The Grandmaster HCHT
Doctahawk
The Doctahwak
4130
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.
The Doctahawk is the most purposeful and aggressive hardtail we have ever made.
key features
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.
The Doctahawk includes a custom paint job of your choice!
To read more about what's included and what's possible click here.
Due to the fact this item is custom painted, lead times may vary, we'll be in touch about your paint job and delivery date once you complete checkout!
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.
Yes, steel might be a little heavier than it's more flashy contemporaries, but these bikes are built to last.
Unlike aluminum frames (which have ticking clock the minute you start riding them), steel can theoretically last forever provided it's ridden within the scope for which it was intended.
Whether you get your bike in a box, or roll it out the front door here at Chromag HQ, you can rest assured your bike has been pored over with pride, and built with the utmost attention to detail by one of our extremely talented mechanics.
Threads are chased, seat tubes are reamed, head tubes are honed, fits are checked and checked again, all to make sure when you get your bike, everything is absolutely dialed.
The UDH is designed to optimize shift performance across all bikes as well as create a sensible solution for replacing damaged hangers. The UDH has been widely adopted throughout the cycling industry with hundreds of models already featuring it.
as long, low & slack as it gets.
geometry
The Doctahawk is the result of seeing how far we could push the envelope. While the 62.5° head angle might seem like we went too far, take a minute to understand that hardtails don't operate the same way as a full suspension platform. Paired with a suitably steep seat tube, the Doctahawk is a proficient climber despite it's aggressive nature on the way down.
The Venn diagram of riders that this suits is unquestionably small, however for those that land deep in that circle of gnar there is no other.
| Frame Size | STypical Rider Height: 155cm - 165cm | MTypical Rider Height: 163cm - 174cm | M/LTypical Rider Height: 172cm - 183cm | LTypical Rider Height: 181cm - 192cm | XLTypical Rider Height: 190cm - 200cm |
|---|---|---|---|---|---|
| 638 | 638 | 638 | 647 | 656 | |
| 429 | 451 | 472 | 497 | 522 | |
| 581 | 602 | 623 | 651 | 678 | |
| 105 | 105 | 105 | 115 | 125 | |
| 1201 | 1223 | 1249 | 1293 | 1323 | |
| 48 | 48 | 48 | 48 | 48 | |
| 323 | 323 | 323 | 323 | 323 | |
| 669 | 694 | 730 | 756 | 792 | |
| 425 | 425 | 425 | 435 | 435 | |
| 356 | 382 | 419 | 445 | 482 | |
| 176 | 202 | 239 | 265 | 302 | |
| 62.5° | |||||
| 76.5° | |||||
| 29.0'' | |||||
* Max. post insertion based on Rockshox Reverb
THIS IS AN APPROXIMATE GUIDE, SOME PEOPLE HAVE LONGER LEGS THAN OTHERS!
Sizing
If you're between sizes, it's a good idea to try to ride them both, either by hopping on a demo or stealing from a close friend. If that isn't an option, examine reach, stack and ETT numbers on your current bike and compare. If in any doubt, please get in touch and we'd be happy to chat about it with you.
You could also check out the review section, to see how this bike fits other people.
The Doctahawk is available in almost any colour your heart desires.
gallery
Builds & Specs
• Fork // Rock Shox Zeb Ultimate 170mm Boost 110x15mm
• Stem // Chromag HiFi 40mm
• Bar// Chromag OSX 25mm Rise, 800mm
• Headset // Cane Creek Forty ZS
• Crank // SRAM X1 170mm
• Brakes // SRAM G2 RSC
• Rotors // SRAM 180mm
• Shifter // SRAM X01 Eagle
• Cassette // SRAM X01 Eagle 10-52t
• Derailleur // SRAM X01 Eagle
• Rims // Chromag 29" Phase30
• Hubs // Chromag R4
• Tires // Maxxis Minion DHF/DHR
• Seatpost // RockShox Reverb
(125mm - S) (150mm - M) (175mm - M/L) (200mm - L, XL)
• Saddle // Chromag Trailmaster DT
• Grips // Chromag Format
• Chain // SRAM X01 Eagle
Build options are subject to availability and liable to change without notice.
