All I need some info from the hive. I’m hitting the Alps for a few days road riding in a couple of weeks time. As usual with these things i’ve not done as much training as i’d have liked in preparation, and even if I did I doubt any of the hills around me could fully prepare me for what’s to come, so i’m looking to put a different cassette on with some lower gears. I’m currently running Shimano 105 10 speed compact setup with an 11-28 rear cassette. I’m eying up a Tiagra cassette in either 11-32 or 11-34 range. My question is can I run an 11-34 with my 105 rear mech? Not fussed about not running the 34 tooth sprocket with my large chainring, happy to limit my gears to 9 speed when in the big chainring if cage length is a problem.

Thanks.

In my limited experience, the roads are no steeper than in the UK, they just go on much further.

That’s my understanding too – 30km climbs instead of a couple of miles max. But i’m thinking about day 3 and 4 with tired legs, the extra gears might come in handy! The mate i’m riding with is a far better and lighter road rider than me, and an Alps veteran so I will need every bit of help I can get!

We go on the 4th of June, I’m planning on a compact and a 28. Hopefully that should see me up most things.

There’s no heroics in being over-geared, particularly if you consider less oxygen at altitude and possibly temperatures of 30 degrees plus – there’s no real comparison to riding in the UK IME. Sitting and spinning generally produces better results than trying to mash unless you are a fairly strong rider and can ride out the saddle comfortably for extended periods. If you google Shimano tech docs with your rear mech details it should define the maximum cassette sprocket size – this is down to the distance of the upper jockey wheel from the hub centre. If you are exceeding the total mech capacity, then be careful in the big chainring as it is possible to completely jam the transmission i.e. stay out of big ring and sprocket combos

Thanks Dovebiker. I suspect with my mech 28T is already the max. from other reading i’ve done but will refer to the tech specs as you suggest. I have no intention of being heroic and would like to have a granny gear or two in reserve just in case. I can’t imagine i’d be spending much time in my big chainring anyway so have no problems staying out of the biggest one or two sprockets if I need to. I can get up anything with my 28T cassette – there is some very steep stuff near me, just not long, but I know a couple of days in with tired legs then any granny gear I have will be used. I’ll be there for 4 days, riding every day with one ‘big day’ so would rather prepare for the worst. Looking forward to it though.

what front ring are you using? I’ve ridden compact 34t front and 28t cassette on rear on lots of alps trips.

11/34 was fine with my short cage ultegra rear mech.

I’ve run 11-36 with a 105 rear mech (long cage), worked fine. Since used it with a linderet road link – even better.

You may have to watch which gears you are in if you have a short cage on the mech thou (but sounds like you are aware of this)

The UK tends to be steeper but the Alps are longer. I would have thought whatever you run in the UK would be fine. The GF has a Madone and managed a week with the gearing that came with as standard.

There’s no heroics in being over-geared

Aye Sir Brad ran an xt cassette for stage 14 in 2012

Thanks Ianfitz. A long time ago when I commuted on an MTB I put a 105 mech on off my old knackered roadbike so am aware that I probably won’t have access to all chainring/sprocket combinations, that’s fine with me, like I said, I don’t think i’ll be spending much time in the larger ring.

Nipper – I take it you were running a compact chainset? what limitations did you have on gears?

I have a CX bike ( 35mm off road tyres) that was running 36/46 chainring and 11-28 cassette and I always felt I was pushing to high a gear,put a 11-32 cassette on and found it a lot better. I live in the alps so know how the long climbs just grind away. I ride mountain bikes more than road so maybe I’m just soft 🙂

If you google Shimano tech docs with your rear mech details it should define the maximum cassette sprocket size

which isn’t worth the paper it’s not written on. Shimano have under-rated their maximum for years, a quick google will give you hundreds of people happily, reliably and safely using larger cassettes than Shimano suggest is possible. When they increased the range of the short cage they did nothing to mech itself…

A short cage will work with a 30T – I’ve done it – but 32 or 34 will be too much.

I’m going to the Dolomites this summer with the missus and we’ll both be riding compact and 28T cassettes.

Aye Sir Brad ran an xt cassette for stage 14 in 2012

with a standard, not compact chainset?

I’m in the Pyrenees at the moment. The hire Giant TCR I’m on is 11-32 and is ok with fresh legs for everything. However the difference is the length of the climbs. I live in ‘hilly’ Yorkshire and thought I’d be ok as after all I’m used to the Cow and Calf etc. The hills out here are not as steep as you get in the UK but it takes some getting used to the fact that for 10 miles you will not do anything but pedal up a 7% + gradient.

IMO first day do 1 col and build from there, your legs do get more used to it.

with a standard, not compact chainset?

can’t tell 😉 , IIRC i did read somewhere part of the reason for the xt cassette was no “smaller” oval rings were available, but it kind of misses the point.

Standard (SS) 105 10speed mech is rated to 30 tooth but many report getting it to work on 32s or even 34 but I think you’ll need to be a pretty good gear fettler.

I use the Ultegra 12/30 cassette in the Alps and I do use the 30 quite a bit.

So I would say If your basically fit not overweight and just want a decent range of gears get a 12/30 for £30 quid, if your worried and want proper baliout gears get a 12/34 or 36 and a (GS) rear mech. If your not planning any massive days or happy to take your time stick with the 11/28 dont worry about it.

I think i’ll pump for the 32T cassette, the 34 might be too much of a stretch. I’ve read varied reports from people – some say you can’t fit a 32 or 34 and some say they have without a problem. I’ve got 4 days there – the first day is a warm up ride, the 2nd day is a ‘big day’ in my mates words, so i’m assuming an 80-ish mile ride and a good couple of thousand metres of climbing, which will be stretching me to my limit – i’ve done the distance before but not with the amount of climbing. I’ve done 1800 metres of climbing before but only over 30 miles.

I love a good climb but not built for it but will give it a good go.

You’ll be fine have a good’un.