First Look: Genesis Tarn Keeping It Real With UK Steel

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Made from steel, the Genesis Tarn is a dedicated 27.5 Plus bike for riders wanting the spring of steel, the boing of chunky rubber and the confidence and stability a modern geometry offers.

We’re not sure how the bods at Genesis went about developing the Tarn 20 but it’s clear to us that they managed to get their hands on a checklist for someones dream steel hardtail and went to town.

genesis tarn first look
Low slung and purposeful.

Versatility seems to the name of the game with the Tarn 20. Dual bottle bosses clearly point to a bike that you’re going to spend many many hours on, and with plenty of room on the slender frame to fit luggage, we can picture the Tarn 20 being the perfect choice for a spot of winter bike-packing.

genesis tarn first look
Plenty of standover for fun in the woods.

That said, the long, low, sloping top tube does have an aggressive look to it, and with pretty sorted geometry we wouldn’t mind getting a little rowdy on the Tarn 20 too.

genesis tarn first look
Skinny steel tubing for that patented steel ‘ping’.

The Tarn 20 is built around a two-tone black frame with gold details. The material isn’t just basic steel, but Genesis Mjölnir seamless double-butted cromoly tubing. Those words were actually really satisfying to type and bring back thoughts of classic skinny frames from the early 90’s, not that the Tarn 20 is anything like those bikes of old.

genesis tarn first look
All Tarn 20’s get the same length chainstays.

Our medium sized frame comes with a 440mm reach, 638mm stack, and a wheelbase of 1159mm. Genesis offers the Tarn 20 in four frames sizes, S, M, L and XL, all with the same 68° head angle and 74° seat tube, and all with the same length 432mm chainstays. On our bike that makes for quite a balanced and centred ride, we’re not sure how it would feel on the XL with 490mm reach though.

genesis tarn first look
120mm travel is more than enough for a sorted hardtail.

The not too slack head angle has a quality RockShox Pike RC Solo air fork with 120mm of travel plugged in.

As mentioned above, the frame is designed as a 27.5 Plus only bike, but there is a lot of tyre clearance out back, perhaps a 29er wheel could fit?

genesis tarn first look
Just try and clog the Tarn 20 with mud.

Plus tyres are provided by Maxxis, with Rekon Dual Compound EXO TR 60TPI 27.5 x 2.8in tyres fitted front and rear. This chunky rubber wraps around a pair of WTB Scraper i40 32h rims built on Shimano centre lock hubs.

genesis tarn first look
Shimano MT500 Deore brakes front and rear.

Shimano is very well represented on the Tarn 20 and everything from the drivetrain to brakes comes from the Japanese giant. The complete drivetrain comes from the SLX family and is 1×11 only out of the box, although we see no reason why a double couldn’t be installed if you were inclined to do so.

genesis tarn first look
SLX 1x chainset lives inside a threaded BB.

Brakes also come from Shimano this time a set of price-conscious MT500 hydraulic levers and callipers clamping on to a  180mm front disc and 160mm rear rotor.

Genesis covers a lot of the build kit with its own brand range of parts. The handlebar is a Genesis alloy number measuring 760mm wide with a 5mm rise. The stem is another Genesis item. The custom design has a 0° rise, but measures in at a lengthy 60mm.

genesis tarn first look
Genesis 60mm stem and 760mm bars.
genesis tarn first look
Genesis MTB saddle fitted to an X-Fusion dropper post.

Genesis has also raided its own parts bin for the Genesis branded MTB saddle, pedals and Genesis Loc on grips.

An X-fusion cable operated dropper posts ensure you can get your saddle out of the way for the fun bits, and if the 150mm drop isn’t enough, then there’s a QR installed for further adjustment too.

genesis tarn first look
External cable routing.

While the dropper is a stealth model, it’s only this short section of cable that is routed inside the Tarn 20 frame. All other gear cables and brake hoses are all externally routed for ease of maintenance.

genesis tarn first look
Fancy a Tarn 20 for yourself?

If this all steel, chubby wonder, does it for you then you can pick up the Genesis Tarn 20 as for £2199.99. Share your thoughts on the Genesis Tarn 20 in the comments section below.

Comments (4)

  1. “the spring of steel” nice looking frame but this got my bullshit detector going.

  2. I have last year’s model (same frame), and love it to pieces, but it’s certainly not the whippiest or springiest steel frame I’ve ever ridden. Not a bad thing though, my wife for example has an old Rocky Mountain Blizzard which is a thing of beauty, but has a bit too much flex. The tubeset selection on the Tarn is about right. Thick enough walls to get the power down, keep it pointed where you want it and take a beating. But not too heavy, and with just a little bit of ‘give’ to keep things comfortable and controlled in the rough stuff.

    “the frame is designed as a 27.5 Plus only bike, but there is a lot of tyre clearance out back, perhaps a 29er wheel could fit?” – actually Genesis did a Tarn 29 model using this same frame in the 2018 range. I have a pair of 29er hoops for mine and they fit just fine with a 29×2.35 Spesh Ground Control Grid in the rear. Could probably get a 2.4 in there without too much bother. The bike sits a little taller on the 29ers, but handling remains good.

  3. pretty sure it’s the same frame as last year, which i run as a 29er. 29×2.4 on a 30mm rim fits fine. it is a very comfortable frame and the geo is great. although i wish it was a little lighter. still haven’t tried mine in plus flavour. can’t bring myself to buy a boost fork.

  4. ‘and with plenty of room on the slender frame to fit luggage, we can picture the Tarn 20 being the perfect choice for a spot of winter bike-packing.’

    Am I looking at the same bike???

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