Wrong size Phil BB – will I damage something?

I’ve started to build my bike and I’ve realised that I’ve bought the wrong size Phil BB – 108 instead of 110.5. I’ve got about 4mm of thread sticking out on the drive side with none showing on the non-drive side. I’m tempted to use it whilst the new BB is on its way but do you think I’ll damage anything? Not that bothered about the BB itself but the BB Shell.

I think it's too small because the chain ring teeth are up against the outside of the chain while the sprocket teeth are up against the inside of the chain.

What do you think?

108 refers to the width of the spindle and not how the spindle fits into the shell and cups,

so not sure why you have threads showing (unless its one of these where you can adjust the chainline by adjusting the cups)

all you'll damage is the chain assuming its been installed correctly but i doubt that will happen anyway, just not as quiet or efficient as normal.

When you say "thread" do you mean you can see the thread on the cups sticking out fro the shell? If so then changing the spindle length might not help at all. The BB is made to match the shell; spindle length is independant.

Do you know if you are matching English/English or Italian/Italian? You might just need the threads in the BB shell chased to let the cups sit deeper.

yup... the threads are meant to be exposed, you can adjust your chainline 2mm either way (i.e under the other cup and tighten up the stickyout one..

http://velocio.com/Bikes/BBInstallation/

Yeah, the threads on the cups. My chainline doesn't feel right, I think it needs to go out a mm or so but I think 'cos I've got the wrong side spindles I can't go anymore. I'm gonna get the 110.5mm Phil and see if that works better.

After reading that guide - thanks for that tilover (I had seen this months ago and forgot all about it, should have printed it off when I first saw it!) I've screwed up anyway: I've put grease on the threads on the BB and it says the cups will come loose if I don't use the blue thread-lock stuff - Ah well, it's all a learning experience.

also make sure you are buying a bottom bracket with a taper matching your cranks. ie. ISo on ISO and JIS on JIS

It's Sugino 75 which is ISO and the Phil is ISO so that bit I've got right.

Looking at the guide I can pull the spindle through a few mm by using a crank bolt and a vice - might give this a go tomorrow.

the b/b is only 2mm shorter than the one you need, which is also only 1mm shorter each side,(which is not worth worring about) the b/b is also adjustable so you should get it to fir no probs.
it's just odd you have 4mm sticking out?

It's baffling me too. i know it shouldn't be this hard....

Bob Jackson Frame = 68mm BB shell
108mm Phil wood BB with cups
Phil wood 1/8th cog

According to everything I've read it should all fit nicely. - The only thing I'm missing is a caliper so I can check if the cups have seated on the BB properly: it's one hell of a tight fit so I might not have applied enough force.

I'll give it another go tomorrow when I've got fresh eyes.

Cheers for the advice all.

Are you sure it's a 68 x 108 BB and not a 73 x 108 BB?

Yep, defo 68mm BB shell.

Another thought.... how many times can you screw and unscrew the cups on a brand new steel BB before you start to do damage? I guess over a bike's lifetime it should only happen on average a few times. I've already done this 5 times trying to get the chainline straight.

As long as it's well-lubed it should be fine

the cups should sit flush if it is centred. so if it is 108 instead of 111mm, it will sit 3mm out. but should be fine as there is still almost 15mm of thread sitting in the BB

OK, I've got it all together and me, being a bit dense sometimes had it completely wrong: my chainline was too far out and needed to come in. Anyways, I've got a good line now but the spider arms on my sugino 75 are no more than 1mm ( the thinkness of 2 thin pieces of card away from the chain stays) is this too close? If the spider didn't sit on the inside but was flush I'd be laughing.

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It's obviously too close!! I'm being a dick but the lunacy was descending as I've been fucking around with this for hours. I've moved it out a mm or so and the chainline, though not perfect isn't bad.

then don't ride it and wait till the proper BB arrives. saying that a couple mm is fine