Cassette Upgrade on Giant Defy 2

squa

Hopefully some bike experts might be able to help me out with some advice!

I'm planning some Alpine cycling during the Summer & would like to upgrade my cassette from the existing 11-30 to 11-32 or even 11-34 if possible. My existing groupset is the stock Shimano Tiagra 10 speed that comes with the Giant Defy 2 (2015)......I'm pretty sure it's the Tiagra 4601 model. I measure the cage on the rear derailleur this morning & it appears to be 60mm, but I'm not sure if that's classed as medium or large. So, my question really is if my existing derailluer will be able to accommodate a 11-32 or 11-34 with just some adjusting to the B position screw? Or do I need to change the rear derailluer to be able to accommodate the bigger gear & provide the clearance needed?

I don't plan on changing the wheel and/or groupset to accommodate an 11 speed cassette, so I'll stay with 10 speed & was thinking something like this would do the trick;

http://www.wiggle.co.uk/shimano-tiagra-4700-10-speed-cassette-11-3211-34/

Thanks in advance for any advice/suggestions!

Squa

benneca1

That is a short cage if it is 60mm centre pulley to centre pulley you need at least  a medium if you go the way you intend. A tiagra on wiggle is about the same price as the cassette. Factor in you'll need a new chain and cable inner. If you want it to work well is change the last section of outer also.

Zen0

Shimano techdocs here

http://bike.shimano.com/media/techdocs/content/cycle/SI/SI_5XN0A/SI-5XN0A-001-Eng_v1_m56577569830746860.pdf

suggest that the max capacity of both the short and med cage 4600 rear derailleur is 30 teeth on the cassette. The med is intended for a triple iirc. You may need a different derailleur, but now you are into finding a model with the same pull ratio. Google can help there. I think 9 speed Shimano mountain bike RDs have the same pull ratio, but I wouldn't swear by it. Not everyone wants to put an MTB RD on their road bike. That's definitely fred territory, although I'd regard it as smart-fred rather than mad-fred.

Or you could try squeezing in a 32.

squa

Thanks for the feedback everyone.

I think the quick fix might be to just go for the 32t & see if it will fit! According to the Shimano Tech sheet neither the short nor medium cage RD will take anything more than 30t, but I guess that's just keeping it well within the manufacture's tolerances.

I might make a trip to my LBS tomorrow & see what they say? I hadn't planned investing a lot in this particular upgrade, as I want to buy a new saddle & some carbon shoes too!

Eamonnator

http://soshanger.com/PILO-Alpe-DHuez-FairyS14-adapter-for-road-rear-derailleur-and-upgraded-cassette

Eamonnator

http://soshanger.com/PILO-Alpe-DHuez-FairyS14-adapter-for-road-rear-derailleur-and-upgraded-cassette

If it doesn't work, you might try one of these.
I put a 32 cassette on my bike, using one of them with a Sram Red rear mech.
It works perfectly.
It or something similar may be available elsewhere cheaper.
BTW I tried the 32 cassette before I put on the Alpe Fairy. It was not a success.
However Shimano may be different to Sram.

squa

Thanks Eamonnator, that's a really useful workaround. Great to hear that you have actually tried & tested it also.

From reading various posts online, there doesn't appear to be a whole lot of difference between Shram & Shimano setups in terms of dimensions etc. I also inspected my RD this morning & there is very little clearance as it is between the lowest gear & the top of the DR. So if I'm being truthful with myself I don't think a 32t will work without some change to the RD setup.

Did you have to make many adjustments to your setup once the Alpe Fairy was fitted or was it just a matter of re-indexing the gears & away you go?

Eamonnator

I didn't even have to adjust gears, however, I think I may have been lucky in that I had a good length of outer cable between the cable stop and rear mech. I'm not sure, but I reckon, if the outer had been much shorter, I would have had to replace that section of outer cable with a longer one and installed a new inner cable.

squa

Will keep that in mind.........thanks.

G1032

http://www.bikeradar.com/road/news/article/relic-mtb-40t-road-extender-49508/

squa

Thanks G1032........probably a bit more than I had intended to upgrade to, but 40t would definitely make a difference on those Alpine hills!!

squa

For anyone that might be interested, I completed this DIY upgrade earlier & it appears to have been successful. I say "appears" because I have not yet actually cycled the bike, but since the gears indexed successfully after the update, I don't really foresee any problem once I get on the bike.

In the end I went with a 11-34t rear cassette (original was 12-30t) & just fitted the RD extender advised by Eamonnator;
http://soshanger.com/PILO-Alpe-DHuez...raded-cassette

There was no need to fit new inner/outer gear cables as I had enough slack on the existing setup to my RD. I just had to re-index the gears to make sure all cogs were accessible & fit a new chain.

Other than the cassette tool, chain whip & chain break, nothing else was needed other than some HowTos from GCN on YouTube & a bit of time (approx. 2 hours between cleaning, fitting, greasing & just enjoying the job).

I've attached a few photos as evidence, but the RD extender gave plenty of clearance for the bigger cog on the cassette.

Thanks again for everyone's advice, especially to Eamonator.....would still be sizing up a new RD if it wasn't for his advice to buy the extender