lowering Shimano 105 gearing

[alvechurch wheeler]

hello all, I have a fantastic Specialized bike with a Shimano 105 9 speed setup but the previous owner put on a high gearing on it. It has a front cog setup of 30/42/52.....rear is 25 downwards....... I know I can put a 28 cog at front instead of 30 but can the back set be dropped to say 34T downwards....?

 

[Smokin Joe]

Putting a 28t inner on the front won't make much difference, it's on the rear you'll really notice it. I'd go for a 30 or 32t sprocket on the back. Believe me, five extra teeth on the largest rear sprocket will make a massive difference.

 

[Apollonius]

Definitely. The cheapest and easiest solution is a new cassette with the range you want - and 9 speed Shimano are pretty cheap. Put a new chain on while you are at it.

 

[rich p]

Won't he need a new rear mech with a 32 or 34?

 

[mrbikerboy73]

Won't he need a new rear mech with a 32 or 34?

I was the thinking the same myself. Maybe get away with a 30t but not much more without a long reach cage although I cannot be certain of this!

 

[Dave Davenport]

Being a triple it should haver a long cage rear mech already.

 

[Smokin Joe]

Being a triple it should haver a long cage rear mech already.

^^This^^

 

[Racing roadkill]

Putting a 28t inner on the front won't make much difference, it's on the rear you'll really notice it. I'd go for a 30 or 32t sprocket on the back. Believe me, five extra teeth on the largest rear sprocket will make a massive difference.

On a mountain bike.

 

[Racing roadkill]

Being a triple it should haver a long cage rear mech already.

My 9 speed triple ring bikes, all came with quite a long cage, certainly long enough to cope with a 30 tooth big sprocket out back. The only issue was that the chains were typically 112 link, and they were very close to maxed out on a 30t sprocket. That said, with a triple up front, I've not found any inclines that warrant more than 28 teeth.

 

[lpretro1]

Not the capacity there for a 34t I'm afraid - not with a triple

 

[alvechurch wheeler]

hello, do you mean that even a long cage will not take a 34T cog ?

 

[the snail]

M...a long cage, certainly long enough to cope with a 30 tooth big sprocket ..

Long cage (or rather medium cage like GS) gives a bigger capacity (difference in teeth between large/small rings and sprockets), but it doesn't automatically mean that it will take a larger sprocket than a short cage mech. e.g. 5700 RM, SS will take 30T, GS 28T (according to Shimano)

 

[Racing roadkill]

Long cage (or rather medium cage like GS) gives a bigger capacity (difference in teeth between large/small rings and sprockets), but it doesn't automatically mean that it will take a larger sprocket than a short cage mech. e.g. 5700 RM, SS will take 30T, GS 28T (according to Shimano)

Trial and error soon sorts out the issues

 

[Kajjal]

A thirty on the back will make hill climbing much easier.

 

[Racing roadkill]

A thirty on the back will make hill climbing much easier.

On a mountain bike.