Pick from three different flavours of wheel size and two frame material with the Spanish brand revamped trail bike, the 2018 Orbea Occam.

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2018 Orbea Occam AM LTD

2018 Orbea Occam need to know

• Occam AM is a 150mm travel 27.5in all-mountain bike
• Occam TR is a 130mm travel 29in/27.5+ trail bike
• Fox EVOL forks and shocks
• Metric Fox Float DPX2 on the Occam AM
• Increased size range
• Aluminium or carbon models
• SRP £1,699 to £6,499

2018 Orbea Occam TR 29

According to Orbea, their customers “want an Occam TR & AM with more travel, larger tires, extra stability and more opportunity for MyO Lite customization”. So that’s what the 2018 models are all about.

For the 2016 Occams, Orbea split the model into two. The Occam TR was the 120mm 29in trail bike, the Occam AM was the 140mm 27.5in all-mountain bike.

For 2018 they’ve upped the travel 10mm on all Occams and also introduced a 27.5+ option to the Occam TR. They’ve also changed the geometry although not radically. Size ranges have been bumped up; the Occam TR now comes in a Small and the Occam AM now comes in an XL size.

The general Occam aspects remain. So it’s still available in alloy or carbon. The swingarm has designed-in flex rather than stay pivots. It’s Boost 148.

So the Occam is a trail bike, right?

Yes, but really it’s three bikes; a mid-travel 27.5in bike and a shorter travel 29er with the third option being to run the 29er as a 27.5 Plus bike much like we’ve seen with other 2017/2018 trail bikes like the Santa Cruz Hightower and the 2018 Scott Genius.

Visually, there’s much in common between the big wheeler and the inbetweener. Both have a roomy front triangle with space for a water bottle, the shock nestled into a recess beneath the top tube, and a shock extender that attaches to the seat tube mounted swing link.

It looks a bit like a Stumpjumper, doesn’t it?

Indeed, and by choosing a similar layout of the suspension parts – by way of the shock position, shock extender and swing link – it also gains in terms of eliminating stiction and improving small bump compliance from the full compliment of bearings. Which, incidentally, are supplied by the acclaimed brand, Enduro.

I can’t see a pivot on the seatstay or the chainstay. How does that work?

To help achieve the impressive 1.99kg frame weight (size large, without shock) Orbea has actually got rid of the dropout pivot completely, and engineered flex into the carbon swingarm to take up the variation in angle between the chainstays and seatstays through the travel.

It’s something the brand has been running for around seven years on its XC race frames, and plainly it has the experience and confidence to take it to another level in terms of travel and application. As the suspension compresses, the seatstays flex upwards 25mm. It’s a movement that adds around 5kg of extra force at the saddle.

But why bother? And won’t it break?

This design saves 150g, simplifies manufacture and reduces lateral flex. It’s unsprung weight, too, so the difference is even more significant.

And the fact that Orbea still offers a lifetime warranty on the frame tends to suggest the engineers won’t be losing too many nights sleep about potential failures.

What about geometry?

It’s a fairly familiar chorus line from Orbea with respect to geometry. The words long, low and slack being repeated many times. In reality, the Occam is roughly in line with what you’d expect from a contemporary trail bike.

It’s not as progressive as a Mondraker, but it’s definitely not as conservative as a Santa Cruz.

We’re talking 66.5° head angles for the AM and 67.5° for the TR. BB heights are 340mm for both bikes.

Chainstays are fairly short, at 425mm for the 27.5in bike, and 440mm on the 29er/27.5+ (5mm longer than before to fit in the extra tyre clearance).

To achieve this, with room to spare for 2.4in tyres on the AM and Plus rubber on the TR), the Occam adopts the Boost 148mm hub spacing at the rear. This gives 3mm extra each side, moves the chainline out, and takes away much of the headache associated with designing a bike around short chainstays.

How many sizes are available?

The AM 27.5in bike is offered in small, medium, large and extra large. For 2018 the TR 29er/Plus comes in small, medium, large and extra-large.

What about all the details?

There’s internal cable routing (with the option to run external), a removeable front derailleur mount, moulded chainstay and downtube protectors, a bolt-on fin to stop the chain wedging between the cranks and the BB, 160mm post mount direct rear brake on the chainstay and the press fit BB92 bottom bracket. The rims are bit wider for 2018 too; 23+mm on the TR 29er, 30mm on the AM and 35mm on the 27.5+.

Anything else I should know?

You can customise your Occam through the MYO program. When you order online, you can select different stem lengths, bar widths, crank lengths and even frame colours.

Is there an aluminium version?

Yes, the hydroformed alloy Occam loses none of the carbon bike’s curvaceous good looks, gains 700g and uses a more conventional concentric axle (like the Rallon) instead of flexible stays.