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I've a an old Beinn 20 large. It's a 5 sp.
Can it be upgraded to 7 sp easily?
Anyone?
It would depend on the dropout spacing, I believe that 7 speed and above is 135mm, six speed used to be 126mm IIRC. If it is 135mm, it's an easy upgrade mechanically, you just need a new cassette, shifter, probably a rear mech, and to account for wear and tear a new chain and ring.
yes it can.
just remove the 5 speed freewheel and screw on a 7 speed freewheel, when screwed on if the 7speed freewheel fouls the r/h dropout so the drive side OLN doesn't reach just re-space the axle slightly (axle spacing is not crucial as even on an alu frame there will be plenty give in the stays to run a slightly wider axle). change the shifter, adjust the cable tension/indexing and that's it.
I'd doubt very much if your kid has worn the chain or chainring enough to cause any problems.
OLN =Over Locking Nut = the nuts on each end of the axle that lock the adjustment for the cones.
I thought this thread was going to be about Dads fitting hope hubs and chris king headsets to lslabikes and trying to source the correct size ti bottom brackets...
TI bottom bracket and hope hubs...
There's an idea!
Thanks guys
just remove the 5 speed freewheel and screw on a 7 speed freewheel, when screwed on if the 7speed freewheel fouls the r/h dropout so the drive side OLN doesn't reach just re-space the axle slightly (axle spacing is not crucial as even on an alu frame there will be plenty give in the stays to run a slightly wider axle). change the shifter, adjust the cable tension/indexing and that's it.
To reiterate this one, by doing this you're moving spacers from one side to the other. The OLN doesn't change, but you may need to re-dish your wheel.
If you add/remove spacers from the axle and change your OLN especially on freewheel hubs you run the risk of bending or snapping an axle.
on a solid nutted axle you can space it pretty much how you like (within reason) so ong as there are still enough threads to attache the wheel nuts outwith the drop outsTo reiterate this one, [b]IF IT'S A HOLLOW QR AXLE[/b] by doing this you'll be moving spacers from one side to the other. The OLN [s]doesn't change[/s] [b]can still change slightly (a few mm)[/b], but you may need to re-dish your wheel.
Don't worry yourself, this simply isn't true! we're talking about a few mm more leverage on a steel axle here! plus, we're talking about a kids 20" wheel bike (ie. for a 5-7yr old) 🙄If you add/remove spacers from the axle and change your OLN especially on freewheel hubs you run the risk of bending or snapping an axle.
You may be right re: 20" kids bikes, but I'm not referring to the additional length of the axle making a difference, more what it does to the dropouts, they will no longer be parallel. This can load an axle uneavenly and on freewheel hubs lead to bent axles and possible failure.
Most common failure of freewheel hubs isn't down to hitting things hard, it's more down to alignment of the dropouts.
Sorry if I wasn't clear.