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Send-it-all on the new Sentinel.A bike that says yes to every trail, every ride and begs for more.
Send-it-all on the new Sentinel.A bike that says yes to every trail, every ride and begs for more.
Transition

2025 Transition Sentinel Carbon Frame - White

£3,399.00
Pre-Order

With Pre-Order, you can purchase the latest items added to our store in advance of them arriving with us.

Your Pre-Order is prioritised (at no additional charge); meaning that as soon as the product arrives with us, we can wrap it straight back up; ready for collection via Click & Collect or despatch to you — it often never even hits the stock room shelves!

Pre-Launch

With Pre-Launch, the date when we expect to receive the product ourselves is still a little too hazy to be confident in accepting Pre-Orders.

So, instead, you can submit your email address against the item you are interested in and we will email you as soon as stock arrives on the system.

Estimated Delivery & Collection Dates

Estimated Delivery & Collection Dates are given on Pre-Order and Pre-Launch products. They are for indication purposes only and can change at any time without notice.

The dates we provide are based on indications given by our suppliers. Whenever we get updated information from our suppliers we will endeavour to update the Estimated Delivery & Collection Dates provided on product pages.

We estimate this will be ready for despatch to you or collection via Click & Collect on Undetermined
No Hassle Returns


Our policy lasts 30 days. If 30 days have gone by since your purchase, unfortunately we can’t offer you a refund or exchange.



To be eligible for a return, your item must be unused and in the same condition that you received it. It must also be in the original packaging.

Several types of goods are exempt from being returned. Perishable goods such as food, flowers, newspapers or magazines cannot be returned. We also do not accept products that are intimate or sanitary goods, hazardous materials, or flammable liquids or gases.

Additional non-returnable items:

  • Gift cards
  • Custom painted items
  • Items that have had custom decals fitted or frame protection
  • Custom built items such as wheels or bikes
  • Special order items
  • Some health and personal care items

To complete your return, we require a receipt or proof of purchase.

Please do not send your purchase back to the manufacturer.

There are certain situations where only partial refunds are granted: (if applicable)

  • Book with obvious signs of use.
  • CD, DVD, VHS tape, software, video game, cassette tape, or vinyl record that has been opened.
  • Any item not in its original condition, is damaged or missing parts for reasons not due to our error.
  • Any item that is returned more than 30 days after delivery


Refunds (if applicable)

Once your return is received and inspected, we will send you an email to notify you that we have received your returned item. We will also notify you of the approval or rejection of your refund.

If you are approved, then your refund will be processed, and a credit will automatically be applied to your credit card or original method of payment, within a certain amount of days.

Late or missing refunds (if applicable)

If you haven’t received a refund yet, first check your bank account again. Then contact your credit card company, it may take some time before your refund is officially posted. Next contact your bank. There is often some processing time before a refund is posted.

If you’ve done all of this and you still have not received your refund yet, please contact us at info@mechmonkey.co.uk.

Sale items (if applicable)

Only regular priced items may be refunded, unfortunately sale items cannot be refunded.

Exchanges (if applicable)

We only replace items if they are defective or damaged. If you need to exchange it for the same item, send us an email at info@mechmonkey.co.uk and send your item to: 2A Balmoral Link, Belfast, BT12 6QB, United Kingdom.

Gifts

If the item was marked as a gift when purchased and shipped directly to you, you’ll receive a gift credit for the value of your return. Once the returned item is received, a gift certificate will be mailed to you.

If the item wasn’t marked as a gift when purchased, or the gift giver had the order shipped to themselves to give to you later, we will send a refund to the gift giver and he will find out about your return.

Shipping

To return your product, you should mail your product to: 2A Balmoral Link, Belfast, BT12 6QB, United Kingdom.

You will be responsible for paying for your own shipping costs for returning your item. Shipping costs are non-refundable. If you receive a refund, the cost of return shipping will be deducted from your refund.

Depending on where you live, the time it may take for your exchanged product to reach you, may vary.

2025 Transition Sentinel Carbon Frame - White

Season:2025

Brand:Transition

Code:TR.FS.25.SENT.CRBWHT

Send-it-all on the new sentinel

A bike that says yes to every trail, every ride and begs for more.

