InSearchOf GRXT Di2 £4,050.00

Colour

  1. FilterGreen
  2. ElementGrey

Size


InSearchOf GRXT Di2

"..if you are looking to tackle more extreme off-road, while still having the ability to roll along comfortably on tarmac, or if you plan some serious bikepacking expeditions, it lets you go further and more extreme than just about any other drop bar bike."
 
 

"Sometimes a bike comes along that completely delivers in its capabilities, looks and build quality. The Mason ISO - In Search Of -  is one of those bikes. With an Italian hand-built frame, a superb level of finish and detail it nonchalantly comes along and redefines what a drop-bar bike is assumed to be capable of being."

off-road.cc | 5/5

 

This new bike is still firmly in the #FastFar, #ContinentCrushing vein but a progressive new frame and fork design allow it to use 29 x 2.4” or 650b x 2.8 wheels, meaning steeper, rougher and deeper terrain are well within its adventure capabilities.

Multiple mounting points, a bespoke load-bearing mudguard, specific rack systems, 160/180 flat-mount braking and 100mm suspension-ready geometry mean that the InSearchOf, once again, does not shy away from the ‘Progressive’ word in our title.

Our GRX-T Di2 build blends the best ergonomic and rider-tuned features of Shimano's latest GRX brakes and shifters, with the highly durable, lightweight and off-road focused XT Di2 drivetrain to build the ultimate multi-terrain, Continent-Crushing InSearchOf bicycle.

Complete builds with 'The Search' Dynamo Wheelset are +£160

Complete bike images and details will be updated as soon as possible. Please contact us for more details.

 

InSearchOf x FURTHER. See how they use them HERE.

Features

  • Blend of Custom-formed, Progressive-butted, Dedacciai ‘Zero’ and Reynolds 853 steel tubing.
  • CNC machined dropouts are produced in the UK by BEAR components and developed specifically for the InSearchOf frame. Special hanger design isolates gear changing and wheel mounting loads.
  • ‘Anything Cage‘ style bosses on-top-of and underneath Down Tube and also on HotShoe fork blades, maximise luggage and fluid carrying capacity
  • HotShoe Carbon Fork: Designed by MASON exclusively for ISO. Featuring ‘Tri-Mount’ crown system for use with Mason Shutter mudguard and upcoming range of modular accessories. Internally routed for dynamo light systems and eyeletted for rack and mudguards.
  • Unique HotShoe 160/180mm flat-mount braking system. Mason are the first to develop and offer this standard.
  • Comes with our exclusive 'Shutter' Mudguard; Unique 'Load Bearing' design, will take up to 2kg. Designed to provide extra load space & effective coverage from dirt & debris when riding at speed and in mud. Keeps you fresher and protects the headset too.
  • This bike is available with the specially developed Mason x Hunt The Search Dynamo wheelset as shown, a Non-Dynamo version is also available, or the back-country ready HUNT TrailWide 27.5 wheels.
  • Extended MTB milage over rugged trails and looser conditions such as sand and snow: 27.5 TrailWide spec'd with WTB Ranger 2.8" tyres.
  • For seriously long solo rides into the unknown: 29 x 2.4" 'The Search' Dynamo wheelset with SON hub and WTB Ranger 2.4" with Tan-wall option.
  • Shimano's latest GRX-815 Di2/Hydro shifters paired with the precise, rugged XTDi2 mech.

