Pipedream Sirius S5

Pipedream Sirius S5 review

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Pipedream Sirius S5
Pipedream Sirius S5

The Pipedream Sirius S5 features in our ‘Going to unextremes’ bike test

The S5 is the latest Pipedream Sirius to hit the trails after its first ancestor emerged from the mud in 2006. Here the ‘DOG’ philosophy translates to a 65° head angle, 77.7° seat angle, and a 465mm reach on the ‘Long’ I rode here. Chainstays are the same across all sizes, with replaceable and adjustable dropouts giving a range of 425–441mm. I tested mine at the minimum 425mm setting, as with 2.3in tyres I had no need for more clearance, and no desire for more stability through a longer setting.

The Pipedream website allows you to buy a frame only, or to add a range of pick and mix items from its stock to build your frame with. It’s recommended that you pick either its rigid fork – with plenty of luggage mounts for bike packing – or a 120mm fork. You can build it with a 130mm fork, but it’ll raise the BB and shorten the reach by approximately 5mm and slacken the head and seat angles by approximately 0.5°. Our test bike came built up with a selection of build items not all available on the website pick and mix, plus an on-piste RockShox SID Ultimate 120mm fork.

Gotta ‘ave a ‘ead badge

Being built with a selection of parts based somewhat on immediate availability rather than those that can be picked as standard from the Pipedream website, it’s perhaps a little unfair to comment too much on the build, though it may give you fuel for thought if you’re doing your own, so I’ll touch on some of the choices. A Pro Koryak 170mm dropper post was the standout item on this bike, in the wrong way. Perhaps the length of it and past use had worked against it, but it had some significant waggle between the two shafts of the post and became very stiff to drop. Coupled with an apparent inability to grip the saddle firmly – I lost track of the number of times my saddle repositioned itself with a groan on my test rides – it could be quite the source of distraction. Given the frame is designed to have a substantial length dropper post on it, I’d suggest you invest in the best you can afford here.

The Pro Tharsis bars took me a bit of getting used to – they’re quite flat with little sweep or rise to speak of compared to what I’m used to, which combined with the low stack of the frame to put a fair amount of weight on my arms. I resisted the urge to remove the bars after the first ride and grew to enjoy the directness of the steering, though in the longer term I think my wrists would thank me for a little more back sweep. The brakes were the first time I can recall using Maguras, and these entry level MT Sport Trail didn’t really sell themselves to me. The distinctive lever shape might sit better with me if I felt like the stopping power I wanted was on the other end of them, but to me they lacked power – especially when whizzing along on a short travel hardtail that lures you into hitting warp speed.

Singlespeedable dropouts and a multi-storey brake mount

Cable routing is pleasingly external, save for where the dropper runs around the outer bottom bracket shell and into the seat tube. With plenty of points to hold the cables in place, I had no trouble with any untidiness. One curiosity is the position of the bottle mounts – they’re very low down on the frame, which puts some bottle cages too low to fit a bottle in without butting up against the curve of the seat tube, and is certainly too low for one of those cages with a tool stash in the bottom. Expect to need an adapter to mount some cages higher up the frame, especially the tool stash ones.

To give the frame the attention it is due, it is beautifully put together with super smooth welds, neat paintwork that has withstood all I’ve thrown at it, and a minimal amount of branding and graphics. I’m not sure I’m convinced by the Vintage Green/‘Cow Poo in the Sun’ colour – or maybe it just clashes badly with the blue SID fork. The CNCed yoke adds stiffness and is shaped to give clearance for up to a 34T chainring, and the chainstays sweep back from it without any heel-catching flare. The yoke also does a good job of not collecting mud and grime on a ride, leaving you plenty of clearance for up to 29×2.6in or 27.5×2.8in tyres – although with the chain stays set to the shortest option and 29×2.3in tyres fitted, the bike had a nice agile feel well suited to the climbs and moorland rides I’ve subjected it to. You could, build it up as more of a monster truck – suited perhaps to bikepacking for comfort not speed, or the kind of trundling over mountainsides that only Scottish access rights allow.

Clean lines…

This build is no perfect spec carefully chosen for weight weenie points and it weighs in at 13.1kg – the Long frame has a claimed weight of 2.6kg.

The Ride

Perhaps exacerbated by me being on the upper end of height for this Long bike, I did find myself feeling a little perched on the bike, bum up, head down in a manner I’d not personally choose, but still less aggressive than many faster riders favour. But it’s been a while since I rode anything with cross-country/trail aspirations rather than trail/enduro desires. Not that Pipedream says this is a cross-country bike – apparently it’s “a fusion of modern geometry, exceptional engineering and short travel efficiency. Is this Downcountry? Is this XXXC? We don’t care, this is mountain biking.”

…even when muddy

Once I’d got past the ‘oh yes, some people like to go fast up as well as down’ and ‘you should probably do flexibility exercises’ reminder from my back and neck, I also remembered that some people like to ride attached to their bike. In fact, it seemed almost plausible that I might do the same. Riding a regular local trail that clings close to a wall, I was amazed to find myself at the end of it having achieved a hallowed ‘no dab’ clear run. Every time I approached a tricksy little move like one requiring me to pedal towards the wall, around the drop to the left, then back away from the tussock sitting at the foot of the wall, I’d think ‘there’s no way I’ll make it this time’ and brace myself for a body check on the wall or a tumble into the ditch below, only to find myself steering onwards along the trail. And this was in flats, where the temptation to dab is so much greater than clips. A little part of me wondered if I might even be faster if I wore some disco slippers… but since when have I been interested in uphill times? What was this bike doing to me? If I wasn’t careful I might find myself training, or rehydrating with electrolytes.

