1X vs. 2X Drivetrain Comparison Follow-Up
Jim’s Tech Talk
By Jim Langley
Thanks everyone for sharing your thoughts and preferences in comments regarding “1X” and “2X” drivetrains (say “one by” and “two by”), which was the subject of last week’s column: Should You Consider a 1X Drivetrain on Your Next Road Bike?
Within the comments were a couple that are worth discussing a little more, which we’ll do here.
First, a reader named Gary M. Keene called us out for just saying that “a 1X bike might not be much lighter at all from a 2X bike.” We said that, because the companies and influencers pushing 1Xs typically claim significant weight savings when you go to 1X. Gary asked why we didn’t give actual weights of the components.
The answer is that, the only way to get those weights is to weigh the components ourselves and that’s not possible without already owning or buying them (which we don’t and can’t). So Gary, the best we can do is to compare the claimed weights given by SRAM. Here we go…
1X SRAM Force XPLR AXS
10-46 13-speed cassette with 1X crankset with 48 tooth chainring
Cassette: 346 grams
Crankset: 565 grams
Bottom bracket: same
Rear derailleur: 418 grams
Chain: 244 grams
Lever: same
TOTAL: 1,573 grams
2X SRAM Force AXS
10-33 12-speed cassette with 2X crankset with 35/48 chainrings
Cassette: 266 grams
Crankset: 720 grams (no power meter)
Bottom bracket: same
Rear derailleur: 284 grams
Chain: 180 grams
Lever: same
Front derailleur: 209 grams (including battery)
TOTAL: 1,659 grams
Based on these SRAM numbers – as best we could track them down and trying our best to match components (chains vary a lot), the SRAM 1X drivetrain beats the 2X by 86 grams (or 3.034 ounces). The most remarkable comparison in our opinion is the weight of the 13-cog 10-46 cassette only weighing 80 grams more than the 10-33 12-cog, which is hard to believe looking at the giant 13-cog cassette.
Then, the other comment came from “Herbert” in Germany, who wished we had included a column in our gear chart in metric units. I had to look up how to convert them, and found this on Wikipedia: “To convert gear inches to metric units (known as metres of development or rollout distance), multiply the gear-inch value by pi (π ≈ 3.1416) and 0.0254 (the conversion factor from inches to meters).” I’ll let anyone interested in the metric units do the math themselves.
Or maybe you’ll be able to use the reference Herbert also provided in his comment: “I’d like to point out this excellent graph showing ‘gearing’ and allowing comparisons: https://ritzelrechner.de.”
Thanks for the comments Gary and Herbert and everyone else! And, as my late colleague at Bicycling Magazine, Frank Berto – a bicycle gearing specialist – used to sign off, “gears to you!”
Jim Langley is RBR’s Technical Editor. A pro mechanic & cycling writer for more than 40 years, he’s the author of Your Home Bicycle Workshop in the RBR eBookstore. Tune in to Jim’s popular YouTube channel for wheel building & bike repair how-to’s. Jim’s also known for his cycling streak that ended in February 2022 with a total of 10,269 consecutive daily rides (28 years, 1 month and 11 days of never missing a ride). Click to read Jim’s full bio.
I love reading this column when it comes out. At age 76, I have been riding seriously since middle school when I bought an all Campy “10-speed” from Sears. After that came a handmade Cinelli with sew-ups and all Campy components and a used Bianchi track bike. I was never a very strong racer, but I did a fair amount of bike touring and camping on the CInelli, believe it or not. I am sold the Cinelli to an antique bike lover several years ago and have been riding a Cannondale synapse for 8 years for exercise and fresh air.
So, when I read the bit about 1x vs 2x component weights, I thought to myself that most of your readers should focus more on balalnce in their lives and their bikes as low impact aerobic fitness opportunitties. Most heatlh resources support conssitent aerobic exercise as the best way to extend one’s health and functionality. I have not added weight training but that is another valuable component, if you have the appetite for it.
Jim,
Just wanted to point out — to somewhat mitigate the point about shifting being easier with a 1x since you only shift the rear derailleur: on most electronic shifting systems (like my Dura-Ace Di2), a setting can be chosen to shift both the front and rear derailleurs with only the right shift paddle. Not only does this mean you really never need to shift the front derailleur—but the system also finds the optimal gearing combination so it’s impossible to cross-chain. Just wanted to add this to the mix, belatedly.
Jim, thanks for your detailed reply re: weights! I hope you received my initial comment/s in the spirit of the opening line– “I appreciate the usual thoroughness here”. It was only in that light that I gave a poke toward testing the myth of lighter weight (and acknowledged that would be ‘tedious’) I also assumed that having the equipment in your possession to test inferred that you could do with it as you please = not so much!
All of this is in the context of what IMHO has been a long pattern in bike / equipment reviews in most OTHER bike rags over the years of allusions, rumors, and after the fact assertions that were never made the first place (“Yeah, everybody KNOWS how noodley titanium frames are”– well that’s not what you said when they came out!) I enjoy and respect RBR because it’s rider and fact based, so keep leaning into that.
Thanks Gary, yes, I definitely received your comment in that spirit. And I wish I had the parts in my hands to actually weight them. While I was at Bicycling Magazine (1988 – 1999), one of the awesome things was that we could request components from manufacturers and they’d send them for testing. Magazines then were on a 3 month deadline approximately, so we’d have the time to wait for the stuff to arrive and also to try things out before writing our columns. Boy, the internet has changed things! I enjoyed using it to track down the weights best I could to try to answer your question more with facts than assumptions. Thanks for the push to do it, appreciate it!
In cycling,
Jim
A belated reply, but I rode a 1X electric mid motor Orbea with a 42 cassette SRAM shifting supplied by the tour operator in Switzerland and it was an absolute pig of a thing. The extra small ring was really missed on the challenging climbs irrespective of the tight cassette and it tapped out on the steep descents. Horses for courses I know but my take on the 1X is that as a gravel bike or general knock around without too much onride maintenance it’s probably a reasonable workhorse, but for the mountains it’s pretty useless. The thing kept dropping the chain searching for the small cogs which ended up as a major stack with oncoming traffic in in a wet alpine tunnel. As a workaround I used it for climbing and swapped to a conventional non electric 2X for the descents and yes, I needed an ebike to get up the climbs! Conversely, at home in Oz I ride a 3X gravel specialised oldy for general purpose with a 9 speed cassette and never had a climbing or descent issue. A Trek 2X 12 speed mid electric Domane speed on the road ….. as I say, horses for courses.
Thanks for the great comments everyone!
Jim Langley