Replacing the 53 with 50 - FSA Gossamer MegaExo Crank

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Anonymous's picture

The 53 ring usually too much for my riding ability (the 39 is okay). Is it possible to change the 53 to a 50? Is such a chainring available using the 130mm bolt. Can I use any brand of chainring or do I need a specific FSA one? Final question, where would I find a 50?

BTW, I used to ride a compact 50/34 but I found the 16 teeth difference too much, it also lead to the chain being dropped.

Anonymous's picture
Paul (not verified)

"Going from a 53 to 50 in a 23 will only alter your gearing by <5"", which you might never feel.

Like you, I tried a compact setup but the difference was too huge. I later picked up a Sugino triple with a Shimano 105 front derailer ($110 total for both + $5 for the shop to remove my old crank) and have been happy ever since.

Anonymous's picture
Tony Rentschler (not verified)
Not hard to do

You can replace the 53 chainring with any other 130 mm bolt circle ring, but for the smoothest shifting, you should get one with shifting ramps and pins. Peter White Cycles has nice TA rings:

As Peter notes on his web page, many cyclists replace the stock rings with smaller ones.

Good chainrings can be expensive, so you could also consider a new cassette with larger cogs. That would depend on what you have now.

Anonymous's picture
JIM N (not verified)
I did just this

"I replaced the 53 my bike came with with a 50. ""A"" Bicycle Shop special-ordered a Salsa one for me (it is Ultegra cranks and shifter). I figured I'd have to adjust the front derailer, but I've put a couple hundred miles on it and it's working fine without adjustment.

The difference is noticeable. Until I'm strong enough to go 35 mph under my own power, I can live with the compromise of having to coast down really long hills.

This will help you calculate your new ratios."

Anonymous's picture
<a href="">Peter O'Reilly</a> (not verified)

"You have plenty of choices for a 130mm bolt diameter, 50 tooth chain ring. Search online or have your local bike shop source such part in the ""QBP"" catalog.

While having shifting ramps and a pin on the chain ring is nice, it is not necessary. I rode for years without one and the shifting was quite fast and crisp given the shorter range of travel.

While I never recall dropping the chain like shifting to the 39 ring from the 50, on infrequent occasion I would drop the chain on the outbound side. This would occur maybe twice a year despite someone who is absolutely meticulous at maintaining his bike.

I now ride a 50/34. While the shifting is a tad bit slower, chain drop is not an issue since I use a chain watcher thing-a-mah-jig.

Anonymous's picture
Richard Pu (not verified)
Gear Chart

"You should construct a gear chart. The chart will show what gear ratios you add by changing the chainring size. It may be that the change will mostly reproduce ratios that you already have with the 39 tooth chainring. Or it may be that you can accomplish your objective by changing the cogset in the back.

I constructed my chart using a spreadsheet function in Wordperfect and a formula from a book by Greg Lemond. Here is the text from Lemond's book: ""... take the number of teeth on the chainring and divide by the number of teeth on the freewheel cog. Then multiply by the diameter of the wheel (usually 27 inches on adult bikes.)"" As an example, Lemond computes that a 52 x 14 yields a gear ratio of 100.3 inches.

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