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Testing an Oval Chainring and 1x12 Group-Set on My Mountain Bike

I have been Mountain Biking for many years, first on a cheap apartment store bike, then a "proper" Hard-Tail and then Full Suspension

My Upgraded Mountain Bike

My Upgraded Mountain Bike

Why I Wanted to Try an Oval Chainring

The 2x10 Groupset on my Giant Anthem MTB was worn out completely, and I had a big 100-km (about 65-mile) single-stage event coming up in about a month's time. The Groupset had to be replaced before the event.

I had the choice of replacing the components with the same, or upgrading to the system that most of the pro riders use, a 1x12 system with an oval chainring on the front. Upgrading would cost about twice as much as replacing the worn parts with similar ones.

After a lot of pondering about it, I decided to go for the 1x12 upgrade. I had to do this with enough time left to get used to the new system.

After all, including the upgrade cost, the bike cost me one-third as much as a new bike with close to the same spec.

The Upgrade

I dropped off my bike at my local bike shop, East Coast Cycles, where Kevin Taljaart and his team were taking good care of it. Having done more than one Cape Epic, and multiple other prominent MTB events, his experience and expert advice has proven to be of immense value in the process of deciding which way to go with the upgrade.

I got the bike back; it sure was looking great and the Sram Eagle GX 1x12 was shifting as smooth as butter. Only one thing left to do: take this baby for a long ride!

The Test—A 51-Mile Ride

Looking at the weather forecast for the weekend, the prospects were not good, with strong winds and hectic gusts predicted. I took Thursday morning off as it was the only "good weather" day available.

I left home at sunrise, heading off into the countryside on gravel roads with beautiful scenery. A couple of deep valleys provided some steep downhill sections with climbs on the far side.

The 1x12 system did prove to be much simpler to use than the 2x10, as you only have one set of gears in ascending levels, as opposed to combinations of gears between back and front on the old system.

There is obviously a small sacrifice in range, and this will be felt either at the top end or the bottom end, depending on the chainring size you choose.

While many riders opt for a 32t on the front, I went for a 34t, to reduce the range loss at the top end, with a small loss on the low end.

The oval chainring, due to its design, takes a bit more effort on the "power" part of the revolution of the crank, but eases off around the vertical pedal position where you have little force on the pedals.

I started to feel the extra effort within the first 15km (around 9-10 miles), but at 45 km (28 miles) to the end of the 81 km (51 mile) ride I was feeling the strain.

At the end I was completely exhausted, stopping at times to stretch as I felt early symptoms of cramping in my quads.

Close-Up of the 12 Speed 11-50 Sram Eagle GX Cassette

Close-Up of the 12 Speed 11-50 Sram Eagle GX Cassette

So Is the Oval Chainring Worth the Investment?

Yes. At some point during the ride I surely thought that I hated it due to the discomfort in the moment, but I was warned by experienced guys that the oval chainring would take a week or two to get used to, and I am confident that as soon as I get used to the system, the extra strain that I felt will convert to more torque on the cranks and that means more speed on the trail.

Happy riding, and stay safe.

Jan van der Westhuizen

Jan van der Westhuizen

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2019 Jan van der Westhuizen