Orbea Oiz M21 mountain bike review

The Orbea Oiz M21 might be the brand’s entry-level carbon cross-country bike, but it’s far from basic. With impressive performance and solid componentry, it’s a capable machine for riders looking to push their limits. Some quirks and areas would welcome improvements, but the Oiz M21 still delivers a fast and efficient ride, both uphill and down.

• Rockrider RACE 900S mountain bike review
• Canyon Lux Trail CFR review
• Trek Top Fuel 8 Gen 4 mountain bike review

The Oiz lineup features 120mm of travel and comes in alloy and carbon framesets. Alloy models start with the H30 at £3,000 and top out with the H10 at £4,000. Carbon options begin with the M21 (pictured here) priced at £5,000 and built around Orbea’s OMR carbon construction. At the top end, the range stretches to the M-Pro, featuring the OMX frameset and a premium £12,000 price tag.

Orbea Oiz M21 Shock.jpg, by Matthew Page

Orbea Oiz M21 – Technical details

Orbea has different grades of frame construction, with the OMR version pictured here being the lowest, with the OMX above, which is likely to be lighter. The Oiz M-Pro is the cheapest model in the range and features the OMX frame at £6,700.

The Oiz is a bike designed for racing and more aggressive XC use with 120mm travel at the rear. Orbea claims the frame gives efficient suspension and tuned rigidity. There are four different sizes available, each with specific recommended rider heights ranging from 155cm to 198cm for the XL size. The key geometry numbers for these framesets include a head angle of 67 degrees for all sizes, a seat angle of 76.5 degrees, and 436mm chainstays. The reach figure varies between 425mm for the S, 450mm for the M, 472mm for the L, and 496mm for the XL frameset.

The Oiz suspension uses the UFO single-pivot setup with flex designed into the seatstays. The main pivot sits above the 34T chainring to improve pedalling efficiency. There is a neat rubber cover over the area to keep some of the mud and muck out of the hard-to-reach area.

Orbea Oiz M21 shock 2.jpg, by Matthew Page

The Oiz M21 features the Orbea Squidlock, which manages both lockouts for the fork and shock and a remote lever for the dropper seatpost into one neat lever. The lever for the lockout moves through open, climb and lock settings.

Orbea Oiz M21 Squidlock.jpg, by Matthew Page

All Oiz framesets come with an internal cable routing called the SIC System. The cables are fed through grommets inside the top headset bearing, giving the bike’s front end a clean look. However, if you need to replace the headset bearing, you will also need to disconnect every hose that is fed through. If you prefer to ride with a lower front end, you can purchase a Low Stack Headset Cup for an additional £25, which allows for a possible 8mm lower front stem height, if riders want a slammed setup. All frameset versions use a standard BSA threaded bottom bracket.

Orbea Oiz M21 routing.jpg, by Matthew Page

Orbea Oiz M21- Componentry

The M21 model offers some flexibility in component choices, but our test bike came with the standard specification.

Orbea Oiz M21 drivetrain.jpg, by Matthew Page

At its core is the OMR carbon frameset, paired with a RockShox SID Luxe Select+ three-position shock. The RockShox SID Select fork provides 120mm of travel, featuring DebonAir+ three-position internals.

Orbea Oiz M21 Fork.jpg, by Matthew Page

Drivetrain duties are handled by SRAM’s GX Eagle mechanical groupset, featuring a 34T chainring and a 12-speed SRAM XG-1275 cassette (10-52T). One downside, however, is the lack of chainset length options – a surprising omission given the available build choices. Braking is taken care of by Shimano M6100 stoppers with 180mm rotors front and rear. Riders can also choose their preferred brake setup, either the UK standard (left rear, right front) or the European configuration in reverse.

Orbea Oiz M21 handlebar.jpg, by Matthew Page

The bike rolls on Oquo Mountain Performance wheels, featuring MP28 Pro alloy rims with a 28mm internal width. The stock tyres are Maxxis Recon Race 2.4in, though Schwalbe Wicked Will Evo 2.4in is available as an alternative.

