Bicycle Mechanics - Tips to keep the chain properly tensioned?

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vsopking
10-25-08, 08:51 AM
Hi there, I am riding daily and since June on a Trek Soho 2. This bike rides nice, however almost after each ride I notice that the chain loosens and needs to be re-tensioned at least once a week. Does anyone have a tip? The bike has an internal shimano nexus hub and to tension the chain, I need to loosen the bolt on the chain side, pull the weel backwards and re tighten the bolt- To get the wheel in line I sometimes also need to loosen the bolt on the other side and do the same. This sucks, I thought that the chain would settle in after time?
operator
10-25-08, 08:54 AM
Does anyone have a tip?
Proper torque on axle nuts.
Make sure that the axle is greased where the nut would sit and the nut/washer interface is tri-flowed.
Retro Grouch
10-25-08, 09:36 AM
I agree with operator that adequate torque on the axle nuts is vital. If that's not working for you, here's a couple of additional ideas:
1. Since this is a relatively new bike, take it back to where you bought it and have them check to be sure the dropouts are parallel. This takes a special tool that looks like 2 mushrooms that bolt to the dropouts. When the mushrooms line up perfectly, the dropouts are parallel. If the shop starts by running a piece of string around the head tube, it means they don't understand the issue.
2. BMX shops have a variety of add-on gizmos to eliminate this issue. The easiest and cheapest are serrated axle washers. They'll do the trick but they'll bugger up the paint on your dropouts. BMX chain tensioners also might work. That's a metal thingie that goes around the axle and pulls it back into the dropout.
vsopking
10-25-08, 10:28 AM
Thank you, the bike has been serviced - and the loosening came back - I'll bring the bike back in. Have them check once more. Thanks also for tip 2: these metal chain tensioners sounds good - had them in the old days - just loosen the axle bolts and twisted the bolts to have the axle pulles back.
operator
10-25-08, 10:39 AM
1. Since this is a relatively new bike, take it back to where you bought it and have them check to be sure the dropouts are parallel. This takes a special tool that looks like 2 mushrooms that bolt to the dropouts. When the mushrooms line up perfectly, the dropouts are parallel. If the shop starts by running a piece of string around the head tube, it means they don't understand the issue.
+1
BCRider
10-25-08, 10:39 AM
If you're riding in very sloppy weather and there's a lot of mud and grit buildup it may be possible that the chain is wearing out instead of the axle moving.
One way to check for certain would be to use a fine tipped marker pen to put a small mark onto the frame and washer and check it daily for signs of movement. If you find it creeps then it's time to look at the dropouts or possibly a tensioner.
Also keep in mind that the correct tension for this setup is actually NO tension. You don't want much slop at all but the chain should not be actually tight. For other fixed length bikes this amouts to about 1/2 inch (1cm) of easy vertical play midway between the sprockets. If you're actually setting it so it is completely tight then this may be accelerating the chain's wear.
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