Sito

Hi, hoping for some miracle solution from one of the bike tech geniuses here


I got this irresistible deal on a FSA K-Force Light crankset (https://shop.fullspeedahead.com/es/cran ... o-crankset) So I bought it to use it on my gravel bike, assuming that I could just use any four-bolt 110BCD chainring to convert it to 1x.


Turns out that assumption appears to have been a little naive. FSA says they don't have a 1x chainring for this chainset (they have for their Gossamer and SL-K chainsets which are also 110BCD asymmetric but apparently those won't fit the K-Force). I've also been in touch with Wolftooth who make 4-bolt chainrings for Shimano and SRAM and they say they won't fit because all three brands use different bolt patterns.


The guy at Superstar Components, said it might be worth a try with one of their rings but there's a good chance it won't work.


What do you think? Do I have to write it off and either sell on or use as 2x on one of my road bikes? Or is there ANY way (that doesn't require me to spend stupid amounts of money) to convert this into a 1x chainset?

Iride01 

Just don't shift on the front a voilà it's 1x.

Or did you get this with no rings at all?

Sito

It does come with 52/36 rings but neither size would I want for a 1x setup, plus we'd be running into chainline issues here and, most importantly, it would just look wrong

Iride01 

Chain line issues? Gosh what do those that run 3x systems do? What is so different about your bike that you have to have a chain ring within less than 3 mm of the chain line?

Any how the BCD is going to be the main thing that keeps you from selecting a chainwheel if you desire a ring with a low tooth count. However that crank is "stylish" so it has a spider that wants matching sculpting and design at the attach points just for aesthetics. Otherwise it will look more wrong than just having a 2x crank with no front DR.

IMO of course.

Sito

Well, if you run a 3x chainset (do those still exist?) you would not combine the smallest ring with the smallest cog, would you? Same on a 2x system. That's why a 1x ring is usually a few mm offset to the left if mounted on the big ring. Makes a lot of sense in my opinion.

And no, the BCD is not the main issue here. There are plenty of 110BCD chainrings around but they don't fit because apparently four-arm bolt-patterns are specific to each brand (whereas I believe 5-arm designs all used a standard bolt pattern). Believe me, I have looked into it.

Iride01 

Sounds like you might be coming to the realization I had 5 years ago when I bought my first four arm crank.

Which is simply...... buy the crank with the ring or rings you want on it. Later, if you need other ring sizes or a replacement ring, buy an entirely new crankset.

Sito

I've had other four-arm cranksets before and changed ring sizes and even converted on of them to 1x without any problem. For Shimano and Sram cranksets you'll find plenty of 1x chainrings from several brands, not for this specific FSA one though, hence my initial post.

dsbrantjr

The OP is running into everyone's different so-stupid-it-would-not-have-occurred-even-to-me asymmetric 4-bolt pattern that seems to be popular recently. Even dumber than the Campagnolo 1-hole-of-5-offset pattern. WTF were they thinking? Or is this the new planned obsolescence?

Iride01 

Well your experience with 4 arm spiders is opposite mine. I was never able to find rings that fit at a price that didn't make purchasing the entire crankset more cost effective as the bare crank can be re-sold on ebay to recoup almost the entire cost.

Still, your previous experience led you astray perhaps and you assumed that it would be easy-peasy to swap rings on any crank. You might find something though, then you can claim victory. I will have given up and just bought a new crank.