Moving From Triple Chainset To Double

[jsaipe]

Hi

I'm riding a Cube Peleton Pro (2012) which was shipped with a Tiagra groupset. I am just about to replace the rear cassette (which is worn out) with a 105 10 speed cassette (11-28) as well as a new chain.

The bike was shipped with a triple chainset, but I very rarely use the inner chain ring as I cycle commute every day and my fitness level is good.

I'm therefore contemplating replacing the front chainset with a 105 double compact one to reduce the weight and increase performance.

I've never fitted a chainset myself and I was wondering what issues I might have with the existing front derailleur and gear shifter given that they are set up currently for a triple chainset?

Would these need replacing too? And in the case of the gear shifter can I just limit it rather than replace it?

 

[accountantpete]

You won't get a noticeably increased performance with a 105 chainset but you will get a slightly short Q factor (width between cranks) which is more efficient (we are told).

The front shifter may be ok or it may not - give it a go. I suspect it will work but not as well as a double mech.

With the gears you just use the limiters on the mech - I think Shimano recommend using clicks 1 and 2(granny and middle ring) for the double leaving the 3rd one (big ring) unused.

 

[boydj]

Seems like a lot of money to spend for the minimal performance gain you'll get from the small amount of weight saved. I'm sure there are more worthwhile upgrades - e.g. wheels - if you have money burning a hole in your pocket.

 

[jsaipe]

Good to get your views on this. Maybe I'll hold fire for a while - at least until the current chainset is worn out.

It does beg the question why double chainsets seem to be so popular when they have minimal effect on performance?

 

[jsaipe]

Back on this thread after 6 months, I've decided eventually to change my triple chainset for a double or compact.

Last question, how do I know if the new chainset will fit on the existing bottom bracket? I'm likely to go for one of the following 105's http://www.wiggle.co.uk/compare?ReturnUrl=/?s=105+chainset

 

[User6179]

If the triple is still usable just take off the small ring and you will have a double!

 

[smokeysmoo]

The Tiagra FC-4603 chainset that is on your bike now uses Shimano's Hollowtech II bottom bracket cups.

You can fit any from DEORE through to DURA-ACE when it comes time to replace them. It's a very easy DIY job and the only 'specialist' tool you need is a Hollowtech II SPANNER.

IME any chainset that states it's Hollowtech II will be compatible with your existing BB, although as accountantpete says, your front mech may or may not be..

FYI - RIBBLE usually come out cheapest whenever I've bought a HTII chainset over the last couple of years.

Hope that helps.

PS: I do agree with Eddy though, if your triple is still OK just whip off the granny ring and adjust the limiter screw to 'lock out' the front mech accordingly.

 

[sreten]

Hi,
Remove the granny ring and fit a smaller middle ring if you can.
TBH though your real problem is the rear range is too wide IMO.
rgds, sreten.

 

[Sterba]

My advice, like others here, is...........Do nothing. It's not worth the effort or the cost. Just forget the inner ring is there and spend the time saved doing something more pleasurable, like listening to Tony Joe White singing Even Trolls Love Rock and Roll.

 

[oldroadman]

Quite how removing a chainring which weighs a few grams will "improve performance" is hard to see.
If you have a cassette 11 upwards (why???), 10 speed, 34/50 compact, there will be all the gears you ever need. Just forget the inner chainring is there. Improve performance by riding more and faster!