Technical info

Select size
 

Dimensions
(mm unless specified)
A > SEAT TUBE C/T 420
B > SEAT TUBE C/C 380
C > BB DROP 76
D > REAR CENTRE 445
E > TT EFFECTIVE 542.3
F > TT ACTUAL 527.3
G > STACK 608.3
H > REACH 365.8
I > S/O - 27.5 x 2.8
(Measured vertically, 50mm in front of BB centre)
74.0
I > S/O - 29 x 2.4
(Measured vertically, 50mm in front of BB centre)
76.0
J > OFFSET 50
K > TRAIL 86.1
L > FORK CROWN HEIGHT 483
M > HEAD ANGLE 69.5
N > HEAD TUBE LENGTH 100
O > SEAT TUBE ANGLE 74.0
P > WHEELBASE 1056.7
Q > HANDLEBAR (OUTSIDE DIMENSION) 420
Dimensions
(mm unless specified)
A > SEAT TUBE C/T 460
B > SEAT TUBE C/C 415
C > BB DROP 75
D > REAR CENTRE 445
E > TT EFFECTIVE 553.2
F > TT ACTUAL 534.3
G > STACK 619.3
H > REACH 373.8
I > S/O - 27.5 x 2.8
(Measured vertically, 50mm in front of BB centre)
76.5
I > S/O - 29 x 2.4
(Measured vertically, 50mm in front of BB centre)
78.5
J > OFFSET 50
K > TRAIL 82.6
L > FORK CROWN HEIGHT 483
M > HEAD ANGLE 70.0
N > HEAD TUBE LENGTH 110
O > SEAT TUBE ANGLE 74.0
P > WHEELBASE 1063.8
Q > HANDLEBAR (OUTSIDE DIMENSION) 440
Dimensions
(mm unless specified)
A > SEAT TUBE C/T 500
B > SEAT TUBE C/C 445
C > BB DROP 75
D > REAR CENTRE 445
E > TT EFFECTIVE 557.6
F > TT ACTUAL 536.4
G > STACK 628.3
H > REACH 375.7
I > S/O - 27.5 x 2.8
(Measured vertically, 50mm in front of BB centre)
79.0
I > S/O - 29 x 2.4
(Measured vertically, 50mm in front of BB centre)
81.0
J > OFFSET 50
K > TRAIL 82.6
L > FORK CROWN HEIGHT 483
M > HEAD ANGLE 70.0
N > HEAD TUBE LENGTH 120
O > SEAT TUBE ANGLE 74.0
P > WHEELBASE 1068.9
Q > HANDLEBAR (OUTSIDE DIMENSION) 460
Dimensions
(mm unless specified)
A > SEAT TUBE C/T 540
B > SEAT TUBE C/C 490
C > BB DROP 75
D > REAR CENTRE 445
E > TT EFFECTIVE 566.6
F > TT ACTUAL 544.7
G > STACK 637.7
H > REACH 382.0
I > S/O - 27.5 x 2.8
(Measured vertically, 50mm in front of BB centre)
82.5
I > S/O - 29 x 2.4
(Measured vertically, 50mm in front of BB centre)
84.5
J > OFFSET 50
K > TRAIL 82.6
L > FORK CROWN HEIGHT 483
M > HEAD ANGLE 70.0
N > HEAD TUBE LENGTH 130
O > SEAT TUBE ANGLE 74.0
P > WHEELBASE 1078.6
Q > HANDLEBAR (OUTSIDE DIMENSION) 460
Dimensions
(mm unless specified)
A > SEAT TUBE C/T 580
B > SEAT TUBE C/C 530
C > BB DROP 73
D > REAR CENTRE 445
E > TT EFFECTIVE 586.5
F > TT ACTUAL 564.7
G > STACK 656.8
H > REACH 396.6
I > S/O - 27.5 x 2.8
(Measured vertically, 50mm in front of BB centre)
86.5
I > S/O - 29 x 2.4
(Measured vertically, 50mm in front of BB centre)
88.5
J > OFFSET 50
K > TRAIL 79.0
L > FORK CROWN HEIGHT 483
M > HEAD ANGLE 70.5
N > HEAD TUBE LENGTH 150
O > SEAT TUBE ANGLE 74.0
P > WHEELBASE 1095.3
Q > HANDLEBAR (OUTSIDE DIMENSION) 480

This page gives you some guidelines based on rider 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 and the rider size range is very similar for all our frames with 6 standard sizes [50-60cm]. InSearchOf sizing: We would recommend selecting one size down from your normal 'road' frame size. For example, if you would normally ride a 54cm then a 50cm InSearchOf is probably best for you.

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.

We'll set-up the front brake to be operated by the Right Hand lever for all UK destinations. For destinations outside of the UK, we'll set-up your bicycle with Front Brake/Left Hand as standard. It's no problem for us to set-up the brakes in your own chosen configuration, please state in 'Order Notes' how you like 'em.

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.

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.

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. For adventure and endurance riding, internal routing also has the advatage that it is easy to strap frame packs to the frame tubes without being hindered by external cabling and hoses.

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.

ISO Testing

All our frames complete the intensive strength and fatigue testing to fully comply with ISO standards. The AdventureSport range of frames are put through the tough road race ISO testing, with its brutal Horizontal Fatigue test. The Parallax fork goes through the MTB test with it's even tougher 'Drop Testing' standards. Because of this we are confident that these frames will last you a lifetime of hard riding.

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.

Custom Mason X Dedacciai Tubing

Almost the entire tubeset was developed in conjunction with Italian tube gurus Dedacciai, using their new 'ZERO', fine grain, micro-alloyed, progressive butted steel tubing. We work very closely with them to develop our Alu, Ti and steel tubesets for Bokeh, BokehTi, Definition and now the ground breaking ISO model. Read more about the tubing design in THINKING.

Custom Tubeset ISO

For the ISO every tube has a custom profile, section or bend to work exactly how we want it for ride quality, clearance and durability.

