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It might be alien to some but 29+ wheels are a real thing, especially now that you can get tires with serious tread, like a Maxxis Minion 3.0.

The Arcturian started off as an experiment…to see if it could really work.  29+ bikes have been growing in popularity, due to their ability to carry momentum and offer a soft ride when things get rough, even with a bunch of gear strapped on.  The big wheels are great for long trips and adventure riding where you’re mixing up road surfaces with sections of trail.  But could they also deliver as a real-deal trail bike for proper technical riding?  The answer is yes.  The Arcturian - a bike with our most progressive dimensions and angles, corrected for the gargantuan diameter of 29+ tires.  

Gravel roads with cross ditches and log piles?  Mountain passes with ridge traverses and winding descents?  Technical climbs with a healthy scattering or slippery roots and edgy rocks?  Descents that slab and chunk their way to the valley floor?  The Arcturian is ready.

Almost all Chromag frames are made from quality 4130 chromoly steel tubing. Chromoly is an abbreviation for chromium-molybdenum indicating the materials that the steel is alloyed with.

The added chromium helps increase the steels hardenability and also provide some corrosion resistance.
The molybdenum helps to increase the toughness of the steel.

It has a high tensile strength but is also malleable which is what gives our frames their notorious ride quality and feel. Chromoly is often used when more strength is required than that of mild carbon steel.

It falls under the AISI (American Iron & Steel Institute) 41XX designations which is where the “41” comes from. The “30” indicates it contains approximately 0.30% carbon by weight.

Chromoly is much stronger than traditional 1020 steel and it has a higher strength to weight ratio and high tensile strength, which means we can use less material and achieve a product that can withstand the abuse that riders love to throw at it.

Chromag 4130 Tubing

Hub Spacing // Boost 148mm (Axle and Hanger Included)
Headset // 44-56 Semi Integrated
Seat Clamp Size // 35mm
Seatpost Size // 31.6mm
BB // 92mm Press Fit (PF92)
Wheel Size // 29+
Recommended Fork Travel // 140 - 160mm
Builder // Mike Truelove
Weight // 7.2lbs / 3.2kg (M/L)

Click here to view the frame user guide.

Build options TBD are subject to availability. 

To purchase a complete build, please contact us directly. We are happy to answer all your questions about our bikes and products. Call: 604-905-6667 Email:

Head Tube Badge

Your bike is special. The head tube badge is the finishing touch so we’ve always made a point of taking the time to do something interesting with it. Our head tube badges have changed over the years and are an indication of the time each bike was made. Whether it’s a cast bronze, or polished stainless steel, water cut aluminum or a 3D CNC carving, each one represents our commitment to detail.

Chromag Headtube Badge


As 12mm through axles have proven to be solid, reliable and convenient, we have committed most of our models to utilize this format.   Our 12mm dropouts are accurate and tough and feature a removable derailleur hanger with a sturdy interface for strength and reliability.  All 2017 models (excluding Monk and Nice Dreams) will follow the 148mm boost spacing.

chromag boost dropouts


Our ‘Yokel’ design is a small machined junction on the chainstay that helps accommodate both tire clearance and chainring clearance. Our first versions were huge CNC yokes that bridged the entire front end of the chainstays. Over time we refined this to minimize weight by arranging our chainstay layout asymmetrically and reducing the yoke to a minimal size. It’s one of our most unique frame features and has been copied by other frame makers.

Chromag Yokel

Chain Stay Protector

All Chromags now ship with our injection moulded chain stay protector to help keep the paint fresh and the noise low. These have an adhesive applied, but also slot for zip ties if they come unstuck years down the line, or if you want to apply it to another frame.

Customer Reviews

Based on 5 reviews
This bike is the dream!

Honestly this bike is literally the dream. I was riding a first batch Surface for 7-8 years and absolutely loved it. The newer Chromag geometry was tempting but I always wanted to see them come out with a 29+. Well here it is and it's just full of awesome.

I'm 6-6 and the XL fits like it was custom made for me. My climbing, cornering and descending just went to another level overnight. I feel like they got everything right with the geometry here and of course the traction of the monster tires gives tons of confidence. I'm finding 14-15 psi optimal in the rear and a few psi less in the front.

The BB is very low which contributes to the handling but it also means you need to watch for pedal strikes. A totally worthy trade-off in my opinion. The stock bike comes with 170mm cranks which surprised me (I normally use 180) but I understood why immediately. The bike was too long for our older north shore rack so we had to replace it with the newer model.

Everything on the complete bike is pretty much what you'd want. My bike came with a 50mm stem but I reduced it to 40mm as it felt a bit long. I put a 200mm 9point8 dropper on it although I definitely have room for a longer post. Having two bottles on the down tube allows for this and is a nice touch.

I really can't say enough good things about this bike and I can't imagine how it could be made any better but I'm sure Chromag will find a way. Until then I'm going to ride the piss out of this one. Thank you!

Go 9r Plus, Never Go Back!

I have a 9r 150mm front and back full sus trail bike but I ride the Arct more because it begs to be ridden and pushed hard. Like Bonham driving Led Zep. This is a beast of a bike that shreds single track and climbs well. Makes you a stronger rider. Love the custom paint and get lots of + remarks. I will only sell it if I buy another one !

Sean D.

HI. Yeah I work here. People spend all day asking me what bike I ride and what bike I like and what I ride now is this frame. I set it up with a 180 Lyrik. i have a 3.0 tire up front and a 2.6 tire out back. We have a non-official bicycle comparison factor called "Plow Factor". It refers to the bikes ability to hold the line in rough terrain. The trade off is low speed agility. Think truck vs car. i really like this rig. i only gave it 4 stars because 5 star reviews create suspicion.

Great ride!

I have had an Arcturian since last year and love it. I also have a Rootdown that my son now rides because I do not ride it anymore.
I agree with the other reviewers- climbing, cornering and descending are awesome. It's just fun.
I find the seating position great and the 29+ tire size tires help make hardtail riding more comfortable through the roots/rocks. Only new addition to stock build I have done is Cushcore which turned out better than I had thought it would.
Thanks Chromag, see you in the summer.

Crazy Fun Ride

Recently I flew out to whistler on vacation and decided with the friends I was travelling with that it would be fun to stop in at chromag and check out their space and look at the new shiny bits. Sitting outside the door was a demo arcturian, a bike I only learned the existence of a few days earlier.

I had not planned to buy a bike while visiting, but even after a short pedal it was obvious I wasn't going to be able to shake the bike. After two days I managed to sell the bike I flew out with and bought chromag's demo arcturian.

This bike is unbelievably fun to ride, despite having the longest wheelbase of any bike I've ever owned the bike handles tight switchbacks well, and plows down steep rocky and rooty shoots. When the trail points upward it does take some effort to control the front end, but it is manageable.

One thing that surprised me about this bike is that when I took it into bike park riding the huge diameter and volume of the tire actually let the hardtail ride over breaking bumps faster and smoother than the full suspension bike I was previously riding. When faced with tech trails it is more obvious that the bike is a hardtail (who'd of thunk it), but the big tire does still remove the nastiest shocks of the impact and you stay fresh longer riding the bike.

In conclusion, this is the most satisfied I've been about a bike and extremely excited to see where this bike will take me in the future.