The Pipedream Sirius S5 continues to perform away from the steepest and techiest of climbs. It makes its way along the trail with a much more purposeful sensation than the longer travel hardtails I’d usually ride, but with more confidence than the gravel bikes I’d also go for. On draggy climbs and undulating ground I really noticed how my ride position seemed to work with the strongest parts of my legs, my body relaxed and no fatigue in the knees. If you did want to put the miles in, this is a great bike for the job. It’s efficient to pedal, it’s robust enough to not feel delicate – and it makes the descents fun.

Lowering the dropper, you become the rider of a very nice steel hardtail with a nicely capable fork up front and body positioning that feels entirely familiar. The precision handling and steering that helps out on a tricky climb continues on the descents, with the bike going just where I want it and not where I don’t. Up to a point, anyway – that point being the limits of the brakes, which are just not powerful enough to deliver the line choice you need at the speeds this bike will make you happy to travel at. Luckily there is forgiveness here for some ragged lines – the slack head angle and steel frame give room to ‘ride it out’ rather than being pinged unceremoniously off into a bog when catching the edge of a rut. Even on consistently rocky trails like Rivington Pike’s Ice Cream Run I found myself able to plough onwards without feeling like I was being bucked and bounced around.

In a loud world of bigger is better, gimme more travel, the Pipedream Sirius steps forth with its understated paint job and classic steel lines, quietly delivering mile after mile of fun, whatever the gradient.


The Pipedream Sirius S5 is no match for a super stiff carbon bike in terms of power transfer or weight, but the angles on it make it a pleasure to pedal purposefully onwards. I’ll happily trade a bit of snap for comfort, and while it isn’t a cross-country race bike, if you’re carbon-frame averse you could certainly build this up a bit lighter and do a good job of pitting yourself against the weight weenies.

With its 120mm fork, I think you’d soon want for something burlier if you frequently throw yourself off drop-offs and down big bouldery descents – and for that there’s the Moxie – but if your riding style is more wheels on the ground this is a great proposition. If you’re looking to get yourself onto a bike that lets you play without just trundling over everything, then there’s plenty of fun to be had here – perhaps making it ideal for the rider who’s been around long enough to have a shed full of bits needing a new home? Treat your build to a top-notch fork and dropper plus your favourite brakes to get the most out of this fun hardtail that loves to pedal up and play down.

Check out all our mountain bike reviews

  • Frame: Pipedream Sirius, 4130
  • Fork: RockShox SID Ultimate
  • Hubs: Pacenti
  • Rims: Pacenti PI30-END
  • Tyres: Maxxis High Roller II 29×2.3 / Maxxis Minion DHF 29×2.3
  • Chainset: Shimano Deore
  • Rear Mech: Shimano SLX
  • Shifters: Shimano Deore
  • Cassette: Shimano SLX 12-speed
  • Brakes: Magura MT Sport Trail
  • Stem: Pro Tharsis
  • Bars: Pro Tharsis Three C
  • Grips: SDG
  • Seatpost: Pro Koryak
  • Saddle: SDG Radar
  • Size Tested: Long
  • Sizes Available: ‘Longish’, ‘Long’ and ‘Longer’
  • Weight: As Tested 13.1kg/28.8lb
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Review Info

Brand: Pipedream Cycles
Product: Sirius S5
From: pipedreamcycles.com
Price: £699 frame only, £3,000ish as built
Tested: by Hannah for 2 months
Author Profile Picture
Hannah Dobson

Managing Editor

I came to Singletrack having decided there must be more to life than meetings. I like all bikes, but especially unusual ones. More than bikes, I like what bikes do. I think that they link people and places; that cycling creates a connection between us and our environment; bikes create communities; deliver freedom; bring joy; and improve fitness. They're environmentally friendly and create friendly environments. I try to write about all these things in the hope that others might discover the joy of bikes too.

More posts from Hannah

Viewing 5 posts - 1 through 5 (of 5 total)
  • Pipedream Sirius S5 review
  • chartersr100
    Full Member

    “making it ideal for the rider who’s been around long enough to have a shed full of bits needing a new home?”

    This is exactly what I did with my S5 – sold my 2017 Whyte T130 frame and whacked everything onto the Sirius, making it singlespeed. Absolutely perfect for messing around in local woods and riding up and around the Ridgeway in West Berkshire.

    Free Member

    I have the same potential idea – If I can’t get much for it as a full bike then I may just sell my Giant Anthem 27.5 as frame and shock only and put the 130mm fork, DT Swiss wheels and XT groupset onto a Sirius frame.

    Full Member

    I’m wanting.
    In deep sparkly blue.

    Full Member

    Hannah, I think you must have had a duff bleed or knackered pads in those Maguras. I’ve got the trails on my fs, 180mm rotors front and back, 85kg and they’re ridiculously powerful.

    Full Member

    On some Maguras one has to do a few emergency stops to get enough heat in the pads to chemically change them. If you don’t do that they stay soft don’t bite and wear out.
    Oh and the frames all have the same head tube length. B-

Viewing 5 posts - 1 through 5 (of 5 total)

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