RecordAceFromNew
Swinging Member
- Location
- West London
Having just reread that old thread you linked to earlier, I noticed I asked you twice then what the chainline was and did not get an answer. I also explained why it is senseless to introduce rear spacer to deal with your problem - elementary geometry dictates that to achieve a 1mm additional clearance at the front mech requires moving the cassette outboard by ~5mm (which happens to be approximately 1 sprocket width)! I am sorry you took a bad advice, but it was your choice and a nature of internet forums.
The solution starts with some measurements - you have hopefully measured the chainline accurately already, the next thing is to check that the pedals (or the crank arms where the pedals are screwed onto) are equal distance from the centre of the frame. If yes all well and good, if not record them so that any asymmetry can be reduced during the fix.
The most obvious fix, whether it is done by yourself or a local bike shop or Decathlon, is to replace the bottom bracket (if the chainset is ok and not worn). If I were doing it I would first identify what type it is (because it dictates which tool is needed and how to use the tool). Chance is it is square tapered, which you can see if you remove the dust caps at the centre of the chainset (like this). If it is indeed square tapered, the chainset should be removed using a crank remover so that the length of the bottom bracket spindle can be measured. Better still use a bottom bracket remover to remove the bottom bracket and read its label, which should indicate its dimensions and help minimise measurement errors.
The identification of the existing bottom bracket dimensions is the basis for identifying a correct one. While I have been able to extract a catalogue from Prowheel's steam-driven website, it is difficult to be sure whether the triple square tapered ounce chainsets in it are the same as yours - although if they are they are all supposed to deliver a 45mm chainline with a 116mm spindle. Given Prowheel is a Taiwanese/Chinese brand, it would be practically certain that their square tapers are JIS, not ISO, standard. Once the existing bottom bracket dimensions are known for certain, I may be able to let you know which should deliver a better chainline, while maintaining pedal symmetry or help correcting asymmetry if any.
Of course alternatively you can just take it to a good local bike shop and let them to do it.
If I were you I would remove the newly introduced spacer from your freehub and return the cassette to its original state. Removing the smallest cassette sprocket is not risk free - usually it has a special serrated face that matches a correctly sized lockring for security.
Hope it helps.
