Seeking advice & opinions on bike upgrade path

LateJunction

I would be grateful for some advice and opinions on updating my 2013 model year Giant Defy 2, small frame, in Giant's ALUXX material. It's fitted with 10 speed Tiagra (4600 or possibly 4500), but with an 11/32 cassette and 50/34 chainrings. Wheels are now Mavic Aksium.


In general, I like the bike a lot as it suits someone of my years (late 70s) and limited bike control skills. It's also commendably light (9.8 Kg with fittings for lights, reflectors, bike computer, flat pedals with straps), but I would like to get a closer fit to my requirements in certain aspects, so wonder if a change of bike is justified or whether I can upgrade the current components.

Here is what I would like to fix:
1. Derailleurs: the Tiagra mechs work OK, but a far from smooth and not exactly quick or light. I would like to change to 105 or Ultegra (but not the 10 speed 6700). Can this be readily done? I assume that both (left and right) brake/levers/shifters would need to be changed; would this also imply the calipers would need to be changed? Can I continue to use the 11/32 Tiagra cassette?
2. If the change to the derailleurs also means a change to 11 speed will I have to change the rear hub/wheel to accommodate the wider cassette? Will the current chainrings work on an 11 speed system? Do I need a new chain too?
3. Weight: having said the current bike is commendably light, I am a little obsessed with the idea that reducing weight further - by switching to a carbon frame (e.g. Giant Defy Advanced) will make it easier for me to get up hills. Am I deluding my self here, and the gains will be marginal at best? For example, when I weighed a carbon Liv Avail Advanced at my LBS it weighed 9.9 Kg!
4. Geometry: I have an awkward physique: leg length suggest I should be riding a medium sized frame; torso and arm length mean I need a small size frame. The result on the small frame is that the cockpit is too low once I have adjusted the saddle for correct leg positioning. It seems to me that the Women's Specific Design (e.g. Liv Avail - or any other brand's WSD) in a medium size would be a better bet.

Would the differences available through the above changes justify the expenditure of 1.5K to 2K pounds on what would be a 5th bike?


Sorry for long post. Comments would be appreciated.

pblakeney

1. If you want. 105 is a pretty good groupset. No need to change the calipers, but they will come with the groupset anyway and it is usually cheaper to buy a groupset than individual components. I doubt you can use a 10 speed cassette in an 11 speed set up.
2. If you go to 11 speed your wheels will be fine but you will need a new chain.
3. You may save some weight but the gains will be marginal.
4. Only you know if you are comfortable.

In conclusion, a new groupset will possibly make gear changes better but won't make going uphill any easier, just closer ratios. A new bike may improve things marginally, buy what you wish. most importantly, use your bikes.

joe_totale-2

Changing the groupset is an awfully expensive way to lose a bit of weight. Maybe a service from your LBS would get it performing better?

A good and cheaper way to lose some weight and increase performance would be to swap the flat pedals and straps with some clipless pedals. Shimano's SPD system is very easy to get used to so there's no reason to worry about it.

svetty

Your bike is now 5 years old. It is likely that the components will have a fair degree of wear. I'd swap the groupset to a new one - with new R7000 you could get an 11-34 cassette. This would make the whole bike smoother and restore that 'new bike' feel as well as giving you a lower bottom gear. Shifting is much improved on the new series gruppos - esp at the front.
After this getting lighter wheels and new tyres would also improve things.....