Compact Chainsets

[Markymark13]

I am currently running a Shimano 2300 setup, with a 52/39 on the front and a 12/26 on the rear. I can currently get up anything up to around 15% gradient, but I have a couple of Sportives planned for next year which will require lower gearing, as well as wanting to take the bike to the lakes for a week or so and maybe up to the Highlands or down to Devon.

Anyway, I am looking at buying a compact chainset. The bike currently has a square taper BB. I do not have tons of money, so am looking along the lines of the Shimano 2350 or the FSA Vero.

Has anyone had any experience with these or any other options?

 

[cyberknight]

http://www.velominati.com/the-rules/
Rule 5
You really need to comapre the bcd and number of bolts holding the cranks to yours, if the numbers match its should fit
eg bcd 110 is the standard compact double although i cant say i have ever seen a 39 on that chain ring size.Assuming its a standard you could get a 50/34 .

 

[Markymark13]

Surely rule 5 does not apply to gradients over 30%... If it does, then have you tried it on a standard double?

How do you calculate bcd?

 

[cyberknight]

Not sure if rule 5 applies to gradients over 30%. If it does, then have you tried it on a standard double? ;-)
.

How do you calculate bcd?

I used to ride a 52/42 with a 12-21 block about 20 years ago ,nowdays i spin a compact double rather than grind
Its should be printed on the chain ring
http://sheldonbrown.com/gloss_bo-z.html
If in doubt take it to the LBS and ask them what you have

 

[Markymark13]

Thanks for that. It is 130. Am I right in thinking that this would only matter if I wanted to change the rings and use the same crank arms. As long as I change the full unit though then it wont matter will it?

 

[black'n'yellow]

130 is standard BCD, so you will struggle to get a smaller ring than 38 on the inner. Stronglight make a 110bcd compact chainset which is square taper fitting. Usually a few on ebay...

 

[Markymark13]

Can I not just replace the whole chainset (rings and crank arms) for a compact as long as it fits on my bb?

(Sorry if the technical language is not correct. I have done a lot of cycling and am handy with maintenance, repairs and tools, but not so up on the lingo!)

 

[jay clock]

Can I not just replace the whole chainset (rings and crank arms) for a compact as long as it fits on my bb?

(Sorry if the technical language is not correct. I have done a lot of cycling and am handy with maintenance, repairs and tools, but not so up on the lingo!)

Yes you can replace the whole chainset. The issue to look at then is the fixing of the front mech to the frame. A few bikes have a braze-on that will not allow sufficient adjustment.

To be honest I would not buy a chainset to fit your BB. I would buy a good value chainset and new BB as they are not pricey, and the extra you spend can probably be saved by having a much wider choice of chainset (not ltd to one type of BB)

 

[Markymark13]

Yes you can replace the whole chainset. The issue to look at then is the fixing of the front mech to the frame. A few bikes have a braze-on that will not allow sufficient adjustment.

To be honest I would not buy a chainset to fit your BB. I would buy a good value chainset and new BB as they are not pricey, and the extra you spend can probably be saved by having a much wider choice of chainset (not ltd to one type of BB)

Thanks for that. It is a bolt on mech, so will be able to lower it easily enough. Might just need to fit a new cable.

I am pretty sure that my current BB is 68x113, so what would you suggest?

 

[black'n'yellow]

Can I not just replace the whole chainset (rings and crank arms) for a compact as long as it fits on my bb?

yes - the Stronglight chainset which I described in my previous post.

 

[Markymark13]

yes - the Stronglight chainset which I described in my previous post.

Thanks, will take a look.

 

[Markymark13]

Just had a look at the stronglight, is that a better option that the shimano 2350 or the fsa Vero? I have seen these new for £35 and £55 respectively (both reduced apparantly)

 

[black'n'yellow]

I personally like the Stronglight stuff, but TBH, if you can get the Vero or 2350 for those prices, I would go for it - there's not going to be a lot of difference and the price is pretty much a no brainer...

 

[jay clock]

I had a Stronglight and thought it was made of soft alloy. But reasonable quality bit of kit. Spa cycles do them

 

[Rob3rt]

Quick suggestion, why not change the cassette, the 5 tooth difference on the small ring between your current chainset and a compact is in equivalent terms, just over 1 tooth extra on the rear, so if you can get an 8-spd cassette with a more teeth then you are laughing! However the rear mech may be a boundary here, worth checking the spec's IMO though. Easier to swap between cassette's than chainrings of you are going to alternate.