cog

  • Garbaruk rear derailleur cage and oversized pulleys in-house anodised

  • Enve Post and bars with in-house anodised parts and custom paint logos

  • Enve M525 Rims with custom paint logos laced to Chris King ISO hubs

  • FSA ICR NS MTB Stem in-house anodised

  • Custom machined headset cups in-house anodised

  • Custom machined 56mm head tube

Photos by Nikoo Hamzavi