Sunday, 7 December 2014

Fixing a broken spoke - removing the gearset

Three tools for removing rear sprocket clusters.

Some time ago, I did a short piece on replacing a broken spoke.
It was, quite rightly, pointed out that, unlike the hub-gear set-up I illustrated, many bikes have a derailleur set-up, and require an additional step.

If you break a spoke on the "drive" side (that's the side with the gears) of a bike with a derailleur set-up, you usually have to remove the set of gears from the wheel in order to have room to get the new spoke in.

Plenty of advice is available elsewhere on the web for this, so I will just cover one topic which may be of interest to the rider about to undertake this for the first time.

Derailleur bikes, except Campagnola models, and some vintage models, tend to have one of two types of rear gearing.
There is the "freewheel" design, still fitted to lower-priced new bikes, including 6-speed Shimano SIS set-ups.
Then there is the "freehub" design, which is fitted to bikes with eight-speeds and above. There are a few older 8-speed "freewheel" hubs about, but the design flaws with that was a major reason why the "freehub" design has become dominant for more than 6 speeds.
If you have seven speeds, you could have either design!

Anyway, there are a couple of different tools to undertake the job.
The Park Tool FR-1 is for removing a "freewheel" set of gears, while a Park Tool FR-5 is for removing a "freehub" set of gears.
An FR-1 can be used in place of on FR-5, but not the other way round, as an FR-5 has deeper ridges and won't fit into a "freewheel"!
The Park Tool FR-5 has deeper ridges than the FR-1
Although an FR-1 will normally fit both types (freewheel and freehub), it is better to use the FR-5 with a freehub, as the deeper ridges mean it will engage easier, and it reduces the amount of wear on the freehub if it is hard to undo.

As for low-priced tool kits - it is a bit lucky dip which tool you get.
The gear remover in my low-priced Lidl "Crivit" tool set turned out to be an FR-5 type tool.
So the cheap tool set had a tool that fits a dearer bike (!).
On the "plus" side, though, the Lidl tool had a head that takes a standard 1/2" wrench (spanner) arm, as well as a "hex" shape to the top, while the "genuine" Park Tool FR-1 and FR-5 only have a "hex" head, so one would need to find an appropriate socket wrench AND a wrench arm.

Hope this helps with tool selection!
Of course, I have all three tools featured in the pictures in my tool box, so if anyone wants further details/pics, then ask away!

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