Mountain Bike Reviews Forum banner
1 - 20 of 265 Posts

·
Registered
Joined
·
15,106 Posts
Discussion Starter · #1 ·


I've riding a Cotic BFeMAX for over a year as my trail bike going full hardtail and letting my FS bike gather dust. We had some great adventures and I documented my thoughts on that bike at this link. I wanted a SS friendly frame for my winter bike this year and I wanted to "fix" some geo issues I had with the Cotic. Mainly that was wanting a frame with shorter CS and shorter WB for a more agile/playful ride. I ride a lot of tight techy forest trails so being able to get up on the rear wheel and maneuver the bike quickly is important to me and I enjoy the feeling of manipulating the bike vs. being along for the ride on a bigger frame.



So I pulled the trigger on a Pipedream Sirius S5 hardtail. It's main claim to fame is an aggressive geo designed around a shorter travel 100mm-120mm fork. It also happens to have sliders so that makes for an easy/clean SS setup.
 

·
Registered
Joined
·
15,106 Posts
Discussion Starter · #2 · (Edited)


I'll be using most of the parts off my Cotic BFeMAX build for the Sirius. The 160mm Lyrik isn't a good fit for a bike designed around a 100-120mm fork so I'll move that fork to my GG Smash and I'll move the MRP Ribbon coil on the Smash over to the Sirius. The MRP can be lowered internally from the current 160mm to 140mm. I'm hoping that won't be too long as Pipedream talks about using a 130mm fork on the Sirius. Anyways it's a fork I own so I'll try it. If I love how the frame rides and I want a lower travel fork for it I don't mind getting one later.

The 9 point 8 dropper will swap over. The Sirius has a steep STA on paper and I don't love being pushed forward over the BB, but with a bent seat tube and longer fork the Effective STA at my ride height might be okay and if it is too steep I'll put a 1" setback head on the dropper to get my saddle further back.

At the moment Shimano 11 speed is my "go to" drivetrain in the fleet so I'll just hang onto those parts off the Cotic for use on another bike when the Bike Gods decide to rip a derailleur off or smash a shifter on a rock. I ordered a few SS cogs so I can try some different ratios out. I know what I like on road/gravel with big 29+ hoops [34 x 20T], but not sure how I'll feel on techy trails. I'll probably start with something like a 30T x 22T ratio and see how that feels.
 

·
Registered
Joined
·
1,815 Posts


I know what I like on road/gravel with big 29+ hoops [34 x 20T], but not sure how I'll feel on techy trails. I'll probably start with something like a 30T x 22T ratio and see how that feels.
I'm using a 30x22T ratio on my Lenz Behemoth and I like it. I'm sure our areas of riding are quite different, but for me it is a good way to build some strength and get stronger with it. I just re-did my Pugsley and only had a 20T cog, so that will be 30x20 with 29x3.25/3.0 combo, maybe the hardtail will be easier to pedal with the higher ratio?
Looking forward to your in-depth build and review of the Pipedream :)
 

·
Registered
Joined
·
15,106 Posts
Discussion Starter · #5 ·
Interesting frame, interesting geo. I think I'd want to run the 140 fork at a minimum to offset the really low bb, and boost the stack number a bit.
If I could customize the geo I'd make the headtube longer and the STA slacker. That BB drop works around here [with a taco bash] as I have another HT with the same BB drop.

If a 140mm fork is too short then it's just the wrong frame. I don't mind running some spacers under the stem and using a high 75-80mm bar.
 

·
Registered
Joined
·
15,106 Posts
Discussion Starter · #6 ·
I'm using a 30x22T ratio on my Lenz Behemoth and I like it. I'm sure our areas of riding are quite different, but for me it is a good way to build some strength and get stronger with it. I just re-did my Pugsley and only had a 20T cog, so that will be 30x20 with 29x3.25/3.0 combo, maybe the hardtail will be easier to pedal with the higher ratio?
Looking forward to your in-depth build and review of the Pipedream :)
Thanks. (y)

I've got 28T and 30T rings. I might even have a 32T ring in the parts bin. For cogs I have 22T, 20T and 18T. I don't mind buying another cog once I settle on what ratio is going to work well. I know what I like for road/gravel, but really no idea for trail riding. There are lots of techy punchy climbs which suggest a low gear, but I don't want to be spinning like a hamster the rest of the time. I've run into people riding SS here so they are making it work.
 

