11-40 9-speed cassette for Sora...

[andyoxon]

mrsao has a bike coming with Sora R3000 (9-speed) groupset, 11-32 & 50-34, & RD-R3000-GS  cage.  I want to fit a larger max sprocket cassette for lower gearing.  I'm aware shimano are quite conservative with their max compatible sizes (34t I think), but wondering if anyone has experience, or thoughts, on whether we could push it to a, say, 40t?

[chrisbainbridge]

What about changing to lower at the front.  I run 46/30 which with a 34 at the back gives me an insanely low gear but 46/11 loses me a minuscule amount of top speed. Easier than messing with out of spec cassettes

[quixoticgeek]

What about changing to lower at the front.  I run 46/30 which with a 34 at the back gives me an insanely low gear but 46/11 loses me a minuscule amount of top speed. Easier than messing with out of spec cassettes

Because that would mean changing the whole chainset, which is a lot more than just a cassette.

J

[robgul]

Rule of thumb is that whatever Mr Shimano decrees is the max - and add 2 more teeth before the mech wont work.

I've been experimenting (recent thread) with trying to get a 42T to work with a Tiagra 10speed triple (that's with a Wolftooth Goat10 hanger extender) - it sort of works in the workstand but not on the road.  I've been running with a max 34T - I'll probably have to settle for a max 36T and put more effort in!

[Duckfoot1606]

Watching this with interest, as i'm seriously contemplating going 12 - 36 on an otherwise stock Sora set up, or possibly higher with a hanger extender. Those lovely folk at Spa Cycles can probably advise on this too?

A

[andyoxon]

OK thanks all.

Sora RD GS is a 34t max.  So 36t should be OK...  11-40t can be had for £25, so could get one of these to test, with a derailleur extender (<£10) just in case.

I guess it's probable that the derailleur may not be able take up all the slack in a chain with 11-40, towards 'small - small'.
So probably 36t doable, 40t may not be ideal...

At least the bike is much lighter (~9kg), than current bike  - though has a triple cs..


ETA.  No real smaller inner chainring options for the Sora FC-R3000 34t, owing to it being a 110BCD 4arm.  I suppose a 46-30t square taper would be an option. 
ETA 1.  I have a M591 Deore 9 speed in the cupboard, but despite being an SGS max sprocket is officially a 34t, as with the Sora.

[iandusud]

I think what you're suggesting sounds like a good idea. I think that you'll need the extender but assuming that you're running a 34/50 chainset you need a rear mech capacity of 45t. The Sora's stated capacity is 43t so IMO it'll cope comfortably based on my experience of running Shimano rear mechs well beyond their stated capacity (even if it means a bit of slack chain on small/small combinations that I never use).

[quixoticgeek]

ETA.  No real smaller inner chainring options for the Sora FC-R3000 34t, owing to it being a 110BCD 4arm.  I suppose a 46-30t square taper would be an option. 

Iirc the absolute black oval 46/30 rings would fit on this chainset. But that's not exactly a cheap option.

J

[Duckfoot1606]

See here

https://airbike.uk/products/9-speed-mtb-cassette-fits-shimano-sram-11-40t?currency=GBP&variant=39654091784325&utm_medium=cpc&utm_source=google&utm_campaign=Google%20Shopping&gclid=CjwKCAjwg5uZBhATEiwAhhRLHvX-EzAnQM0IbC72zDheP4cwUFDsWzJhqHUQ7zK96cnLB4ueAs_73BoCOgsQAvD_BwE

implies it can be done?.

A

[robgul]

As said - I've been looking at lowering gearing on a Tiagra groupset - the difference in "gear inches"*  between 34 front/36 rear and 34 front/40 rear is only 2.5 .. . . not massive in the scheme of things . . . and can you pedal fast enough to maintain balance 

* a pretty meaningless measurement in my opinion but a reasonable guide to comparison

[quixoticgeek]

As said - I've been looking at lowering gearing on a Tiagra groupset - the difference in "gear inches"*  between 34 front/36 rear and 34 front/40 rear is only 2.5 .. . . not massive in the scheme of things . . . and can you pedal fast enough to maintain balance 

* a pretty meaningless measurement in my opinion but a reasonable guide to comparison

As someone who went from a 28/34 to a 28/40 bottom gear. I can recommend it as a revelation. If you're not someone who can pump out tons of watts on a climb. Cycling at 5kph is entirely doable with this.

