Going from 12-26 cassette to 11-34

I'm thinking about changing from the SRAM PG950 12-26T cassette to one that is 11-34T (brand or model not picked yet). The thing is that I find the 11-34 cassettes in the MTB sections of catalogs, not the road bike sections. Would there be any problems replacing my 12-26 cassette with an 11-34? I live in a fairly hilly/mountainous area and could use a lower end. I don't want to go to a triple crank. Oh, and any recommendations on brand/model number of cassette would be much appreciated. Thanks!

Well, that depends on the equipment you're riding with.
I assume shimano 9 speed? 9s MTB cassettes do fit on your hub and the spacing is the same, but a shimano road-rear-der can take a 27 tooth as maximum officially, although a 28 will work fine. Anything higher than 28 will NOT WORK!!
But I think personally that a 39x28 is light enough, it's the same as a 30x22.
If that's not low enough, you could consider the possibility of changing the cassette and also changing the cranks for compact cranks, that can take a 36 of even 34 chainring.

Actually, I'm in the process of changing to an FSA Pro Elite Compact 50-34 cranks. I'm going to see how that goes with the current 12-26 in the rear and my local hills/mountains. Hopefully that'll be enough. I posed the question here to gather info for the contingency plan.

You are correct; Shimano 9s, so I suppose that I can't go beyond 28. If I still need more after changing the cranks, then I'll look to changing to something like a 12-28 or 11-28 configuration in the rear. Thanks for the reply!

BS....they will almost always work with a 30 and sometimes a 32 depending on the appllication.

www.sheldonbrown.com/gears


He also custom-makes cassettes and upto and inlcuding 30t sprockets WILL work with a short cage rear road mech.

Problem is , the bugger wants 100 bucks for the 13-30 cassette which is the sort of gearing i want on my double (have the same problem as you , and my bike was only available with a crappy 13-25 block)

I would try to get the cassette and/or rear mech fixed before touching compacts.You may need to adjust things like BB aswell if you change chainrings.
I'm debating 12-27 cassette but dont think it'll be enough for the climbs i do , so if i dont stump up 100 bucks for a custom cassette the other option is an 11-32 MTB cassette and a new MTB long cage rear mech (the last 2 sprockets on a 11-32 are 28 and 32.Would prefer a 30 to be honest - thats probably 100 bucks too...)

Seems like theres a massive hole in the shimano cassette market for 'alpine' gearing.
Campag have a 13-29 cassette for roadies that i wish i could use.

Still debating what to do , let me know how you get on.

..........and how many bizillion times does it have to be said.Cage length has nothing to do with it. Large cog spec is the same for Shimano road long and short cage RDs derailers. Cage length is about ability to wrap chain, not shift large cogs.But depending on the cog spread,and cahinring sperad one might need a long cage to get sufficent wrap, even with a double.

Are your sure about that? I really think its impossible. The der. pulleys would hit the sprocket, I think.

No problem.Campy will sell you everything you need. There are also compact cranks and triples (Yikes ) .

Danian, have you ever tried calculating your gears?
I mean, a 34x34 can even take my dad up a hill
I think a 34x26 will be sufficiënt, it equals 30x23

The poster did say he/she was going to try the 34x26 first.

I didnt know the reasoning i'm new to road bikes , i was just going by what everyone tells me (ie , needing a new rear mech for higher teeth sprockets) : is it because i have a 53/39 double that i need an MTB rear mech to shift an 11-32 block?

Im still looking for the cheapest way to change my 9spd shimano 53/39 : 13-25 double into something more forgiving for the Pyrenees.
Any ideas?

(i like to ride at 90 rpm , often 100 rpm and spin uphill - a steep mountain that i train on near my parents i go up at about 16km/hr on my MTB , so that's like 39/30 at 100rpm on my roadbike.Maybe can get away with 39/27 as i dont have to worry about suspension forks! but i'd still like a bail out gear for a long climb on a logn day out there)

You have two issues with that 11x32 and 53/39. The MTB dreailer will be a better bet with the 32,and you need a long cage to wrap the chain unless ou avoid a bunch of small cogs when in the small ring. The cheap way is a MTB casette,and RD,but the ratios suck.

Yeah, I calculated it out. I also calculated out my triple crank on my old bike and compared the two. Looks like the gear inches I used primarily on the old bike is equivalent to 34-26. Factoring that and the fact that I'm a stronger cyclist now, the 34-26 set up SHOULD suffice. I was just curious to see if and what I could change if I needed to go that route.

Perhaps the custom 13-30 is the best option then (a standard 12-27 but removed the 12t and has a 30t at the top)

Still seems extremely expensive at 100 dollars when i can buy a 12-27 in the UK quite easily for 25 GBP.

11-12-14-16-18-21-24-28-32 is an MTB 9spd. Whys that suck so much compared to 12-13-14-15-17-19-21-24-27.
Theres no jump too drastic and plenty of cover at both ends for climbing and rolling.
I guess i cant have it perfect both ways.If i was spending all day on the flat i wouldnt have this problem.

You're just guessing.I know. Enuf said?