Compact to Semi Compact

Hello ALL In Sufferlandria.
So im joining the Big Boys with a 52-36 Ultegra Chainset arriving tomorrow, with some nice new shiny carbon pedals. I am going from a 50-34. Everywhere I look on the web opinion is pretty divided as to wether I need to lengthen my chain, running 11-30 medium cage on the back.
Any thoughts welcome


Just put an 11/28 short cage on to complete the package :smiley:

Hello Joel.
Yes I do plan to ditch the Nancy boy 30 tooth at some stage.


Hi - sadly the reason the web is 50/50 is it depends on how your chain was set up I’m afraid. Adding two more teeth might not be the end of the world as far as your RD is concerned. Last two times I had a shop service my bike though, once the chain was already too short for big/big, and the other it was slightly longer than I needed for big/big. In the latter case adding two teeth (which I’ve done, same as you) was no issue. I couldn’t have done it with the previous setup or the RD would’ve been super stressed. I had just changed the chain and cassette at that point anyway as well, so it meant everything was new/new/new to keep wear in line

Assuming you’re just undoing a quick link and rejoining - just put it on and see what it looks like big to big and take a call.

(Bearing in mind if you’re changing chanrings that were worn, you run the risk of messing with wear everywhere else if the three are too far ‘out of sync’ in terms of wear (the three being cassette, chain, rings))

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Thanks Sir M
Don’t worry I’m aware of the wearing at the same time issue. Chain and both cassettes for bike and turbo are bought recently so only done about 500 miles.

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You’ll likely need an extra link or so.

Nancy boy 30. Pah, I run 11-30 and I can assure you I’m not bad up the hills…:wink:

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Good news ladies and gentlefolk.
Didn’t need an extra link but was filled with dread when I had to move the front mech up a bit. My nightmares are plagued by front mechs not monsters lol. But more good news it was a breeze and did a planned outside ride and liked the feel especially in the small ring. However I have decided to go 11-28 and small cage RD.
I will be putting the 2 11-30 cassettes and medium RD for sale on here later this evening.
Thanks all.

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Whether you need a new chain depends on the frugality of the person who set it up last time. In my experience manufacturer installed chains are quite generous & you won’t need to change it. If you installed it yourself then you will need to extend it.

I switched from a compact to a standard (49 or 50 to a 53) & didn’t need to (my powermeter had a 130bcd spider).

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im afraid I proved you wrong Eerke lol I fitted chain myself and didn’t need to extend it.

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The power of foresight … :slight_smile:

Hmm. Interested.

I’m not too surprised that the new chainrings would work for you without a new longer chain. I believe half links are 0.5 inch each, and so one set of links is 1 inch(minimum add/remove). The chain wrap on your crank is approximately 50% of the chainring circumference. Between the 50 vs 52 would be 50%(chain wrap) of 25 and 26 inch circumference which means 12.5 to 13 inch. You need a half link extra.

To determine if this will work for your current setup, if you put your bike in the 50/30 combination, and then measure how far forward your rear derailleur can move(do this by pushing it forward with your hand); so long as it’s more than 1/2 inch, you should be fine.

Dear Joel.
I refer you to your earlier post, I have taken your advice (even though the setup worked fine) I have ordered Short cage RD and 11-28 cassette. So might end up actually removing a link.