REVIEWED: The Pipedream Sirius 4G


The Pipedream Sirius 4G hardtail

Tested by Rich Thomas / Photos by Jacob Gibbins

Key features
Custom, triple butted, heat treated, CroMo 4130
15.5″, 17.0″, 18.5″, 20.0″ sizes
Designed for 130 – 160mm travel forks
Compatible with 27.5×2.8″ or 29×2.4″ wheels
Sliding and replaceable drop outs
£549 with Funn Descend headset, Funn Frodon seat collar & rear axle

That special time of year

The Pipedream Sirius 4G landed with us at that special time of the year when the trails are at their very, very worst. Axle deep ruts, puddles like duck ponds, rides that are more about mud plugging than mountain biking. Exactly the worst time of year for expensive, complicated, uppity full suspension bikes. Exactly the time of year when sturdy, simple, uncomplicated and unflappable hardtails rise to the fore.

Now the sun is shining, spring has sprung and summer is round the corner … it’s time to check in on how it faired.

The Sirius 4G landed with test pilot Rich Thomas and instantly became his winter mud-plugger. Richie’s riding involves a lot of quick laps round the local woods. There’s a short, nasty climb, a flat plug across a bogged out field, some pinballing down the old school down hill tracks then a final schlep up to the trig point with a slippy, slidey descent back to the van at turbo pace to finish. Those rides are usually smashed out before or after work and are as much about just getting it done than anything else. Lots of roots, lots of ruts, lots of mud. Lots of bike washing. Perfect hardtail territory.

A quick history lesson

Pipedream is probably not a brand that’s familiar to the under 30’s out there. It was born on the Singletrack forum when owner Alan got frustrated with bikes and made a few of his own. He started selling a few at the forum user’s behest and things gradually grew into a proper business with proper bikes. The popularity of the bikes ebbed and flowed as they become less or more available but took a bit of a hiatus in recent years. There’s a good interview with Alan here on Wideopen.

The Pipedream Sirius 4G

The Sirius 4G is the 4th generation ‘hardcore hardtail’ for Sirius and marks Pipedream’s relaunch. It’s designed to be – Pipedream say – a “long-travel, semi-skimmed, slack and low frame that’s ready to rail and riot for rock-shrugging fun”.

Stripping away the jargon – it’s a steel hardtail designed for big wheels (27+ or 29″) and longish forks (130-160mm). The frame is made of heat treated, triple butted 4130 chromoly that Pipedream claim performs to the same standard as big gun Reynolds or True Temper steel.

Custom tubes

According to Pipedream, the tubes are drawn in the same factory as the frames are made which helps them keep a close eye on quality and consistency. We’ve got no evidence to disagree – the bike shrugged off the riding Rich threw at it without any problems. He’s spent years racing elite downhill on long travel bikes so isn’t shy of giving a bike a bit of a pasting. There’s a decent blog up on the Pipedream website that explains all about their tubing.

Rich’s test bike

Rich’s test bike was a full build that came kitted out with Funn cockpit, Zelvy carbon wheels, Funn carbon cranks and a SRAM groupset. Up front was the very lovely DVO Diamond fork which was an absolute pleasure to ride.

Whilst we had a full bike, the Sirius 4G’s will be available as frame only (with Funn headset and seat collar) and or as a bundle with a DVO Diamond fork (which works out as a cheap way to buy a great fork) and / or a Hope wheelset.

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Big wheels or bigger wheels

The frame is designed around big(ish) wheels. It’ll take 27.5+ wheels with up to 2.8″ tires or 29″ wheels up to 2.4″. Teamed up with Zelvy carbon rims on Funn hubs the bike rolled beautifully fast and kept weight down. The Funn rear hub also has a pleasingly loud bzzzzzzz that gives the bike a fast, up-for-action feel when freewheeling along.

We’re not here to debate the merits of plus size wheels … but they were an interesting choice for the time of year. On loose, rooty, rocky stuff they offered a really stable footing and plenty of grip and bump absorption in equal measure. They were fun and sure footed on those fast, well ridden downhill tracks that litter our local woods.

Where they fell down was the slop, with a tendancy to aquaplane on the really slippy, wet, muddy stuff rather than cut into it. You can anticipate this and adjust your riding style … but they definitely suit rough, harder packed conditions better in our opinion. Of course, if you don’t want to run plus size wheels, the Sirius 4G will accommodate conventional 29″ wheels very happily.

On the trail

The angles and material of the Pipedream are of course what give it its personality. The flat Funn handlebar didn’t blow Rich’s mind and gave a slightly odd body position. We swapped that for a riser bar and it was way more comfortable. No big deal there, you’ll be building a custom bike if you get a Sirius anyway.

The bike is built to be a versatile – both in the trails you ride and the way you build it up. That’s the essence of the Pipedream in our eyes.  Where some bikes are built for a specific and single purpose, the Sirius is about doing as wide a range of rides as possible. The sliding drop outs allow for geared hubs, single speed or a conventional derailleur setup. You can switch between 27+ and 29″ wheels.

The geometry is a jack-of-all-trades design that’ll happily see you round big, nasty, all day adventures and quick spins of the local. Despite Pipedream’s born-in-the-90’s heritage, the angles are actually decently modern. There’s a decently slack head angle (65d with a 140mm DVO Diamond fork), a roomy-enough cockpit (439 reach on a large frame) and the 430mm chain stays took us by surprise. They’re actually pretty short compared to other bikes out there.

Generally though, none of the angles are extreme and the bike takes a balanced approach that’s ever so slightly bias towards packing in some distance than out-and-out gravity riding.

Rich is used to dragging full suspension bikes up, across and down his local ride. Whilst we don’t have a number for the frame weight – he complimented how light and nimble the bike felt, making it easy to put the hammer down and get it moving. Over rough terrain he felt happy to get the bike up to speed and attack some rough stuff without feeling too held back by a lack of rear bounce. That’s partly thanks to the geometry we talked about above and partly thanks to well chosen materials.

The bike for you?

If you’re into big rides, big laps of trail centres and churning out some distance whilst still having a blast on the downhills then it’s definitely worthy of your consideration. If you want a bike that (like Rich) you can fire out quick rides going hammer and tongs round your local trails then it’ll do you proud.

It’s a bike we’d love to take on some big days out round Exmoor or Dartmoor. It’d go great guns round Afan, Brechfa or any of the big, wild Scottish trail centres. It’s tough, simple, understated with some very good materials and shapes that’ll see you through all sorts of adventures.

Pipedream’s bikes are available direct from their website at