Need Lower Gear Ratio - Best Method?

kmahony

Hi,

I'm currently running Shimano 50-34 & 12-27 with short cage (10sp Ultegra)

I know to most of you, this will seem more than ok, but I'd love to have a couple more teeth.

What's the best way to do this:
- Fit 12-29 (will the rear mech work?)
- Fit 12-29 and long rear mech (do they do medium?)
- Change front ring to 30 (will front mech work?)
- Lose Weight???

(I'm about 100kg and did 3 HC/Cat1 climbs in the Alps last weekend and off to do Ventoux in September - I can make it up without walking, but I think 1 or 2 more teeth will make it more enjoyable!!!)

thanks

Monty Dog

Dunno about Shimano rear mech capacity, but to fit a larger cassette sprocket you'll probably need to fit a long arm rear mech.
Don't think you can fit anything smaller than a 34 tooth chainring to your 110mm PCD chainset - smaller chainrings will require a triple where the third ring in bolted seperately to the inside.
The fact that you can make it up these hills is a good start and perhaps a winter of training will help with the weight-loss and fitness - should mean that you'll be strong enough without the kit changes for next year?

xbenhanleyx

Hi

You may struggle to get more than 28 on the back with a road bike mech and you will definitely need a long cage. A 29 may just work, but I would take it to your local bike shop and see what they can do, as you will need to be fairly spot on with the chain length. My girlfriend was on a similar set up with a 12-26 and I fitted a cassette with a 12-32 cassette and a Mountainbike (e.g. Deore) rear mech and it works a treat - the mountain bike mech gives you more clearance for the bigger cogs. Alternatively you could go for a triple, but depending upon what you have already, this may mean a new front mech, bottom bracket and STI.

Otheriwse keep training and you'l only need the 34-27 for the real steep hills!

Ben

aracer

A long arm rear mech won't help with fitting a bigger sprocket, as the parallelogram angle is the same on both long and short cage mechs. You'll need an MTB mech to clear a bigger sprocket.

However your bigger problem is that you can't put a standard sprocket in the last position on 10 speed as that sprocket is dished, and Shimano don't make anything bigger than a 27. Fortunately Marchisio comes to your rescue with a 30T last position sprocket - you could put this on the back of your existing cassette and remove the 16.

aracer

...oh, but you'd then need a different spacer between the existing cassette and the 30 sprocket...

bryanm

This thread is exactly my current predicament! Casstte (and probably hub), chainrings, STI's, derailleurs - I'm beginning to think I should either buy a new roadie and spec it with the gears I want, or just take the MTB out on slicks when I know the route is going to be too hilly!

nick hanson

Without being cheeky,yes,a bit of weight loss would help loads.
Just a few kilos will be like having a lower gear.
Plenty of long,steady rides will shift the weight.

maddog 2

or fit a different chainset..............?

like the Middleburn Duo

small riing 29 or 32
big ring 42 or 44

http://www.chainreactioncycles.com/Kits ... delID=3345

Stronglight also do a similar one

http://www.spacycles.co.uk/products.php ... 2b0s109p43

Jonathan Mcp

But if the guy is riding Ventoux in september, he doesn't have much time to achieve a decent weight loss.

I'm a confirmed triple fan. OK, more weight than a compact, but in terms of the scenario the OP describes, it allows me to use an 11-23 cassette for nearly all my riding, but then allows a cassette swap for the hills, to say a 13-25, or even down to a 28 (campag 9 speed).

Also means that I can have as wide or a wider range of ratio's than a compact without the big jumps in the ratio's on the cassette.

But going triple is probably the most expensive route to take.

kmahony

Thanks for the replies. All useful.

Taking it from the chainset side, does anyone know if it's possible to swtich the inner chainring with a smalller one from the triple range.

For example, swap the 34T from my compact:
http://www.chainreactioncycles.com/Mode ... elID=18488

with the 30T version the triple:
http://www.chainreactioncycles.com/Mode ... elID=18487

I'm guessing shifting won't be good, but would it work and would there be any chain issues? This is only a short term option for this trip - I'll be lighter next year - honest.

As I mentioned, made it up the Joux Plane and the Colombiere last weekend, but my cadence was very, very low at times.

aracer

Unfortunately, as Monty Dog already said, 34 is the smallest you'll get on your current chainset. To get a 30 you'd need to use a different chainset (a triple or a MTB compact double).

maddog 2

110 bcd will actual stretch to 33

but nobody makes them............... :roll:

this tells you all you need to know

http://www.sheldonbrown.com/gloss_bo-z.html#bcd

aracer

Hadn't realised 33 was possible. According to http://www.specialites-ta.com/images_tech/techRte.pdf TA do make one - and indeed Sheldon sells it http://harriscyclery.net/itemdetails.cfm?ID=1420

ut_och_cykla

As a chubby 40 + girrly I LOVE tripples - not much help for you but when I bought my TREK 1000 I specced a triple and a MTB deralier (Shimano). When I 'did' the Alps this summer I swapped rear cassette for a knee saving 32 which allowed me to make stately progress for HOURS!
And yes for hilly things a slick kitted MTB is an acceptable way to go, as slow speeds are less affected by wind etc. I did it for Ventoux.
Good luck and enjoy ... and perhaps it will be a spur to help you lose a few pounds? It was for me

acorn_user

10 speed is a problem here. There are two Shimano 10 speed cassettes with ca.32t rear cogs that I know of. Shimano makes one for Tandem company Santana, and Interloc Racing Designs (IRD) makes another. YOu'ld need a long cage mtb rear mech and a new chain. If you want to go triple, you could simply buy a cheaper but nice touring triple like the Stronglight Impact. Alternatively, a few people make "tripleizer" rings for doubles; Stronglight, TA and IRD are the ones I can think of. You'ld probably need a new front mech for that, and maybe new shifters.

If only you had bought Campag; then you could have had a 29
[meant in jest everyone!]