Can I change 8 speed sprocket to e.g. 10 speed ??

[Dave7]

I am asking on behalf of a friend who (hard to believe) knows less about bikes than me .
He has an "older" bike with tripple 8 speed. He is struggling on the hills and wants to get bigger gears on the rear.
So............
In theory/principle........is it possible ??
If so.......
a) what does he need to know e.g (stupid question coming up ). if its the number of teeth he has on each cog-how does he get that information e.g. does he literally have to sit down and physically count them ??.
b) does he need to know which model i.e. Tiagra etc ?
c) Would he need a new chain & rear mech ?

I do have some slight knowledge as I am in the process of swapping my 11-28 to 11-32 but trying to ascertain if its possible/practical for him.
Thanks

 

[vickster]

Surely he'd need 10 speed shifters, but presumably there are 8 speed cassettes and chainsets with different numbers of teeth, for example

http://www.evanscycles.com/products/shimano/hg50-cassette-8-speed-ec005232

If he's struggling with a triple, he would likely also struggle on a compact double even with 2 more gears

Yes, he needs to count the teeth on the smallest and largest cogs at the back and on the three rings at the front

Perhaps he should ask his local bike shop to help?

 

[Spoked Wheels]

I am asking on behalf of a friend who (hard to believe) knows less about bikes than me .
He has an "older" bike with tripple 8 speed. He is struggling on the hills and wants to get bigger gears on the rear.
So............
In theory/principle........is it possible ??
If so.......
a) what does he need to know e.g (stupid question coming up ). if its the number of teeth he has on each cog-how does he get that information e.g. does he literally have to sit down and physically count them ??.
b) does he need to know which model i.e. Tiagra etc ?
c) Would he need a new chain & rear mech ?

I do have some slight knowledge as I am in the process of swapping my 11-28 to 11-32 but trying to ascertain if its possible/practical for him.
Thanks

10 speed or 11 speed will not solve the problem. He needs a cassette with larger sprokets , ie, MTB cassettes. He would need a medium size cage derailleur to be able to run a MTB cassette.

 

[Dave7]

Surely he'd need 10 speed shifters, but presumably there are 8 speed cassettes and chainsets with different numbers of teeth, for example
http://www.evanscycles.com/products/shimano/hg50-cassette-8-speed-ec005232
If he's struggling with a triple, he would likely also struggle on a compact double even with 2 more gears
Yes, he needs to count the teeth on the smallest and largest cogs at the back and on the three rings at the front
Perhaps he should ask his local bike shop to help?

Sorry.........I explained that very badly/incorrectly.
Its not more gears he needs its more teeth/bigger cogs.
He is going to a LBS but I am trying to get some background knowledge so he knows roughly what he needs.

 

[Dave7]

10 speed or 11 speed will not solve the problem. He needs a cassette with larger sprokets , ie, MTB cassettes. He would need a medium size cage derailleur to be able to run a MTB cassette.

Yes.....As soon as I started to read your reply I realised I was wrong..........its a sprocket with with bigger cogs/more teeth that he needs.
Thanks

 

[vickster]

Yes there are 11-32 and 11-34 MTB cassettes I believe. He may need to look at the front chainrings too, a shop should help

 

[Pale Rider]

There is no wider range of gears than a mountain triple, which he already has.

So it comes down to cog sizes.

A wider range at the back should work, or he could look into a smaller small ring at the front, or both.

However, changing into these gears can become problematical if he goes too far.

This is where the services of a competent bike mechanic are required - such a person will know what will work and what wont.

It may be your friend will have to compromise with a clunky change into the lowest gear.

Also, biggest at the front and back may not work at all.

Obviously, it's not good to 'cross chain' like that and there's no reason to do it, so it's just something to bear in mind.

 

[Jenkins]

What does he ride at the moment - road bike triples are generally 30-39-50 chain rings, hybrids 28-38-48 chain rings and mountain bikes 22-32-42 chain rings.

Could a chain set with the smaller ratios be fitted up front to help out as well/instead?

 

[stoatsngroats]

If his bike has Acera rear derailler, (MD-360 i think!) it's probable that he can fit an 11-34 megarange cassette, (I did it on our tandem recently, but that's all i can tell you as I don't know much more than this!

 

[Spoked Wheels]

Yes there are 11-32 and 11-34 MTB cassettes I believe. He may need to look at the front chainrings too, a shop should help

Yes that's certainly another possibility but a more expensive one if you end up changing crankset and maybe even bottom bracket. To be considered if a bigger cassette is not enough I think.