I just posted the second part of my Cotic BFeMAX review and noted in it that I have a new frame and swapped the Cotic parts to it…more or less. This is the new frame! In this part of the review I’ll go over why I choose the Sirius, what parts I built it up with, and provide some initial ride impressions.
When I decided to get a new frame I wanted a few things in the new ride:
- The frame to be available to actually buy!
- Shorter CS.
- Adjustable dropouts for SS.
- Shorter Reach.
- Lower travel fork than the 160mm on the Cotic.
- Moderately slack HTA.
- 31.6mm dropper.
- Fit 29 x 2.6″ tires.
- High Stack.
- STA that wasn’t super steep.
- Flexible frame.
- Works Component headset compatible.
- Colour I didn’t hate.
If you go through this ^^ list you’ll see that I managed to get everything other than the high Stack in the Sirius. I debated getting the Moxie frame as the MRP fork I had on hand could be adjusted from 140-160mm which fits the design of the Moxie better, but in the end I decided the Sirius was the better frame for me.
- Sirius S5 frame in silver [Long size]
- 140mm MRP Ribbon Coil
- Hope hubs + Velocity Blunt 35 wheels
- Maxxis DXF/DHR 29 x 2.6″ tires with a Tannus Tubeless insert in the rear
- Shimano Deore 4 piston brakes 200mm/180mm rotors
- 30T x 22T SS drivetrain
- RF Next R 170mm cranks
- RF Chester pedals
- I9 35mm stem
- Ergotec 780 x 70mm rise bars with Ergon grips
- 9point8 150mm dropper
- WTB Pure saddle
- RRP front fender
- Mudhugger rear fender
- Rock Bros frame bags
- PDW DT splash guard
- Fabric bottle
Dealing with Pipedream was easy. Their website tells you what’s in stock and buying the frame for shipping to Canada was not a problem. The cost including shipping, taxes, and brokerage was $1315CAD or ~$1053USD. I ordered a SS dropout and a few small hardware spares so my bill was a bit higher than just a stock frame. I lucked out as they had a batch of frames landing right when I was ready to buy one.
It took 7 business days to get to me here in British Columbia, Canada. The frame was well packed and arrived undamaged. The fit and finish were excellent. This is clearly a quality product. The silver powder coat was particularly lovely and I am glad I went that route. The frame + dropouts + axle weighed ~6.3lbs.
I put the fork from the Cotic onto my GG Smash since it was running a 160mm MRP Ribbon Coil. The Ribbon can be internally adjusted down to 140mm travel. That didn’t take too long and allowed me to clean/lube the lowers so I know the fork is ready for battle. The Sirius was designed for a 100-120mm fork and I am over-forking it. That’s not ideal, but I didn’t have a better option that I could use on short notice…plus this option was free.
My first ride around the neighbourhood on the freshly built bike I thought the 140mm fork was too slack and didn’t like how the bike steered. As it turns out once actually on the trails that feeling went away in 5 seconds and it handles great. I suspect the aggressive weight forward riding style that SS demands sags the fork compared to seated pedaling such that the dynamic ride height is low enough to hit the design’s sweet spot. That said I wouldn’t hesitate to spec a 120mm fork on this bike if I was buying new parts.
Like all my bikes the Sirius got full MTB fenders and a bunch of frame bags so I can do a long ride with nothing on my back. The frame comes equipped with only 1 set of bottle mounts. However, it would be pretty easy for me to install a second cage inside the frame and a third under the downtube if I wanted all day riding hydration in the summer. For winter riding one bottle is enough as I rarely drink much in our cool moist weather.
The frame does fit a Maxxis 29 x 2.6″ DHRII, but with the dropouts slammed forward the clearance is less than what I would deem useable. The way the CS are shaped near the BB every mm you pull the rear wheel backwards you get a lot of additional tire clearance. So you can still have fairly short CS and a big tire. You could run a Maxxis 29 x 2.5″ tire with the dropouts all the way forward. I didn’t try any 27+ tires.
I took the Sirius to my local XC trails just down the road. Think rolling forest terrain with enough roots to be entertaining. I was really blown away by how well this bike performed there. The Pipedream carved tight corners well and was able to take flight off of every small feature. Getting the bike on its rear wheel was easy. The lack of any extended steep climbs meant that the SS drivetrain worked well and the experience was very engaging. I’m stoked about this because now that I have trails right by my house I want to ride them and really enjoy them. Having a bike that does that is great.
Next up was taking the Sirius to the “real” mountain bike trails in Cumberland. These are more techy and feature steeper climbs and faster longer descents. Thinking just about how the bike handled it did very very well there. What I may have lost in terms of riding a shorter less aggressive bike I got back because I felt really in control of the machine and could push it harder. The more active riding style on this bike was a ton of fun. I definitely liked the shorter CS on this bike. That just feels more natural to me and I can both corner and climb better with the rear wheel tucked in close to me. The steering felt very neutral….neither too fast nor too slow. I was all smiles on the bike.
I have to say riding SS on steeper techy trails was a lot harder than the rolling XC trails near my house. It’s clear I need to work on my SS fitness as I was tired and breathing heavily a lot more than I would have expected. I did a few laps on the same trails and my ability to climb tech sections got better with a bit of trail knowledge as I could get on the gas a second earlier for stuff coming around the corner and that translated into cleaning stuff I walked the first lap. 30 x 22T is not a bad gear, but I think I will try 28 x 22T or 30T x 24T for an easier gear…at least to start. I am enjoying learning the ins and outs of SS on the trails. It’s definitely something I want to get better at and to do a lot.
How a frame flexes matters a great deal to me. I hate overly stiff frames. They feel dead and they do not perform well for me. I have had frames that were too flexible and that causes handling issues when you are riding aggressively. Of course frame flex is hard to judge in advance. I’m happy to report the Sirius is a pleasure to ride. It’s more flexible than the BFeMAX and less flexible than my Daambuilt Mega Krampus. That’s just about ideal for the kind of riding I want to do on it. The frame feel plus the coil fork make me think this will be a very comfortable all day machine.
When I started this project I had three questions:
- Would I enjoy the Sirius frame enough to make it worth swapping in for the Cotic?
- Would I enjoy singlespeeding real mountain bike trails?
- Could I ride SS for all my trail riding?
I feel like I can already say yes the Sirius provides the ride experience I was missing from the BFeMAX and I am really happy to be on the smaller more agile bike attacking the terrain. I can also say yes I enjoy the SS trail riding experience a lot and it’s here to stay. What I don’t know yet is how much of my trail riding can I do SS and how much do I really want a geared bike for? I plan to use the Pipedream as my main and maybe only winter mountain bike to see what happens. I will report back next year!
Anything I don’t like? Sure. I’m a fan of taller head tubes and the resulting higher Stack so I wouldn’t say no to a 130mm or 140mm head tube. While we are at it let’s make the seattube 30mm longer as well. I’m running a 150mm dropper because I had it and I’d put a 175mm dropper on there if I was buying a new part. I don’t need more dropper than that on what is a Medium size trail bike and I’d enjoy more frame space inside the main triangle. I’d move the dropper cable routing to the top of the downtube. I’d add a second set of bottle mounts above the first and a third set under the downtube. I’d tweak the CS/BB area so a 29 x 2.6″ tire would fit with the dropouts slammed forward.
None of these items are deal breakers for me or I wouldn’t have bought the frame and you can’t buy a production frame without some compromises.