Which cassette for SHIMANO Deore 48-36-26 crankset

grifterxl

Hi - new guy here.

Looking to replace my suntour sr chainset with the above deore with 48 - 36 - 26 gradiation.

I will also be replacing the cassette and chain but I am unsure which cassette configuration to go with regarding the number of teeth knowing as little as i do about gears. The cassette i am looking at comes in the following gradiations

11-28 (11-12-13-14-16-18-21-24-28)
11-32 (11-12-14-16-18-21-24-28-32)
11-34 (11-13-15-17-20-23-26-30-34)

Which would be most suitable for the chainset i will be buying, or what would be implications of each be gearwise?

Thanks

cooldad

Google gear calculator and you can work it all out.
But what is on there at the moment? What you are looking at is a trekking style, so if you are replacing a mountain bike style, you will probably need to raise the front mech, or even replace it, possibley even the rear. And a new chain.
Suitability also depends on what you ride, where, and your style, spinning or pushing big gears.

grifterxl

Hi

Existing chainset is a suntour sr 42 34 24 - this is a for 2nd hand 20" kraken which i am looking at renewing as i go along but the chainset is kinda spongey, noisey and also has a bend in the outer ring i think.

I previously had a 15 year old bike with bigger chainset and longer arms and it just felt more powerful than this bike so i am wanting to emulate that feel from the older bike. Its pretty flat where i live and i mostly ride on the occasionally muddy path with only gentle climbs.

The Rookie

Do you run out of gears at speed? If not you don't need the bigger chainrings. 44/11 should see you hitting about 35mph easily.

You may have clearance issues with the larger inner chainring, how much clearance do you have now?

I doubt your old bike had longer arms, 175mm is very much a standard.

Giraffoto

As stated above^ - if you're not spinning out to 120rpm+ in your top gear. don't bother. If you're desperate to change something, go with the 11-28 cassette: this will give you some of the same effect of slightly higher gears as bigger chainrings, but will require fewer other changes. And if anything else felt "more powerful", make sure everything's running smoothly on the bike and then check the engine . . .

grifterxl

Hi

Thanks - I have taken on board the advice and decided to get the deore 44 - 32 - 22 chainset .

So the 11 - 28 cassette would be the one to go for with the bike being used on the flats? are there any possible incompatibility issues with existing parts if i change cassette size?

cheers

Chunkers1980

Nope, I'd go with 11-32 better range and a lower one should you need.

cooldad

I agree with ^^^^^.
You get the same highest gear with all of them, just depends whether you want lower gears or not.
As long as you are swapping out for a 9 speed cassette everything should work fine.
Also depends which Deore chainset. If it's HT11 you should have the BB bracket faced. You'll also need the right tools.

grifterxl

it's a SHIMANO Deore crankset Hollowtech II FC-M591-S

I have already been told that the frame would need facing for the external bb. I plan to have lbs do this bit and perhaps then fit the chainset myself after swatting up on tutorials
would it be possible to take the bike to the shop minus original crank for them to face frame or would they need the new crank to work off?
What does facing the frame involve and why is it needed?
thanks

cheers

The Rookie

Remove the old cranks and BB, an LBS will then charge £10-15 to face it, leave them in and they'll charge to remove them, often worth getting your BB tools for the bearinsg and preload as my LBS rights most it off against the cost of the facing so it ends up cheaper than buying online.

grifterxl

The Beginner wrote:

Remove the old cranks and BB, an LBS will then charge £10-15 to face it, leave them in and they'll charge to remove them, often worth getting your BB tools for the bearinsg and preload as my LBS rights most it off against the cost of the facing so it ends up cheaper than buying online.

sorry do you mean get the bb tools from the lbs?

also what exactly is facing and why is it needed?

thanks

The Rookie

Yes get the tools you need to fit the HT2 from the LBS (unless you already have them.....)

Facing is to make sure the axle runs square through the bearings, if the ends of the BB shell aren't square, as you do the bearing up it will tilt, then the axle doesn't run square through it and it wears about rather quickly...it doesn't matter with cartridge bearings as they are held square by being supported on both sides of the BB shell.

grifterxl

thanks.much appreciated