Seatposts are surprisingly varied in their design and function. You’d think that by this time, we would have standardized on a clamp that works with round and oval rails, but that’s not the case. Unless you opt for one like the Zipp Service Course SL 20 seatpost.

Zipp Service Course SL 20 Seatpost Features:

  • Weight: 220g (stated)
  • Diameter: 27.2 or 31.6mm (tested)
  • Length: 330mm
  • Setback: 20mm
  • Weight limit: 300lbs
  • Torque for saddle rails: 7.0Nm
  • Minimum insertion length: 90mm
  • MSRP: $131

Zipp Service Course SL 20mm Setback Seatpost

Service Course SL Seatpost is Stiff and Adjustable

When it comes to aluminum seatposts, there’s little question that Zipp has an edge. Just one look at the Service Course SL and there’s no doubt — it looks sexy and fast. Now, while the shiny looks will win over that first-glance, it’s beauty is more than skin deep. There are two critical functions of a seatpost: 1) Hold the saddle in place and 2) provide a pedaling platform. Let’s dive into the first point.

Zipp Service Course SL Seatpost Adjustments

Saddle adjustments can vary wildly from seatpost-to-seatpost. Just this past weekend, I swapped out a saddle on a house-brand seatpost on another bike and about lost my mind doing so. Zipp takes a different approach — one that eschews modern side-clamping designs and instead goes with a no-nonsense top/bottom clamp design that can accommodate round rails or both 7×9 or 7×10 carbon rails without adapters. I know… sounds crazy but it’s true. I have been able to swap between various carbon and titanium rail types (Specialized S-Works Romin and Bontrager Serano) without worry and get perfect saddle placement every time. Cha-ching.

The other great part about the adjustability of the 20mm setback version is the ease of micro adjustments. Since both fore and aft adjustments sit behind the post itself, getting an allen wrench in there is a breeze. And, the easy-to-read guide further enables you to dial things in. Kudos again.

With its etched lower tube, the Service Course SL Seatpost stayed put in the Devinci Leo SL test bike. A little carbon paste and everything has stayed put without fuss.

Devinci Leo SL

As expected, the Service Course SL Seatpost offers a very stout riding platform. As Zipp says, you won’t waste an ounce of energy, but your hind end will notice. I softened the blow by using a carbon-railed saddle, but switching to a carbon post has provided a marked improvement in ride quality.

I opted for the 20mm setback variety for maximum adjustability and found it perfect for dialing in the proper cockpit. And, the setback version offers easier saddle adjustments.

The Good

  • Easiest saddle adjustments you’ll find
  • Stiff pedaling platform
  • Could be the lightest aluminum post on the market
  • Black two-tone design looks quite fetching

The Bad

  • Offers a stiff ride
  • Price is approaching low-end carbon

The Bottom Line

When maximum ease-of-adjustment is desired, there’s no denying that the Service Course SL 20 is the seatpost to beat. Swapping saddles and re-adjusting them was a complete breeze. However, you do pay for that adjustability with a go cart-type ride.

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About Author

A Seattle native, Jason developed a love for the outdoors and a thing for mountains. That infatuation continues as he founded this site in 1999 --sharing his love of road biking, mountain biking, trail running and skiing. That passion is channeled into every article or gear review he writes. Utah's Wasatch Mountains are his playground.

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