What do I need to go from 2 to 3 chain rings ?

[BADGER.BRAD]

Just found one with 40 teeth !

 

[EckyH]

Just found one with 40 teeth !

Please keep in mind that the rear derailleur must handle such large sprockets and the bigger difference between the gears in "big chain ring with the bigger sprockets" and "small chain ring with the smaller sprockets". Is the derailleur on your bike capable of that?

E.

 

[Punkawallah]

The chain line would have been terrible but I have just counted the number of teeth on the rear sprocket for the lowest gear which is 24, as it seems very easy to obtain cassettes with 36 teeth as the lowest gear I going to go with that and see if it is enough for my purpose. I have used these before on MTB based commuters but of course you still have another lower chain ring on the front mech , I'm not sure how this will compare with a bike with 20 inch wheels.

A quick look at a ‘gear inch’ calculator tells me that on your current chainset a 32 tooth gear would give you a 50% improvement over your 24 tooth gear. Apparently this should get you up 10-15% inclines.

 

[BADGER.BRAD]

Please keep in mind that the rear derailleur must handle such large sprockets and the bigger difference between the gears in "big chain ring with the bigger sprockets" and "small chain ring with the smaller sprockets". Is the derailleur on your bike capable of that?

This was the next thing to look at as well as is the current chain long enough to cope with the two large gears. It seems that in solving one problem ie: how to carry a bike with my small car allowing me to commute over the river saving me 8 miles in the car each way and giving me some exercise has caused a load more problems else where. I hope I can solve it as no other way is possible !

 

[Sharky]

This was the next thing to look at as well as is the current chain long enough to cope with the two large gears. It seems that in solving one problem ie: how to carry a bike with my small car allowing me to commute over the river saving me 8 miles in the car each way and giving me some exercise has caused a load more problems else where. I hope I can solve it as no other way is possible !

Usually recommended to fit a new chain, with a new cassette, but before you cut the new chain to fit, try with the old chain first. As long as you don't use the big/big combination, you should be ok.

But your rear mech needs to be able to cope with the larger sprocket.

If considering changing the chainset to a 50/34 or smaller, can the front mech be moved down an inch or so?

It's going to be a lot of trial and error and needing deep pockets.

Good luck

 

[BADGER.BRAD]

But your rear mech needs to be able to cope with the larger sprocket.

If considering changing the chainset to a 50/34 or smaller, can the front mech be moved down an inch or so?

Just been having a look, with the current lowest gear combination this is how it looks

The mech is as far back as it can go ruling out a smaller front chain wheel , to use another 3rd front chain wheel would cause the angle to be even worse !

Then the opposite (large front sprocket and large rear sprocket )

This is with me forcing the derallier forward to max travel,there is a fair bit of play this way so the rear cluster with a bigger low gear idea seems possible. Tomorrow morning I'm going to try the journey as it is . As I have just about made it in the past on a MTB in the lowest gear I'm not holding my breath !

 

[Sharky]

The old saying "If it ain't broke, don't fix it", might be applicable here.

 

[BADGER.BRAD]

The old saying "If it ain't broke, don't fix it", might be applicable

I'm not quite sure what you mean here !

 

[Ming the Merciless]

A quick look at a ‘gear inch’ calculator tells me that on your current chainset a 32 tooth gear would give you a 50% improvement over your 24 tooth gear. Apparently this should get you up 10-15% inclines.

Surely (32-24) / 24 = 8 / 24 = 1 / 3 = 33.3333%?

 

[Sharky]

I'm not quite sure what you mean here !

Basically, you have a good working transmission, with all components matching and working. Trying to change bits for a marginal gain, (ok substantial going uphill), could be a lot of effort to get a better transmission