·
Registered
Joined
·
303 Posts
Thanks. (y)

I've got 28T and 30T rings. I might even have a 32T ring in the parts bin. For cogs I have 22T, 20T and 18T. I don't mind buying another cog once I settle on what ratio is going to work well. I know what I like for road/gravel, but really no idea for trail riding. There are lots of techy punchy climbs which suggest a low gear, but I don't want to be spinning like a hamster the rest of the time. I've run into people riding SS here so they are making it work.
What size tire are you going with on this build? If doing 2.6 or smaller, I would start out at 32X20 ratio or 30X18 since you have that combo already. You will be surprised what you can push, especially since you already have SS experience on your gravel ride.

Also, let us know how the frame feel/compliance is on this Sirius. I am tempted to get one as well!
 

·
Registered
Joined
·
15,106 Posts
Discussion Starter · #8 ·
What size tire are you going with on this build? If doing 2.6 or smaller, I would start out at 32X20 ratio or 30X18 since you have that combo already. You will be surprised what you can push, especially since you already have SS experience on your gravel ride.

Also, let us know how the frame feel/compliance is on this Sirius. I am tempted to get one as well!
I'll leave the tires from the previous bike on the wheels. So 29 x 2.6" DHF/DHR. Maxxis sizing so not a large 2.6" tire.

I'll definitely post some thoughts on frame compliance/ride quality. That aspect of hardtails is near and dear to my heart. I hate a dead/overly stiff frame.
 

·
Registered
Joined
·
15,106 Posts
Discussion Starter · #10 ·
Will be interested on a general frame/geo review and how you like 29x2.6, was looking at getting a sirius also but didn't know whether to go 27.5+, full 29, or mullet.
If you just want some general 29 x 2.6" feedback I've ridden that tire size a lot. Note I am talking Maxxis 2.6" which might well be a 2.5" tire in another brand. But, Maxxis is what I've been using lately and is pretty common so let's stick with that as a reference.

My feelings to date on tire size use are [all Maxxis sizing]

  • 2.4" and less: Doesn't interest me. I always feel like I don't have enough volume and want a large casing.
  • 2.5": I like this for a FS bike that is ridden hard. Enough volume I don't hate life, but not so much volume that tire deforms too much when pushed hard.
  • 2.6": I like this for a HT bike or lighter duty FS. More volume feels good on a HT or short travel FS and those bikes aren't pushed as hard so the bigger volume is fine.
  • 2.8" - 3.0": I like this for bikepacking/gravel grinding. The higher volume is very comfortable and forgiving on soft/mixed surfaces. Light tread patterns roll well, but grip enough to ride trails as needed. Bikes aren't pushed hard so large volume doesn't cause issues.
I'm not a mullet or 27+ fan so I can't really comment on those options. Other people love them so I am not saying they aren't worth a look, but I stick to 29er/29+.

For 29 x 2.6" tires I've used a lot:

  • Rekon: rolls great and grips surprisingly well. I loved this tire a lot more than I expected and it's my go to general purpose tire at the moment.
  • DHF/DHR: I've enjoyed these on my HT for shredding. Not as good a tire option for general use, but better than Rekons for shredding...especially in the wet.
 

·
Registered
Joined
·
15,106 Posts
Discussion Starter · #11 ·


Pipedream landed yesterday. Dealing with the company was easy and everything arrived undamaged 7 business days after I ordered it. Weighs ~6.3lbs with axle and dropouts.



