The Union

The Union is our medium-large hardtail, influenced by those halcyon early days when one bike did nearly everything.

Like everyday life, the cycle industry is a noisy place. It bombards you with the latest must-have products in the latest categories, all depicted in epic environments at sunset. The Union is our escape from that.

The Union is made from repairable steel and you decide the colour. The decals are replaceable. It's a simple tool, made to make you want to get outside.

A modern, beautiful heritage.

The Union is the first frame based around our short/long sizing and proportional wheel sizing idea. It's a beautifully mannered handmade frame that combines modern standards, geometry and materials with old ideas, sleek lines and slim tubes.

The butted and shaped steel tubes add that desirable spring, medium length stays keep the front wheel stay down while climbing, and the longer wheelbase mean it's stable on the descents, well mannered while crossing ground quickly and rider weight is placed centrally. Combined with a short offset fork, the considered head angle makes the whole package a whole lot of fun.

How to get one.

Frames start at £1,250 for standard geometry in either a short or long, and frame kits start at £1,400.

Frames are made to order in batches of 10 so there may be a wait of up to three months until your order is ready. For an additional cost certain frame elements can be altered to customer requirements.

Note: the photographed frame is a prototype. The final frame will feature a chainstay yoke, slightly different profile stays and tweaked dropper seatpost routing.

The frame

Head tube
The X44 head tube is suitable for 1 1/8", tapered and 1.5" steerer forks, as well as running slackening headsets. It also provides a large weld contact patch for the top and down tube.
Top tube

The oval top tube is designed to flex a little to add a little comfort to the ride, but is also free of cables to make carrying luggage and shouldering the bike easier.

The top tube/seat tube brace also has enough room underneath to mount a large light battery for nightriding, commuting and 24 hour racing.

Seat tube

The 30.9mm (internal diameter) seat tube is a compromise between the more comfortable 27.2mm width and newer, larger standards; 30.9mm can fit the latest generation of longer dropper posts while still having a small degree of comforting flex.

There is also stealth routing for the dropper post as standard and a second set of sealed bottle bosses with clearance above for a 185mm dropper.

Bottom bracket

Versatility, parts availability and fewer creaks make the English threaded bottom bracket the best option. It's not perfect, but until someone comes out with something better, we're sticking with this.

There's also a drain hole to help get water out of the frame. Influenced by hardy winter bikes ridden by road racers in the dark and wet depths of the off-season, we feel it's an appropriate addition on frames which are ridden in the wet, regularly hosed down and run stealth dropper seatpost cable/hose routing.

Seat and chain stays
There's no seat stay-mounted cables to make mounting a mudguard easy, all TIG welding blow holes are filled after welding to stop water ingress, and there's clearance for 29 x 2.4" or 650b x 3" tyres. Dropouts and derailleur mount are Syntace X-12 standard.

The details

Tubing
Tubing is a mix of Reynolds 853 DZB, Reynolds 853 and Reynolds 631 (excluding the bottom bracket and brace) which is 20 times stronger than high-tensile steel. Certain tubes use shaping to benefit from – or reduce – flex. None of the tubing on the main frame is kinked, which means lines are cleaner and judging sizing from the spec sheet is easier. Each frame is fabricated and TIG welded by Limit Fabrications in Norwich.
Short and long sizing
Short and long sizing comes from a cycling discpline with an great history of racing and innovation – BMX. Long, low, manouverable mountain bikes are probably closer to BMXs than any other form of cycling, and now long dropper posts are available we thought it made sense to embrace this. We estimate short and long sizing covers heights from 5'6" up to 6'1".
Wheel sizes

Plus-sized wheels are one of the reasons we decided to start Cain Bike Co. Finally we could have a playful, comfortable, low-maintenance hardtail that with a change of wheels could be switched to a winter-ready bike with a huge amount of mud clearance, or a comfortable big-wheeled mile muncher.

As a general rule we consider 650b+ better for dry, loose and rocky conditions, and fast-rolling 29" for quicker/longer rides and winter (with thinner winter tyres.)

Boost spacing
148mm Boost rear wheel spacing provides greater wheel triangualtion and less dish, which makes a stronger, stiffer wheel.
Fork
We recommend a 120mm travel Boost-spaced fork and a short fork offset. The Union was tested with 51mm and 46mm offset forks, and for the slower, twistier trail riding prevelant in the UK the shorter offset felt far more linear and predictable.
Cable routing

No top tube cable routing makes shouldering the bike, carrying luggage and mounting a light battery easier, and keeps the seatstays clear for attaching a rear Mudhugger. Mounting the cables on top of the downtube keeps them away from rock strikes, combine with bottle cage mounts and are easy to access and maintain. It also means cables can easily be mounted either UK/moto style or European/North American.

Two sets of bottle bosses

Two sets of bottle bosses are added to make carrying water and spares – or water and a battery – possible without needing a bag. Bottle bosses are also internally capped to make them watertight, preventing water getting into the frame.

Removal of internal material
It's a small thing, but getting rid of material that is not doing anything saves a little weight. It won't make getting up hills drastically easier, but it's a few grammes you won't need to carry. And it looks lovely!
The finish

The frame is powder coated in a solid RAL colour of your choice.

Decals are applied vinyl and not lacquered on, so easy to replace should you wish to freshen up your frame.

Weight
A long frame weighs approximately 2.3kg/5lb.

The Frame Kit

Frame Kit
A frame kit includes all the little details you'll need to start building a bike:
  • Hope seat clamp
  • Seat clamp spacer
  • Syntace X-12 deraileur mount
  • Syntace X-12 12mm axle (148mm Boost, unless otherwise specified)
  • Machined cable guides (for double and triple down tube cable routing)
  • Stainless steel bolts.

Geometry

120mm fork, static *

  Head angle Seat angle Reach Stack Top tube (effective) Wheelbase BB drop Chainstay Seat tube (c-t)
Short 65.5° 73° 434mm
17"
621mm
24.4"
625mm
24.6"
1193mm
47"
45mm
1.8"
445mm
17.5"
458mm
18"
Long 65.5° 73° 454mm
17.85"
621mm
24.4"
645mm
25.3"
1213mm
47.75"
45mm
1.8"
445mm
17.5"
458mm
18"

120mm fork, 25% / 30mm sag **

  Head angle Seat angle Reach Stack Top tube (effective) Wheelbase BB drop Chainstay Seat tube (c-t)
Short 67° 74.5° 445mm
17.5"
623mm
24.5"
620mm
24.4"
1179mm
46.4"
60mm
2.35"
445mm
17.5"
458mm
18"
Long 67° 74.5° 465mm
18.3"
623mm
24.5"
640mm
25.2"
1200mm
47.2"
60mm
2.35"
445mm
17.5"
458mm
18"

* Geometry for an unloaded frame.
** Geometry with a rider onboard and suspension set at 25% sag: i.e. normal riding position.

Side view of the Union
Open Imagination
Open Imagination
Open Imagination