Orbea Oiz M21 rim.jpg, by Matthew Page

Orbea sticks with its in-house components for the cockpit. While the two-piece OC Mountain Performance stem and 760mm alloy handlebar offer a clean look, some riders may prefer an integrated setup. That said, handlebar width and rise can be customised to suit different preferences.

Orbea Oiz M21 Cable routing.jpg, by Matthew Page

The Oiz M21 also comes with an OC Mountain Control M22 dropper seatpost, offering a 125mm drop as standard with 150mm and 170mm options available at no extra cost. Rounding out the build is a Fizik Vento Argo X5 saddle.

Orbea Oiz M21 Seatpost.jpg, by Matthew Page

Orbea Oiz M21 – Performance

Orbea claims the Oiz is an efficient design but with the fork and shock fully open, I found it quite reactive to input. There’s noticeable movement while pedalling, especially when pushing hard or riding out of the saddle. However, this fluidic feel makes it excellent off-road, particularly on technical climbs, flat sections, and descents. On smoother trails or Tarmac, the Squidlock remote becomes essential, but fortunately, it’s easy to use and keeps the cockpit looking clean. With three positions, though, switching back to fully open requires cycling past the lockout, which isn’t always ideal. The throw is also quite long, which may be tricky for some riders, and there’s only minimal sideways adjustment.

Orbea Oiz M21 linkage.jpg, by Matthew Page

One noticeable drawback is the wide seatstays – I found my calves brushing against them while riding, which became frustrating. My riding position is fairly typical, with neither short pedal spindles nor an exaggerated inward foot position, yet this was still an issue. Over time, I naturally adjusted my position to minimise contact, but it’s not something I’ve commonly experienced on other frames.

Orbea Oiz M21 tyre clearance.jpg, by Matthew Page

Component-wise, shifting is smooth, and the gearing range is well-suited to a variety of terrain. However, the fully internal cable routing could be a maintenance headache –replacing cables may take significant time or come with a hefty shop bill. Wireless setups largely avoid this issue, but mechanical rear derailleur cables will likely require frequent replacement, particularly in typical British weather conditions.

While the Oiz’s geometry isn’t as progressive or slack as some rivals, such as the NS Synonym, it remains a capable and fun bike on technical trails. It climbs well, and the Squidlock allows quick lockouts on smoother sections or a mid-setting for more technical terrain. The RockShox SID Select+ fork performs impressively, offering a surprising improvement over the Fox 34 Step-Cast found on the more expensive Orbea Oiz M-Team AXS.

Orbea Oiz M21 linkage 2.jpg, by Matthew Page

Despite the Oiz M21 feeling fast, the spec isn’t fully race-focused, and the tyres were a letdown. The Maxxis Recon Race tyres don’t feel particularly fast and also lack grip, especially up front. Swapping the front tyre would be a simple way to improve downhill confidence and speed. For racing, there are better options available that provide similar grip but roll much faster.

Orbea Oiz M21 – Verdict

While the M21 might be the lowest specification, it retails at £5,000, placing it among many other similarly priced and specced cross-country bikes. NS Bikes have the Synonym TR, which is even more progressive with the geometry, and the components also point towards a more aggressive angle, with the TR2 model at £4,400. Canyon has the Lux Trail CF9 for a little more but features a specification that is hard to match, with SRAM AXS groupset and dropper seatpost at £5,300.

Orbea Oiz M21 Frame.jpg, by Matthew Page

The Orbea Oiz M21 is a fast and capable cross-country bike with a high-quality OMR carbon frame and a suspension platform matched to the Squidlock remote that helps keep things firm when needed and climbing. The geometry strikes a balance between agility and stability, though it’s not as progressive as some rivals. Component performance is generally strong but the internal cable routing may pose maintenance challenges. Overall, the Oiz M21 is a fast, fun bike that delivers strong performance but requires a few tweaks to reach its full potential.

• orbea.com
• The reader’s guide to Off-Road.cc’s review scoring system

You might also like:

• What is downcountry?
• Cross-country mountain biking: everything you need to know
• 15 Great British bike brands made right here in the UK