Larger chainring

[biker grove]

I've got a sports hybrid with a triple chainset and the larger ring is 48 teeth. I've been given a triple chainset with a 50 tooth large ring which would give me better gearing. Is it possible to use this chainset without needing a different front mech? The front mech is a Shimano Tourney so not high spec but developed for use with 48T max.

 

[themosquitoking]

You should be fine, you may need to raise the front mech a couple of mm though.

 

[ColinJ]

Define 'better'!

(It would be higher gearing, but you don't need it unless you are spinning out on your 48. I reduced my Cannondale from a 53 to a 48 and I can still hit 35 mph, even though the smallest sprocket on my cassette is a relatively large 13 tooth.)

 

[ColinJ]

Sorry, I misunderstood your post ...

You meant the triple would give you better gearing. I am a fan of triples, so yes, as mosquitoking suggested!

 

[ColinJ]

Damn - I must stop speed reading ... I got it right first time! Ignore my second post and stick to my first one!

 

[biker grove]

Damn - I must stop speed reading ... I got it right first time! Ignore my second post and stick to my first one!

You're right - I meant "higher". Just lately I've had a couple of occassions where I've felt I could do with something a bit higher. I've got the same as you here, then. 48T front, 13T rear. I'm not sure how much difference it would make in making the change. Just feel it could slow my legs down

 

[themosquitoking]

Did i miss something here?

 

[biker grove]

Did i miss something here?

?????

 

[ColinJ]

You're right - I meant "higher". Just lately I've had a couple of occassions where I've felt I could do with something a bit higher. I've got the same as you here, then. 48T front, 13T rear. I'm not sure how much difference it would make in making the change. Just feel it could slow my legs down

The only time I do that 35 mph is downhill and if I want to go faster than that I just stop pedalling, get as aerodynamic as I can and let gravity do the rest!

50/13 is only about 4% higher than 48/13 so it isn't going to make a huge difference. Changing the cassette to one with an 11 or 12 would make a lot more difference.

 

[byegad]

As to the 'will it work' question.

The answer is probably! Although you are exceeding the 'limit' for the front mech, I've found there is a lot of lee-way in Shimano's limits, all my trikes have gearing that 'shouldn't' work.

 

[biker grove]

Thanks for your help all. I'll leave as is, I think. It looks like the chain line will be different too which means faffing about with a new BB. Too much effort for too little gain at the mo.