Threaded BB

The ISO frames use high quality stainless steel 73mm, BSA, threaded BB’s. This 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.

6x Bottle / Accessory Mounts

The InSearchOf is designed to travel, so all ISO framesets have a full compliment of bottle and accessory mounts. We do not reduce the number of mounting points with smaller frames.
There are 2 x bottle/accessory mounts on the HotShoe fork + the TriMount for the Mason Shutter load-bearing mudguard and upcoming rack systems.
The frame has 3 x bottle/accessory mounts. The smallest [42cm] size has an extra boss on the down tube which allows greater adjustability to make space for extra bottle on seat tube or a larger frame-bag on the top tube.

Suspension-Ready

The InSearchOf geometry and tubing is designed and tested to accomodate a suspension fork. The custom down tube allows plenty of clearance for the crown.
Crown height is 483mm, equal to a typical 100mm travel XC fork with 20% sag. Please check your chosen suspension fork tech data before fitting to ensure that the travel is no more than this stated dimension. Using forks outside these dimensions will void warranty and could result in frame failure.
Forks with 51mm offset are recommended.

Dropper-Ready

A dropper is great for getting the saddle out of the way for steeper, rougher and more technical riding, especially with a loaded up bike.
The 31.6 post size allows the use of most modern dropper-posts. The seat tube has internal ‘stealth’ routing which can be blanked-off when not in use and there are specific eyelets for dropper cable routing on the down tube.

160/180 Flat-Mount

The HotShoe fork is the first carbon fork to have Flat-Mount capability for 160 and 180mm rotors. We know this, because we designed the fork prior to the standards being released. This allows huge stopping power when loaded and in steep, rough conditions.

31.6 Seat Post

The Reynolds seat tube is Ø31.6 internally to be compatible with all popular dropper posts and our own Penta carbon seatposts.

27.5"/29"

The ISO is designed to work with both 27.5” [650b] and 29” [700c] MTB wheels and tyres, meaning this bike can be ridden over an extremely wide range of terrain. Recommended tyre sizes: 27.5 x 2.8” and 29 x 2.4”.

DForm Down Tube

We worked with Dedacciai to design and tool for the exclusive Mason ‘DForm’ down tube for the ISO frame. The special 'D-Section' shape where it meets the BB gives a flat wide weld for maximum stability at the pedalling platform and avoids excessive tube overlap onto the seat tube which can lead to fatigue failure.

I.S.O Tested

All our frames and forks are fully ISO tested before being produced. We test beyond the required standards and with the InSearchOf frameset we have produced our own specific test methods to more closely replicate the expected usage of the bicycle.
The Hotshoe fork is tested to full MTB standards, the frame is tested to both MTB and Race Bike levels, with a 50% increase to fatigue tests.

HotShoe Carbon Fork

As with all our framesets, we design and tool for our own fork. The ISO required a very special fork, so we designed the HotShoe carbon fork specifically for this frame. The refined shape gives ride quality and feel and there are multiple mounting points for accessories, including our TriMount on the fork crown for ‘Mason Shutter’ load-bearing fender. Internal routing for hose and dynamo wire and light mount on crown. Huge clearance for + size 29” and 27.5” tyres.
Fully tested to MTB standard with 483mm crown height [equal to a typical 100mm travel XC fork inc. sag] and 50mm offset.

Reynolds Seat Tube

A super high quality Reynolds 853 butted tube, oversize Ø34.9mm for 'Core Stability' and Ø31.6 internally to be compatible with all popular dropper posts and our own Penta carbon seatposts. Exclusive Mason Macro Ø34.1mm seatclamp tops it off. Seat tube also has internal routing for stealth dropper.

BOOST Spacing

148 x 12 at the rear and 110 x 15 at the front for max compatibility with modern MTB wheels. Boost spacing allows us to optimise frame clearance and stability and run large rim widths and big volume tyres.

Switchlever ISO

The InSearchOf uses SwitchLever Thru-Axles front and rear. This high quality axle system features a removable lever to be used with both axles. Store the lever in the front axle for quick use or remove completely for extra security and a clean, low-profile look.

Shutter Mudguard

ISO tested to 2kg and specific to the HotShoe TriMount. Standard equipment with ISO framesets and bikes. The Shutter helps keep dirt and water away from the rider, meaning you stay fresher on longer rides + it keeps your packs cleaner/dryer. The load platform is for bulky/lighter loads or frequently accessed items, It's ideal for something like a sleeping mat, bivvy bag or jacket etc in drybag. it avoids having to always use a bar-bag which can be annoying and restrict hand positions and mounting points. The flare at the front is for max coverage with large tyres to help stop stuff blowing back, the 'kickup' at the rear is to stop water/grit being hurled into the headset to prolong the bearing life.

