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by Brucey
18 Mar 2024, 7:49pm
Forum: Bikes & Bits – Technical section
Topic: Well that was an interesting afternoon....
Replies: 14
Views: 793

Re: Well that was an interesting afternoon....

Pendodave wrote: 15 Mar 2024, 11:09am Gearing - when I got my bike, it had 50/34 and 11/28. Once I went anywhere slightly hilly I found I needed 11/34 on the back. I had to buy a new cassette and new (long cage) derailleur (and a chain whip and other bits to fit it. It might be worth a chat with the shop to see if they'd bung something on to save the time and trouble.
if you need lower gears on a bike with a 'compact double' then not only is it possible to change the cassette, but it is also possible to do something with the chainrings. A 33t chainring is usually possible (because they just aren't trying) and it is also usually possible to fit special 46/30 rings, provided you are happy to deal with a chainline that is moved leftwards a few mm.
by Brucey
18 Mar 2024, 6:47pm
Forum: Bikes & Bits – Technical section
Topic: Snap ring ordering details
Replies: 6
Views: 283

Re: Snap ring ordering details

I would probably address this by making the sprockets/spacers very slightly thinner eg. by lapping them (or the snap ring itself). FWIW I don't really rate this particular conversion because IIRC it leaves the hub pretty well unsealed.
by Brucey
18 Mar 2024, 6:19pm
Forum: Bikes & Bits – Technical section
Topic: 8 speed chain on 10 speed chainset ?
Replies: 11
Views: 379

Re: 8 speed chain on 10 speed chainset ?

mattsccm wrote: 18 Mar 2024, 5:52pm "It doesn't work the other way round though"
Oh yes it does.
Out of interest I dropped a12 speed chain on an older chainset. Works fine.
there speaks a man who has presumably worn the requisite 1/128" off...
by Brucey
18 Mar 2024, 6:02pm
Forum: Bikes & Bits – Technical section
Topic: Help removing child freewheel & chainstays bent on same bike - advice?
Replies: 11
Views: 435

Re: Help removing child freewheel & chainstays bent on same bike - advice?

the usual cause for freewheel removal is replacement and the usual cause of replacement is wear in the sprocket. However your sprocket is not worn, ergo you probably don't really need to take it off.

The other posters are quite correct the freewheel lockring does unscrew on a lh thread. btw if you can be bothered to make one (eg. via welding) freewheels like these can always be removed without damage using a special tool. Commonly a bit of a clean-up, a re-shim, and maybe some fresh balls is all that is required to restore normal function inside.

Fixing freewheels wouldn't normally be my first choice, but here the sprocket is pretty much unworn and it looks like you are going to have to take it all apart anyway, so it seems almost rude not to at least try.

btw if the frame is steel I would certainly try to straighten it.
by Brucey
18 Mar 2024, 3:57pm
Forum: Bikes & Bits – Technical section
Topic: 8 speed chain on 10 speed chainset ?
Replies: 11
Views: 379

Re: 8 speed chain on 10 speed chainset ?

mattheus wrote: 18 Mar 2024, 12:38pm
Brucey wrote: 18 Mar 2024, 12:22pm
...
However, in practice lots of used 8s chainrings have at least 1/128" worn off them on the side of every tooth, so will happily work with the narrower chain. This means that it is usually possible to run 9s chain etc. on used 8s chainrings.
Here's a tangential question: will the narrower chain run better/worse on those chain-rings? And shifts be slicker/worse? More fussy?
all chainrings have a dirty little secret and that is thickness tolerance Now 3/32" is actually over 2. 3mm, yet 8s chainrings are commonly about 2.0mm wide in the teeth., and chainrings meant for 9s,10s,11s etc. are thinner again. The 0.3mm discrepancy is there mainly to facilitate shifting. Rather confusingly, an 11/128" chain will appear to fit over these wider teeth, but it won't ever shift properly. This means that the only way to be reasonably sure it is going to work properly is to measure up very carefully.
by Brucey
18 Mar 2024, 2:35pm
Forum: Bikes & Bits – Technical section
Topic: Re-using an old 8-speed Campagnolo wheel
Replies: 16
Views: 542

