Here’s a reminder to you all! This week, we have FSA joining us to field your questions on super compact gearing and ultra-short cranks for gravel riding.

button to submit questions for bikerumor AASQ series

Summer is on the approach. There’s no better time to get your offroad adventure bike, gravel race bike, or bikepacking/touring bike dialed with an efficient drivetrain that best works for you and the terrain you plan on exploring.

What should you ask FSA?

The majority of bikes are spec’d with crank arm lengths of 170mm, 172.5mm and 175mm, but how do you know which of these (if any) is best for you, personally? 


The cycling industry is now putting out some ultra-short crank arms of sub 165mm. The Gossamer chainset from FSA is now available with 145mm crank arms! In what scenario is a crank length that short going to be useful? Could it improve your cadence, or aerodynamics?

Over the last few years, FSA have developed their compact gearing, which they call Micro Compact, also known as Sub-Compact or Ultra-Compact gearing. It offers really small chainring combos…including little rings with as few as 30 teeth.

button to submit questions for bikerumor AASQ series

But can you use them on regular road bikes? How small is too small? Which front derailleurs are compatible? What does it do to chain length? What else do you want to know about putting these on your bike?


The extremely short crank arms were launched mainly at the request of their sponsored triathletes, who wanted to keep their pedaling motion closer to their running motion so they could, quite literally, hit the ground running.

Read more about those in this post, then click that button below to ask your questions and we’ll get FSA to answer them!


  1. Benny Watson on

    Why is 46/30 (with options to go smaller) not the standard 2x gearing for recreational gravel / adventure bikes? We aren’t all 25 y/o and chasing podiums or Strava KOMs.

  2. Eggs Benedict on

    Why don’t the manufacturers offer a range of chainrings so you can pick your own ratios. That would be the best option.

  3. Hexsense on

    What can you do with frame that has blaze on front derailleur tab that doesn’t go low enough for 46/30 or 44/28 chain rings?
    Do you have an adapter to lower front derailleur?

  4. Joseph Ott on

    @Hexsense They do make an adapter to drop braze on style derailluiers but it usually does not show up on the web site. Email the FSA sales or Tech department and they will get you a part number for it.


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