Sirius | Scorching | The “Dog Star” | Trail hound.
“…unlike any other bike I’ve ridden…I’ve never known a bike to climb this well, descend this well and still be this playful.” – Hardtail Party
A Pipedream classic, the Sirius is reborn. Like the brightest star in the night sky, this bike is an absolute scorcher, ready to light up your trails and burn off the competition.
Go far, go fast, but most importantly, go for fun. This is the short travel bike we’ve always dreamed of, a fusion of modern geometry, exceptional engineering and short travel efficiency. Is this Downcountry? Is this XXXC? We don’t care, this is possibly the epitome of an ATB.
The Sirius is all about fast, comfortable efficiency. Modern lightweight forks are more capable than ever and have redefined what we can expect from a short travel hardtail. Push it hard, cruise for hours, race XC or take it bikepacking: the options are limitless.
With a rigid fork, the Sirius can be a confident adventure bike to take into the back of beyond. With a burly 120mm fork, it can run alongside the ‘big’ bikes and go play in the mud and on the steeps.
Useful things to know.
- Frame-only (includes sliders, bolts and guides)
- 29er, 27.5+, 27.5 or ‘mullet’.
- Optimised for a 100-120mm 29er fork.
- Compatible with a 120-140mm 27.5 fork.
- Steep seat angle for easier climbing.
- Our signature, optimised, dropper-specific seat tube.
- 3 sizes to fit riders from approx’ 4’11” to 6’2” (1.5-1.88m).
- Custom butted, heat treated CrMo 4130
- 44mm head tube (fits all steerer tubes).
- CNC CS/BB yoke for compliance and tyre clearance.
- 1 set of bottle bosses on DT.
- Sliding dropouts give +16mm of chainstay length adjustment.
- Includes Boost™ axle, M12xP1.75.
- Metal headbadge.
A rigid 29er CrMo fork is available which compliments the frame and is perfect for load-carrying, bike-packing duties.
- 482mm axle to crown.
- Optimised for 27.5 or 29er tyres.
- 29×3.0″ maximum recommended tyre.
- Double-butted CrMo.
- Tapered, 28.6/22.0mm.
- Straight steerer tube, 30cm uncut.
- 110x15mm axle (included, M15xP1.5)
- 180mm post mount.
- 47mm rake/offset
- Multiple bosses for bottle or load-carrying cages.
- 2 versions (rack/no-rack mounts)
- ED corrosion resistant treatment.
Straight from the horse’s mouth.
“…an intelligent discussion about the modern state of the hardtail and geometry.” – Hardtail Party
Technical information data sheet.
Custom tubing.The long read
Frame only. Images of bike for illustration only. Specification of frame is subject to change without prior notice.
|Longish (S)||Long (M)||Longer (L)|
|A: Head Angle||65°||65°||65°|
|B: Seat Angle||77.5°||77.5°||77.5°|
|C: ST C-T||395||420||420|
|D: TT (effective)||594||612||632|
|E: HT Length||105||105||105|
|F: BB Drop||64||64||64|
*The frame is optimised to work with a typical 100-120mm 29er fork and geometry numbers as listed are with a 100mm fork (sagged). Stack with a typical 120mm fork (static, no sag) is 605mm i.e. +19mm.
If you have any questions about our geometry and bike set-up then please contact us: we’re happy to discuss things in more detail.
Drop Optimized Geometry®
This is our philosophy, a combination of what we believe to be the best possible geometry for mountain bikes. A balanced blend of confidence, comfort and efficiency, Drop Optimized Geometry® gives you all the encouragement you need.
“Learn the rules like a pro, so you can break them like an artist.” – Pablo Picasso
Optimize v. (used with object), op·ti·mized, op·ti·miz·ing.
to make as effective, perfect, or useful as possible.
to make the best of.
to take the full advantage of.
Still with us and want to go further? Then read on…DOG
Long, Longer and now Longish…..what does that even mean?
However, with only 2 sizes the normal monikers of small (S), medium (M), large (L) and extra-large (XL) didn’t seem appropriate so we chose Long and Longer instead. S/M and L/XL might have been more recognisable but really, they’re not that much more informative without ‘numbers’: one brands’ medium might be another brands’ large and herein lies the problem with labelling. With the addition of smaller sizes to our line-up, Longish was the natural choice. Confused?
This is one of the reasons why geometry tables are provided. But, how do you use this data?
If you compare our geometry to the data for your current bike (or some other reference frame), this should give you some indication of fit.
Designed for dropper posts.
Our Drop Optimized Geometry® can accommodate most riders between 4’11”/1.50m and 6’4”/1.93m with the selection of the appropriate length dropper post.
Current dropper posts offer around 100-215mm of adjustment allowing a wide range of riders to fit a frame with a 16.5″/420mm seat tube. Maximum usable length of seat tube is 260mm.
The table below illustrates recommended frame size for rider height.
“…the S5 is unique and unlike any other mountain bike I’ve ridden…” – Bikepacking.com
“The Sirius S5’s brilliance comes from the combination of two otherwise distinct elements: very progressive modern geometry and short-travel efficiency.” – Bikepacking.com
“I was immediately blown away by how well this bike handles when pointed down just about anything. Despite only having a 120mm fork, it was decidedly more confident and capable than any of the full-suspension bikes I’ve tested in the past five years, many of which were equipped with longer 140mm forks.” – Bikepacking.com
“It simply goes down anything and maintains best-in-class traction while doing so.” – Bikepacking.com
“I discovered a bike that essentially replaces several bikes, including a full-squish trail bike.” – Bikepacking.com
“There were few moments when writing this review that I wanted to use the word perfect…However, I can say without hesitation that this is the most capable and interesting hardtail I’ve ridden…” – Bikepacking.com
“In summary, the Pipedream Sirius S5 is an extraordinary steel short-travel hardtail…” – Bikepacking.com
“A short-travel hard-charger from the future…unlike any other bike I’ve ridden.” – Hardtail Party
“I’ve never known a bike to climb this well, descend this well and still be this playful.” – Hardtail Party
“What a special bike! It has so much special sauce in all the right places.” – Hardtail Party
Just Ride Bikes
“…a really capable, but still lightweight and agile, responsive hardtail.” – Just Ride Bikes
“…fast and agile…” – Just Ride Bikes
“…the bike doesn’t hold back at all.” – Just Ride Bikes
“…a supremely fast bike.” – Just Ride Bikes
“Pipedream…continue to prove that hardtails still have a valid place.” – Just Ride Bikes
“…a really, thoroughly capable, and enjoyable trailbike that does everything so well.” – Just Ride Bikes
“A big thumbs up…” – Just Ride Bikes
Mapdec Cycle Works
Sirius | Scorching | The "Dog Star" | Trail hound.
"...unlike any other bike I've ridden...I've never known a bike to climb this well, descend this well and still be this playful." – Hardtail Party
The Full Monty (British, slang) | Something in its entirety | Everything you could expect it to include; all that you want or need.
"It’s a hell of a bike." - Pinkbike
"...intoxicatingly fun..." - enduro-mtb
“A.L.I.C.E. comes ready for adventure...a fantastic modern-day touring machine...” – bikepacking.com
Mox·ie (mŏk′sē) n. | Courage; guts | Aggressive energy; initiative | Skill; know-how.
“The Moxie inspires confidence and makes you want to push it further and faster…This bike isn’t just a great descender; it can be ridden all day, trail centres, a razz in the woods, uplifts at your local DH track and all-mountain adventures. Nothing is out of bounds for the Pipedream Moxie!” – IMBikemag