The Sentinel rides the lines between planted bottomless sender and playful, poppy trail pony. This leaves he Sentinel right in the sweet spot, as we like to call it. Its versatile attitude helps riders excel and push their limits, making it the "one bike" most will need. Its intuitive nature makes it easy to ge acquainted with; you'll find yourself sending lines, jumps, and maneuvers you always felt were beyond your ability. Where before you went around, now you go over. Where you pushed up, now you pedal. Where your rolled, now you boost. It's time to send-it-all.

Refining the legend

The new Sentinel may have a similar silhouette, but we've fully redesigned th frame with update industrial design, features and geometry to turn it up a notch. The leverage curve supports the bike higher in its travel, keeping it quick, nimble and light on its feet while leaving plenty of room for big hits. This gives it the lively, sporty attitude felt in the Spur and Smuggler without sacrificing its capabilities in rougher terrain. New size-specific chainstays and a 64 headtube angle keep riders balanced with great traction on climbs and descents. All of this crates a bike tht encourages new riders tyo push their limits while ensuring a seasoned Pro feels none.

Refined details

We added internal frame storage in the downtube of our carbon frame. The boom box (burritos or other munchies) is positioned below and isolated from the water-bottle cage mount. This allows you to leave your bottle installed in your cage while easily getting into the boom box, reducing clutter and fuss on the trail. It also prevents noise and potential failure since it doesn't place any weight on the door itself. With an easy access lever and two supplied gear bags, riders can stow away snacks, tools, a tube, or anything else they want to have along for the ride.

Geo adjust flip chip: the lower shock mount has a geo-adjust flip chip to accommodate mixed wheels, and features a new design that allows water, dirt and debris to easily wash away.

Mud guard: the sentinel comes with a pre-installed mudguard to protect the main pivot area, improving the bearing life.

Chainstay protector: an all-new chainstay protector minimizes chain slap, so you can enjoy the sound of your favourite turns.

Cable ports on the side of the headtube allow for easy and simple cable routing with customizable options for mechanical or wireless shifting as well as left or right rear brake setups. The new port stops cables from getting kinked during a crash and holds them tight to prevent rattling. If you aren't using the port at all, simply cover it with the supplied insert to prevent dirt or water from getting inside your frame and keep a clean aesthetic. These ports help improve the looks of the frame while remaining functional and simple for maintenance.

Fidlock ready

The new Sentinel is Fidlock ready. We know water bottle capacity is a priority on every bike and can be tricky on smaller sizes. To give you the most options on all sizes, every sentinel will come with a fidlock base installed. Fidlock bottles give you more volume for water in a smaller space, allowing for a Fidlock 450ml bottle on our xs frame, up to 590ml on sm, and up to 750ml on m-xxl.

  • 29" wheels s-xxl and mixed wheel compatible, dual 27.5 on xs.
  • 160mm travel front, 150mm travel rear (up to 160).
  • Boom box in frame storage with supplied frame storage bags on carbon models.
  • 64 headtube angle.
  • Size specific chainstays (xs 436, sm/md 442, lg/xl/xxl 448).
  • Increased size range (xs-xxl).
  • Main pivot mud guard.
  • Carbon and aluminium frame options.
  • Available in 3 colors.
  • New cable routing ports.
  • Refined kinematics create a lively, progressive platform.

Carbon and aluminium frame options

We want everyone to have the bike of their dreams, so we are offering the sentinel in both carbon and aluminium. To make this bike as accessible as possible, we crafted the aluminium frame to remain simple, keeping costs and weight to a minimum. This means it does not have the boom box, but does still have the flip chip and all other features found on the carbon frame. The aluminium frame is available with two build kits, Shimano deore and xt, as well as frame only. The carbon frame is available in three build levels, Shimano deore, XT, and SRAM X0 AXS as well as frame only. Each carbon build has the same high quality carbon construction including the boom box and frame bags.

Giddyup suspension design

We want to make it as easy as possible to experience great rear suspension performance. The giddyup suspension system is designed to behave intuitively across a broad range of setup. Because, we get it, sometimes you just want to grab your bike and giddyup, without checking your setup. When you do, it will always feel good.

We did this by balancing a 25% progressive leverage curve with a consistent linear rate of change. Anti-squat is tuned to enhance pedaling performance and acceleration. Overall chain growth is moderate and reduces after sag so chain tension doesn't get in the way of the suspension working.

