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Sonder Frontier SX Eagle Recon Rumpus

Quick, lightweight 650b+ modern mountain bike with SRAM SX 1 x 12 groupset, Recon fork and Love Mud Rumpus wheelset.

£999.00

Available on finance, from per month*

Pictures are for illustration and some components and finishing kit of this build may be different. Please refer to the detailed spec sheet before placing an order.

  • Sonder Frontier SX Eagle Recon Rumpus 650b+ mountain bike in black - Black
    Black
  • Sonder Frontier SX Eagle Recon Rumpus 650b+ mountain bike in green - Forest
    Forest
  • Sonder Frontier SX Eagle Recon Rumpus 650b+ mountain bike in white - Crayon
    Crayon

How To Order

All our bikes are built individually to order. If you want to change any part of the spec to suit your needs then get in touch.

  • Frontier Frame [V2]

  • 1. Select Size

    Please select a size. See the fitting guide for size information

    In Stock
    Small
    In Stock
    Medium
    In Stock
    Large
    In Stock
    X-Large
    2. Select Colour

    Please select a colour. If your desired colour is not available, you can request a Stock Alert and you will be emailed when the product is either back in-stock or on pre-order.

    In Stock
    Black
    In Stock
    Crayon
    In Stock
    Forest

    Please choose from the options above

    Please make sure you have read and understood the terms of a Pre-Order purchase before placing your order. Payment will be taken immediately and your item will be despatched when stock arrives. If you require additional items please place a separate order as it will be held and sent together. More about Pre Orders

Please allow 20 working days for us to build, check, pack and despatch your Sonder.

Alternative payment options

Guide to paying with Cycle to Work Schemes

Klarna Finance
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Alpkit Ltd acts as a credit intermediary and offer credit products provided exclusively by Klarna Bank AB (publ). Klarna Bank AB (publ) is Authorised by the Swedish Financial Services Authority (Finansinspektionen) and is subject to limited regulation by the Financial Conduct Authority. Details about the extent of our regulation by the Financial Conduct Authority are available from us on request. Finance is only available to permanent UK residents aged >18, subject to status, terms and conditions apply. Registered office: Sveavägen 46, 111 34 Stockholm, Sweden. Corporation ID number: 556737-0431.
At a glance
  • 6061 aluminium frame
  • Set up as an XC for speed or relaxed for comfort and performance
  • Rockshox Recon suspension forks
  • Hydraulic disk brakes
  • Bolt through boost 148mm rear spacing
  • Rear mudguard and pannier rack mounts
  • 650b+ and 29” wheel size compatible frame

Frontier is our multi-activity hardtail mountain bike. Ride hard at the trail centre, load it up for a midweek bikepacking trip, pocket your passport and continue around the world. With full rack mounts at the back and multiple boss mounts on the fork, Frontier is an adaptable off-road explorer.

The geometry is for long day comfort but it’s no slouch.

The 6061 aluminium frame provides a durable and stiff chassis giving a responsive kick as you demand power when the slope steepens or enjoy feedback and precision through the corners.

Available as a fully rigid or with 100mm suspension fork. Set it up for XC race speed or for all day big mile comfort.

Tyre clearance gives you the choice of 27.5+ or 29in wheelsets. Bolt through 148mm boost rear spacing provides the benefit of stronger, stiffer and more efficient wheels.

Why SX Eagle?

SRAM Eagle drivetrains are designed, engineered and manufactured to work as complete drivetrain systems. Its 1x drivetrain is built to be lightweight, strong and intuitive, with the gear range to ride on any terrain.

SX Eagle provides the same Eagle performance benefits as NX Eagle, but at a lower price point. The main differences stem from the choice of materials and finish options, but functionally SX is fully compatible with SRAMs Eagle groupset.

Aluminium Frame

The 6061 aluminium tubing is durable, light, low maintenance and stiff.

Internal Cable Routing

Clean lines and tidy cables thanks to internal downtube routing. Frontier also incorporates routing for a dropper seat post.

Wide Tyre Clearance

Extra width between the chainstays gives you the choice of running 27.5+ tyres up to 3 inches or 29 inch tyres up to 2.5 inches.

Boost Axle Width

The Frontier frame is designed around bolt through Boost 148mm rear spacing providing the benefit of stronger, stiffer and more efficient wheels. Seatstay mounted disc brake for clean lines and damage protection.

