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Constantly Having to Adjust Chain Tension


Chakers1998
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Hello all,

I've recently built a 26 comp bike that uses horizontal dropouts, and I'm having to constantly undo my wheel bolts to add more tension to the chain with the snail cams I've got. The cams are the steel Trialtech ones with lots of fine points. I'm not sure what is causing my chain to need constant adjustment after 15 mins of hopping around on the back wheel, but I sanded the dropouts and bought some more grippy Tarty axle bolt washers (the Jitsie race ones are horrid and have no grip at all) to see if that would eliminate it, which it hasn't. The wheel also isn't coming out of side to side 'true' with the rim brakes that I notice it, nor is it moving noticeably enough that the pads are coming out of alignment. I also can't see it being the chain bedding in, there's no way a chain would stretch that much to need constant tensioning. 

 

Should I file bigger notches in the drive snail cam to have more positive and secure clicks that do not have the possibility of winding back off? The Trialtech steel cams are very very finely cut with 108 clicks, compared to other brands who use around half that number. 

 

Any insight would be greatly appreciated. 

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i used to have this issue way back on bmx days, then on dirt jumper and I hate face plants. So to save extra $$$ for the chain and effort of re-adjusting, I made a chain tensioner to all my bikes. It may look awkward, but it worked for me. 

I hate snag and loose on chains which is always the case...

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How old is the bike/chain and what chain is it?

 

It could be as simple as it being a relatively new chain that’s just stretching. I think people underestimate how much chains stretch especially some of the ones comp riders use (the KMC Kool chain stretches loads!).

If it is just the chain it will eventually calm down and need fewer adjustments but sone chains are stiffer than others and personally I’ve found the KMC Z1eHX to be the stiffest/least stretchy chain I’ve ever used.

Of course it could be something slipping but the chain could be something that a lot of people over look

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I'm sure you've already been told this by plenty of people, but use plenty of grease on your axle bolts! Your axle bolts should be the things keeping your wheel in place when you're riding, so if things are potentially shifting then they're a good place to start looking. If they're fitted either dry or with only a token amount of grease/lube they can bind and feel like they're tight whereas in reality they're not anywhere near close to the torque they could be at with grease involved. Make sure the threads are all good on your bolts and axle too.

One thing you could do to check is to use something like a marker to mark a line across the edge of your cams and snail cam bolts. That way if the cam slips or rotates, it'll appear out of alignment with the line on the bolts.

As Ali said, new chains do stretch much more than people expect, so it could simply be that if it's a brand new chain. New chain to used chain on my Arcade equates to about 2mm of movement back in the dropouts, so that 2mm via clicks on a snail cam will be quite a lot of clicks.

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Hi Ali,

I'm using a KMC Z1eHX chain which has a few hours on it now. The bike also has a few hours on it now and I've stopped having to adjust my headset, brakes etc. I do weigh a fair bit, which has the advantage of breaking in chains quite quickly, but it's certainly making the chain loosening worse. 

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Found that I'd mashed the cam. Luckily, my dad has some needle files that were small enough to file some bigger indents on the cam. I had to file another indent on the cam after trying it the first time, because it mashed the cam again. The extra indent made the chain too tight, but when the cam bedded into the snail cam bolt, it got to an appropriate tension. This tension didn't change after bouncing around on the back wheel for 20 mins. I'll have to see how it holds up on the DJ ride, but fingers crossed I won't have a sloppy chain. 

PXL_20220512_174313063.jpg

PXL_20220512_180202587.jpg

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Weird. The egde of the cam looks so beaten up! Never seen one like that before. Wondered if the snail cam bolt might have been weird / in a mess / something else, but no.

Hopefully the new axle bolt washers help. Plenty of grease on the axle bolt threads and under the head, give it plenty of torque (Y)

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1 hour ago, AdamR28 said:

Weird. The egde of the cam looks so beaten up! Never seen one like that before. Wondered if the snail cam bolt might have been weird / in a mess / something else, but no.

Hopefully the new axle bolt washers help. Plenty of grease on the axle bolt threads and under the head, give it plenty of torque (Y)

I think the issue was when the bike was new I was using the Jitsie axle washers which have next to no teeth at all. Plus me probably not tightening down the bolts enough lead to the hub sliding in the dropouts and the cam taking all the load, hence the mashing. I had to swap out a borrowed BB today, which gave me a chance to look at the dropouts and the Tarty axle washers have left a good mark on the frame, plus sanding the frame where the washers clamp on must have helped a bit. Hopping around outside the house for a while hasn't made the chain loosen off, so it's looking like all systems are go. Thanks Everyone!

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