Hi all.
I have installed a larger front chainwheel (42 instead of 35 teeth) on my Kalkoff Sahel. It has a spring loaded tensioner in the back, and this points straight down now, instead of slightly backwards. That is because the chain is 7 links too short now. Bike runs OK, but will there be some long-term ill effects?
Any advice will be appreciated
.
My experience is with earlier chain arrangements on the ProConnect and Agattu; all with hub gears but using only a front tensioner at the chainwheel end. However, a couple of observations may still be relevant to your setup.
First, I am guessing that your new chainwheel is 41 teeth rather than 42 if it is a Panasonic drive. An increase of 6 teeth around the chainwheel means that the chain will see an extra 3 teeth because it only passes round the front half of the chainwheel.
My understanding of one full chain link is that it comprises an inner pair of plates and an outer pair of plates, so covers 2 teeth of a chainwheel. So I would say that your chain is 1 1/2 links short.
Does this matter ?
On the Sahel, is the rear wheel bolted into a slot (dropout) that runs more or less front to back, allowing the wheel position to be adjusted to affect the chain tension ? I can't recall whether the rear tensioner was added to allow just a single (fixed) position for the wheel.
I only ask because I have a preference for the wheel to sit well back into a horizontal dropout, allowing the serrated washers to grip over as much area as possible including the back of the slot. If the wheel is only just into the slot, there is a tendency for the chain tension to overcome the wheel nut, and cause the wheel to shift on the chain side.
So, if the wheel is well back in the dropout and there is still a small amount of give in the front and rear tensioners, I would think that it will be OK.
Quite possibly you have done some miles on the original chainwheel, and the chain has already stretched a bit. Go for one extra full link when fitting a new chain.
Last point - has the new position of the rear tensioner altered the amount of chain wrap around the rear sprocket ? I am guessing that it won't have reduced the number of teeth in contact with the chain, which can cause a faster rate of wear.
James
