How long should my chain be on my bicycle? If you don't have an old chain to work from, we show you how to measure the correct chain length which works on most bikes including a road bike chain and most mountain bike with few exceptions which we'll describe below.
As we can see here, when we place the chain in the smallest chainring and smallest cassette cog (a gear we don't usually use), the chain rubs on the pulley wheels indicating that the chain is too long. So first we'll remove the old chain with our chain breaker.
Size bike chain using this drivetrain method which works for most cases with a few the following exceptions:
Using a "shadow derailleur" requires one more full link (an outer plate and inner plate constitute an chain link).
If bike uses a chain guide, be sure the chain is routed through the guide.
If the bike is equipped with a SRAM derailleur, 10 or 11-speed cassette on a single front chainring and no rear suspension, or if the bike has rear suspension then see the video from Park Tools.
Move the rear derailleur to the smallest cog to get it out of the way. Now move the front derailleur over the large chain ring. Wrap the chain around the largest cog. If one end of the chain has just outer links, feed that end forward onto the large chain ring and hold in the 5 o'clock position. If the chain uses a masterlink, install half of the masterlink. Now the rest is the same whether you're using a master link or special rivet. Pull the rest of the chain snug and place on lower part of the large chain ring. Make sure the chain is securely on the large cog and we've bypassed the rear derailleur completely. We will add some extra chain links at the end to make up for this.
Find the closest rivet where the 2 ends can be joined. If we have an outer link matching up with an inner link, this is our reference point. Now count 2 rivets down and mark the chain. This is the rivet we'll remove to cut the chain with a chain tool.
If we have an outer link matching up with another outer link, these cannot be hooked together. So go down one more rivet. This will become our reference rivet. Count down 2 rivets to find the rivet that we'll remove.
This is the easiest way for bicycle chain sizing when you don't have an old chain that you removed to work from (i.e. replace your present chain). Once we have the correct length, we also show chain installation using a masterlink. Note: When replacing a masterlink, look for an arrow on the masterling. If present, it points in the direction of chain movement when pedaling. On Shimano chain, the writing faces out toward you. Master links are available for most chains including SRAM, Shimano, Connex and KMC (KMC makes masterlinks for 5 speed up to 12-speed).
15 мар 2022