Essential Dimensions: InSearchOf

BRAKING

Rotor Size: The fork can take Ø160mm or Ø180mm rotor [using adaptor]. Mason Cycles is the first to develop the 160/180 Flat-Mount standard for a rigid fork. Ø160mm is recommended at the rear. Ø140mm can be fitted using adapter.

Caliper Type: This frameset is designed for Flat-Mount calipers. It's possible to fit Post-Mount calipers front and rear with the use of a Flat > Post-mount adapter. Please contact us if you would like guidance on correct components to use.

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 + AXLE SPACING

The InSearchOf is designed around the 'BOOST' standard. The front hub is 10mm wider and the rear is 6mm wider than 100/142mm standard road thru-axle spec., allowing wider wheels and high volume tyres with larger clearances front and rear. The wider hub flanges result in a hugely stiffer wheel, giving enhanced bike handling and shorter/wider stays allow progressive geometry, whilst a wider rear hub helps give a greater choice of chainrings.

SwitchLever: Ø15mm Thru-axle Front / Ø12mm Thru-axle rear.

Front axle spacing: 110mm. Rear axle spacing: 148mm.

Axle length/pitch: Front - 134mm/1.5P. Rear - 172mm/1.5P. 

TYRE SIZES

All frame sizes are designed for and tested with both wheel sizes [29"/700c and 27.5"/650b] and a range of tyre sizes.

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

Max tyre size: 29" x 2.5" | 27.5" x 2.8".

Min tyre size: 29" x 2.0" | 27.5" x 2.8".

SEAT POST

31.6mm.

DROPPER-POST

31.6mm/Stealth-routed.

SEAT CLAMP

34.1 [InSearchOf Specific].

FRONT MECH

InSearchOf is designed with 1x transmissions in mind but will work with MTB 2x cranksets and is Di2 routed. Use 34.9mm, Low clamp/Side-Swing/Front-Pull.

BB TYPE

73mm shell width. BSA threaded.

CHAINRING FIT

1x Cranksets: SRAM - Use 3mm offset chainring. Shimano - Use BOOST spacing crankset. 
Max single ring: 36t round.

2x Cranksets: InSearchOf is designed with 1x transmissions in mind but will work with MTB 2x cranksets. Please contact us for recommended chainring sizes and crankset fit data.

HOTSHOE FORK

Dimensions: Crown height - 483mm [Equal to a typical 100mm travel XC suspension fork with 20% sag]. Offset - 50mm.

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.

'Shutter' Fender: Max load capacity 2kg. Recommended straps MasonxVoile 20".

TriMount: Max load capacity 2kg. Use 16mm x 5mm bolts.

Mounting Bolt Torque: 4Nm.

Accessory Cages: Max load capacity 3kg per side. Follow manufacturers installation and loading instructions.

SUSPENSION FORK

The InSearchOf frame was designed and tested for use with a typical XC Suspension fork of 100mm, with up to a 506mm crown height. Check fork manufacturers data to ensure chosen fork falls within this dimension, longer forks will void warranty.

Crown Clearance: Down tube design gives suspension fork crown clearance for most modern forks. We cannot guarantee ALL forks will clear, so please check when installing. 

Offset: 51mm offset is recommended.

 

Specifications

Our frame sets deserve the best components, so we put a great deal of thought into the mix of parts used for each bike build. Bars, stem and crankset are sized to match frame size choice. See Geometry chart for component sizing.

Frame Custom-formed Progressive-butted Dedacciai / Reynolds Steel tubeset.
Fork Exclusive 'HotShoe' Carbon, ThruAxle, Flat-mount fork with multiple accessory mounts.
Headset DEDA Low profile integrated headset.
Colours FilterGreen. ElementGrey
Bike Weight 11kgs - 50cm.
Sizes 42, 46, 50, 54, 58.
Shifting Shimano GRX-815 Di2 Shifting, XTDi2 Rear Mech.
Chainset Shimano Deore XT
Cassette Shimano M8000 11-42.
Chain Shimano HG701 11 Spd.
Braking Shimano GRX-810 Hydro Calipers.
Tyres WTB Ranger 29 x 2.4 / Ranger 27.5 x 2.8 / Schwalbe choices.
Wheels Mason X HUNT 'The Search'' Dynamo 29" / HUNT 27.5" TrailWide
Handlebar Ritchey Venturemax WCS
Clamp MASON Macro alloy ultralight.
Seatpost MASON Penta carbon, microadjust.
Saddle Fabric Scoop, Shallow, Pro
Bar Tape Fabric Hex tape.
Stem Ritchey Trail