|   What is the proper way to measure chain length? NM | cheetos316
Apr 3, 2002 6:14 AM | | |
| I've always measured it... | uber-stupid
Apr 3, 2002 6:36 AM | | ...on the bike, from biggest chainring to largest cog. As long as there's enough, and just enough, to do that, the bikes have worked just fine. If you're replacing an old chain, don't hold them side by side, as the links may have stretched out some on the older one. Count the links, instead. |
| Simple trick to determine length | Scott in Jersey
Apr 3, 2002 7:20 AM | | Put the new chain around the outter chain ring & largest rear cog WITHOUT going through the rear derailluer, where the end of the chain meets the other side, add 4 links, then remove any excess links. That's courtesy of my old LBS & works well. |
| Add 2 links for SRAM. nm | Mr Magoo
Apr 3, 2002 7:29 AM | | |
| Small to small also | Erin
Apr 3, 2002 8:45 AM | | If you are running compact rings and installing a wide range; i.e., 42-44T chainring with a 34T cassette, large to large will not always work as your derailleur may not be able to take up the slack in the small to small combo. Another way to adjust the chain length is to measure from the small to small...In this case, run the chain through the derailleur around the small chainring and the small cog. Then check the chain length for slack on the bottom chain run (from the guide pulley to the chainring). The chain should just clear the pulley. If it touches the pulley, remove links.
I used to do the large to large technique but found the small to small is more effective and easier (faster) to do. Just an alternate method though, IMHO. |
| Wh-wh-what??? | næstep
Apr 3, 2002 9:27 AM | | The big-big method results in providing just enough chain that, should you accidentally shift to this combination, you won't break anything. Normally big-big shouldn't be used.
The small-small method you're suggesting doesn't solve anything. This is tantamount to suggesting it's OK to accidentally shift to small-small, but you'd better never-ever accidentally shift to big-big lest you wind up with a broken derailleur or bent chainring.
The big-big sizing method solves the accidental shift to small-small by, at worst, dropping your chain, but never breaking anything.
næstep |
| I totally agree. | Kapusta
Apr 3, 2002 10:28 AM | | The consequences of going big-big with a chain that is too short are potentially huge. Small-small with too long a chain is just anoying.
Even if you are very careful about cross chaining, it can sometimes happen accidentally, or when some idiot takes your bike for a spin aroung the parking lot.
Kapusta |
| Wh-wh-what??? | DISTURBER
Apr 3, 2002 1:03 PM | | ACTUALLY, THERE IS A LOT OF VALIDITY TO DOING IT SMALL TO SMALL. I WORKED FOR A SHOP THAT HAS BUILT BIKES THAT HAVE WON NATIONAL CHAMPIONSHIP RACES AND THAT IS THE ONLY WAY THEY EVER WOULD DO IT. REALISTICLY, IF YOU SIZE IT UP IN THE BIB- BIG COMBO, YOU NEED TO PUT IT IN A MUCH SMALLER GEAR TO CONNECT THE CHAIN ANYWAY (IT'S A LOT TO MANAGE TO PULL THE CHAIN TOGETHER AGAINST THE FORCE OF THE REAR DERAILLUER, WHILE HOLDING BOTH ENDS OF THE CHAIN, HOLD THE TOOL AND ALIGN THE PIN , AND TURN THE HANDLE ALL AT ONCE). EXCEPT IN THE CASE OF A HIGH FORWARD SINGLE PIVOT BIKE THAT EXHIBITS CHAIN GROWTH (LIKE A SANTA CRUZ) THIS WORKS EXTREMELY WELL. AT THE SAME TIME IT SHOULD HAVE JUST ENOUGH SLACK TO GET IN BIG-BIG COMBO. |
| Well, congratulations on your championship wins... | næstep
Apr 3, 2002 4:20 PM | | ...but when you size for big-big, we don't run the chain through the rear derailleur. And once it's cut, it can be installed in any gear combo desired.
The small-small method is still only a guess at best whether the chain will get you into trouble if you force big-big on accident. The only good reason I see small-small sizing is if for some reason you wanted to ride that combo.
næstep |
| Hmmmm.... | Erin
Apr 3, 2002 9:46 PM | | Small to small was just a suggested alternate method. My LBS with over 20 years in the repair business uses that method. Big to big is OK too. Just saying both will work.
No one advocates using the big to big combo when riding nor the small to small.
Aside from shifting, one of the derailleur's function is to take up the chain slack when in smaller gear combinations. Too much loose chain causes the it to run on the pulley. "Nuff" said here.
Actually if you have the inclination and want to experiment, you may want to try the small to small (through the derailleur) chain length adjustment method. As I said, I used to use the big to big method but after experimenting I now use the small to small method. Faster, easier and I haven't had any problems with it even when accidentally shifting into the big-big combo (...ouch!)... |
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