Definition 'Rolling Chassis' £1,493.00

Size

Colour

  1. Shutter Black
  2. Lens Blue
  3. Element Grey

Wheelset Option

  1. 4 Season Disc
  2. Aerolight Disc
  3. 30 CAD
  4. 50 CAD
  5. SuperDura Dynamo Disc

The ultimate Mason Definition build kit.

The Definition 'Rolling Chassis' bundles save you money - our hand-crafted Aluminium Definition frameset perfectly matched up with a choice of 5 award-winning HUNT wheelsets and finished with our proprietary carbon 'Penta' seatpost.

To celebrate our stunning new colourway ALL Definition bundles are now available with Schwalbe Pro-One or G-One Speed tubeless tyres supplied and fitted FOC for a limited time only. Carbon wheelsets may be subject to a slightly longer lead time.

Our Definition frameset uses lightweight, Premium Dedacciai aluminium tubing to provide a responsive and engaging ride. It has more of a race-bike feel, although it still retains a beautiful ride quality because of the advanced tubing, custom BoatTail stays, advanced taper steerer Aperture carbon fork and of course the capacity for larger tyres. Learn more about the frameset

Teamed with the fingertip control of a modern disc brake system, this frameset is the basis for a hugely entertaining, practical and addictive bike.

 

Mason X HUNT 4 Season Disc     £1493.

After spending so much time on detailing and functionality for the frames, we found that the right wheelset just didn't exist! In stepped hand-built wheel supplier HUNT Bike Wheels.

HUNT listened to my list of essentials, added their own expertise and we came up with the MASON x HUNT 4Season Disc wheelset. It's absolutely perfect for our bikes.

Learn more about this wheelset

 

HUNT AERO LIGHT DISC        £1595.

Tubeless ready, super-light aero rims combined with bladed aero spokes and straight pull hubs deliver your power with maximum efficiency. We think these responsive Alu. rims are a perfect match to the Definition. 1469g.

Learn more about this wheelset

 

HUNT 30 CARBON AERO DISC £2125.

Aero, super-wide, incredibly-lightweight. Designed specifically for disc braking from the ground-up the 30CAD is the next step from the Aerolight wheelset and is versatile carbon wheelset. 1338g.

Learn more about this wheelset

 

HUNT 50 CARBON AERO DISC £2225.

The super-wide 27mm rim provides superior aerodynamic performance. The U-profile serves up great handling and reduces drag across multiple wind yaw-angles. The extra wide 21mm internal rim bed opens out your tyre profile providing exceptional vibration reduction, grip and low rolling-resistance, a 25mm Schwalbe Pro One tyre measure 28mm. The evolution of disc brake specific construction has allowed massive weight savings over equivalent rim brake-rims. 1436g.

Learn more about this wheelset

 

HUNT SUPERDURA DYNAMO DISC £1673.

Following on from Josh Ibbett's winning of the Transcontinental Race 2015, HUNT started developing a light-weight durable and fast wheelset that provides you with freedom from constant charging of lights for your on and off-road bike-pack adventures, fast commuting and daily winter training. The HUNT SuperDura Dynamo wheelset is the result, using HUNT's proven wide tubeless asymmetric Gravel Disc rim with extra sealed and shielded 4Season Disc rear hub and a durable high 32-spoke count build of Pillar's light and extremely strong triple butted PSR spokes. Even with the extra 240g of the dynamo hub this wheelset is still lighter at 1939g than many disc brake wheels fitted to bikes as original equipment!

Learn more about this wheelset

 

MASON 'Penta' Seatpost

Our own 27.2mm 'Penta' seatpost is constructed from unidirectional carbon bonded to a lightweight forged and CNC-machined head and alloy rail clamps.

Learn more about the seatpost

Features

  • LTD Release offer with Schwalbe Tubeless upgrade applies to all colours.
  • Dedacciai performance Aluminium frame with Mason Aperture2 full carbon thru-axle fork.
  • Unique Mason MultiPort adaptable internal routing.
  • Specially developed, Mason x Hunt disc-specific wheel set.
  • Seatpost graduated for accurate height adjustment.
  • Micro-adjustable seatpost clamp.
  • Choice of 5 HUNT wheelsets from Dynamo endurance to 50mm carbon performance.
  • All wheelsets are tubeless ready and supplied with tubeless valves.
  • Centre-lock disc mount.
  • Micro-adjust seatpost.

