BB / Crankset fitting advice please

[Paul Drawmer]

Oh B****** !!!!

Now I've collected all the bits for my 'old fat man' bike, I've already cocked it up.

I bought a bare frame (a magnesium Saracen Kili Flyer as sold off by the shop in Tyneside) and, seeing as the cost to fit was less than the spanner, I got my LBS to fit a shimano square shaft BB.

So, now I get my nice black Shimano Alivio crankset and bolt it on. Err, except that the inner part of the chainset is a plastic ring which binds on the BB shell, and the granny ring is toooooooo close the the rear stay.

Am I supposed to fit spacers?
Should I have specified a certain length BB spindle?
Is there a specific spindle / crank combination for the Alivio?
Is it possible that the LBS have fitted the BB set round the wrong way (ie is there an offset)?
How do I get the bloody thing off, is it possible without a special tool?

I not only feel pi55ed off, i feel stupid, 'cos I just assumed it would all fit. I trial fitted everyhting on my GTM, but I just didn't this time.

Edited to say: I've just read Niel in Cardiff's posts on another thread - I won't be upset if you say 'I told you so'!

Edited by Paul Drawmer on Thursday 7th December 23:22

[beyond rational]

Paul Drawmer said:

Err, except that the inner part of the chainset is a plastic ring which binds on the BB shell

Plastic ring?

Anyway;

Am I supposed to fit spacers?

No. (in this instance at least, on some BBs you can gain a few MM)

Should I have specified a certain length BB spindle?

Depends on the sequence of events really - If you bought the BB from the shop to specifically fit your frame then they should have provided the correct length spindle/bottom bracket shell width. If you already had the BB and took it to them to fit, they probably just assumed you knew what you were doing - though a good mechanic should have spotted that there might have been an issue IMHO.

Is there a specific spindle / crank combination for the Alivio?

In this instance there will not be a problem with the interface between a Shimano BB and those cranks. Shimano recommend a 110-113 spindle but that can be irrelavent depending on the chainstay thickness/geometry etc - i.e fat chainstay tubes may require a longer spindle to clear them.

Is it possible that the LBS have fitted the BB set round the wrong way (ie is there an offset)?

If it looks like the bottom bracket screws in from the drive side i.e the side the flange is visible on, then it is on the correct way (if its not, the bike shop needs to publicly strung up!). Spindles can be offset if they are designed to fit different width bottom bracket shells, but this difference will be on the non drive side.

How do I get the bloody thing off, is it possible without a special tool?

Best not to! Can result in frame damage and will definatly wreck the bottom bracket itself. If the bike shop supplied and fitted the incorrect length bottom bracket it is probably worth going to see them, especially if they sold you the cranks at the same time.


Edited to say: I've just read Niel in Cardiff's posts on another thread - I won't be upset if you say 'I told you so'!

I'll reserve my right

Depending on how things happened, it could well be the shop made a mis-judgement - a decent shop will do their best to put this right if it is the case.

[beyond rational]

Any update on this

[Paul Drawmer]

I plan to pick it up from the LBS this pm.
He says he did fit a 73mm BB, but 'the frame takes an unusually wide spindle' or something. Ii's supposed to be OK, but the the cranks will be further apart than usual.
I dunno, I'll see later on.

Frustrating; as I've got all the bits sitting waiting to be assembled. I'll have to pick my times carefully since we're moving soon, and the Location Manageress is restricting my play-time at the moment!

[Paul Drawmer]

I've picked it up. I gather the problem was due to the Alivio chainset that I bought (from Woolyhatshop) it's an old style one, and needs a long BB spindle to clear the wide chain stays on my Saracen Kili Flyer magnesium frame. I'm putting it all together now.

[Xenocide]

The plastic bit that you speak of is just a bit of a guard to keep some dirt and crud out of the bb (Sealed anyway). It grips on one side only.