Wondering why you’d want ultra-compact gearing for your gravel bike? Or whether crank arm lengths as short as 145mm will improve your cadence…or aerodynamics?

Now’s your chance to ask Full Speed Ahead anything you want about either, so you can get your offroad adventure bike, gravel race bike, or bikepacking/touring bike ready for its next big ride!

button to submit questions for bikerumor AASQ series

What should you ask them?

Over the past few years, FSA has released exceptionally small gearing and crank options aimed at (mostly) gravel cyclists. Their compact gearing, which they call Micro Compact, also known as Sub-Compact or Ultra-Compact gearing, offers really small chainring combos…including little rings with as few as 30 teeth.

FSA SLK LIGHT MODULAR CRANKSET SUB COMPACT GEARING

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?

button to submit questions for bikerumor AASQ series

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.

FSA K-FORCE LIGHT ULTRA COMPACT GEARING CRANKSET GRAVEL

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

button to submit questions for bikerumor AASQ series

6 COMMENTS

  1. Why does FSA have a stigma attached to them? I’ve noticed on past BR posts and other social media that the commentary can be unfavorable. I’ve never owned anything FSA but curious as to what the hang up is because their stuff seems legit.

    • I wonder the same thing. Every part I’ve ever had from FSA has been fine. I’ve got their oil slick stem on my new bike and it’s beautiful. I’d love to see them step up more to compete with the big S corps.

    • Some of this perception is justified but most of it is an unfair double standard being applied by forum trolls.

      For sure FSA has been guilty of launching some vaporware. They have also borrowed some things they learned from their OEM customers but the same could easily be said of Giant which is one of the most highly respected manufacturers in the industry.

      The real double standard is one of scale and perceived industry position. When Big S sits back and watches a developing standard or category, they legitimize the category when they finally move in. Linear pull brakes, compact road chainrings, and even their current crank design were all pioneered by small companies before Big S released their take on those products. If the reverse happens and FSA offers products that have materials or features already offered by Big S or Little S than according to the trolls FSA is just another Taiwan copy brand.

      I don’t mean to undercut the FSA/Bikerumor marketing exercise but in this particular instance it seems like someone from Rotor or Cobb would be more of an authority on uses for cranks under 165mm.

    • fsa used to produce well advertised, glossy but cheaply made products. the wear rate was quite often appalling due to low quality aluminium theyd use. any new bike i had with fsa parts had them stripped before id even riflde em. wasnt worth the headaches nor the cost of replacing them. i was chewing up a chainring every few months as the chain would wear it away. also the stems..badly formed threads and some dangerously thin clamps on some models. and take a look at the handlebars i have an fsa here and you can see where its been cut down the metal is about 4mm thick (that cheap aluminium). in comparison to my latest bar (spank oozy) where the good quality alu is only about 0.5mm at the bar end. the difference in production efforts and costs is very noticeable.

      • I think You mistook original FSA components for their counterfeit products. Since K-Force series back then had really flashy graphics, it was often copied by chinese companies that offered fake FSA branding combined with poor quality, but people bought it cause they looked awesome, and then crashed on a bike cause of it’s structural failure.

        I own original K-Force MTB bars and seatpost and those are strong as f**k, survived 6 years of down-country racing. The only problem is that the UD finish graphics get scratched easily.

  2. Small front gear is good for gravel riding to get lower gear ratio with closer rear cassette. However, in general smaller front ring is not the best for power efficiency. (Big gear is better than inner small gear usually) How much energy transfer loss can be expected in comparing to known compact like 50/36? BTW, I have power box super compact, currently only option i could find to get subcompact power meter spider.

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