Why do so many ss bikes have slack chains?

[mustang1]

... I thought one of the advantages of ss bikes was lack of maintenance, but judging by how many slack-chained ss bikes I see, I think the riders may confuse lower maintenance with no maintenance.

 

[Deleted member 1258]

I ride fixed, one of the little problems I've come accros is uneven chain wear, so when I'm setting the chain tension I have to check where the tight and slack parts of the chain are so I can adjust it at a tight spot.

 

[rogerzilla]

A slack chain on a SS isn't especially dangerous. It can be on a fixie; the worst-case scenario is that the chain jumps off and gets caught up on the pedal spindle, which causes the bike to fold up as the rear triangle is pulled over.

 

[Threevok]

Most of the problems with my chain becoming slack is the inability to tighten the QR up enough to stop the wheel slipping forward.

I have (DMR) chain tugs that are designed for the bike, but they do not have enough range of movement to accommodate the larger sprockets I use, even after modification.

I purchased a slimmer (Genentic) set with more range of movement, but both these and the DMR ones are so wide, that there is very little thread protruding - to safely do the QR up - even when running just the drive side tug.

I have converted the rear hub from QR to 10mm with a thru axle, in the hope that I can torque this up sufficiently to prevent slippage. If not, then it looks like a bolt up conversion may be the only option for me.

So when I see SS with slack chains, I feel their pain

 

[rogerzilla]

I run an old straight-lever Campag QR on the back of my SS bike (which happens to be a fixie right now) and have had no slippage, even up steep climbs. No need for tugs. Do you have chrome ends? These are more challenging as they're so hard and slippy. Otherwise, get a proper enclosed-cam QR from Campag or Shimano with steel teeth on the acorn nut and QR body, oil the cam and it will clamp as firmly as axle nuts, if not more so.

 

[Drago]

Lube them with viagra, that'll tighten them up nicely.

 

[tyred]

You will also find that some chainsets aren't that accurately made and the chainwheel isn't centred.

 

[Deleted member 1258]

You will also find that some chainsets aren't that accurately made and the chainwheel isn't centred.

I know, there's fun to be had in trying to centre your chainring.

 

[Illaveago]

I was wondering if a bit of chain rotation would help with chain wear ?

 

[Deleted member 1258]

https://www.sheldonbrown.com/chain-wear.html

 

[Smokin Joe]

Sheldon's bike -

 

[mangid]

I think tight spots are inevitable, it really does take much movement in my experience for it to go from too tight to 'slack'.

I know the tight spot, and always walk the wheel back just before that spot. Tight spot is RHS crank at 25 past, so tighten with it at 15 past. I then spin it a couple of times, reassuring myself that I got the tight spot right (there will be a slight binding). Then just loosen one nut with the crank at the binding point (25 past) and let the tightness take care of itself.

I used to be pretty paranoid about slack chains, and did run tugs for a few years. But time and experience have convinced me that even a fair bit of movement when at it's loosest isn't an issue.

I've thrown a chain 3 times, once chain was too loose, 2nd time sprocket came undone, third time was down to damaged stays flexing.

Currently the tightest spot has maybe 5mm travel, and the loosest has ~15mm travel. Chain is approaching EOL at 9K miles.

 

[silva]

I ride fixed, one of the little problems I've come accros is uneven chain wear, so when I'm setting the chain tension I have to check where the tight and slack parts of the chain are so I can adjust it at a tight spot.

The cause of that is a gear ratio that is an integer, ex 48/16.
Same chain links re-engage at the moments of putting force (crank arm locations).
There is no rotation of the most stressed links throughout the chain.
So your chains wear concentrates on two series links, no spreading.

Another potential problem is a non straight chain line.
Then wear concentrates on one side of the chain, causing the chain to become tilted.

 

[Deleted member 1258]

The cause of that is a gear ratio that is an integer, ex 48/16.
Same chain links re-engage at the moments of putting force (crank arm locations).
There is no rotation of the most stressed links throughout the chain.
So your chains wear concentrates on two series links, no spreading.

Another potential problem is a non straight chain line.
Then wear concentrates on one side of the chain, causing the chain to become tilted.

Holy thread resurrection batman! If that's the case how come I can take most of the slack spots out by reseating the chainring on the spider? Currently I'm running 46 X 18 and usually run 44 X 18

 

[rogerzilla]

You also get slack and tight spots with brand new components. The usual culprit is the chainring being less than perfectly round and/or not being perfectly centred on the spider. Sometimes the spider isn't great for concentricity, either. You have to pay a lot for the best and roundest track kit.

A workaround is to use bigger cogs, since these are less fussy about concentricity errors.