Adding a longer RD to a Tiagra 10 spd bike to be able to use a much wider range cassette

[Spiderweb]

You can buy a wolfs tooth derailleur hanger extender which will massively extend the range of your cassette.
There are cheaper brands available too eg. Sunrace etc.

 

[Dan Lotus]

Thanks all, appreciate the invaluable knowledge, input, experience and opinions, HUGELY appreciated :-)

Theoretically at 161cm, she is marginally small for it, however as her mum is 173cm, and I'm 178, I don't think she will be growing that much taller, so I'd like to think as an 'occasional' bike, I could probably make it fit with a longer stem etc, as long as she doesn't get incredibly tall.

I'm going to do a bit more mulling, and then make a decision on it soon.
I'm flying out there in Easter half term with her, so it would be a nice surprise if it was waiting when we got there - all be it a job to change the cassette out and RD etc - I have some basic tools out there, but enough for that job.

 

[Dan Lotus]

You can buy a wolfs tooth derailleur hanger extender which will massively extend the range of your cassette.
There are cheaper brands available too eg. Sunrace etc.

I have tried those before, maybe I was unlucky, or inept, but I was unable to get it work efficiently - that was on a 105 5700 setup.

 

[Spiderweb]

You will need a longer chain too.

 

[roubaixtuesday]

You will need a longer chain too.

Possibly, but maybe not - 6 teeth more is only 1.5 links of chain (two teeth per link, and only wraps half way around). So unless the current chain is right on the limit for big/big, it could well be OK. Though it's not a bad idea to replace it while you're at it anyway

 

[Dan Lotus]

A quick search in the garage tonight has unearthed a new Ultegra 10spd chain, theoretically my partners bike might need it, but I changed it a couple of years ago when I added an 11/34 cassette to her bike, so I don't think that's going to need to be changed anytime soon - she doesn't ride it very much :-(
I also found a short Specialized stem, I recall I bought it 2nd hand ages ago for some project (Might have been when I was trying to finesse my position), but never used it - it's probably 60mm, but has those adjustable shims that allow you to change the angle, not sure how it works, some kind of black magic, but I'm thinking that the chances are it might be a little bit of a stretch for her to start with, so this way I could drop the bars down a bit if required, and bring them closer to her.

So currently, it just looks like I need the RD and a 10spd cassette, the RD I can get from Halfords for £23 after BC discount and work savings card thingy, but they want £39.99 for the 11-34 cassette, so will have to source that elsewhere.
Tredz are favourite currently (£23.99), who are part of the same company as Halfords 😕