Shimano 105 and 30 tooth sprockets?

[Manonabike]

Whether a road mech works with a large sprocket is nothing to do with the cage length - it's about whether the top jockey wheel fouls the large sprocket or not. This depends on the B-screw setting, chain length, and how long the mech hanger on your frame is.
Pushing the quoted limit by 2T (i.e. 28T to 30T for most road mechs) is usually OK, but not always. That someone else can use a certain size of sprocket with a particular mech doesn't necessarily mean that you can.

Just going by the description of a short and medium cage 105 derailleur:


SS: Short Cage
compatible with 8-/9-/10-speed
· 2 Teflon coated connection pins
· Wide Link design for increased rigidity
· max. sprocket size: 25 - 30 teeth
· min. sprocket size: 11 - 14 teeth
· total capacity*²: 34 teeth

SG: Medium Cage
compatible with 8-/9-/10-speed
· 2 Teflon coated connection pins
· Wide Link design for increased rigidity
for double cranksets max. sprocket size 27 - 32 teeth
· for triple cranksets max. sprocket size 25 - 30 teeth
· total capacity*²: 40 teeth


Further info on the subject:

How to calculate the capacity of a derailleur?

"According to United Bicycle Institute:

1. Determine Maximum Chainring Difference by subracting the number of teeth in the smallest chainring from the number of teeth in the largest chainring
2. Determine Maximum Cassette Cog Difference by subtracting the number of teeth on the smallest cassette cog from the number of teeth on the largest cassette cog
3. Determine Total Drivetrain Capacity by adding Maximum Chainring Difference to the Maximum Cassette Cog Difference
4. Record the Maximum Cassette Cog (the number of teeth on the largest Cassette Cog)

For Shimano:
SS - Short Cage Road Double - Maximum Cassette Cog is 27 and Total Capacity is 29
GS - Medium Cage MTB/Road Triple - Maximum Cassette Cog is 34(MTB)/27(Road) and Total Capacity is 33(MTB)/37(Road)
SGS - Long MTB - Maximum Cassette Cog is 34 and Total Capacity is 45
For SRAM:
Short - Maximum Cassette Cog is 34(MTB)/28(Road) and Total Capacity is 32(MTB)/31(Road)
Medium - Maximum Cassette Cog is 34 and Total Capacity is 37
Long - Maximum Cassette Cog is 34 and Total Capacity is 45
For Campagnolo:
Short - Maximum Cassette Cog is 26 and Total Capacity is 27
Medium - Maximum Cassette Cog is 29 and Total Capacity is 36
Long - Maximum Cassette Cog is 29 and Total Capacity is 39
NOTE - THIS INFORMATION IS SUBJECT TO CHANGE BY MANUFACTURER"

It seems the information has changed since the above info was published on the net..... but it still gives us an idea.

 

[antnee]

SoHaving Read all the above post and scanned the net for suitable results and not finding any All I want to know is the sprocket sizing between the 11-30 Sprockets on a 9 speed cassette I can't find any sizing per cassette As I want the 30 sproket and the next down to be at least two teeth between.
Does Any one know these sizing please?
reagards Antnee

 

[youngoldbloke]

SoHaving Read all the above post and scanned the net for suitable results and not finding any All I want to know is the sprocket sizing between the 11-30 Sprockets on a 9 speed cassette I can't find any sizing per cassette As I want the 30 sproket and the next down to be at least two teeth between.
Does Any one know these sizing please?
reagards Antnee

How many cogs? What brand? Rose list the sprockets on their website - e.g. 8 speed 11-30
So do Shimano Tech Docs - e.g. Sora cassettes
Edit - sorry - you did say 9 speed - see HG50/9

 

[antnee]

Hi Young old Bloke And Thanks. I did say 9 Speed And Shimno or Sram will do as fitted Shimano 105 Flight deck ST-5510 Shifters ( bought off ebay 2nd hand (new are just too expensive?) on the bike. As becoming fed up of having to get off the bike on the 11% hills up the Mendips and As the winters here I'm finding that I'm going a bit slower on the Wet and Leaf strewn roads Too. BTW Iv'e tried an old 11-32 Cassette And that worked with a Sora rear derailleuer So am Presuming that a 11-30 would work to going on the calculations in the above posts?

 

[antnee]

Ah Just Found this Cassette Which perhaps will fit the bill

Cassette Sprocket (9-Speed)
CS-HG61
-9 ar

Though It does go from 28 to 32 which Ideally I wanted 28 to 30 as the last sizing As don't want to upgrade large Chainring from a 50 tooth to 52 as yet Though looking at this I could perhap do 52 44 34 (or something like that needs more research) on the triple

 

[antnee]

Also just found this Which could help a dummy as I am.

http://sheldonbrown.com/k9.shtml

 

[youngoldbloke]

I'm using an 11-30 9 speed HG50 with Tiagra (old-ish mech) 50/34 compact no problems. The new Shimano mechs appear to be able to accommodate bigger rear sprockets - the GS mechs up to 32T. My new bike has Ultegra GS 11 speed, 11-32 cassette, and 50/34 compact. Interesting that Shimano appear to have no plans for an Ultegra 6800 triple chainset, and seem to be increasing the range of their rear changers to provide lower gears.