Extending transmission service life on my crank drive

[georgehenry]

The lazy approach to extending drive train service life on a crank drive bike....

I have managed to make my rear cassette last a year and 1,868 miles.



I use my 2015 Haibike Yamaha to commute to work and back, generally 14 miles cross country to work and then 10 miles back home again.



This is particularly hard on the chain as it gets dirty on the cross country ride to work, gets a splash of oil on top of the dirt at work before my ride home, and then ridden 10 miles home, oily and dirty.

In reality it hardly gets cleaned at all and then off I go again.

So I used a basic park tools chain checker to keep an eye on the chain. This is one of the ruler type ones that slots into the chain to show stretch. A bike mechanic has told me these are not very good and it is all too easy to miss a chain stretching too far.

Anyway using this imperfect tool I determined the chain needed changing at 700 miles. At almost the same point the top gear cog (12 tooth cog) started to show signs of wearing out (slight jumping)

On the ride home I travel faster, (30 minutes for a 10 mile journey), using more higher assist and the 12 tooth top gear cog is the most prone to wear out prematurely in comparison to the other cogs that have more teeth.

So I changed the chain and also the 12 tooth top gear cog having found individual cogs being sold on ebay.

On I rode and this time allowed the chain to pass the wear limit as the whole drive chain would need changing the next time. Anyway my second chain and replaced top gear cog on a part worn cassette worked without issue for another 1,168 miles.

This is with little washing/de-greasing and probably too much chain lube applied.

So for the cost of my individual 12 tooth top gear cog £3.01 and a new 9 speed chain and a very lazy approach to maintenance I extended the life of my part worn drive train and got a full year of 50% off road commuting and 1,868 miles out of my rear cassette.

I have now changed everything, chain, chain ring, cassette, and jockey wheels. The rear mech took some de-greasing from all my regular applications of chain lube!

I bought a couple of my 12 tooth individual cogs and will now buy a couple of chains to allow me to continue this approach.

I will also buy a better chain checking tool.

My commuting days are almost over as I head into retirement and I should have time to clean my drive train more regularly but have learnt not to underestimate my talent for idleness. However my laziness will be overcome by my liking of making things last as long as possible and dislike of spending money coupled with the high cost of bits at the moment.

I am also down to the last of a job lot of shimano 9 speed cassettes I bought a few years ago when they were incredibly cheap on amazon at £12.50 each delivered. They are not that any more!

So Stats, New Cassette and chain fitted 07/10/20

New chain and top gear cog fitted 10/03/21

New Drive train fitted 06/10/21

1,868 miles ridden, all weathers, 50% off road,

Only eco and off for 14 mile cross country route to work and 25 to 30% battery used of 400Wh battery

Eco and middle assist of the three I have used for the 10 mile road commute home to average 20mph and achieve a thirty minute journey time

Original 400Wh battery now six and a half years old.

First motor replaced under warranty after 6,000 miles right on the two year ownership point, second replacement motor now up to 8,266 miles.

Bike cost £1,750 in March 2015.

 

[chris_n]

For contrast my most worn gears are third and fourth, shows how much time I spend going up silly long hills with an average ride over 1000m of climbing. As soon as I leave home virtually every road / track goes up.

 

[georgehenry]

On my cassette 3rd and 4th gear have 28 and 24 teeth respectively, which are much more resistant to wear than my top gear 12 tooth cog. I also use a single narrow wide 42 tooth chain ring and know that you use a double chain ring set up.

I am jealous of all the riding you do in the Austrian Tyrol with gradients that necessitate spending the majority of your time in third and fourth and probably a 36 tooth inner chain ring.

It is my ride home on the road at higher speeds and power settings that effects my top gear 12 tooth cog.

In retirement I think I will lower my gearing for the more varied off road leisure riding I will do, at first simply by replacing my 42 tooth chain ring with a smaller 38 tooth single narrow wide chain ring to see if that gives me a low enough bottom gear to climb the steeper routes in my area that I do not encounter on my off road route to work.

To counter that smaller chain ring I will get two individual 11 and 13 tooth cogs to replace the 12 and 14 tooth 8 and 9 speed gears.

This is the simplest thing to do. If that does not work to my satisfaction I will need to put a double front chain on like you have done, although I have grown to like the simplicity of a the single narrow wide chain ring set up I use.

I could also consider the wider range 9 speed cassettes that are available but which are more expensive than the one I use. These are the sort of pleasurable problems that retirement is designed for!