NS Bikes Define AL 170 is a big-hitting aluminium enduro bike with 180mm front and 170mm rear travelMullet wheels mix a 29in front and 27.5in rear.

Product Overview

NS Bikes Define AL 170 1


  • Modern geometry and sizing. Excellent suspension components and tyres. Recessed cabling looks sleek but without the hassle of proper internal routing.


  • Rides like a shorter-travel bike.


NS Bikes Define AL 170 1: first ride review


Price as reviewed:


With big travel and mullet wheels, the enduro-ready NS Bikes Define AL 170 is easy to pigeonhole… or is it?

Can you identify a bike’s intended use by travel alone? I don’t think you can, and the new NS Define AL 170, an aluminium enduro bike that boasts 170mm travel and comes with a 180mm-travel fork and mismatched wheels, is a prime example.

Read more: Best enduro mountain bikes in 2021

ns bikes define al 170

X2 shock is supportive rather than supple and falls 10mm short of stated travel

There are two models in the Define AL 170 range and both use the same chassis – the 1 here and a sibling called the Define AL 170 2. That model has a RockShox Zeb fork instead of the Fox 38 and a coil-sprung X-Fusion rear shock, not the air-sprung Fox X2 you see here. Yes, it is a heavier build but it’s also £1,100 cheaper and, when I spotted it on the NS website, it looked like a bike you could take to BikePark Wales for a dirty weekend or find some steep off-piste to let your hair down.

180mm-travel Fox Performance 38 fork is made for the roughest of rides

Now, the reason I’m banging on about the Define AL 170 2 when I’m supposed to be doing a comprehensive first ride on the 1, is because I’m convinced that they’re different sides of the same big-bike coin.

The Define AL 170 1 is essentially a long-travel bike with aggressive geometry that you can pedal to the mountain top and ride down it, whereas the coil-sprung Define AL 170 2 is the kind of bike you’re more likely to sling on the uplift.

ns bikes define al 170

Guide RE brakes offer high performance without bloating the budget

And there’s overlap. At the heart of both bikes is a hydroformed aluminium frameset. It’s nicely put together and has some cool features like the hybrid cable routing which runs inside a recess on the underside of the down tube. This means you can’t see the cables from the side, so they don’t spoil the clean hydroformed lines, but you can access them easily for maintenance or servicing.

There’s also a geometry adjust feature built into the lower shock mount and by flipping the offset chip you can change the BB height by +/- 5mm and the head tube/seat tube angle by roughly half a degree. The default setting is the lower one, and having spent some time in this configuration I can’t see anyone changing it (except maybe out of curiosity) especially if you use this bike for its intended purpose.

Read more: How to change your mountain bike’s geometry

ns bikes define al 170

Well-designed in-house stem epitomises NS’s attention to detail

The specification on the Define AL 170 1 is totally in keeping with its hard-charging attitude. The Fox 38 Performance series fork and X2 rear shock steal the headlines but NS has really sweated the details elsewhere. The in-house components are not just labels; there’s some real thought gone into the design of the stem, for example, with its interlocking twin face clamps, similar to a Renthal Apex stem.

Maxxis High Roller II tyres come stock and although the 2.4in rear tyre is a little narrow on a big-travel bike, NS has done the smart thing and opted for the tougher, reinforced DH casing out back. The bike also gets the excellent X-Fusion Manic dropper post – it’s low profile, uses a multi-adjustable remote lever and is length-specific across the three frame sizes. The size medium featured here gets a 150mm post, the large has a 170mm and the small a 125mm drop.

ns bikes define al 170

X-fusion Manic dropper post with adjustable remote and size-specific travel

The drivetrain is entry-level SRAM NX Eagle with an 11-50t cassette, but it’s nice to see a Truvativ crank with an oversized DUB spindle, not the cheaper third-party components you get on a lot of bikes. NS has been dead clever with the brake spec too – it’s fitted budget SRAM Guide RE brakes with 200mm rotors. They offer top performance at a competitive price, which is why they’re previous winners in mbr disc brake tests.

How it rides

NS Bikes Define AL 170: how it rides

When a bike turns up with a burly 180mm fork and boasting 170mm travel at the rear, it’s usually party time. Not so with the AL 170 1. In fact, on our first rides together there were no fireworks, and I wasn’t attempting crazy lines or hitting big doubles without a care in the world. And I reckon there are a couple of reasons for that. First, it comes up short on rear travel, I measured it a touch over 160mm. It’s only a small short fall but the rear suspension also didn’t feel that compliant or capable, which isn’t what I’d expect from a bike with this much going on at the back-end.

A restrained ride belies the NS’s big numbers but the rest of the spec sheet is hard to fault

In its defence, NS Bikes does say that it put the focus on pedal efficiency, which explains a few things. The bike climbs really well and sprints out of turns with ease, but it also feels pretty firm when hammering through rough, rooty sections. If this sounds familiar it’s because when I reviewed the Define AL 150mm last year, I said pretty much the same thing – no wasted energy stomping up the climbs, but it didn’t seem to have the travel advertised.

So while the NS Bikes Define AL 170 1 is efficient on the ups, it’s also muted on the descents. Which is why I’ve asked NS if I can get a spin on the coil-sprung Define AL 170 2 for a first ride later in the year. Hopefully that’ll be the bike to finally get the party started – watch this space.

NS Bikes Define AL 170 1


Frame:6061 aluminium, 170mm travel
Shock:Fox Float X2 Performance
Fork:Fox 38 Performance, 180mm travel
Wheels:NS Rotary 110/148mm hubs, Octane One Solar 30mm rims, Maxxis High Roller II 3C Exo 29x2.5in/Aggressor Exo + 27.5x2.4in tyres
Drivetrain:Truvativ Descendant 6k DUB 170mm 34t, GX r-mech, SRAM NX Eagle shifter, SRAM PG-1210, 12-speed 11-50t cassette
Brakes:SRAM Guide RE, 200/200mm
Components:NS bar 35 800mm, NS Quantum Lite 45mm stem, X-Fusion Manic 150mm post, Octane One Crit saddle
Sizes:S, M, L
Weight:15.9kg (35lb)
Size tested:M (low)
Head angle:63.4°
Actual seat angle:70.4°
Effective seat angle:77.5°
BB height:343mm
Front centre:825mm
Down tube:760mm
Top tube:624mm