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12 posts • Page 1 of 1
can you reverse chainrings?
i'm building a bike up out of old spares which i intend to give to my brother for a xmas pressie and am looking at whether to buy a new crankset or whether i can get away with reversing the worn rings on an old crankset.
so far i've discovered that:
1. the mounting points and teeth are not in the same plane, so when you reverse a chainring, the spacing between the next one (this is a triple chainring) goes out of kilter. i'm thinking maybe i can pack it out with a thin washer?
2. there is a pin on the outer face of the outer chainring, which seems to stop the crank arm from fouling the chain ring (can't see that happening though?) when i reverse the chainring, the pin is then on the inside and would block gear shifts between middle and outer ring. solution - 30 secs. on bench grinder
3. the chainrings have 'profile shifting' ramps or whatever shimano calls them, presumably to smoothen shifts between chainrings. reversing them would mean losing the benefit of those - no big deal i'm thinking?
has anyone else tried this? spare chainrings are not that cheap and my brother isn't about to enter the Tour de France so i thought i'd save a buck.
The pin on the outside of the big ring is to stop the chain jamming under the crank on an over-shift. I managed to overshift somehow this week, with a car up my clacker. I'm very glad the pin was in the right spot.
I'm not sure I'd contemplate the idea. Maybe upgrade yours now and give him your hand-me-downs
On the other hand, if you really don't like your brother ... go for it
When all else fails, persistence prevails -- Lew Hollander
so it is.. oh well, his problem
mine's pretty new Deore. this is my commuter bike so i don't really do upgrades, it's too expensive to put quality bits on it, as i wear them out pretty quickly. chainrings last ~ 1 year.
could be funny
i've still got a bit of time to play around before i hand it over.
i replace my chainsets when they will not transmit any decent torque anymore, with a worn chain. they're pretty useless by that stage - they just slip.
Plus the rings are recessed for the ummmmmmm I can't remember the correct name for them but the bolts that hold them in place!
I don't suffer fools easily and so long as you have done your best,you should have no regrets.
Yes, if you're running Rohloff, Alfine or SS and you have a Thorn chainring (designed for reversability - no ramps or pins, and the ring is symetrical side to side)
Mandatory helmet law?
"An unjustified and unethical imposition on a healthy activity."
Don't cut the chain drop pin off, drill it out from the other side with a 2.5mm drill. You can then tap it to M3 and install it on the other side of the ring. To keep it clean, use a countersunk screw.
I did this when I was fitting new 10 speed rings to an old C-Record crankset and didn't want to pay Record prices. The C-record cranks' arm position differs from the usual crankset so the pin ended up 36 degrees out of kilter.
Maybe try a WTB thread. There are plenty of guys on hear with lots of old parts. I've got a couple of old NOS Shimano 5 bolt MTB Chainrings that I'd give you for post cost if they suit.
Always looking for new rides & ride partners in SE QLD area
Ribble usually stocks Stronglight chainrings which are pretty cheap.
Keep your eye out though sometimes whole cranksets on sale are cheaper. I have been known to buy a crankset just for the rings before.
12 posts • Page 1 of 1
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