Mechanics and Fixing Any Questions Answered

I've done that with success too.

Leverage trumps muscle.

Give me along enough lever and I can move @hippy

Is this like the sun vs. the wind allegory?

A long enough lever would move hippy, but so would putting an apple pie somewhere nearby...

I had this once with an spd-m something. After the allen hole was rounded the only thing I could do was pull the crank, remove the pedal body, grind two flats in to the spindle with an angle grinder, clamp the flats in a vise and wallop the other end of the crank with a lump hammer.
You could try clamping the crank arm and hitting the allen key - impact can be more effective than the progressive application of torque, hence the impact gun or manual impact wrench
and before you do that, heat it with a camping stove, gas hob, or something better designed for the job like a MAPP torch; needs to be hot enough to sizzle water at least

Cheers hopefully i dont lose the pedal but we will see.

Hi,
to corroborate what Ndeipi said:
https://www.wiggle.co.uk/campagnolo-centaur-tapered-bottom-bracket
caveat: Campag usualy makes the bbs that fit their cranks and brands them as the same GS. What follows is an educated guess:

centaur square bbs came in 111 or 115.5 which is probably double and triple. These are ISO.

JIS tapers have the same angles but are a bit fatter
https://sheldonbrown.com/bbtaper.html

"If you install an ISO crank on a J.I.S. spindle, it will sit about 4.5 mm farther out than it would on an ISO spindle of the same length."

so your shimano (JIS) spindle would need to be 102mm and to complexify a bit more, I would imagine that if you do find a 102 JIS spindle, it could be the low profile kind which will have a different compensation factor.

ebay is your friend

https://www.lfgss.com/conversations/316234/?offset=50

Staggeringly i'm still going with this build.

Hit a snag with drivetrain. I'm using a sora 9 speed compact chainset 50/34 - and a 12-24 cassette. I know cross chaining is to be avoided but when fiddling with setup - running the chain on the 34 to the 12 means it rubs on the inside of the 50. I read somewhere that this can be common with compact chainsets on short chainstay bikes - is it a short chainstay bike anyway ? - dunno.

It's also originally a 7 speed bike - with the 126 dropouts re-spaced to accept modern 130 OLD The other thing is that i've needed a spacer behind the cassette to fit 9 speed on a 10/11 hub of the EA70s.

I wonder if these things combined pushes the small sprocket of the cassette out to a position where the unnatural chain angle rubs....

Moral of the story - buy a bike from a shop - ride it - waste less money and time. but very grateful if anyone could shed some light - this project is breaking budget and my enthusiasm

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That's all pretty normal, don't use small/small.

Guide for measuring up where to cut carbon steerer. Seems a lot of info online on this. From what seems to be the consensus, as I want to run a 5mm spacer above the stem, is to get the fork in place with headset and spacers below the stem. Then add a 2mm spacer above the stem and mark here to cut? Does this sound right?

Dont forget your stem height.

Thanks :) Now I'm a bit confused about measuring as I need to take into account the carbon expansion bung thing which adds about 2mm to the steerer length. So, how does that affect where I cut?

That would work. I usually just add the stem and spacers I plan to use, mark the steerer, disassemble and subtract 2 or 3mm from my mark

Cut an extra 2mm off.

Make sure if your top cap is heavily conical that it still clears the bung once all assembled. Or else use a flatter top cap

This is the bung and top cap.

So fit headset, spacers, stem, 5mm spacer above stem. Make a mark. Remove all parts, and measure down 2mm and cut here.

If that's right, then when everything is fitted, then the top of the bung will sit flush with top spacer?

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You don't want the top of the bung to sit flush with the top of the top spacer otherwise you won't be able to get any preload on the headset.

No you'll have to remove an extra 2mm for the bung

Ah, I get you. So, assuming I'm running a 5mm spacer above. If I measure flush with the stem and cut there. When I add the bung, that would leave 3mm from top of the bung to top of the top spacer so I can get proper preload?

If the bung wont grip which has happened to me roughen up the stem inside a bit to get a purchase plus assembly paste.

All, looking for some advice to prevent a miserable outcome second time around!

I built up a Kona Honky Tonk after paint (will get a thread up I promise), and during its first ride the rear mech/chain seized, causing it to move round with the cassette and bend the hanger before the chain parted at the weak link. I was mid-cassette so the chain did not drop between the cassette and wheel. Chain was a used 11 speed KMC and a second-hand 10-speed Dura Ace 7900 rear mech. I had also ridden about 3km before this happened, shifting up and down the cassette and big ring/small ring without issue.

Anyone have an idea why this might have happened? Only things I can think of is a) B-screw was poorly adjusted and top jockey wheel hit cassette/jammed the chain or b) rear mech cage was weak and gave out when I shifted gear (the cage plate nearest the spokes has parted by the upper jockey wheel).

**UPDATE: Also fitted a used chain and rear mech to my MTB and checked it in the stand. Would pedal for a few revolutions before the chain (bit dirty and not super smooth) would suck. Rear mech pivot against the frame not moving smoothly makes the effect of this worse. Seems to be the case. Strip and re-grease everything before installing!

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I can’t imagine a ten speed cassette and 11 speed chain were happy together.

How worn out are the chainrings and cassette?

Did the chain get stuck and you kept pedalling leaving only the mech and mech hanger to give way?

Thanks James. Front chainrings hardly used, cassette is new. Checked the chain and not physically possible to drop between two cogs, no stiff links either. I couldn't find any evidence online to suggest why the chain shouldn't work but happy to hear otherwise - believe the inner spacing of the links is the same? I've bought a 10 speed replacement anyway.

It happened within a flash: shifted up a cog on the rear, continued forward on the flat and didn't have time to stop before the drive train locked up and the chain snapped!

this looks puzzling. was the chain routed the right way into the pulleys ? not catching the little retention tab

I can’t imagine a ten speed cassette and 11 speed chain were happy together.

Stridsland (can’t remember their forum name) has been posting stuff on Insta that suggests otherwise. Think the internal width is the same but the external is smaller on 11 speed chain so it actually runs smoother and quieter on an 10 speed cassette.

I'm certain it wasn't - although can't find pictures of it built up to double check! I'd ridden it a little way without issue before this happened though, was shifting nicely and no noise.

Found one, chain routed correctly! Only thing I can imagine is the upper jockey wheel being too close to the cassette and causing the chain to jam?!?

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