Lower gearing

[redjedi]

I am thinking of lowering the gearing on my Bianchi 1885, because I can really struggle on steeper climbs.

I currently have a 53/39 with 130mm cranks on the front, and a 12-25 Campag cassette with a short cage RD.

But I'm not sure which way to go. Should I replace the front chainrings for 50/34 making it a compact, or change the cassette to a 13-26/29.

I'm no good at all this gear ratio stuff so I'm not sure which would be better.

I am looking for the cheapest option if possibe, ie I don't want to start changing derailleurs if I can help it.

Could we also avoid the "cheapest way is to get fitter" comments for now please

 

[MacB]

39x25 gives you a low of 41 inches
39x29 = 35 inches
34x25 = 36 inches
34x29 = 31 inches

If you stay with a 39 ring then I believe campy to go above a 29 cog to 35 is your limit. If you want a 29 on the rear thebn I think you'd need a new derailler, but not certain. If it fits then a straight swap from 39 to 34 on the front is cheapest.

Personally I'd go with new rear derailler, cassette to 29 and 34 ring on front plus front derailler if needed. Some of these bits can be sourced very cheaply on e-bay. There may be some spares floating around on here as well, from camp users!!!

 

[Tollers]

My take on the practicalities is.....

Option 1) Change chainrings to compact size - I'm not 100% on this, but i believe campag's chainsets use a different spider diameter between stanard and compact sizes.

Option 2) Buy compact chainset - This works

Option 3) 13-26/29 casette - With your standard chainset, this would prob require a new derailleur + a few extral links in your chain

As such, i believe the quickest/easiest/cheapest way is to buy a compact chainset.

Hopefully someone will correct me and you will be able to replace the chainrings alone.

Tollers

 

[woohoo]

Depending on where I'm going, I sometimes run a 13-29 cassette with a 50/34 compact Campag set-up and still use my short cage rear der. Although it will go into the 50-29 combination (just!), I never use this (obviously) or the 34-13 combinations (equally obviously).

 

[MacB]

Luke, just so you know 31 inches is the low I get on my Giant triple setup.

 

[accountantpete]

I have Campag 27 on mine (39 front) and it can still be tough on long steep hills so I'd go 27 at the back and a smaller inner chainring. The 27 works ok with a short arm rear mech and from the following thread I think a 29 would as well.

http://www.cyclechat.co.uk/forums/showthread.php?t=46265

 

[jimboalee]

Don't start me off.....

 

[addictfreak]

Some good stuff posted on this thread.

I have been thinking of going to a 12-27 on my winter bike, dont have any probs on the good bike with a 12-25. But for some reason I struggle on the steep stuff on my winter ride, and its not that much heavier maybe 1.5 kgs.

So just to get it right, all I need to do is change the cassette and off I go?

 

[MichaelM]

I am thinking of lowering the gearing on my Bianchi 1885, because I can really struggle on steeper climbs.

I currently have a 53/39 with 130mm cranks on the front, .......

Have you really got 130mm cranks?

 

[MacB]

Have you really got 130mm cranks?

Ah, sorry Luke missed that, assuem you meant 130mm BCD, in which case Sheldon says the smallest front ring is a 38t. That gives me the impression you'd need a 110mm BCD chainset to do the Compact bit at the front. hopefully an expert will be along to verify

 

[redjedi]

Have you really got 130mm cranks?

No, I was reading the spec of a website and read the wrong one. Mine are 175mm long cranks. 130mm was the lenght of the stem.

Ah, sorry Luke missed that, assuem you meant 130mm BCD, in which case Sheldon says the smallest front ring is a 38t. That gives me the impression you'd need a 110mm BCD chainset to do the Compact bit at the front. hopefully an expert will be along to verify

How do I know/measure the BCD. What is a BCD?

Don't start me off.....

I've seen what you've written on other threads, so my disclaimer was aimed at you

 

[PpPete]

How do I know/measure the BCD. What is a BCD?

As always, Sheldon has the answer:
http://www.sheldonbrown.com/gloss_bo-z.html#bcd

 

[redjedi]

Should have looked there really.

So my BCD is 135mm which means a 39 is the smallest I can go.

So either I change the entire chainset for about £120 or try the larger cassette.

I'll give the larger cassette a try and see if it'll work with the short cage, if not I'll have to splash out on a new deraileur as well.

 

[accountantpete]

Should have looked there really.

So my BCD is 135mm which means a 39 is the smallest I can go.

So either I change the entire chainset for about £120 or try the larger cassette.

I'll give the larger cassette a try and see if it'll work with the short cage, if not I'll have to splash out on a new deraileur as well.

The only problem is that you get a couple of large gaps in the gearing -depending on the range of sprockets you go for -esp if you go up to 29.

 

[MacB]

The only problem is that you get a couple of large gaps in the gearing -depending on the range of sprockets you go for -esp if you go up to 29.

yes, feel the force young Jedi!!!!!!!! and don't be blindly seduced by various combinations that you can play with on Sheldons site. Having done this, and worked out a compact that would be ideal for me, yep, they don't make them anymore. In fact some of the most attractive rear cassettes listed seem to be like hens teeth(though this is shimano rather than campag).