When to remove chain links?

[AllanVarcoe]

Hey,

So I built my wife a 1x10 bike with a 11-36 cassette and a 42t chainring. It wasn't enough gear on climbs this past weekend and she was struggling up the hills. I just ordered her a 38t chainring.

My question is, is there a rule as to how many chain links I should have based on number of teeth in the largest cog and chainring?

https://c6.staticflickr.com/2/1676/25227378965_1456b71a62_z.jpg (https://flic.kr/p/ErfURK)IMG_20160223_204023.jpg (https://flic.kr/p/ErfURK) by Allan Varcoe (https://www.flickr.com/photos/134737745@N03/), on Flickr
Sorry for ****ty pic.

[dsillito]

Not really. It would also depend on chainstay length. Just fit on the chain as you normally would, using the recommendation of wrapping the chain around the chainring and largest cog (not through the rear derailleur), and then add a link to that length. Some people consider a "link" one set of inner, and one set of outer plates, and others see the distance between two pins as one link. I go for the former definition, and it has always worked for me.

Good luck!

[seanile]

chains come with installation instructions on how to measure them for breaking.

[Mark McM]

If the chain is the perfect length for the original chainring, then to maintain the same relative size you would shorten it by the number of links fewer that the smaller chainring wraps up. Or another way to look at it is this: the chain engages just the front half of the 42 tooth chainring, or 21 teeth worth (21 links). On the 38 tooth chainring, the chainring will wrap up 19 links of chain. So removing two chain links, the relative chain length will be the same.

Two links is a fairly small difference (its the minimum amount you can change the chain length), and rear derailleurs can work over a range of chain lengths, so unless the chain is currently as short as it can be for the 42 tooth chainring, odds are it will work just fine for the 38 tooth chainring without needing to touch the chain. (For example, on my road bike with short cage derailleur, I regularly switch between a 53/39 double crank with a 12/23 cassette, to a 52/36 double crank with a 13/29 cassette, without touching the chain length.)

[AllanVarcoe]

OK, I have a new chain waiting for me to finish my current frame build. I'll read the instructions for it.

Thanks for the recommendations as building up multi gear bikes is kinda new to me.

[Ralph]

Like Mark said....I wouldn't take any links out until she rides it and you see if it needs fewer links.

And BTW.....from 42 down to 38 (around 10% lower gear) is not a lot of change if she was having a hard time with a 42 on a long hill. Hopefully it is enough. I have no idea how strong a rider she is, how experienced, etc.

[AllanVarcoe]

Like Mark said....I wouldn't take any links out until she rides it and you see if it needs fewer links.

And BTW.....from 42 down to 38 (around 10% lower gear) is not a lot of change if she was having a hard time with a 42 on a long hill. Hopefully it is enough. I have no idea how strong a rider she is, how experienced, etc.

Will do. :)

True, I wasn't looking to make a huge change for her. But my thinking is that if it's still not enough then I'd use the 38 on my CX bike and get her a 34 or whatever is close to that and fits a 5 x 110bdc. Wolf Tooth has offers them but they aren't in stock atm.