Diamondback Lumis 3 - Review

We handed over the Diamondback Lumis 3 to Justin Loretz for his thoughts on what he made of their new 27.5in wheel carbon XC / Trail hardtail orientated bike.

I've been riding and testing mountain bikes for thirty years. I've been around the houses (and the woods, forests and hills) a few times. I know what works and what doesn't when it comes to mountain bikes, the difference between showroom sizzle and singletrack sausage.

I'll start this with a personal note. The Diamondback Lumis 3 makes me wish that I was starting my mountain bike career in 2017 and not 1987. I'm not saying I didn't enjoy the constant mechanical attention 20th century mountain bikes required, but if I'd had a time machine, I'd rather have spent that time riding the Diamondback Lumis 3. Diamond Back were just starting making mountain bikes as I cut my MTB teeth, so they've got heritage and credibility. They've always been there making dirt worthy bikes, but they're turning a page. The classic cross country/trail orientated Lumis 3 hardtail being the preface to a new chapter of Diamond Back bikes. If you like the sound of this 27.5in wheel carbon hardtail, you'll love what else they've got.

The frame

The Lumis 3 uses carbon fibre as its frame material. All very fighter plane and F1 car, but it delivers a matrix of lightweight, strength, durability and design freedom, that makes carbon the go-to material for high performance bicycle frames. It bodes well for the Lumis 3, a bike which from its classical cross country race bike geometry could well ask you to drop the hammer on a climb or add another few miles to the ride. The frame isn't a waif that'll have you worrying about the odd knock, it's built for the rough and tumble of real life mountain biking. It's build with all the modern design cues. The rear wheel attaches with a through axle, the rear disc brake fits inside the left hand rear triangle. The bottom bracket shell is the new PressFit standard. The head tube is tapered – to accept a tapered steerer fork, which adds stiffness and steering precision. The tubes, such as the boxy carbon shapes which join both ends of the frame are sensibly proportioned to deliver a stiff, precise ride that will maximise the energy you put out.

The components

The fork is a RockShox Reba RLT Solo Air 100mm travel, tapered steerer fork, with 15mm through axle dropouts for steering precision. The brakes are Tektro TRP hydraulic units which grab 160mm rotors. The transmission is largely SRAM's excellent X9 series with the key change out item being the Diamondback Cold Forged alloy twin ring crankset. The wheels are Alex Rims laced tightly to Diamondback's own sealed bearing alloy hubset and are shod with excellent 2.25in Schwalbe Rocket Ron EVO tyres – the gold standard for XC speed and traction. The finishing kit is frankly amazing for the money, the seatpost stem and low rise handlebar are all Easton EA70 units, again top quality gear and the sort of parts you'd normally upgrade to, fitted as standard! The saddle is a well padded yet racy looking Diamondback branded part. We've done the maths on the Lumis's factory fit components and whichever way we add it up, you're winning.

The ride

There's a saying that if it looks right, then it is right. Well, a simple look at the Lumis 3 standing purposefully on the trail gives you an inkling that fun awaits. The book and cover match up as the Lumis leads you straight into a classic carbon hardtail ride. On anything resembling a maintained trail the fast rolling Schwalbe tyres just pick up speed and roll with a pace that makes you feel like a pro mountain bike racer. We lowered the bar a fraction and gained some more leverage which helped pin the front wheel to the ground on steep pitch climbs. Steering into the turns happens at the speed and with the timing that doesn't shock or upset. Sure it's a bit quicker than on a full scale trail bike, but XC rides like the Lumis 3 are supposed to be nimble and fleet of foot. Tight woody singletrack all day? Yes, please! The Reba fork demonstrates that RockShox are at the top of their suspension game as it very capably soaks up enough of the hits that you're not left having to wince or do too much body English to get down the trail. We enjoyed having the slick shifting SRAM X9 gearing which was wide enough for us to hammer up and down the steep slippery hills. We never missed a shift either. Good stuff. We gave the Lumis 3 a good thrashing and it never wavered in its mission to give back everything we put in plus a side order of smiles. As for wheels size, there are three to pick when buying an MTB, and 27.5in is the middle sized of the trio. For pure, unadulterated cross country speed, we'd still go with the larger 29in size, but when trails are tight and point and shoot handling is of equal importance, the 27.5in wheel of the Lumis is the preferred choice. With some of the hole bridging roll-over of the 29in and some of the fast turning speed of the old school 26in. Honestly we never really had cause to give the wheelsize a second thought, the Lumis just got one with being a quality mountain bike ride.

Returning to the point made in the intro, you're lucky to have the Lumis 3. In 1987, even in 2007, you simply couldn't buy a bike made this well, specced this well – for twice the price. Plus back then, (especially in '87) you'd have to tear down the bearings for a re-grease and fettle the rim brakes to deliver any sort of power, after pretty much every ride. Not here, and not now. Modern mountain bikes like the Lumis 3 are hassle free bikes which will spend next to no time being wrenched. Just what the rider in you wants.

Long term improvements

What would make the Lumis 3 better. Not much really. We'd probably err on the side of another 20mm of travel in the fork. The frame geometry could easily take it and it'd open the terrain selection and line choices up.

The rims are wide, on the plus side it sets the 2.25 tyres up into a nice beefy shape with minimal roll, on the negative narrower would be lighter and we're suckers for light wheels. We'd opt for a tubeless ready wheelset, this bike would benefit immeasurably from running tubeless with enhanced trail feel and added climbing traction.

If the Lumis 3 takes your fancy, then the guys at DiamondBack are offering a saving of £250 if you buy direct from Raleigh UK!

You can pick up a Lumis 3 directly here from the guys at Raleigh UK