Ask A Stupid Question - ask Bikerumor your bicycle maintenance and tech questions and we'll find the answer

We know, there’s no such thing as a stupid question. But there are definitely some questions too embarrassing to ask your local shop or riding buddies. This is the first in a weekly installment where we get to the bottom of your questions – serious or otherwise. 

Dayne asks – What is the easiest way to remember which limit screw does what? I have to look every time to figure out if it is the high or low end of the cassette I’m adjusting.

When it comes to limit screws, it’s all about high and low gears. The H limit is for your high gears, or the biggest chainring in front and smallest cog in back. The L limit is the smallest chainring in front and largest cog in back. If you’re asking a way to remember which screw does what, when I started I used the mnemonic trick that H comes before L in the alphabet, so the high limit is closer to you when looking at the bike from the driveside than the low limit – or that H is for your hardest gears. The low side and the high side are the same front to back, with the low limit affecting the side closest to the tire, and the high side affecting the side closest to the outside of the bike. Most of the time you should be able to see the H & L written on the derailleur.

If not, since different derailleurs place the limit screws in different locations, the easiest way to ensure you’re adjusting the proper screw is to shift into the highest or lowest gear and inspect where the limit screws contact the derailleur cage. Most often, the proper screw will have the smallest gap, and once you make contact with the limit screw you’ll be able to see the derailleur actually moving. One other trick I’ve seen used over the years is to color the head of both high limit screws with a colored Sharpie if you want to be able to quickly identify it.

Overweight on skinny tires writes – I weigh 275 pounds and stand 6′-2″ tall. I was wondering if I rode a fat bike would it make me look thinner? 

True story – one time I had some plumbers at my house replacing a water heater as part of our home warranty (that’s only pertinent since I want to make it clear that normally I’d do it myself). After seeing one of my fat bikes in the basement, one plumber said to the other (who was probably double your size), “hey, you should get one of those. It would look like a normal bike under you!” All joking and co-worker prodding aside, I can’t say that a fat bike will make you look thinner – unless it’s black. Everyone knows that black is slimming.

WV wonders – Why aren’t we shrinking chainrings instead of using 50t cassette cogs? ex: a 30t x 9-44

When it comes to modern 1x drivetrains, having low gears is important, but equally important is having a wide range of gearing. Shrinking the front chainring will help you gain those lower gears but it will also cut down on the high range. Also, smaller chainrings tend to wear faster than larger ones, and on a 1x drivetrain where narrow-wide chainrings are a big wear item, keeping them running longer is a big plus. Then there is the fact that on a 1x drivetrain, the chainring is the only adjustment a rider can make to the overall gearing so many riders are already going to smaller chainrings to skew the range to a level they are comfortable with. Direct mount chainrings have opened up the possibility of smaller tooth counts, but previously the 104 BCD was often the limiter to what size chainring could be used.

In a system like SRAM Eagle, the introduction of the 50t not only adds an extremely low gear, but also increases the range to 10-50 and the addition of a 12th gear makes for slightly smaller jumps between gears. The other constraint is the size of the smallest cog, which only a handful of cassettes like those from e*thirteen go smaller with a 9t cog. However, the e*thirteen cassettes with a 9-46t spread manage to squeeze out just a bit more range than an eagle cassette. A 46t cog just happens to be the biggest size that you can cram into an 11 speed SRAM derailleur without needing any sort of adapter which is probably why e*thirteen stopped there. I wouldn’t be surprised to see a 12 speed cassette with a 50t cog from e*thirteen in the future once the compatible SRAM drivetrains become more prevalent.

To answer your question, the addition of a 50t cog to a cassette like SRAM Eagle or OneUp’s Shark Adapter which makes an 11 speed 10-50t drivetrain makes for the widest possible range of gearing. That drivetrain can then be used by a beginner who needs all the help they can get with a 28t chainring, or it could be used by a fit racer with a 36t or larger chainring.

Got a question of your own?  Click here to use the AASQ form, or find the link under the Contact menu header up top anytime a question pops into your mind!

7 COMMENTS

    • I’m not sure I would describe a mountain drivetrain with a front derailleur as “elegant.” Aside from being the flimsiest item on any mountain bike, it is also the cause of a huge majority of issues with lesser-experienced cyclists. Know what you eliminate when you go to a 1X? Chain rub. Overlapping ratios.

      The rear derailleur has a huge advantage in shifting due to it shifting the non-loaded section of chain (as opposed to the front derailleur having to shift the loaded section of chain) that it make so much sense to make the rear derailleur do all the work.

      If your only argument about a 1X drivetrain is that the cassettes are visually unusual because of how big they are, then you need to find a better argument.

    • It’s actually the opposite. If the color black is slimming, than a black fatbike will make the fatbike look less “fat”. Which makes the rider proportionately fatter again. Now if you would wear all black cycling gear, that would event things out again. 🙂

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