J

[andyoxon]

Thanks all.

I think what you're suggesting sounds like a good idea. I think that you'll need the extender but assuming that you're running a 34/50 chainset you need a rear mech capacity of 45t. The Sora's stated capacity is 43t so IMO it'll cope comfortably based on my experience of running Shimano rear mechs well beyond their stated capacity (even if it means a bit of slack chain on small/small combinations that I never use).

The Deore M591 RD 9sp I have is 45t total capacity, so that may be a good option is the Sora is not great.

Found this on YT...

Fitting Guide Shimano 11-40 Rear Cassette Road Bike  They seem to manage it using a 105 50-34 & 105 GS RD.
https://www.youtube.com/watch?v=P5G_KtK3LVk

[Tigerbiten]

As said - I've been looking at lowering gearing on a Tiagra groupset - the difference in "gear inches"*  between 34 front/36 rear and 34 front/40 rear is only 2.5 .. . . not massive in the scheme of things . . . and can you pedal fast enough to maintain balance 

* a pretty meaningless measurement in my opinion but a reasonable guide to comparison

As someone who went from a 28/34 to a 28/40 bottom gear. I can recommend it as a revelation. If you're not someone who can pump out tons of watts on a climb. Cycling at 5kph is entirely doable with this.

J

I use 15% for a "standard" derailleur gear step.
So 34 x 1.15 = 39.1.
So going 34t -> 40t is just over another another full gear down.

Luck .........

[chrisbainbridge]

What about changing to lower at the front.  I run 46/30 which with a 34 at the back gives me an insanely low gear but 46/11 loses me a minuscule amount of top speed. Easier than messing with out of spec cassettes

Because that would mean changing the whole chainset, which is a lot more than just a cassette.

J

Possibly would need new cranks if the Sora was not 5 arm standard size. Possibly still cheaper and easier.

[BFC]

What about changing to lower at the front.  I run 46/30 which with a 34 at the back gives me an insanely low gear but 46/11 loses me a minuscule amount of top speed. Easier than messing with out of spec cassettes

Because that would mean changing the whole chainset, which is a lot more than just a cassette.

J

Possibly would need new cranks if the Sora was not 5 arm standard size. Possibly still cheaper and easier.

And check the mount for the front mech has enough adjustment (braze on) or round tube available.... Braze on are the most restrictive normally. Angle of cable entry into the front mech is also affected, but moving lower on the seat tube usually reduces problems with stiff upshifts.

[trundle]

mrsao has a bike coming with Sora R3000 (9-speed) groupset, 11-32 & 50-34, & RD-R3000-GS  cage.  I want to fit a larger max sprocket cassette for lower gearing.  I'm aware shimano are quite conservative with their max compatible sizes (34t I think), but wondering if anyone has experience, or thoughts, on whether we could push it to a, say, 40t?

I have Sora R3000 on my Triban. I ran 12-36 fine with the B-screw wound in with the medium cage and no extender. There were no issues on all manner of rides up to 200km audax.

I've since added an extender so that I can swap to 11-40 for very hilly rides. I ran 11-40 on Up the Downs 200km audax from Reading with 2500m climbing, and the 34/40 was wonderful up the steep stuff.

This will no doubt teach you to suck eggs - but trying to change 50/40 even accidentally will probably eat the hanger/derailleur on normal chain length.

At the moment it's running 12-36 which works for 95% of my riding.

[Tigerbiten]

Ok. Silly idea for a custom cassette.
From what I can see, the 11-42 cassette has the same middle sprockets as the 12-36 cassette.
So take x-36 sprockets off the 12-36 cassette and replace them with the x-42 sprockets off the 11-42 cassette.
That keeps the nice even spaced gears at the top end of the cassette while giving you a granny and a super granny at the bottom end of your gears where the bigger steps don't matter as much.

Luck .......... 

