Pulley Wheel O Rear Mech.

[foxley]

Hi guys, new to the forum as I about to start riding again after 8 years.

I have decided to dust down my 18 year old Gary Fisher Hood Koo E Koo MTB.

Have renewed chain, cables, pads etc.

Decided to remove the 2 pulley wheels on the rear mech. (Shimano Deore XT) for inspection but when I refit them they will not rotate unless I leave the bolts loose.

Is there a difference between the two and if so could this be the cause of my problem.

Thanks in advance.

 

[CAMPYBOB]

Reverse their installation and make sure you have the center bushing in place.

ShimaNO's website has excellent tech docs if you need pictures and assembly instructions. Just look for your derailleur model number and pull up the literature.

 

[dabac]

Best I remember, the top one is called "guide pulley" and the bottom one the "tension pulley".
And according to Shimano designers, a little sideways "float" in the guide pulley improves overall performance. Don't remember if this is achieved by having the pulleys of different thicknesses, or by having the bushings of different lengths.
Some close observation should sort that out.

 

[swampy1970]

The top pulley may have the words "centeron" on it. If you tighten this pulley fairly tight, the black jockey wheel will have some side to side play - this is the way it's supposed to be.

The other pulley has no play built into it.

If you took them apart to clean, a little bit of grease on the center bushing (the little plastic tube looking thingy) may help - but if they're two decades old then maybe it's time for a new pair. They are a disposable part and supposed to be replaced when worn. Tell the bike shop that you're after a 6, 7 or 8 speed (count the cogs and tell the shop) rear derailleur pulley - rather than the usual 10 speed found today.

 

[CAMPYBOB]

shimaNO usually marked the tension pulley (lower pulley installation position) with the words "TENSION" or "TENSION PULLEY" and a direction of rotation arrow.

The Guide pulley (the pulley closest to the freewheel or cassette) is usually marked "GUIDE" or "GUIDE PULLEY" and also has a direction of rotation arrow on it.

 

[foxley]

Thank you all for your observations. I will inspect them this weekend.

Looking at the cost of the wheels would I be better off buying a new rear derailleur set?

 

[dabac]

BBB makes a perfect serviceable set of after-market pulleys that would cost only a fraction of a decent derailer. I'm sure there are other brands too.
BBB makes a perfect serviceable set of after-market pulleys that would cost only a fraction of a decent derailer. I'm sure there are other brands too.