Details


Technical info

Select size
 

Dimensions
(mm unless specified)
A > SEAT TUBE C/T 500
B > SEAT TUBE C/C 452.7
C > BB DROP 73
D > REAR CENTRE 420
E > TT EFFECTIVE 532.8
F > TT ACTUAL 516.8
G > STACK 543.3
H > REACH 380.6
I > STAND-OVER 756.5
J > OFFSET 45
K > TRAIL 66.3
L > FORK CROWN HEIGHT 380
M > HEAD ANGLE 71.5º
N > HEAD TUBE LENGTH 130
O > SEAT TUBE ANGLE 74.5º
P > WHEELBASE 999.1
Dimensions
(mm unless specified)
A > SEAT TUBE C/T 520
B > SEAT TUBE C/C 473.0
C > BB DROP 73
D > REAR CENTRE 420
E > TT EFFECTIVE 537.4
F > TT ACTUAL 522.7
G > STACK 552.8
H > REACH 382.5
I > STAND-OVER 770.8
J > OFFSET 45
K > TRAIL 66.3
L > FORK CROWN HEIGHT 380
M > HEAD ANGLE 71.5º
N > HEAD TUBE LENGTH 140
O > SEAT TUBE ANGLE 74.5º
P > WHEELBASE 1004.1
Dimensions
(mm unless specified)
A > SEAT TUBE C/T 540
B > SEAT TUBE C/C 493.5
C > BB DROP 71.5
D > REAR CENTRE 420
E > TT EFFECTIVE 551.5
F > TT ACTUAL 536.3
G > STACK 565.5
H > REACH 383.0
I > STAND-OVER 787.3
J > OFFSET 45
K > TRAIL 66.3
L > FORK CROWN HEIGHT 380
M > HEAD ANGLE 71.5º
N > HEAD TUBE LENGTH 155
O > SEAT TUBE ANGLE 73.5º
P > WHEELBASE 1009.6
Dimensions
(mm unless specified)
A > SEAT TUBE C/T 560
B > SEAT TUBE C/C 513.6
C > BB DROP 71.5
D > REAR CENTRE 420
E > TT EFFECTIVE 561.1
F > TT ACTUAL 546.7
G > STACK 579.7
H > REACH 388.3
I > STAND-OVER 804
J > OFFSET 45
K > TRAIL 66.3
L > FORK CROWN HEIGHT 380
M > HEAD ANGLE 71.5º
N > HEAD TUBE LENGTH 170
O > SEAT TUBE ANGLE 73.5º
P > WHEELBASE 1019.7
Dimensions
(mm unless specified)
A > SEAT TUBE C/T 580
B > SEAT TUBE C/C 534.1
C > BB DROP 71.5
D > REAR CENTRE 420
E > TT EFFECTIVE 581.3
F > TT ACTUAL 566.9
G > STACK 591.1
H > REACH 394.7
I > STAND-OVER 818.1
J > OFFSET 45
K > TRAIL 63.2
L > FORK CROWN HEIGHT 380
M > HEAD ANGLE 72º
N > HEAD TUBE LENGTH 180
O > SEAT TUBE ANGLE 72.5º
P > WHEELBASE 1024.7
Dimensions
(mm unless specified)
A > SEAT TUBE C/T 600
B > SEAT TUBE C/C 554.0
C > BB DROP 70
D > REAR CENTRE 420
E > TT EFFECTIVE 586
F > TT ACTUAL 574.3
G > STACK 599.1
H > REACH 396.8
I > STAND-OVER 833.1
J > OFFSET 45
K > TRAIL 63.2
L > FORK CROWN HEIGHT 380
M > HEAD ANGLE 72º
N > HEAD TUBE LENGTH 190
O > SEAT TUBE ANGLE 72.5º
P > WHEELBASE 1030.2

This page gives you some guidelines based on height, but these are only a starting point for a proper bike fitting. The dimensions show the extremes of useable frame size based on height.

Sizing chart

Fitting a bike to a rider is an important process, this information is a start to the process but it’s not really possible to give 100% accurate fitting instructions online.

Humans are odd shapes, each person’s physical dimensions: arm, torso, femur length, level of flexibility even skill level are very different. This means that there will invariably be different frame size requirements, even for people of the same height and inseam.

We are experienced in sizing and geometry, so of course we will be on the end of the phone or email to help and advise, but I would always recommend having a proper bike fit done before committing, especially if you feel like you may be between sizes.

We have specified bar width, stem length, and crank length to be the best fit for the majority of riders on each frame size, but we can sometimes make adjustments to this at your request. Please contact us for advice, or just let us know your sizing requirements in the comments box at the checkout page.

If you are between sizes, it’s probably best to go with the smaller size. It’s easier to make a smaller frame fit a little larger than vice versa.

EN Tested

All our frames and forks complete the brutal strength and fatigue testing to comply fully with EN regulations. They are pushed, pulled, dropped and twisted over 100,000 times and must survive without any damage before they can pass.

It's not law that frames and forks have to be tested to their limits like this, but our frames will always be tested in this way, so you can be sure that your MASON frame not only looks beautiful with a ride quality to match, but it is tough, safe and dependable too.

Multiport

Unique to MASON. Our frames use an adaptable, internal cable routing system. Developed by us to allow your Mason frame to be used with a combination of control systems and adapt and evolve with your requirements and riding styles. We are the first to bring this type of system to a performance steel frame. Interchangeable alloy parts allow five options:

1. Full cable outer. 2. Hydraulic Hose. 3. Split outer. 4. Electronic cable [e.g. Shimano Di2]. 5. Blank.

Taper Head Tubes

Our frames use modern 1-1/8” - 1.5” taper head tubes. Pioneered by composite frames, the taper head tube makes huge sense for metal frames too;

The large overall diameter provides a useful weld area. The fully integrated headset is light and has a very low stack-height. Large 1.5” lower bearing, mated to a tapered carbon fork steerer, spreads the load and gives flex-free braking and instant response to steering input.

