New Groupset - Advice Needed (ASAP!)

Secteur

Hi all,

I currently have a triple (50 x 39 x 30) with a 12-27 cassette. It's the old (5600) Shimano 105 system.

I never use the granny (30T) ring, though I suppose it's nice to know it's there. I climb most hills in 39x27 (I.e. easiest gear on the middle chainring), and it's pretty hilly where I ride, if that helps decide.

For various reason I now find myself needing to get a new groupset ASAP, so I need some quick advice...

What compact set would give me the closest approximation to my current triple in terms of gear range. Also, is it true that i won't necessarily lose my 30T granny ring as the easiest gear on a standard compact is similar to the easiest gear on a triple - it's just that on a compact the gears are just more spaced out?

Anyway, I need to order it tonight, ao any advice welcome!

Also, I want white cables - I have heard that gore and jagwire are good - could anyone tell me exactly which set to buy.

I am pretty handy with stripping and building my bike, and this is something I will be doing myself (with your help) so no suggestions of taking it to the LBS!

Thanks.

Secteur

Also, do I need "braze on" front derailleur or not??!

cougie

Look at your seat tube. How does your current front mech stay on ?

Secteur

cougie wrote:

Look at your seat tube. How does your current front mech stay on ?

Like this (but still no idea if this is "braze on" or not):

rolf_f

Assuming you are Shimanoing, the lowest cassette gear you are likely to make work with a short cage mech is 28 (probably 12-28). Anything more and you'll want long cage. I think with long cage you can get to about 32.

Maths is easy enough though. 50/12 is your fastest gear and 30/27 your slowest. With the compact your big ring stays the same but your smaller ring increases to 34 teeth. So to get the same overall ratio you need to work this out.

x/34= 27/30

So it depends on what rear mech you want to use......

The mech is a clamp on. Braze on mechs have a little flange brazed onto the seat tube to which you bolt the mech to (as below). This just clamps on. So now you need to know the diameter of your downtube!

Secteur

Thanks!

I assume that if I now climb all the hills on 39x27, then a compact's 34x27 will be even easier, so I think a short mech / 27T cassette will be more than enough.

Any advice re: cables?!

Wirral_paul

39x27 is a 38 inch gear. The closest gear to this with a 50/34 compact is a 34x23 at 38.8 inch (so almost exactly the same). Given what you say, i'd probably go for a compact with a 12-25 cassette as this will give you an extra bail out gear.

Secteur

Hmmm... quite a bit of googling seems to suggest that the front derailleur in the new 5750/5700 105 groupset is braze on only...

So does that mean I can't "upgrade"?

Hmmm...

EDIT... bit more googling suggests I can convert from clamp on to braze on with one of these;

Wirral_paul

The do seem to be available from what I can see - cant imagine they wouldnt really.

http://www.ebay.co.uk/itm/Shimano-105-5700-Front-Mech-Derailleur-Band-31-8mm-Black-/150835207000#ht_2331wt_1271

Is that the one?

Secteur

That's the one - now all sorted!

Thanks everyone :-)