I am thinking of resurrecting a 5 yr old XT Hollowtech II chainset.

However, I think I recall that there was a plastic shim on the non-drive side, i.e between the crank arm and BB.

Is this correct and is it necessary, as I don't seem to have it anymore.

Not that I am aware of 🙂

The only shims you should need are the ones between the BB shell and the cups. AFAIK, XT never used shims between cranks and cups – unless you mean the plastic shim / bearing cover that's in the BB?

I definitely recall there being a white/opaque colour shim, probably 1/4mm thick.

Maybe it was on the drive side?

Anyway sounds as if it wasn't critical.

Do you mean the metal rubber covered metal washer that goes between the crank arm and the bearing?

Yes, that could be it.

Sorry memory a bit hazy as it removed this crankset over 3 years ago and it's been in a box since.

Have tracked down the parts diagram for the HT 2 on the Shimano website.

It shows an item "No 5" described as "Ring".

I think this is what I am missing.

What model?

Its an O-ring – should be fitted into the crank arm – recessed so it seals the crank arm onto the bearing seals – its not a spacer – have a look into the ends of the crank arm where the axel goes in/comes out ?

Its an O-ring

No it's not it's a matal washer with rubber on one side.

Looks like 2 O rings to me? But if your sure SSS?

Yep.

Metal side faces outwards. Rubber side "grips" the bearings.

When I said O-ring I was thinking of the type above? I have them on my HT systems inc road cranks. Back to the OP they are seals not a shim !!

When I said O-ring I was thinking of the type above?

An O ring is just a rubber ring. These are a metal washers with rubber on one side.

Back to the OP they are seals not a shim !!

They're a bit of both TBH.

I'll have to check when I get home, but I don't think I'm missing those "O-rings/washers" and not sure I even had them.

My crankset definitely had a plastic shim!

On the above photo it fitted where the "silver ring" is showing on the crankarm.

It was an '04 model so maybe the design has changed.

Sorry SSS have agree to disagree about being a shim – They are there primarily for sealing purposes under compression – As you tighten the cap the rubber part becomes compressed sealing against the outer bearing seal. The metal part is recessed and there fore not acting as a shim 🙂 Pedantic I know 🙂

The idea of the metal backing is so that is doesnt deform due to the crank turning and the split non-drive crank. But we are really taking about the same think here 🙂

Was it this one?

King BB's come with white plastic shims for spacing out the arms on slightly odd sized BB shells. I've never seen a Shimano one with a plastic shim though and I've got "quite a few" XT cranks from the older type to the latest. 😉

Edit.

**** me you must be bored too. Arguing about a shim/spacer/o ring. 😆

BTW I did have a plastic shim on an old set of Shimano HT II 105 cranks – this was on the drive side presumably to correct the chain line?

Edit: seems to agree with SSS 🙂 Probably frame specific so if the new BB is std then I wouldn't worry about it 🙂

The crankset came as an OEM part on a new bike and I had quite a lot of issues with wrongly or badly installed parts on that bike.

I also went through BB's in next to no time, hence why I removed it, so maybe it was missing the "metal washers" from day 1 and thus letting in too much crud.

It'll interesting to see when I get it out of storage later.

FM – I bought some OEM FSA carbon mega-exo cranks and one o ring (yes it was all rubber) was missing and on the forums this is attributable to early wear of the megaexo cranks from what I have read – perhaps this is true of yours? I replaced it with a small suitable tap washer I had – Just a thought 🙂

Yes, could be that it was a frame specific fix.

So sounds as if I can live with out it, as IIRC it was only 1/4mm thick, so unlikely to have any effect on chainline.

Besides I am now intending to put it on a different bike.

Thanks and happy to brighten up your afternoon. 😀

Are you sure it wan't just the plastic bearing shield that was stuck to the crank rather than against/in the bearing?

There should be 3 2.5mm shims

Shimano say on their website to put two on drive side and one on non drive side.

Nooooooooooooooo – Thats for the BB not the cranks set 🙄

Walk away…………..

facepalm. 😉

Quiet day Rich? 😉

yes for once 😉 Goin 'ome new 🙂

Dug chainset out of box and there is a metal/rubber "washer" on the drive side and not on the non-drive side.

Have no idea whether there ever was one (I assume that there must have been) and if so when it went "missing"

Can I get a spare? I assume LBS can source.

I have both, 2004 HTII chainset (as pic above) and 2007 HTII chainset, I can't think of what you are talking about!. There are some little shims (as pointed out by foxyriders diagram), but they are so small that I don't think that their loss would affect anything other than crap getting to the non driveside spline, maybe?. The important bits are pedal threads, spline on the non driveside and maybe the preload screw to pull everything together. Anything else you recall might possibly come from the BB.

It's the rubbery/metal/washer/o-ring thingy as shown in the picture above that is missing.

And yes without it I expect crud has got in and either gone outwards onto splines on inwards onto spindle.

The spindle is quite worn on the non-drive side where it was in contact with the plastic BB shim. I expect as a result of crud getting in due to lack of aforementioned rubbery/metal/washer/o-ring thingy!

The washer/rubber/o ring/spacer/shim thing on the drive side is stuck into the crank arm and difficult to see.

Drive side washer/rubber/o ring/spacer/shim thing is there and yes it was hard to see. But non-drive side is awal.

I have contacted LBS and they are going to try and source a replacement. Failing that I will just use a standard O ring from some other source.

I am still convinced that I have lost a very thin plastic shim, but as it is not shown on any Shimano docs, I'll live without it.

Thanks for all your replies and assistance.

I am still convinced that I have lost a very thin plastic shim

I have to warn you that if you ride without that none standard shimano part you will eventualy* die.

*maybe of natural causes.

LOL – glad all is going well with the washer/rubber/o ring/spacer/shim thing 😉