The powdercoat and decals are very nice. One of the nicer finishes on any bike I have owned. The frame has a single set of water bottle mounts, which is fine for a winter shred machine. Lack of moisture won't be an issue here. o_O



Threaded BB and I am glad to see ISCG tabs despite this being a trail bike frame. We have enough rocks and logs here I'll mount a taco bash guard.



CS/BB detail.



I'm hopeful I won't have to pull my wheel too far backwards to fit the 29 x 2.6" DHR on the rear wheel. I want to run a fairly short CS. Basically as short as I can go with reasonable SS chain tension.



I'll be running a rear Mudhugger fender, but it's still nice to see small details like a forward facing slot on the seat tube.



Clean dropper housing port.



Brake hose and shift housing run under the TT with the dropper housing running under the DT.



Housing/hose runs under the seatstays at the rear. Nice as that makes mounting the rear Mudhugger easier/cleaner.



The frame comes with a geared DS dropout, but I ordered the SS dropout for a cleaner look. I'll hang onto the geared dropout in case I can't handle SS trail riding.



Nothing fancy going on with the axle and dropouts, but everything looks well made.



44mm head tube so it's adjustable headset compatible. With a 140mm fork I'll run a normal headset though. Nice head badge. :love:
 

·
Registered
Joined
·
15,106 Posts
Discussion Starter · #12 ·


I threw the rear wheel from the Cotic in the Pipedream. It's a 29 x 2.6" DHR on a 30mm IW rim. Slammed it rotated, but clearance was almost zero...so not practical for riding like that. However, as you can see from the photo above the way the CS are shaped near the BB means that you get a lot of clearance with a small amount of rearward movement of the axle. Setup SS I'll have to pull the wheel back a bit to tension the chain and that should be enough to make this wheel work. 🤘

If I was going to run this frame geared and wanted the CS slammed I'd need to run a Maxxis 29 x 2.5" tire or put a 27+ wheel/tire on the rear.
 

·
Registered
Joined
·
15,106 Posts
Discussion Starter · #15 ·
It looks great! I'm anxiously awaiting a ride report.
Thanks. I'm swapping forks today and then I'll open the MRP Ribbon Coil, do a lowers service and set travel at 140mm. That's the only hard part of the build unless I run into a compatibility issue as I am swapping stuff over. So the Pipedream should be rolling shortly.
 

·
Registered
Joined
·
15,106 Posts
Discussion Starter · #16 ·
How is the frame weight compared to your Cotic?
I was looking through my BFeMAX thread for a measured weight as I recall weighing the bare frame, but I can't see it. Based on just lifting the frames they seem comparable and the BFeMAX product page says 6.1lbs for frame/axle and the Sirius weighed 6.3lbs for frame/axle/sliders so that's basically the same given the Cotic doesn't have the extra weight of sliders.

What really matters to me is how the frame flexes. I hate an overly stiff frame. I've read good things about Pipedream in that regard, but the proof will be in the pudding.
 

·
Registered
Joined
·
15,106 Posts
Discussion Starter · #17 ·


It's against my religion to ride with a pack so of course I was keen to see how the Sirius would fit frame bags and bottles. The bag shown above has all my tools, pump, spare tube, etc... in it and a single bottle will be fine for winter riding. I'll have a another top tube frame bag [same model shown above] mounted by the bars and stem. I put my phone, energy bars, spare jacket, etc... in that bag as it's easy to access while riding. These bags are waterproof so they do well on a winter rig. :geek:



I mocked up a second bottle inside the frame just to see if I could add more water if I wanted to ride this bike in the summer. A second bottle fits fine and I could even add a third under the downtube if I wanted. (y)
 

·
Registered
Joined
·
15,106 Posts
Discussion Starter · #19 ·
Another option could be 1-1.5 liter bottle paired with the Looney bin bottle holder.
Yes that would work. I also have a Wolf Tooth dual bottle cage adapter that changes a single mount to a dual mount and I could put another cage under the DT either a 750ml or a 1.5L bottle. So all in all hydration won't a problem! :geek:
 
1 - 20 of 265 Posts
Top