Spreng Reng 2.0 – Can This Chainring Make You Climb Faster?

PEZ Pre-Production Product Preview

There’s a lot of debate about the science and benefits of oval chainrings, but PEZ’s Chuck Peña is a “non-round” convert.  It’s maybe not bad company to keep – as 3 x Tour winner Chris Froome likes ’em too. Chuck’s been riding a pre-production version of the Spreng Reng 2.0 “quasi-heagonal” chainring and offer PEZ readers his first impressions.

PEZ readers will know that I’m a fan of oval chainrings with Absolute Black oval chainrings on my Felt FC and Rotor Q Rings on my Colnago V3. Since the beginning of summer, I’ve been riding a pre-production version of another “non-round” chainring: Spreng Reng 2.0, and I wanted to give y’all some first impressions.

A little background first … The Spreng Reng 2.0 is the brainchild of Doug Brown, Jr., who’s spent the last 5+ years developing it. There’s a lot more technical detail behind the design of the Spreng Reng 2.0 than I will tell you about, but a few things worth noting:

  • The Spreng Reng 2.0 is not an oval chain ring. Doug calls it a quasi-hexagonal shape for which there really isn’t a geometric name. Design-wise the shape “has six ‘curved’ segments (instead of being straight as typical with a true hexagonal shape) between six ‘rounded’ vertices (the location where two segments meet and would typically form an angle but are curved instead of being angular as with a true hexagon).”
  • According to Doug, the result of this unique shape “is that all gear tooth valley radii vary above or below what would be normal for the total gear teeth on the chainring.” For comparison: “the total gear teeth valley radii count for a 34-tooth round chainring is: 34 x 34 = 1,156. The total gear teeth valley radii count for a 34-tooth Spreng Reng is: 1,153.52, a reduction of 2.48 teeth.”
  • So what does that mean? According to Doug, “By comparing the total gear teeth radii counts for each Spreng Reng version vs. a typical round chainring it is obvious we are effectively reducing the ‘net’ total gear tooth valley radii without reducing the gear tooth count which is beneficial because we are increasing the gear torque but still providing the same gear tooth count.” [emphasis added]

To the naked eye, Spreng Reng (left) is more round than oval (Rotor Q Ring, right)

In more simple terms:  The Spreng Reng 2.0 is designed to make climbing easier/faster.

But does it?

I don’t have any hard statistically significant data, but my subjective answer is “yes.”

The first thing I noticed on my maiden voyage on the Spreng Reng was that even on flat ground I was spinning both faster and easier than I normally would have. Even if the Spreng Reng didn’t live up to its claim of increased performance climbing, that’s a benefit in and of itself.

But ditto for when the road tilted up. Not only could I spin easier/faster, but I could also ride a bigger gear more comfortably. The other thing I noticed is that I could stay seated in a bigger gear. I’m a climber by nature (not to be confused with being a good climber), but I’m also now squarely in senior citizen territory. Yet my regular riding partners (almost all of them 10+ years younger than me … some of them 20+) have commented on how well I’ve been climbing this season. And on some rare occasions, making everyone else hurt on climbs. I know that’s subjective, anecdotal evidence but trust me … that’s not the norm (and yes, I know some of that may be the result of just better fitness).

Wednesday nights are my Wednesday Night Hill Ride (WNHR aka Peña Peña aka Pain Party) that I’ve been leading for the past 5+ years. 15-20 miles with at least 100 feet of elevation gain per mile. It’s an urban ride with a lot of punchy climbs (many of them double-digit grade). The longest climb is not quite a mile and a quarter. Everyone rides the climbs as hard as they want/can, but then we re-group and ride easy in-between climbs. One way it’s been described is weight lifting and intervals all at the same time.

This year, I’ve managed quite a few PRs on climbs over the summer, as well as Xert breakthroughs. In particular, in addition to improving my PR on the aforesaid longest climb, my times have consistently hovered near my PR on the climb. Yes, I know improved fitness is a factor. But I also know that with the Spreng Reng I’m able to put down more power in a bigger gear for a longer time than with my Rotor Q ring (which I also know I ride better than a round ring) just by looking at the numbers on my power meter when I’m riding.

I also know I’m spinning faster because all my riding partners comment on my cadence. I wouldn’t call myself a high cadence rider by nature. Not that I can’t spin at higher cadences, but my “natural” cadence is probably mid-80s rpm. With the Spreng Reng 2.0 I find myself more naturally spinning in the mid/high-90s rpm (meaning without consciously trying to spin faster) and a lot of times even 100+ rpm. One benefit is that this has translated into doing the same in the big ring.

But just don’t take my word for it. I know this is from three different efforts spaced out over several months — so not apples-to-apples-to-apples (maybe more like apples-to-oranges-to-lemons?) — but it is some data and evidence with actual numbers for the Spreng Reng. Keeping in mind that it’s not a controlled experiment where variables are held constant, my Strava data and Xert power for the Molte Piccolo Mortirolo segment on my WNHR (please don’t laugh at my power numbers…) that shows both higher cadence and power riding with the Spreng Reng 2.0.


The 3.5% average gradient is deceptive because of the lumpy-ish run-in with some downhill sections. The back half of the climb is a fairly steady 5-6% with two short double-digit sections.



April 27, 2022 – Riding with my Rotor Q Ring (I know I wasn’t going as hard as I could go from start to finish because this was one of the first WNHRs of the year, but I know I made a good effort on the last part of the climb, which is it’s own segment)


June 1, 2022 – My first time up the Molte Piccolo Mortirolo riding with the Spreng Reng 2.0 and I got a PR! (I can’t remember what my previous PR time was). Power and cadence numbers speak for themselves.


July 20, 2022 – Improving on the above PR with slightly higher average cadence and power numbers

Another thing worth noting … I had no problems whatsoever adapting to the Spreng Reng 2.0. For me, there are no noticeable differences in my pedal stroke. That’s going from oval to quasi-hexagonal, but I’m guessing it would be fairly similar going from round to the Spreng Reng 2.0 since the Spreng Reng shape is more “round” than “oval.” And another thing to remember if you’re contemplating trying any non-round chainring … you still pedal in circles. (NOTE: At the end of the summer, I started riding a LOOK 795 Blade with 52/36 round chain rings and made that transition no problem-o.)

Overall, I’m impressed with the Spreng Reng 2.0. It’s not just that I found it easier to spin. Combine that with making it easier to ride a bigger gear and you have a recipe for better climbing. At least for me, I could notice enough of a difference. It’s not night-and-day. And it’s not like I can rocket up hills and out-climb guys that are just stronger than me. But with more than 1,500 miles on the Spreng Reng 2.0, I can say climbing is easier/faster. #marginalgains that are noticeable. It might only be a few, but watts are watts.

PEZ doesn’t have a release date to the riding public yet for the Spreng Reng 2.0, but we’ll keep you posted. In the meantime, Doug is trying to talk me into riding a 36t Spreng Reng 2.0.

For the techno weenies … from Doug’s patent for the Spreng Reng

Note: If you have other experiences with gear or something to add, drop us a line. We don’t claim to know everything (we just imply it at times). Give us a pat on the back if you like the reviews or a slap in the head if you feel the need!

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