• Fork // Rock Shox Lyrik Select 160mm Boost 110x15mm
• Stem // Chromag HiFi BSX 40mm
• Bar// Chromag OSX 25mm Rise, 800mm
• Headset // Cane Creek Forty ZS
• Crank // SRAM GX 170mm
• Brakes // SRAM G2 RSC
• Rotors // SRAM 180mm
• Shifter // SRAM GX Eagle
• Cassette // SRAM GX Eagle 10-52t
• Derailleur // SRAM GX Eagle
• Rims // Chromag 29" Phase30
• Hubs // Chromag R4
• Tires // Maxxis Minion DHF/DHR
• Seatpost // RockShox Reverb
(125mm - S) (150mm - M) (175mm - M/L) (200mm - L, XL)
• Saddle // Chromag Trailmaster DT
• Grips // Chromag Format
• Chain // SRAM GX Eagle
Build options are subject to availability and liable to change without notice.
• Wheel Size // 29" or 27+
• Recommended Fork Travel // 170mm (±10mm)
• Material // 4130 Chromoly Steel
• Frame Weight (M/L) // 6.89lbs
• Hub Spacing // Boost 148mm (Axle Included)
• Headset // 44-56 Semi Integrated
• Seat Clamp Size // 35mm
• Seat Post Size // 31.6mm
• BB // 92mm Press Fit (PF92)*
• Hanger // UDH (Included)
• Brake Mount // IS
• Frame Origin // Canada
• Builder // Brad Howlett
* We hand ream PF92 BB shells carefully to a high tolerance and BB cup dimensions from different manufacturers vary. We follow SRAM-Dub specifications and SRAM BB cups are our first recommendation for the most accurate fit. If there is a specific BB/Crank combo you wish to fit to your frame, we can assist in evaluating the fit and even potentially ream and fit the BB for your new frame.
Questions?
Buying a bike is a big deal.
Don't hesitate to reach out with any and all questions!
Worldwide shipping
We ship bikes anywhere in the world with competitive rates from UPS and FedEx. Alternatively you can pickup right here at Chromag HQ.
Warranty
All of our bikes are backed by a 1 year warranty.
After that we still have your back with our crash replacement program.
FAQ's
This is possible but does notably change the geometry. The change results in approximately 1° slacker head and seat tube angles, 20mm shorter reach and BB height 10mm closer to the ground.
A 2.5” Maxxis fits with appropriate room around it.
No, there are no ISCG mounts on the Doctahawk.
All our frames can work with +/-10mm of fork travel. To generalise the geometry change is around a 0.5° slacker head tube and seat tube angle for every 10mm added.
All geared hardtails run a standard boost chain line (52mm)
With a 52mm chainline (SRAM boost standard), the Doctahawk can fit up to a 34-tooth chainring.
For context, most of us here are running a 30t, with a 10/52 cassette.
There is a serial number on the back of your fork arch, adding this to Rockshox Trailhead app along with your weight gives a good baseline setting.
It does, however the specific blend of steel we use (CR-MO) has very good corrosion resistant properties. You can further protect things internally if you live in a partially harsh area or have concerns. Fluid Film is our recommended product for this.
Nothing of note on this frame. Please let us know if you have tried to fit a more obscure component and faced issues.
Greasing you seat post prevents this issues, we strongly recommend re-greasing every 6 months at a minimum.
Not much! Here's what you need to do if we shipped your bike to you:
• Inflate tires to desired pressure. (Sealant is already installed)
• Install brake rotors, tightening bolts to 6.2Nm.
• Attach derailleur to frame, tightening to 9Nm making sure that the B-tension tab rests properly against the derailleur hanger stop.
• Grease headset bearings, install fork and handlebar, positioning the headset spacers above or below the stem according to rider fit.
• Align handlebar stem, preload headset and tighten stem pinch bolts to 8Nm.
• Install wheels, tighten axles.
• Install chain with quick link.
• Grease pedal threads and install pedals using pedal washers supplied.
• Adjust brakes, shifters, saddle position and height for personal preference.
• Set up suspension.
• Bed-in brakes. (Roll down a gentle gradient dragging one brake at a time. Avoid locking them up.)
• Go ride!
Note: If you had to Google "Nm", or you don't know which way to install your rotors, you should probably get a qualified mechanic to build your bike!
Here's what's been done:
• Chain length adjusted.
• Gears adjusted.
• Brakes set up and bled.
• Handlebar tightened to 6Nm.
• Grips tight on handlebar.
• Crankset tight, bottom bracket tight/adjusted.
• Saddle and seatpost tight.
• Seatpost greased *make sure to re-grease every 6 months!
• Tire sealant installed.
• Cassette tight.