This translates to killer small bump compliance and great mid-stroke support that gradually transitions into an end of stroke ramp that is subtle, yet supportive. The amount of consistent progression is carefully optimized for both air and coil shocks. Riders are able to add or remove volume spacers in air shocks to suite their individual riding style and there is no compromise to bottom out support with coil shocks. The sentinel has 150mm of rear wheel travel when used with the supplied 205mm x 62.5mm stroke shock. It is also possible to install a shorter, 205mm x 57.5mm stroke shock, to decrease the rear wheel travel to 140mm.

A wide usable sag range of 25 - 35% allows the rider to tune the feel of the bike; from poppy and playful, to planted for plowing. Wherever you end up, you can focus on the trail without remotes, levers or knobs. Just grab your bike and giddyup.

Technical Information
Frame Specifications

REAR TRAVEL: 150mm (Compatible with 160mm)

FRONT TRAVEL: 160mm

WHEEL SIZE: 29" or MX (XS 27.5 only)

SIZES: XS, SM, MD, LG, XL, XXL

FRAME BEARINGS: 2x 6903, 2x 6902, 4x 6802, 2x 3802, 2x 6900

FORK AXLE TO CROWN: 578mm (Includes headset) (XS 560mm)

FORK OFFSET: 44mm (XS 37mm)

REAR SHOCK SIZE: 205mm x 60mm (compatible with 205 x 65mm)

SHOCK HARDWARE: Trunnion Mount Top / 30mm x 8mm Bottom

HEADSET (TOP): 44mm Zero Stack

HEADSET (BOTTOM): 56mm Zero Stack

BB SHELL: 73mm BSA Threaded

CHAINLINE: 52-55mm

REAR BRAKE MOUNT: 180mm Post Mount, Max Rotor Size 223mm

REAR AXLE: Transition Axle For UDH, 12mm x 148mm Spacing

ISCG TABS: ISCG05

SEATPOST DIAMETER: 31.6mm

SEAT CLAMP: Carbon: 37.0mm, Alloy: 34.9mm

MAX CHAINRING SIZE: 34T Standard Single Ring

MAX TIRE SIZE: 29" x 2.5"

REAR SHOCK SAG: 150mm/60mm: 16-20mm (26-32%)
Sizing Information
XS
27.5"
SM
29" | MX
MD
29" | MX
LG
29" | MX
XL
29" | MX
XXL
29" | MX
A. REACH415430 | 426455 | 451480 | 476505 | 501530 | 526
B. STACK592615 | 618621 | 624633 | 636642 | 646651 | 655
C. CARBON EFFECTIVE TT LENGTH527549577605632660
ALLOY EFFECTIVE TT LENGTH534557586614642670
D. SEAT TUBE LENGTH360360390430460490
E. CARBON EFFECTIVE ST ANGLE79.8°79.3° | 78.9°78.7° | 78.3°78.3° | 77.9°77.9° | 77.5°77.6° | 77.2°
ALLOY EFFECTIVE ST ANGLE79.2°78.7° | 78.2°77.9° | 77.5°77.3° | 76.9°76.8° | 76.4°76.5° | 76.2°
SADDLE HEIGHT FOR EFFECTIVE ST ANGLE560600660720780820
CARBON SEAT TUBE OFFSET AT BB696969696969
ALLOY SEAT TUBE OFFSET AT BB878787878787
F. HEAD TUBE LENGTH100100110120130140
G. HEAD TUBE ANGLE64°64° | 63.6°64° | 63.6°64° | 63.6°64° | 63.6°64° | 63.6°
H. CARBON CHAINSTAY LENGTH436442 | 440442 | 440448 | 446448 | 446448 | 446
ALLOY CHAINSTAY LENGTH434442 | 440442 | 440446 | 444446 | 444446 | 444
I. CARBON WHEELBASE117312081237127313021332
ALLOY WHEELBASE117112081237127113001330
J. BOTTOM BRACKET DROP1525 | 1125 | 1125 | 1125 | 1125 | 11
K. ESTIMATED BB HEIGHT340350 | 344350 | 344350 | 344350 | 344350 | 344
All measurements in degrees and millimeter
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