Re: Re-using an old 8-speed Campagnolo wheel

FWIW you can always modify a 9s, 10s or 11s sprocket so that it fits an 8s body, by grinding.
by Brucey
18 Mar 2024, 12:22pm
Forum: Bikes & Bits – Technical section
Topic: 8 speed chain on 10 speed chainset ?
Replies: 11
Views: 379

Re: 8 speed chain on 10 speed chainset ?

rareposter wrote: 18 Mar 2024, 9:57am It'll be fine.

It doesn't work the other way round though - you can't use a 10sp chain on 8sp chainset/cassette.
there are presently two different derailleur chain internal widths in current use; 3/32" and 11/128". 8s or lower uses 3/32"(*), and 9s (or higher) uses 11/128". Now the difference between these is very small, just 1/128"; nonetheless when everything is new, 9s chain won't run properly on 8s chainrings. However, in practice lots of used 8s chainrings have at least 1/128" worn off them on the side of every tooth, so will happily work with the narrower chain. This means that it is usually possible to run 9s chain etc. on used 8s chainrings.

(*) unless it is IG.
by Brucey
18 Mar 2024, 10:43am
Forum: Bikes & Bits – Technical section
Topic: Re-using an old 8-speed Campagnolo wheel
Replies: 16
Views: 542

Re: Re-using an old 8-speed Campagnolo wheel

IIRC Miche do sprockets (into the 30's IIRC) to fit campag freehub bodies. Not that it isn't especially difficult or challenging to make your own, but they also do various width spacers, so you can build up miche cassettes to be compatible with almost any modern indexing system.
IIRC ambrosio(?) used to do a replacement cassette where each sprocket used a slightly larger splined fit and the cassette came with spacers and carriers to suit. I mention this because IIRC this system was quite popular BITD,(so there is lots of campag 8s stuff out there), the system supported larger sprockets (which don't tend to wear out) and you could use as many ( or as few) of the special sprockets as you want. Given how useless (for touring) the smallest sprocket in a standard cassette is together with how easy it is to add a sprocket at the other end of the cassette it wasn't exactly surprising to see how many people ran basically standard cassettes but without the smallest sprocket and with an added larger one.

Anyone with a welding set and half an ounce of brain power pretty much has the World at their feet here, I reckon. Whilst it isn't even slightly tricky to weld HG type steel sprockets together so they are strong enough it is tricky to get everything to stay concentric and sufficiently free of distortion. However, if you can manage this, there is nothing to stop you from rebuilding any worn campag fit cassette using shimano sprockets, any size.
by Brucey
17 Mar 2024, 12:01pm
Forum: Bikes & Bits – Technical section
Topic: Bottom bracket size
Replies: 35
Views: 1044

Re: Bottom bracket size

IME the four flats can differ in size and shape considerably. You can have the correct chainline and the exact correct 2 degree taper and still come unstuck. This is why you should try to use matched sets of new parts, or at least 'known good' combinations. If used cranks are to be fitted to any new spindle,you should carefully assess the quality of the fit, as per my earlier post. IME using a simple grease (ie. oil + thickener) during assembly has nothing much to do with how difficult it is to remove the cranks a year or more later; either way, they can have 'cold welded' themselves on, if the pedalling has been sufficiently vigorous. Should you want to suppress corrosion, you can daub on pretty much anything later. Provided the cranks have been ridden on properly, the joint will be consolidated, so that full penetration of any added fluid is unlikely after six months or so. Incidentally, this is also more or less why penetrating fluids don't always work.
by Brucey
16 Mar 2024, 8:26pm
Forum: Bikes & Bits – Technical section
Topic: 1" Steerer- worn threads
Replies: 12
Views: 527

Re: 1" Steerer- worn threads

it is not a headset with a cone adjusting race, but the tange passage can have a low stack height so it might just avoid any damaged threads on the steerer. My guess is that the A9 has a stack height of ~40mm and the chances are that the threads are damaged at 32-35mm or so. The tange passage has a stack height of 30.2mm which probably means it normally uses the steerer threads in the 22-30mm range If you fit the tange passage with a ~9mm spacer, the spacer may straddle the region of the damaged threads whilst allowing replacement of a headset with a much higher stack.

