Building a Custom Road Bike Part IV: The Ride

by Tim Mosso

If you have read the first, second, and third installments of my custom road bike build journal, you’re either extraordinarily determined or as absorbed in cycling as I am.

Now that you’ve made it to the final chapter, you’re probably wondering how this exhaustively planned bike performs. What happened when the rubber met the road?

New bike day is a good day

My first impression was that it felt like a return to my childhood when all the kids rode fat-tire mountain bikes on tarmac. The springs-in-series effect of 36mm+ tires AND <40psi AND a compliance-oriented frame AND a sprung seat post creates a 1950s Cadillac quality of floating over the road.

It’s an odd feeling on a committed performance road bike, but I haven’t sensed any tradeoff in handling or speed. Given my previous experience with a crit bike on 25mm tires at 80psi, the plush ride quality of the new bike has been its standout feature.



Tim Mosso’s new road bike is complete

All the kit works well. THM’s Ulna handlebar required me to let go of the traditional bend Deda Zero100 Shallow that I had ridden as my sole bar since taking up road cycling 16 years ago. The “compact” shape of the THM offended my eyes, but Tim Gresh’s determination to relocate me to the bar tops meant I’d spend little time on the drops of the bar.

Having spent my entire road riding career in the drops, moving upstairs left me with concerns about grip and stability that proved unfounded.

Up top, the Ulna is a wonderful place to be. Its bar-to-hood transition is long and level for easy hours on the road. When climbing steep grades seated, the ovalized tops of the bar combine with the chunky Lizard Skins tape to provide a meaty grip.

Most importantly, the new upright position has relieved me of all previous back and wrist pain, and that’s a tribute to my bike fitter as much as the bar.

When the time comes to drop down for stability in fast descents, traffic, or tense pack rides, the compact curves of the Ulna prove to be more comfortable than they look.

Thanks to a small flat section at the end of the drop, it’s easy to rest my weight in the curved part of the bar without expending extra energy to avoid sliding off the end.

Tim Mosso testing his position on his new bike

It’s hard to say much about the THM Tibia stem other than that it works. It’s my first carbon stem, and I used to believe that this was the single worst candidate among all bike parts for carbon use. While this stem isn’t meaningfully lighter than the lightest alloy stems, its combined strength with the THM bar yields little flex even during sprint-level efforts.

Moreover, there does seem to be something to the idea of a carbon fork, stem, and bar collectively damping high-frequency road buzz. The front end of this bike is less chatty in that regard than my old alloy-cockpit machine.

Front end kit

I regarded THM’s Mandibula seatpost as the single most intriguing and mysterious part of the build. A 160-gram suspension seatpost with almost no online owner feedback and a $650 price point required a leap of faith on my part. I shouldn’t have worried, because it works exactly as it looks.

Setup is finnicky. My saddle persistently shifted and refused to sit level until I revisited the fine print of the voluminous installation instructions. Correct installation of the Mandibula’s “clamshell” saddle rail clasps requires torquing, “settling” the clasps by applying body weight, and re-torquing after settling. Once adjusted this way, the saddle clamp held relentlessly.



THM leaf spring seatpost

I can feel the post’s leaf springs yielding slightly under me while riding, and it allows me to stay at effort in the saddle instead of rising on the pedals over particularly rough road surfaces. Even at my 65kg/140lb weight, I can lean against the post and see it give, so the suspension effect is verifiable.

A significantly heavier rider might sense too much motion from the THM, but anyone seriously interested in a weight weenie build probably understands that light parts have limits.

Compact gearing and a 1:1 climbing gear lets me preserve my knees while making power at my customary 95-100rpm. I can still sustain an FTP of 5W/kg at almost 40 years, but it comes exclusively through foot speed. In hardware terms, I’m now a Dremel rather than a drill.

Secondary pain relief comes in the form of a comfortable lower back. Extreme pedaling forces while seated had begun to cause lower back strain on my old bike.

After nearly a decade living in flat Florida, I realized that Pennsylvania riding would require new solutions. I have yet to experience lower back pain while climbing on this bike.

Bike drive train: 1:1 climbing ratio

Disc brakes modulate well but don’t feel noticeably more powerful than my old DA7900 dual pivot calipers, but I was using those with high quality pads on alloy rims.

Anyone who experienced cork pads on carbon clinchers would tell me that discs are a revelation in stopping power compared to cork on plastic.

Wet riding is another matter. The discs out-stop any rim brake solution whenever water enters the equation. While I used salmon-colored Koolstop pads for that kind of riding in the past, the efficacy of discs in all conditions makes a mockery of pad-swapping to match the weather.

Shimano’s famed shift quality remains as advertised. Even front derailleur swaps under power largely occur instantly, silently, and completely. I stripped and waxed the chain to minimize noise, grime, and maintenance.

Not only does it make the Shimano action even creamier, but it leaves me wondering when wax will become the stock lubricant on factory chains – at least at the Dura-Ace level.

Now that I’m spending more time on the shifter hoods, I appreciate that the current DA hood profiles are long, narrow, and flat. Their extended length combines with the flat THM bar to match my natural fore-aft shifting habits perfectly.



The front end is a comfortable office on the road

Is there anything I don’t like? Of course there is, because nothing’s perfect.

Seven’s geometry mostly delivered what I sought. Stability under 30mph is better than my old crit bike. The Seven doesn’t have the previous machine’s low-speed wobble or propensity to jackknife.

That said, the Seven does seem to trade low speed stability for high-speed liveliness. This appears to be the consequence of the specific rake and trail decisions made to address low speeds.

Given that I don’t spend much time above 30mph, this seems like a fair exchange. Still, I had pushed for 10/10 stability during the factory interview process, and I was talked back to 7 or 8 out of ten on the ten-point scale.

Given that this bike still seems quite agile, I feel like 10/10 might have been the right match for me. Not every rider wants a balance of qualities – some want extremes.

Perhaps more stability?

My left knee remains an area of concern. Tim Gresh did all he could to dial out my lateral knee movement. On this count, success. I can see and feel that they track vertically on this bike. That said, I still feel some knee aches beyond 70 kilometers/45 miles of effort.

Longer pedal spindles, shorter cranks, new cleat setup, and lower gearing definitely helped, but I believe that these knee challenges will require attention from experts beyond the cycling world.

Recent X-rays revealed a structurally normal knee, so this is now a puzzle for a soft tissue expert to tackle from a medical perspective.



Anti-seize thread lock because I’m me

As a mechanic to my core, I went through the entire bike and thread locked, anti-seized, and torqued everything to spec for my own peace of mind.

Now I have an entire summer ahead to dial-in the fit with Tim G, adapt my muscles to the new setup, and bank miles.

New bike day is as much fun as new watch day. But in both cases, the real experience is the cumulative memories you build around the machine.

I’m looking forward to new roads and the adventures they bring.

You might also enjoy:

Tim Mosso Builds a Custom Road Bike Part I: Who, Why, and What’s Involved in getting a Custom Fitted Bike

Tim Mosso Builds a Custom Road Bike Part 2: The Frame

Tim Mosso Builds a Custom Road Bike Part III: The Parts

Tim Mosso visits the New York International Auto Show 2024 (Before it Fades Away): It’s a High-Low-and-No Octane Photofest (Part 1)

Tim Mosso visits the New York International Auto Show 2024 Part 2: This Time It’s a Celebration of Petrol Engine Power!

1 reply

Leave a Reply

Want to join the discussion?
Feel free to contribute!

Leave a Reply

Your email address will not be published. Required fields are marked *