Chain Tensioner for SInglespeed/Fixed

merlinghnd

Hello Guys,
I have a Boardman SC and very, very pleased I am with it.

I tension the chain as per Sheldon Brown( bolt one side tight and move the wheel) which works fine but over a period of time needs retensiioning.

I recall seeing somewhere brackets to be fitted to the rear wheel slots on the frame to push the rear wheel back and tension the chain.

Any thoughts on these and are they worth trying? Any one make/system stands out from the crowd

Thanks for any replies in advance.

Merlinghnd

lae

The brackets that move the rear axle backwards and forwards are called chain tugs. They aren't absolutely necessary.

Are you using quick releases or bolt-on axles? QRs are fine but they do need to be excellent quality all-steel ones (rather than aluminium ones) and need to be done up as tight as you can get them.

WIth bolt-ons the nuts just need to be done up tight with a decent long spanner (not a cheap box spanner that you get with the bike) or a torque wrench.

Also I wouldn't do up one side tight and then do the other - I normally do the nuts up finger-tight, position the wheel, then do up a quarter-turn and re-position the wheel if I need to, then do up both nuts at the same time (i.e. do quarter-turns alternating between the nuts until they're tight, checking the wheel position as you do it).

meagain

Chain tugs shouldn't really be necessary. And more to prevent axle creep AFTER the nuts/QR have been tightened rather than in order to set the tension BEFORE.

Tail end Charlie

I have a Surly chain tug, which works fine and makes tensioning the chain easy. It does cost £20 though.

A friend has two of the MKS tugs which look great (the allen headed ones) but makes it a bit of a pain when you get a puncture.

Monty Dog

First DO NOT put a chain tensioner on a fixed wheel bike - OK for singlespeed/ freewheel but it could be horribly painful on a fixed.
Sounds as though you're not tightening the rear hub nuts tight enough - my masochist techniquie is to use my right hand as a wedge betweed the tyre and seatube as I roll the bike forward and tighten the hub nuts - means you can get the wheel centred too. If drop-outs are worn or soft then chain-tugs might be a good idea

moonshine

Monty Dog wrote:

First DO NOT put a chain tensioner on a fixed wheel bike - OK for singlespeed/ freewheel but it could be horribly painful on a fixed.

why?

I'm running a surly chain tug on the drive side only (which is excellent bit of kit BTW) on my fixed, winter training bike and using a QR. (hollow axle) It has been a revelation. tensioning and centering the wheel is a breeze and punctures are no longer feared.

Last year i used allen bolts to keep the wheel tight and i struggled to get enough tension to wheel from twisting.
Probably managed 2000 miles this winter on it with no problems.

G

majormantra

I think people are talking at crossed purposed here. A chain tensioner (NOT suitable for fixed) is one of these:



A chain tug (which is very useful on a fixed) is one of these:



Matthew

Monty Dog

Confiming the above, a pulley-type chain tensioner on a fixed gear can lead to transmission lock up.

moonshine

makes sense....

I've got the latter of the two... brilliant bit of kit.....even doubles up as a bottle opener!!!

man they think of everything!!!

ex-pat scot

You SHOULDN'T need a chain tug.

However- they are rather useful.

Technique for getting correct tension is to "walk" the wheel backwards in the frame, by alternately tightening one side and moving the other backwards a little at a time.
Apparently some mechanics get a tennis ball and squeeze it between rear tyre and seat tube.

A chain tug is rather nice, as it helps enforce the axle position. I have a Planet X one on the drive side, and it was around £7. Not as pretty as Surly, but not as expensive.

Whatever you have, you will find that as the chain ages and stretches it will need re-tensioning.

meagain

"...get a tennis ball and squeeze it between rear tyre and seat tube. "

Or a simple wedge (a rubber door stop is good) between tyre and chain stay bridge - same one will do for a number of bikes!

rf6

MKS tugs are great imo. not the cheapest, but work nicely.