Triple Bottle Cage Mounts

Fit 2 bottles in their standard location or run your downtube bottle cage a little lower to clear a bikepacking frame bag. Plus there’s an extra bottle cage mount under the downtube.

Frame spec

Frame Weight (kg): S: 1.84; M: 1.9; L: 1.98; XL: 2.03
Rigid Fork Weight - uncut (kg): 1.0
6061 Aluminium frame
Optimised for rigid or 100mm suspension forks
Internal cable routing through downtube
Bolt Through Boost 148mm rear spacing for wheel strength and optimal chainline
Fork built around Bolt Through Boost 110mm spacing
Threaded 73mm BSA BB shell for no-creak assembly
Chainstay mounted disc brake for clean lines and damage protection
Triple bottle cage mount on downtube
Use a seat clamp with integrated mounts for pannier rack compatibility
Clearance for 3 inch 650b+ or 2.5 inch 29er tyres
Reverb Stealth port
EN 14766 compliant

It is important to get the right size bike, if the bike fits you well it will be faster, more comfortable and easier to handle. Generally we recommend:

Small
Riders between 5ft 2in and 5ft 7in
Medium
Riders between 5ft 6in and 5ft 10in
Large
Riders between 5ft 9in and 6ft 2in
X-Large
Riders 6ft 2in and over
Frame size
Size Small Medium Large X-Large
ST - Seat tube 380 430 480 520
TT - Top tube 566 602 622 647
HT - Head tube 110 130 130 150
HA - Head angle 68 68 68 68
SA - Seat angle 73 73 73 73
CS - Chainstay 445 445 445 445
BB - BB drop 50 50 50 50
FO - Fork offset 51 51 51 51
WB - Wheelbase 1089 1127 1147 1174.5
SO - Stand over 764 793 825 853
RE - Reach 390 420 440 460
SK - Stack 566 580 594 613
Build SRAM SX Eagle, 1 x 12 Recon Rumpus 650b+
Frameset
Frame Sonder Frontier Frame
Fork Rockshox Recon RL Silver, 650b+, 100mm travel
Headset FSA Orbit C-40-ACB / 7.8mm Spacer
Seat clamp Love Mud Silent Partner, 34.9 mm
Group set
Brake Front SRAM Level
Brake Rear SRAM Level
Rotor Rear Avid Centreline 160 mm
Rotor Front Avid Centreline 180 mm
Rear mech SRAM SX Eagle Rear Derailleur 1x12 Long Cage
Shifter Rear SRAM SX 12sp
Chainset SRAM SX Chainset Powerspline 32T
Bottom Bracket SRAM Powerspline
Chain NX Eagle
Cassette SRAM PG-1210 12sp, 11-50t
Finishing Kit
Stem Love Mud Piskie, 31.8 mm
Seatpost Love Mud Membar, 31.6 mm
Saddle Love Mud Abode
Tape/Grips Love Mud Clutch
Handlebar Love Mud Aspect Riser, 780 mm
Wheelset
Wheels Love Mud Rumpus 650b+ Wheelset
Tyres WTB Ranger 2.8 Comp
Tubes WTB Inner Tube Presta 27.5
Weight
Frame S: 1.84kg; M: 1.9kg; L: 1.98kg; XL: 2.03kg
Built x.xkg; M: x.xkg; L: x.xkg; XL: x.xkg
Pedals not included with full builds

Swapouts and Upgrades

You can interchange Love Mud components on this build at no additional cost. So if you want a different length of stem, a particular saddle or bar then let us know in the notes section in the checkout and we'll get in touch. We also hold big stocks of SRAM, Rockshox, WTB and regular build with Shimano, Hope, Cane Creek. We'll build your Sonder with any part that suits your needs. Give us a call, with the same experienced mechanic helping throughout your build you know who to call if there's anything you want to know.

Click here for more information

Faqs

Support

Alpine Bond Warranty

We offer a 10 year guarantee on both our handmade titanium and Reynolds steel frames. Our hand welded 6061-T6 alloy triple butted frames and carbon frames come with a 5 year manufacturing defect warranty. All our bikes are built, checked and signed off by Cytech trained mechanics before being despatched to you in a custom-made bike box.

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