At a glance
- 6061 aluminium frame
- 148mm Boost bolt through rear axle
- 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 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.
It is a bike that will likely tick many boxes for anyone planning multi-day rides, without first returning home for their tea.

This cracking value and rock solid machine from Sonder is just crying out to be loaded up and taken to the horizon.

Giving several centimeters of squish, their suspension-like characteristics help the Frontier float over rough terrain. With big handlebars, an upright position, and loads of stand-over, the Frontier is great for roistering about on, and could certainly serve as a regular mountain bike.

Arguably one of the best value bikes in this selection, Sonder’s Frontier Rigid is a 27.5” (or 29” compatible) mountain bike, armed with a wide-ranging SRAM SX Eagle 12-speed chainset. You’ll find plenty of mounting points for bottles, cages, racks and guards, including mounts on the rigid forks.

The Frontier might be considered a Jack of all trades but the clever bit is, it's able to master most of them.

Sizing
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

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 |
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 |