S40 build for randonneuring

Hi folks,
I wanted to get feedback on a proposed S40 build.

Use case: randonneuring, usually in the country around Kansas City. There might be a perception this is flat country - it isn't. All local routes have lots of rollers, and the nice, quiet roads aren't usually in the best shape. So climbing capability and comfort are priorities.

Impetus for this build: my current road bike is a v20C. It's fast on smooth pavement, but not ideal for the rough roads. In reality, most of the routes I ride don't have a lot of pavement that really suites the v20C. I find that over the course of a typical randonneuring course, my average speed is lower than I feel like it should be. I also ride a Q45 set up for gravel. I just feel more at home on the Q45, which I think is down to the seating position just working a bit better for me, easier starting and stopping with a lower BB, a more comfortable ride, etc. My goal with the S40 is to have a road bike experience that's closer to the Q45 in terms of comfort and capability while being a bit faster than the Q45 on the road.

Proposed components:
- SRAM Apex AXS XPLR 1x drivetrain, hydraulic brakes, 11-44 rear cassette
- Cruzbike 145mm crankset with 38T chainring. This yields a lowest gear around 23 gear inches, which from experience should work for me.
- Rear wheel: DIY build of SON 28 hub, robust alloy rims (looking at DT Swiss GR531), add EZgains wheel cover
- Front wheel: something with 50-60mm aero profile, maybe Bontrager Aeolus Pro 51R
- Tires: Rene Herse Barlow Pass with Endurance casing, 40mm, tubeless
- Lights: SON Edelux II headlight + Busch Muller Brake Line Plus tail light (tail light flashes when you brake)
- Sinewave Revoluion for USB charging
- S40 rear rack. I already have the Cruzbike trunk bag and a smaller Arkel trunk bag. The trunk bag holds a lot, but if more is needed I could add the underseat racks which I understand should fit the Ortleib Sport Rollers I already have.

Does anything seem especially silly about this? Please let me know!
 
Last edited:

Ramnob42

Member
Have you thought of trying to convert the Q45 seat to 40 degrees and add the parts to it, you would then have some suspension for the rough roads you mentioned?
 
Yes, and am also considering just getting a road wheelset for the Q45. I'm really comfortable on that bike, and even with the current 650B wheels with gravel tires, it is reasonably quick on the road.
 

McWheels

Off the long run
I run the Babyshoe Pass (650b x 42) on the front and it's excellent, so you're exactly in the right sort of postcode I'd have recommended for tyres that are both low resistance and good for lumpy roads.

For the rack I don't care about a rack-top bag so I'd counsel for the Tortec Velocity (optional hybrid version) to keep things in close, but in truth carrying panniers isn't aero. Frame bags have been measured as significantly better, and there are plenty of places to put them, not least on top of a Tortec Velocity Hybrid(!). But for an S40 I needed 10mm connector nuts to make it all work near the rear axle - not a hardship but it won't go nicely otherwise. There's also the TailFin if you've the inclination.
 
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