When you purchase a new chain, it usually comes with extra length so that it is compatible with most drivetrains. How do you know how much length your bike will need? Well, it’s really quite simple…
The first step is to wrap the chain around the largest sprockets on the front and rear, so that the ends meet on the largest front chainring. For this step, it really important to not run the chain through the rear derailleur.
Next, position the chain on the chainring’s teeth at the tightest spot you could connect the chain. Now add one whole inner and outer link, so that you have approximately one extra inch of slack in the chain. That will be the optimal length for most systems.
In future tutorials I plan to discuss the different types of chain connectors and how to use a chain tool to break the chain. The following links provide some more helpful information.
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Alex,
Very good and simple. I have replaced several chains and did not know there was such a technique. I always did it by “feel”.
You may want to also explain how to determine when a chain needs replacing. Most folks rarely do this.
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Thanks for the info sir. As stated it is important not to run the chain to the rear derailleur on the process. I just wonder if the measured length you’ve mentioned will compensate once the chain is rolled to the rear derailleur? Will I be able to shift to big gear front and big gear rear with this length? Thanks!
Hi Xtreme,
Yes, this length should be sufficient to allow a big-big gear combination. It’s also a good idea to shift your derailleur into the small-small combination, and then check to see if the rear derailleur pulleys are horizontal (the chain should be hanging about one inch below the guide pulley).
As all derailleur/gear combinations are different, it’s a good idea to test both methods to find the optimal length for your bike.
After watching the video, you appear to be pointing to the wrong place to break the link. Breaking it where you are pointing would result in both ends having outer links. I think you should point to the next (longer) inner link.
Hi Dave, after reviewing the video I can see how it might look that way, but the inner link is there, sitting on the chainring (it blends in a little).
yeah he pointed to the okay spot:)
Thanks for all your info on bike repair. When I replace my chain, how can I tell if the gears are still in good condition or if they need to be replaced with the chain.
Your front gears should be ok as it takes a lot longer for them to wear out. However, you’ll likely have to replace at least the smallest rear sprockets, and nowadays most sprockets come as a single unit. To test it, go for a ride with the new chain installed, shift into the smallest rear sprocket on a hill, and pedal hard. If the chain slips under that much pressure you’ll know the rear sprockets are worn.
** Be careful so you don’t hurt yourself if it slips **