So, I’m currently running a 11-26 on a compact system on my road bike. I’m pretty comfortable with this, apart from I’m running out of gears on steeper climbs and having to stand out of the saddle. While this is fine and isn’t really a problem, I’m planning on an Alps trip over the summer and want to do some big hills (alpe d’huez etc).

Has anyone swapped out their cassettes and exp, benefits, disadvantages? Was thinking 11-28. or 11-32. I’m assuming a mtb cassette is the same as a road one right?

Cheers

It is, but if you fit anything bigger than a 28t (or 30t if you’ve got SRAM Wi-Fli), you’ll need a new rear mech to be able to cope, and the associated issues of matching your mech and shifters!

You’ll have bigger jumps, which you may, or may not, find annoying. Good idea for a one off trip though.

David Millar, among others, ran an 11-32 XX cassette and rear mech on some stages of the Vuelta last year.

MTB cassette will require an MTB mech (if over 28T).
Alternatively, look at a triple chainset and get as close to 30-42-52 as possible.
Did the Tourmalet last summer and eventually found I was down to 30 chainring and 27 sprocket for the last 2Km.
Needed the 52×13 going down the other side tho’.
Actually had a cassette with 13 14 15 16 17 19 21 24 27
An MTB cassette will have much larger gaps in most of the gears which can be hard work/unlucky on a slog into the wind.

PaulD

Can you just swap the 11t sproket and fit a 28t one on the end after the 26t? Its on a PG1050.
Or are they all fixed as one unit I cant remember? Do you get what I mean?

About to try this myself. I have 8 speed Shimano on the road bike with double at front and got to do a big hilly ride this summer with a mate (for charidee…).

From what I have read you may be able to get away with a road mech with some fiddling with the B screw (I have no idea what that means but will find out nearer the time!) and will probably need a longer chain. If your mech can’t cope then a cheap mtb one will work as long as you make sure it’s compatible with your shifters.

I have Sora 8 speed on my old Spesh Allez – anyone know what cheap mtb mech I can use if I need to swap (and apologies to OP for thread hijack).

probably need a longer chain

You’ll need a longer chain if you plan on going big/big, not if you’re disciplined. You won’t get much additional clearance even tweaking the b-screw.

Alternatively, look at a triple chainset and get as close to 30-42-52 as possible.

anyone know what cheap mtb mech I can use if I need to swap

Any 8 or 9 speed Shimano MTB mech. Deore will be fine. Not 10 speed.
Not quite sure what makes those the perfect ratios, the Dura Ace 7800 ones were 52/39/30 IIRC! Certainly gives you the range, but a triple is far more faff to sort. Needs new chainset and front mech as minimum and potentially BB and STI as not all are double/triple interchangeable, which gets bloody expensive.

For a one of trip I’d say an MTB cassette is the way to go.

Thanks njee20 for the advice. Will find myself a cheap deore mech and try not to be stupid and ride big/big. Latter may be a long shot if I get really tired and lose the plot…

You’re unlikely to be in the big ring at that point anyway 😉

11-28 will be fine in the alps with a 34-50 compact however if you are using shimano 105/ultegra etc you can run a 30 without having to change the rear mech – it works.

I’m carrying way to much weight and made it up all the climbs we did over there with a 11-28. That was based around Alp d’Huez. The Alps don’t tend to be overly steep, just a long drag to get up to the top (there are exceptions to this rule of course!).

As long as you’re reasonably fit you’ll have no problems with a 28 as long as you’re prepared to get out the saddle for short steep stints, this tends to be around the hairpin bends.