Gearing : resolving the 17t - 20t sprocket jump

[hondated]

I am once again wondering whether the gearing I am using is correct for me 44-32-22 x 9 speed 11 -34 as I seem to spin to much. So last night I searched the forum and found the thread I think started by Colin who mentions the jump from 17t to 20 not being ideal so I checked my bikes out today and it seems that's what my triples have got. Unfortunately these two sprockets are part of the cluster so its not possible to change this ratio. so I was wondering if anyone could advise me on a rear cassette that I could buy that would allow me alter the two sprockets I need to change.

[PH]

How often do you use 22 x 34?
I changed last year from a 34 max to a 28, I think I've needed to get off and walk twice since on hills that I might have ridden up on the 34.
For the other couple of thousand miles, I've had a more suitable range of gears for my use.
This isn't a recommendation, I know we're all different, but I thought I'd miss the extra couple of low gears and I haven't.

[whoof]

Do you need the 17" bottom gear? If you can get away with 22/32 which is 18.5" with road wheel then this SRAM 11-32 (£20)goes ;
11,12,14,16,18,21,24,28,32. The 11-28 is probably 11,12,13,15,17,19,21,24,28

https://www.tredz.co.uk/.SRAM-PG950-9-S ... Jc0fD_BwE#

https://www.sram.com/sram/mountain/prod ... gtpi371h4d

[Brucey]

I am once again wondering whether the gearing I am using is correct for me 44-32-22 x 9 speed 11 -34 as I seem to spin to much. So last night I searched the forum and found the thread I think started by Colin who mentions the jump from 17t to 20 not being ideal so I checked my bikes out today and it seems that's what my triples have got. Unfortunately these two sprockets are part of the cluster so its not possible to change this ratio. so I was wondering if anyone could advise me on a rear cassette that I could buy that would allow me alter the two sprockets I need to change.

44T big ring with a cassette that goes 17T to 20T? Yuk! This leaves you with no gear between 60" and 70" more or less (unless you cross-chain 32/13), which is where some folk spend most of their time riding.

BTW if you buy cheaper cassettes they come apart, the sprockets are not on carriers, you can mix and match and you can make up the exact cassette that suits you best.

With a 44T big ring for touring I'd probably vote for a 12-14-16-18-20.....34 cassette and not bother with the 11T. This knocks out the big gap at the expense of the high gear. But you will still be able to pedal at about 30mph and maybe that is high enough...?

http://www.gear-calculator.com/?GR=DERS&KB=22,32,44&RZ=12,14,16,18,20,23,26,30,34&UF=2185&TF=85&SL=2.2&UN=KMH&GR2=DERS&KB2=22,32,44&RZ2=11,13,15,17,20,23,26,30,34&UF2=2185

cheers

[fredN4]

22/34! quicker to get off and push it?

[Tompsk]

22/34! quicker to get off and push it?

Perhaps, but nowhere near as easy to push a bike uphill than ride it.

[BigG]

22/34! quicker to get off and push it?

No it isn't! Even my 22/38 gear (15.6") gives a speed of 3.25 mph at a comfortable cadence of 70. Bearing in mind that this is only used going up a very steep hill. reaching that speed while pushing a bike is much more difficult than continuing to ride. Keep riding whenever possible.

[PH]

22/34! quicker to get off and push it?

No it isn't! Even my 22/38 gear (15.6") gives a speed of 3.25 mph at a comfortable cadence of 70. Bearing in mind that this is only used going up a very steep hill. reaching that speed while pushing a bike is much more difficult than continuing to ride. Keep riding whenever possible.

It's very much a personal decision, I'm quite happy to get off and push from time to time, sometimes even on hills that I could ride up. I have no difficulty pushing the bike at the same sort of speed as many are able to ride and although I've seen the figures to prove it's always more efficient to pedal, for me can feel like less effort.

[531colin]

I am once again wondering whether the gearing I am using is correct for me 44-32-22 x 9 speed 11 -34 as I seem to spin to much. So last night I searched the forum and found the thread I think started by Colin who mentions the jump from 17t to 20 not being ideal so I checked my bikes out today and it seems that's what my triples have got. Unfortunately these two sprockets are part of the cluster so its not possible to change this ratio. so I was wondering if anyone could advise me on a rear cassette that I could buy that would allow me alter the two sprockets I need to change.

