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Seat and chain/crank alignment help
#1
Ok so my seat is way to high on one side, so as soon as I can get one.. I'll be replacing that.

But also my last drivetrain (front rings) were bent as sin and grinded on the mech.. I thought they were bent but I don't hit stuff on the HR as it doesn't get used off road.
So, new BB and new chainrings, onto existing Raceface Ride cranks, and a new mech.. And guess what's bent as sin? The chainline is straight for the most part, but as it comes around to the part of the cog near/behind the actual driveside crank it's way off, ALL 3 rings.

I can understand the last BB may not of been faced properly, but now this one?! The other crank looks ok but it's abit hard to tell if it's rotating on a possibly pissed BB tbh.

So my question is:
Could it be that my actual frame/BB area is buggered?
Or that BB's hate me?
OR that my driveside crank is somehow mashed?

I can sort of tune the gears to avoid most of the rubbing, but what really worries me is the damage I could be doing to my knees. It's kinda like the chainset is placed on at a slight angle, which I'm can't be good.
My riding is more up and down than the damn area I live in! And the tart's knickers who lives next door - Combined!  :o
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#2
Im no obvious expert, but if it where me and I had such concurrent alignment problems, Id go back to the start to ensure the BB is faced properly with a shop.

Over to someone else with more knowledge, but you would need to start isolating areas first.
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#3
think it might be your driveside crank, if it is slightly missaligned on the bb then it will rotate with a bias, try removing  it and refitting it at 90 degrees to where it is currently positioned, if its the crank then the 'wobble' will remain in line with the crank arm (or where it is right now) if the wobble is no longer noticiable where the crank arm is, or has appeared to move, then the problem is with your bb (i think this is unlikely as it's new)
Keep it foolish...
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#4
Jon, get your BB properly faced in a shop that way you know your BB will sit square in the frame. Most chainlines are 47.5 or 50mm this is measured from the centre of the BB shell to the middle of the middle ring. IIRC most raceface stuff is isis mount, so just clean up the Spindle/Crank interface and see it it makes any difference.
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#5
The BB was professional installed in a shop, and the last one was done by an ex bike mechanic.

Took the crank off earlier and put it back on level with the other one, and at 45 degrees, and guess what.. It's still out of line, behind the actual crank in each position.

Bugger!
My riding is more up and down than the damn area I live in! And the tart's knickers who lives next door - Combined!  :o
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#6
that means your crank arm and hence chainrings are not sitting at 90 degrees to the bb axle. Which sucks, is there damage to the bit where the crank joins the axle?
Keep it foolish...
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