Shimano 105 5750 compact question

[andsaw]

Can someone tell me what the correct BCD is, as i was on planet x and their same crankset is showing as BCD130 i was told the standard 105 is 130 and the compact is 110, i pulled up the Shimano technical docs and it shows as 110 but planet x said its 130, is it possible to have a the compact as 130.

 

[smokeysmoo]

is it possible to have a the compact as 130.

Nope, LINKY.

Standard = 130mm

Compact = 110mm

 

[andsaw]

So why would planet x say the mechanic has measured it and saying its 130, i said are you sure your not measuring the standard, im not saying your wrong Smokeysmoo i think planet x are wrong as well.

 

[smokeysmoo]

So why would planet x say the mechanic has measured it and saying its 130

Dunno

I'm not saying your wrong Smokeysmoo I think planet x are wrong as well.

I know I'm right fella Perhaps it's in the description, a compact is after all a double, but compact and standard double rings are not compatible.

 

[Nigelnaturist]

You can't fit a 34th ring to a 130BCD, the smallest you can is 38th, also you can't fit smaller than a 34th to a 110BCD (though I did hear a 33th might fit).
However it is possible to fit 38/52th to a compact 110BCD

 

[andsaw]

This is what they are advertising http://www.on-one.co.uk/i/q/CSSHOEM105/shimano-105-fc-5700-10-speed-chainset-(without-bb) and http://www.on-one.co.uk/i/q/CSSHOEM105750/shimano-105-fc-5750-10-speed-chainset-(without-bb) so whats the difference.

 

[youngoldbloke]

This is what Shimano say - 110mm

(the new 5800 is 110mm all varieties!)
edit - deleted the link as it wasn't working - but the techdocs/dealers manual shows 110 for the compact, 130 otherwise

 

[Nigelnaturist]

This is what they are advertising http://www.on-one.co.uk/i/q/CSSHOEM105/shimano-105-fc-5700-10-speed-chainset-(without-bb) and http://www.on-one.co.uk/i/q/CSSHOEM105750/shimano-105-fc-5750-10-speed-chainset-(without-bb)

Nothing wrong with the first one. The second is wrong in the details about it being a 130BCD, I came across something like this when I bought some R.A.M. a few years ago, with a lot sites the info is just taken from feeds with very little (if any) checking, I think @SatNavSaysStraightOn might be able to confirm this, however if it comes with 50/34 chainrings it will be a compact 110BCD.
Another thing if you look at the weights, they are the same, the compact should be lighter having less metal work involved, for the record my Spa triple is about the same weight at 740g.

 

[Nigelnaturist]

@youngoldbloke try using this link instead of one from your computer.
http://si.shimano.com/php/download.php?file=pdf/um/SI-1M30A-003-ENG.pdf.

If its advertised as 50/34 its a compact double (you can get compact triples), 39/52 its a normal double, so I would go off the rings.

 

[youngoldbloke]

thanks - less confusion in future with the new series chainsets - but no triples?

 

[Nigelnaturist]

thanks - less confusion in future with the new series chainsets - but no triples?

I know a bit of retro step, though campagnolo re-introduced one I believe (don't know much about them though), where does it leave the likes of quality touring bikes, my set up is a 50/38/26 with a 12-27 I can change that around a lot to a 12-23 and still have the same range as a 50/34 12-30 which much better ratios, unless doing more than 3-4% hills at 90rpm I hardly go lower than a 38x24, that doesn't mean I don't use the inner 26th I do spinning up hills where I have 1th steps between the gears instead of some huge 3 and 4 th gaps.
For the record my current set has a range of 25.3-109.6" on the 12-23 it would be 29.7-109.6" then same as my 52/40/30 12-27 was apart from 4-5" at the top end, the same compact 50/34 would need a 12-30 29.8-109.6" as for weight, I haven't done the maths, but again small cogs on the rear might compensate.
Sorry if this is side tracking a little.

 

[andsaw]

@youngoldbloke try using this link instead of one from your computer.
http://si.shimano.com/php/download.php?file=pdf/um/SI-1M30A-003-ENG.pdf.

If its advertised as 50/34 its a compact double (you can get compact triples), 39/52 its a normal double, so I would go off the rings.

That's the same document i looked at, don't know whats happened to the other link but it this one http://www.on-one.co.uk/i/q/CSSHOEM105750/shimano-105-fc-5750-10-speed-chainset-(without-bb)

 

[Nigelnaturist]

@andsaw it cover all three chainsets, 5700/2703/5750 the first being the double, the next the triple and the third the compact double.
Further to the campagnolo triple they do one in the Athena groupset on an 11sp so maybe Shimano may follow possible on the Tiagra next upgrade.
http://www.chainreactioncycles.com/campagnolo-athena-triple-11-speed-ergos/rp-prod127483
cassettes are not cheap though.