My old thread about merging 2 cassettes is here.....https://forum.cyclinguk.org/viewtopic.php?f=5&t=54328&hilit=nightmare
The 2 cassettes I merged are both 9 speed HG50, which don't have the fancy carriers for multiple sprockets.
One is a "Tiagra" 13 to 25 teeth (for junior racing with restricted gearing) the other is "Alivio" 11 to 34 teeth.

[hondated]

Thanks everyone

PH not very often so 28 sounds good
whoof - Not really Sram options look good

Brucey Glad you agree about the 17 - 20 jump. Cheaper cassettes sounds good to me.

FredN4 Spot on there

Tompsk I do agree but I dare say like for most of us its the very very last option (unless of cause your on a deserted road where there is no one to witness it )
BigG Had to try and keep remembering that some years ago riding up Alpe Dhuez.
531 Colin its your thread that was my inspiration for starting this thread.

I think initially I am going to fit a 48 - 32 - 22 CS I have sitting in my box of parts and see what that feels like. Thanks again.

[markfh]

A few things you may want to consider:-

1. Modern triple front derailleurs have a shaped inner plate with a lowered portion corresponding to the position of the chain when on the middle ring. This can make them quite sensitive to the difference between the middle and outer rings. Looking at several Shimano 9 speed triple chainsets, the difference is typically 11 teeth (50/39/30) for road chainsets and either 12 (e.g. 44/32/22 or 48/36/26) or 10 (e.g. 40/30/22 or 42/32/22) for 9 speed chainsets. So although putting a 48 tooth outer on may be ok for trial purposes you will probably have to also change to middle chainring to avoid problems with shifting.

2. In addition to the shaping of the inner plate, the shape of the derailleur also reflects the radius of the outer chainring. If going to a larger outer chainring you may need to change the front derailleur as, definitely for Shimano MTB front derailleurs, there are different models depending on the size of the outer chainring, e.g. 44/48T or 40-42T. Although you may be able to raise the mounting position of the front derailleur if the curvature puts the lower cage too cloase to the outer chain ring you may then run into a problem with the lowered portion of the inner plate being in the wrong position (see 1 above).

3. Although you highlight the 17-20 gap on the cassette you are currently using, similar relative differences exist at other places on other high range cassettes. 20/17 = 1.176 & 14/12 = 1.167. In order to avoid similar relative differences you have to do down to a 12-27 cassette for Shimano which has a maximum relative difference of 1.143 (24/21).

[irc]

I'm currently running a 12-34 9 speed cassette. As Brucey says - easily made from 2 cassettes. I used the Alivio 12-36 and 11-34. Taking the 12-14-16-18 from the 12-36 along with the 20-23-26-30-34 from the 11-34. The big 17-20 gap gone.

Both cassettes are available from (among others) Chain Reaction.


Shimano Alivio HG300 9 Speed Cassette

]Affordable 9-speed Hyperglide cassette sprocket. Hyperglide sprockets guide the chain quickly and directly to the next sprocket without override.
Features:

Chain Compatibility: Super Narrow HG for 9-speed
Gearings - 11-32T: 11-12-14-16-18-21-24-28-32
Gearing - 11-34T: 11-13-15-17-20-23-26-30-34
Gearings - 12-36T: 12-14-16-18-21-24-28-32-36

http://www.chainreactioncycles.com/us/e ... prod120022

[Brucey]

BTW using a 48T big ring instead of a 44T big ring with the extant cassette just means the large gaps in the cassette are somewhere else in the gear range. I'd probably find it no improvement but others might not agree.

cheers

[rmurphy195]

BTW using a 48T big ring instead of a 44T big ring with the extant cassette just means the large gaps in the cassette are somewhere else in the gear range. I'd probably find it no improvement but others might not agree.

cheers

I have a spreadsheet somewhere which illustrates this, pm me if you want a copy to play with.

[Brucey]

I use the gear calculator (see link earlier) to fiddle about with the effect of gear ratios these days; the changes can be made graphically and the results can be displayed in various ways.

NB if you want to share a given gearing arrangement with others via gear calculator, you must copy the link in the RH corner rather than at the top of the page.

cheers