Chain Length Question

Triathlon Forum
1

I am doing LP this year and was planning on using a 12-25 or 12-27. I have a P2K that came stock with an 11-23.

  1. If I switch to either one of these do I have to put a longer chain on?

  2. Is a month enough time to break in a new chain?

Thanks

2

I’ll take a run at this and say…it depends. If you don’t run ‘big-big’ (i.e. big chainring to big cog) you would be ok with the 12-25 as the second biggest cog is still only a 23. You would likely need to add a link if you ran 12-27 and wanted to have the ability to run your 24 (second biggest cog) and big ring - which by the way I still think is too extreme a chain angle.

So to summarize, if you don’t cross-gear too much you should be able to keep the same chain with all those cogs without any real issues.

3

I doubt you would have to make the chain longer. Setup the bike. You will be able to tell in a hurry. Stay away from crossover gears in any case.

You don’t need to break in a chain.

4

I am able to run any of your gear combinations with either my TT or road bike without a chain length change. I don’t normally use my largest cog with the big ring, but have momentarily done so just to make the crest of a climb without dropping to the small chainring. The real answer to your question really might also depend on how long or short your chain currently is. If it is already on the short side for your 23, then a 27 might be a stretch, but if your pulleys are pretty much vertical while you are in you big ring and 12, you can probably get away with the 27. If you find the chain tight, one additional link might do the job. If this is the case, and your chain is still reasonably new, maybe just getting one of the removable links would get you the extra link, plus help with future chain cleaning/maint.

I’ve not heard of breaking in a chain. I just make sure that I’ve gotten in some rides after putting a new chain on before racing. I’d rather find a problem on a test/training ride.

5

I’ve got a 58cm P2k that I have ridden with all of those cassettes, using the original chain, with no problem.

6
  1. If I switch to either one of these do I have to put a longer chain on?

I never have and have never had any problems.

  1. Is a month enough time to break in a new chain?

Easily.

7

The answer to A is “It depends”. If the mechanic set up your bike correctly you should be ok. If you have a short chain now then the biggers cogs will be a problem and the consequences of too sort a chain can be expensive, up to a ruined frame and srewed drivetrain.

The anser to B is “It depends”. You shouldn’t have to break in a new chain at all. I do recommend doing a good, hard ride in practice before using any new equipment in a race. If you change chains and the shiting is poor, then seems to “break in” you have worn gears or chainrings and are prematurely wearing out the new chain. If you have kept ev erything well lubed and haven’t ridden the current chain more that 1 season you should be good.

Best advice have a shopguy install the new chain. Right before a race is no time for learning, save that for the off season.