Bash Guard/Chain Length

[nappyt]

I replaced my big ring with a bash ring a couple weeks ago. I had the chain drop off in 1x1 last week. It happened once before but I started thinking. Should I remove a couple links since I don't have the big ring anymore?

I have a new crankset and chain arriving today and I was thinking if I should keep the chain length the same or try a link or two less. Not sure what the advantage would be but I thought I would ask you folks.

What do you folks think?

[sailcalifornia]

when i did the same thing the guy i bought the bash guard from told me to put the chain on big in front and big in back, pull it tight and then back off two links. Not sure if this the the proper way to set the length but i have never had any problems so....

[tkblazer]

i think the rule of thumb is to run the chain on the biggest chain ring you have and on the biggest cog in the back, but not run it through the derailluer. Measure how many links you need and then add two links to that.

edit, Park Tool has a somewhat better explanation eh

Chain Sizing - Largest Cog and Largest Chainring Method

An alternative method for determining chain length for new chains is to use the largest size sprockets on the bike. It is easiest to size the chain without threading it through the derailleur.

1. Remove the old chain.
2. Shift the front derailleur over the largest chainring, and the rear derailleur on the smallest cog.
3. Thread the new chain through the front derailleur. It is not necessary to thread the chain through the rear derailleur at this point. Simply wrap the chain around the largest front chainring and around the largest rear cog.
4. Pull the chain tight, and note the closest rivet where the two could be joined. Keep in mind a chain can only be joined by mating inner and outer plates.
5. From the closet rivet, lengthen the chain by counting over an additional two rivets (two links), which is a distance of one-inch. Cut the chain at this point.
6. Remove the chain from the bike and thread it through both derailleurs and join the ends.

MASTERLINK NOTE: If the bike chain uses a "master link", it is necessary to account for the link. Install one-half of the master link on one side of the chain. Size the chain by cutting the other end of the chain.

[nappyt]

Originally Posted by tkblazer

i think the rule of thumb is to run the chain on the biggest chain ring you have and on the biggest cog in the back, but not run it through the derailluer. Measure how many links you need and then add two links to that.

edit, Park Tool has a somewhat better explanation eh

Chain Sizing - Largest Cog and Largest Chainring Method

An alternative method for determining chain length for new chains is to use the largest size sprockets on the bike. It is easiest to size the chain without threading it through the derailleur.

1. Remove the old chain.
2. Shift the front derailleur over the largest chainring, and the rear derailleur on the smallest cog.
3. Thread the new chain through the front derailleur. It is not necessary to thread the chain through the rear derailleur at this point. Simply wrap the chain around the largest front chainring and around the largest rear cog.
4. Pull the chain tight, and note the closest rivet where the two could be joined. Keep in mind a chain can only be joined by mating inner and outer plates.
5. From the closet rivet, lengthen the chain by counting over an additional two rivets (two links), which is a distance of one-inch. Cut the chain at this point.
6. Remove the chain from the bike and thread it through both derailleurs and join the ends.

MASTERLINK NOTE: If the bike chain uses a "master link", it is necessary to account for the link. Install one-half of the master link on one side of the chain. Size the chain by cutting the other end of the chain.

Using the normal chain sizing rule was what I planned. I wasn't sure if it made a difference. It's easy for a lazy guy like me to just remove the old chain and match up the length and go. I think I will just follow the chain size rule.

Thanks.

[spookydave]

so that stretch it tight and add 2 works for all bikes?
What about wheel travel?? Seems like a 4" XC bike would run less chain then a 7" travel AM bike.

[dubjay]

Originally Posted by spookydave

so that stretch it tight and add 2 works for all bikes?
What about wheel travel?? Seems like a 4" XC bike would run less chain then a 7" travel AM bike.

It depends on suspension design. Some bikes have more chain growth than others. If you have an air shock, it's probably not a bad idea to let the air out and cycle it through just to make sure you have enough chain so it doesn't bind on impact.

Whether it's 4" or 7" doesn't matter as much as the distance that changes between bottom bracket and your rear axle. Depending on their axle path, they might even have the same amount of chain growth.

[spookydave]

that's kinda what I'm getting at. The one way for all does not seem right to me.

My 9" travel Brooklyn has zero chain growth and I know my bullit has a bunch. Seems like you would want to know before you install the chain.

I take the shock off and run the swing are up and down and find the max lenght. Then do the wrap chain and add 2 links bit. Donno if I'm doing it right but so far I'm not bending stuff due to not enough chain.

[26'er Zen Master]

Dave you have a brooklyn? is it a link frame or the other one the tmx?

[nappyt]

Originally Posted by dubjay

It depends on suspension design. Some bikes have more chain growth than others. If you have an air shock, it's probably not a bad idea to let the air out and cycle it through just to make sure you have enough chain so it doesn't bind on impact.

Whether it's 4" or 7" doesn't matter as much as the distance that changes between bottom bracket and your rear axle. Depending on their axle path, they might even have the same amount of chain growth.

I don't think with my Superlight single pivot will be a major problem. I will make sure to check it at both full extension and compression but my long cage derailleur should cover the gap for my 100mm of travel.

[spookydave]

Originally Posted by 26'er Zen Master

Dave you have a brooklyn? is it a link frame or the other one the tmx?

link

[nappyt]

I did the install of my new crankset and chain this weekend. Everything went great. I ended up running the chain through the rear derailleur. I set it so my cage is at the 5 o'clock position when in the biggest gears. Everything is shifting fine and did all the regular test to make sure that everything fit right.

Thanks everyone for the help.

[wickedracin]

here is a post on my blog about chain lenght.
http://wickedracin.blogspot.com/2008...in-length.html
Hope it helps

[Red Hot Sloth]

Welcome wickedracin...
Might I suggest going into the "Introduce Yourself" forum so the whole class knows who you are.
No need to worry or feel nervous, there's only a couple people here that bite..

[sir crashalot]

When sizing a chain, compress the suspension so it is at the point of greatest chain growth, wrap chain around the biggest cog and ring you have without routing thru the derailleur, pull tight, then add 2 links, incuding any master link. Sometimes with the master link, its kinda wierd, it can seem like it will only work if you either add 1 or 3 links. better to do 3 than 1.

[CalEpic]

Are you using a chain guide? If so, make sure you route the chain through it before taking your measurement.

Big/big +2 links (not running through rear derailleur) is the method I've always used with good results