FWIW nitto make some quill stems with a longer quill for folk that need their handlebars to be raised but they are certainly not the only game in town.
by Brucey
16 Mar 2024, 5:51pm
Forum: Bikes & Bits – Technical section
Topic: Bottom bracket size
Replies: 35
Views: 1044

Re: Bottom bracket size

there is always a way of removing cranks, especially if you don't mind wrecking them because they are going to be replaced anyway. This means that you shouldn't let the possibility of damaged extractor threads put you off using a set of cranks.
by Brucey
16 Mar 2024, 5:13pm
Forum: Bikes & Bits – Technical section
Topic: Bottom bracket size
Replies: 35
Views: 1044

Re: Bottom bracket size

what I suggest you do is first assess the fit quality between the cranks and the new BB. Typically this can be done by using a marker pen on the flats inside the crank, then trial assembling the parts, torquing the bolts to about half the usual torque before disassembly. The marker pen marks will show where there has been intimate contact or not. If the fit quality is good (all faces showing equal signs of uniform contact) then follow Mr Campagnolo. If however, the fit quality is less than perfect, use Mr Shimano's procedure, but be aware that you only have a few goes at this (resizing) before the cranks might fail.
by Brucey
16 Mar 2024, 3:29pm
Forum: Bikes & Bits – Technical section
Topic: Bottom bracket size
Replies: 35
Views: 1044

Re: Bottom bracket size

Dupont wrote: 16 Mar 2024, 2:03pm I think as my BB is Shimano then I will apply a little copper grease to each taper and locking bolt. 👍
I believe that is absolutely the worst possible thing you could do. 'Copper grease' can contain all manner of things, but it always contains solid lubricants ie it is specifically intended to inhibit those processes which might allow your cranks to be retained if you pedal hard.
by Brucey
16 Mar 2024, 1:30pm
Forum: Bikes & Bits – Technical section
Topic: Bottom bracket size
Replies: 35
Views: 1044

Re: Bottom bracket size

Dupont wrote: 15 Mar 2024, 8:41pm Do I need to put any grease on the square taper part that accept the cranks when I put my new BB in?

There seems to be a differing of opinions from web searches I have done.
the square taper joint is widely misunderstood. Roughly there are two schools of thought; those who follow shimano's stipulation to use grease and high torque,and those who follow campag's mantra of no grease and a lower torque value. So who is right? Well, I think they both might be.
You see it is easy to assume that because shimano's design looks superficially the same as campag's it is same. I don't think it really is. I think shimano's design intentionally allows some yield in the crank so that it resizes and it really fits the spindle. By contrast campag's parts are, I think, manufactured to better tolerances so fit one another better from the start, so no resizing is required. If I am correct, this explains the apparent mystery.
If as I suspect the tolerances are different in each case then probably it is best if you follow campag's advice when refitting the same crank on the same spindle and shimano's when fitting anything to any JIS spindle for the first time. What shimano don't tell you if that their procedure probably shouldn't be repeated incessantly, that the grease should under no circumstances be full of solid lubricants or extreme pressure additives, or that (if you push hard on the pedals) the cranks will probably cold-weld themselves onto the spindle in the longer term anyway.
So you may be thinking that shimano don't tell you much; well neither do campag really, it is 'omerta' all the way. What I do know is that regardless of the method used, it is not a bad idea to check the bolts within the first 100miles or so, retorquing to campags recommended torque if necessary. My suspicion is that this whole thing could be very greatly improved by the simple use of a drop of threadlock compound and a well-chosen belleville washer.