P
Pete Biggs
Guest
My brother used a basic mid-range Trek 820 mountain bike casually for a couple of years with no
problems. Then, a few weeks ago, shortly after fitting bar ends, the freehub broke (made strange
noises and wouldn't freewheel at all). Replacement freehub is now going in the same way after just a
few short rides!! The wheel has an unbranded non-Shimano hub.
Our theory is that the failure is caused by extra pedalling force applied after fitting bar ends and
climbing hills much harder than before. The following notes from Jobst Brandt recently posted to
rec.bicycles.tech backs it up:
> Freehubs generally have the ratchet pawls cramped into a smaller diameter than freewheels of the
> past and are more heavily loaded, especially with the lower gears available today (under gearing
> with chainwheel smaller than rear sprocket). When a ratchet step or a pawl is overloaded, metal
> sticks up where it shouldn't and causes that point to hang up when it passes a pawl or ratchet
> tooth, depending on who ate it.
>
> Yes, it is entirely possible to ruin a ratchet escapement. The presence of all sorts of noisy
> escapements is a sign that there is a problem down there.
>
> Jobst Brandt
~PB
problems. Then, a few weeks ago, shortly after fitting bar ends, the freehub broke (made strange
noises and wouldn't freewheel at all). Replacement freehub is now going in the same way after just a
few short rides!! The wheel has an unbranded non-Shimano hub.
Our theory is that the failure is caused by extra pedalling force applied after fitting bar ends and
climbing hills much harder than before. The following notes from Jobst Brandt recently posted to
rec.bicycles.tech backs it up:
> Freehubs generally have the ratchet pawls cramped into a smaller diameter than freewheels of the
> past and are more heavily loaded, especially with the lower gears available today (under gearing
> with chainwheel smaller than rear sprocket). When a ratchet step or a pawl is overloaded, metal
> sticks up where it shouldn't and causes that point to hang up when it passes a pawl or ratchet
> tooth, depending on who ate it.
>
> Yes, it is entirely possible to ruin a ratchet escapement. The presence of all sorts of noisy
> escapements is a sign that there is a problem down there.
>
> Jobst Brandt
~PB