I have never owned a bike that was as rewarding in terms of the build process and having to dig around to make all the bits and pieces work. For some reason, I decided to sell that bike. To this day I still don't know why. A moment of weakness maybe.

So when the opportunity arose to do another custom build I jumped at it and roped in Bogus again. What was a little different this time, was the involvement of another friend of mine Hasie and the Robots, who I happened to have met in an alternative universe at the same time that I first spoke to Anton from Bogus Designs about the Gulf Oil Momsen.





Fast forward three years and they were working together on a custom design for Momsen's new ST-F frame. We worked through several ideas and settled on what we felt would look great, and suit the soul of the bike best.

Hasie and the Robots was roped in to conjure up some designs and give us a feel for what may or may not work. These were refined, and I finally settled on a fusion of a couple of designs and ideas. From that point on, I was left in the dark by the Hasie (as he is lovingly known), and Bogus as they set about finalising the design and application. The design was then sent to Anton at Bogus Designs who added one or two twists in terms of the colors and how the design was applied to the frame.

Some of the designs considered.

It is just about impossible to describe the level of detail in the spray job, or for me to do it justice with my photography skills. The Momsen logos on the bottom of the downtube are a great example of this, as the way paint was applied means it is not visible from all angles and certainly not in darker conditions. The same with the Hasie and the Robots and Bogus Designs logos - they are there: just not visible from a couple of feet away. The main design incorporates some characters from Hasie's designs for a unique look and feel.

A trial prototype for the rim design.

This time around, I did not go as far as having a saddle and grips reupholstered, but thanks to a bright spark from South Industries, we did tackle a set of rims. There was some R&D involved to ensure the end result would match expectation. Hasie was given complete artistic free rein and decided to go with a city skyline theme. Overall, I could not be happier with how it all came together. Any rider who knows his gear will immediately realise that this is not a stock bike, but it's not over the top flashy so as to attract unnecessary attention.

The Frame

The ST-R29 is being reborn in two new models. The ST-R has a Tange Sliding Dropout for single speed or geared use while the ST-F is the fixed dropout option for geared use only. Even though the dropouts are different, the geometry and other frame details are the same for both models.



I decided to go with gears this time around to give the bike the versatility I want. The bike will gravitate towards being a tourer, with our daughter's Thule RideAlong seat having already being mounted (hence the spacers under the stem) and I will most likely add a bag or two to the bike. The way the bike has been set up and built gives me all day comfort on a bike that can still tackle some local trails when the urge arises.

I really like that there is provision for a dropper seatpost, and that the frame has a threaded bottom bracket. Those add practicality for me.


Frame Specifications & Geometry

  • Headtube: Taper Integrated (44mm Top/56mm Bottom)
  • Max Tyre Size : 29 x 2.4
  • 4 Sizes: S (15”), M (17”), L (19”), XL (21”)
  • 142 x 12mm Thru-Axle (Sram Maxle Thread)
  • Seatpost: 31.6mm with Internal Dropper Seatpost Routing
  • Front Fork Suggestion: 120mm with 51mm Offset
  • Drivetrain: 1x only
  • Chainring Suggestion : 30T to 34T Max Size provision
  • Headset: Internal Type (52mm Lower / 42mm Top)



For the purpose of the build, I moved the drivetrain from my ex-Mercer Hungry Monkey over. It is a straightforward, complete SRAM GX drivetrain with a 32T chainring and 175mm cranks. Depending on how the bike gets used, I may consider replacing this groupset down the line for a GX Eagle groupset for those longer days in the saddle.



The fork is a cheap and cheerful RockShox Reba. Those who have ridden one will know it is stiff, plush and ultra-reliable.


Tyres: Vee Tire Co Crown F front, Rail Tracker rear

I'm familiar with the Crown F having ridden them before on a VIPA Trail, but the Rail Tracker is new to me. To be honest they were mostly picked for their cool skinwalls, but have proven themselves up to the task on the couple of rides I've done on the bike. I'm happy to sacrifice some rolling resistance for the added security of grip with the Cape Town winter upon us.



I am running Morewood's Mamba dropper seatpost that we have on review. There are two options available, an external routed version with the actuator connected to the collar and the internally routed version that I have on my bike. The remote is an above the bar thumb actuator like the original KS seatposts. I would prefer a below the bar shifter or, even better, a 1x dropper lever that takes the place of the front derailleur shifter but will see how this goes with extended use.

Handlebar, Stem & Grips: Momsen All-Rise Carbon, Spank Oozy Stem, Spank Lock On Grips

The Momsen All-Rise handlebar from Momsen's range of carbon handlebars is 760mm wide with a 15mm rise. I have paired the bar with a 65mm Spank stem to give me the reach and fit I want on this bike. The grips are also from Spank and standard affair lock on grips.




Other bits and pieces

As on all my other bikes, I have opted for Specialized Zee Cage II bottle cage as they are some of the best bottle cages on the market. The saddle is a Fizik Gobi M5 we have on review and will be moved between a couple of bikes to ensure it gets the mileage needed to do a proper review. To mount my Garmin 820, I have fitted a K-Edge Gravity Top Cap mount and finished the build off with Shimano XT Trail pedals that I use most of the time.



  • FrameMomsen Bikes ST-F Steel
  • ForkRockShox Reba RL
  • StemSpank Oozy Stem 65mm
  • HandlebarMomsen All-Rise Carbon Handlebar 760mm wide with 15mm rise
  • GripsSpank Lock On
  • SaddleFizik Gobi
  • SeatpostMorewood Mamba Dropper (internal routed)
  • BrakesSRAM Level TL, 180mm Rotors
  • ShiftersSRAM GX
  • Rear DerailleurSRAM GX
  • CassetteSRAM GX
  • ChainSRAM GX
  • CranksetSRAM GX
  • RimsSouth Industries 29XC
  • HubsHope Pro 4
  • Front TyreVee Tire Co Crown F
  • Rear TyreVee Tire Co Rail Tracker
  • Bottom BracketSRAM Threaded
  • PedalsShimano XT Trail
  • Weight12.56kg (including bottle cages & pedals)