As most of you probably know, SRAM's latest 1x12, Eagle drivetrain has been introduced. In a previous posting I wrote, I talked about a little bit about Gear Range and Gears and Gear Inches and I thought it might be a good idea to re-visit the topic again now that SRAM has come out with its 1x12 system.
In the above picture, I'm comparing a Rohloff Speedhub 36T/16T to SRAM Eagle 32T / 10-50T setup. I purposely picked 32T as that matches the 36T/16T well and probably a typical setup someone looking at the Eagle would pick.
The data can be found here and you can try different combinations.
So to start, SRAM is touting the benefit of a 500% gear range which is all well and good except Rohloff has a 525% gear range and have always had this gear range right from the get go, 20 years ago. I think at this point, there is no denying that riders like not having to fuss with a front derailleur/extra shifter and enjoy the simplicity of a single chain ring but Rohloff knew that sooner ;)
Rohloff having 14 gears offers a consistent ~13.5% in each gear increase/decrease. If you look at the chart above for the SRAM Eagle system, the gear step is low as 13% and as high as 20% so what that means is that some gear changes feel larger while others feel more incremental. The gear range for the Rohloff is 70.4 vs SRAM's 67.4. So larger gear range with more gears vs lower gear range and 2 less gears. Which system do you think will give you a higher chance of finding that 'right' gear? Don't forget most riders are not Enduro riders where most of the course is downhill. Finding that right gear is important. And let's get that elephant in the room out of the way, the SRAM Eagle is lighter and cheaper initially (although not by much) and I would argue would end up costing a lot more which I'll explain below.
The drivetrain for the Rohloff hub is inside a hub shell and protected from sand and grit and for the most part everything out there. The SRAM Eagle like any other derailleur system has everything exposed so the gears will wear, that's just a fact of life. The derailleur will wear and the cassette will wear. I know many people that have ridden all over the world with Rohloffs and have only had to do oil changes along the way and replace the seals and maybe bearings for a cost of $150-$200. And that's 10s of thousands of kilometers. The SRAM Eagle cassette and derailleur will set you back $580 US every time you need to replace it. Not to mention the extra cost of the chain ring and chain compared to Rohloff that uses standard narrow wide chain rings and standard 8 spd chain for $40. So we must think about lifetime cost and not just purchase cost. Unless of course we're sponsored by SRAM, then obviously that doesn't matter. Then we'd get our own mechanic and maintenance wouldn't matter either. But of course we don't live in a perfect world with our own personal mechanic cleaning our drivetrain after every ride.
Let's then talk about the durability of the overall system. The SRAM Eagle wheel requires it to be dished, that's just the reality of a derailleur system. The spokes are not tensioned equally on each side of the wheel. A Rohloff wheel has no dish, the spokes are equal length on each side, and hence equal tension on both sides. An equally dished wheel compared to a dished wheel all things being equal means a stronger wheel. That's just physics. The SRAM wheel may be lighter but it'll be weaker and because the gears and derailleur is exposed to the elements will not be as durable.
At the end of the day, the SRAM Eagle as great as SRAM touts it to be is really only lighter. It's not cheaper (see above), offer more gears or gear range, stronger or more durable and requires more maintenance. So there you have it, a comparison between the SRAM 1x12 Eagle and the Rohloff 500/14 Speedhub. Eventually when SRAM and Shimano offers their 1x14 drivetrain, I'll have to do this again. Although I can't imagine how thin the chain and each cassette cog would have to be and how much dish the wheel would be to accommodate that many gears.
Spokewrench