Threaded Bottom Brackets

We choose a more traditional 68mm, BSA, threaded standard for our AdventureSport frames because we believe it gives greater durability and creak-free reliability over many miles. The threaded BB is easier to service using standard tools and you are more likely to find a replacement when adventuring far from home. A properly lubricated, threaded BB is also an ideal interface with a metal BB shell.

ThruBB

'ThruBB' is unique to MASON. The large 50mmØ presents a large weld area to the base of the down tube and then steps down to the 68mm width threaded seats. This step-down provides plenty of space around the outside of the bottom-bracket bearings to allow the control cable and hose to pass through on the way to the chain stays and out to the brake and rear mech.

NOTE: This BB shell design requires the use of a bottom bracket with a 'sleeved' axle. Please contact us if you would like advice.

BoatTail Stays

Unique to MASON. The seat stays flow out of the ovalised top tube and then curve and taper down to meet the chain stays which curve up towards the axle. We call this ‘BoatTail’, a custom bend giving disc-rotor and calliper clearance, helping to avoid chain-slap on the rough stuff and allowing a little compliance to help smooth the ride.

Fork

Unique to MASON. This frame is fitted with our new 'Aperture2' 365g, Ø12mm thru-axle/flat-mount, monocoque carbon fork. Features: Mason F-Stop axle system including replaceable axle inserts and clockable axle, TrueTaper steerer, Internal Routing, Full mudguard clearance, space for 30mm tyres + 'guards, Custom layup UD carbon construction, discrete eyelets.

Dedacciai Tubing

This frame is constructed from Triple Butted, Hand Selected, custom shaped, 7000 series, Dedacciai Alu tubes and tig welded by hand with beautiful Smooth weld beads. The welds require no after sanding or finishing, so there is no thinning and weakening of the tubes at crucial areas. The frame is fully heat treated and stress relieved after welding.

27.2 Seat Post

Our oversize seat tubes don't house oversize seat posts. The large diameter seat tube helps the 'core-stability' of the frame but large, stiff seat posts don't help rider comfort. A 27.2mm post helps to dial out road-buzz and the smoother ride means you stay fresher for longer.

InBoard Disc-Mount

The calliper is mounted on the chain stay, this allows us to use lighter more comfortable seat-stays and gives a flex free mounting for the post-mount components to be welded to. Mounting the brake on the chain stay also keeps it cleanly out of the way of rack and ‘guard stays.

Internal Routing

The cables, hoses and electronic shift control wires run through the frame tubes, guided by our Mason 'MultiPort' adaptable inserts. Interchangeable Internal routing keeps the control cabling away from road dirt and grime, helps avoid accidental damage, makes cleaning easy, de-clutters your bike and means you can adapt your bike easily to work with various shifting and braking methods.

Integrated Headset

Integrated, 41.8ø upper, 51.8ø lower, for taper head tube. Both bearings are ‘ACB’, meaning ‘Angular Contact Bearings’. The head-tube seat angle is 45º.

The headset drops into a tapered seat in the head tube and is tensioned using a headset tensioner within the fork steerer. Tensioning the headset centres it on the taper and prevents any play. The larger lower bearing allows a tapered steerer and larger crown. This gives sharper response, helps reduce flex under braking and spreads bearing load.

Essential Dimensions: Resolution/Definition

BRAKING

Rotor Size: The fork can take a 140 or 160mm rotor [using adaptor], if you are using Shimano IceTech rotors then 140mm rotors either end are fine. A 160 up front is best if you are using cable braking. 140mm is the maximum recommended diameter for the rear.

Calliper Type: Resolution/Definition frames are fitted with the flat-mount front (adaptable to post-mount with supplied adapter) and post-mount rear. There are no clearance issues with modern Shimano systems or mechanical systems such as ‘TRP Spyre’. Some bulky systems like the ‘TRP HyRd’ may have compatibility issues on smaller size frames.

NOTE: This frame is compatible with most modern disc-brake systems but may not be suitable for ALL brake callipers. Please check clearance before purchasing your braking system.

WHEELS

12mm Thru-axle Front / 10mm QR rear.

Resolution/Definition Rear axle spacing: 135mm.

TYRES

The below are guides only. Fitted width may vary depending on manufacturer and rim width. Please check true dimensions of chosen components to be sure.

Resolution/Definition:

Max tyre width with mudguard: 30mm.

Max tyre width without mudguard: 33mm (untreaded).

SEAT POST

27.2mm.

SEAT CLAMP

31.8mm.

FRONT MECH

31.8mm

BB TYPE

68mm shell width. BSA threaded.

FORK

Headset type: Integrated, 41.8Ø upper, 51.8Ø lower, for taper head tube. Angular Contact Bearings. The head-tube seat angle is 45º.

Stack-washer maximum: 40mm below stem is max. recommended for carbon steerer. Warranty is void above this dimension.