[De Sisti]

Ok. Silly idea for a custom cassette.
From what I can see, the 11-42 cassette has the same middle sprockets as the 12-36 cassette.
So take x-36 sprockets off the 12-36 cassette and replace them with the x-42 sprockets off the 11-42 cassette.
That keeps the nice even spaced gears at the top end of the cassette while giving you a granny and a super granny at the bottom end of your gears where the bigger steps don't matter as much.

Luck .......... 

So, what will the sprocket combination be?

[Tigerbiten]

Ok. Silly idea for a custom cassette.
From what I can see, the 11-42 cassette has the same middle sprockets as the 12-36 cassette.
So take x-36 sprockets off the 12-36 cassette and replace them with the x-42 sprockets off the 11-42 cassette.
That keeps the nice even spaced gears at the top end of the cassette while giving you a granny and a super granny at the bottom end of your gears where the bigger steps don't matter as much.

Luck .......... 

So, what will the sprocket combination be?

Starting from 12-14-16-18-21-24-28-32-36 and 11-13-15-18-21-24-28-34-42.
The biggest 3 or 4 sprockets tend to be riveted together in a cluster.
So swap the clusters between the cassette
Plus the odd sprocket as needed if the clusters don't have the same number of sprockets.
That will give you 12-14-16-18-21-24-28-34-42 as the working cassette.
A range of 21.8"-112.5" with a compact double.
46t capacity range, which a long cage derailleur can just do if you don't use small-small.
You will need a mech extender to cope with the 42t sprocket.

The other cassette ends up as 11-13-15-18-21-24-28-32-36.

Luck ........... 

[ElyDave]

I'll  take the 11-36 please

[andyoxon]

UPDATE.     (had forgotten about this thread)

mrsao's new bike came to pass and has:
Sora (9sp) Medium rear & front mechs
FSA Vero Pro 48/32 cs
11-34 Shimano cass

Also short of low gearing as expected.

I've ordered a 11-40t cassette to try take a punt with, plus a Deore M591 SGS 9sp (I have on the shelf) if necessary.  Also long B-limit screw waiting in the wings.
Couldn't find a 9sp 90mmBCD 30T inner for the FSA cs, just a 10/11sp - not sure if this will work(?)

Any thoughts appreciated...

[grams]

The differences between 9/10/11 speed on front chainrings are microscopic to non-existent. The little ring especially so.

[iandusud]

UPDATE.     (had forgotten about this thread)

mrsao's new bike came to pass and has:
Sora (9sp) Medium rear & front mechs
FSA Vero Pro 48/32 cs
11-34 Shimano cass

Also short of low gearing as expected.

I've ordered a 11-40t cassette to try take a punt with, plus a Deore M591 SGS 9sp (I have on the shelf) if necessary.  Also long B-limit screw waiting in the wings.
Couldn't find a 9sp 90mmBCD 30T inner for the FSA cs, just a 10/11sp - not sure if this will work(?)

Any thoughts appreciated...

A Wolf Tooth hanger extender (or clone £2.99 on Ebay) might be all you need. I think this a better option than fitting a longer B screw as you get more wrap around on the cassette teeth.

[Duckfoot1606]

UPDATE.     (had forgotten about this thread)

mrsao's new bike came to pass and has:
Sora (9sp) Medium rear & front mechs
FSA Vero Pro 48/32 cs
11-34 Shimano cass

Also short of low gearing as expected.

I've ordered a 11-40t cassette to try take a punt with, plus a Deore M591 SGS 9sp (I have on the shelf) if necessary.  Also long B-limit screw waiting in the wings.
Couldn't find a 9sp 90mmBCD 30T inner for the FSA cs, just a 10/11sp - not sure if this will work(?)

Any thoughts appreciated...

A Wolf Tooth hanger extender (or clone £2.99 on Ebay) might be all you need. I think this a better option than fitting a longer B screw as you get more wrap around on the cassette teeth.

Apologies for the hijack, but would a derailleur extender like this act as a sacrificial link/derailleur hanger on a frame not already equipped with such a component?

Tks

A

[LittleWheelsandBig]

I don’t know of any hanger extender being designed to fail earlier than the integral frame hanger. It would just be down to luck. Extenders are usually designed for stiffness, to maintain shifting accuracy.

Aluminium breakaway derailleur fixing bolts used to be popular.