new bling - a Shimano HG-500-10 cassette is now on my bike |
Since I went for super-short cranks, I have had a bit of a hill problem.
My 175mm cranks had a triple ring setup, and I used to run 48, 34, 26, along with my 11-32 SRAM PG850 cassette.
The 145mm cranks I switched to (MUCH easier on my ageing right knee) are only a "double) at 48, 34.
So my "crawling up a hill" gearing had gone from 26f/32r (= 0.8125) to 34f/32r (= 1.0625) - a rise in gearing of 30%
Hmm, I thought to myself.
I have friction shifters (so I don't have to worry about indexing), and a "long-cage" derailleur (a Shimano RD-591), so, maybe I just need a new cassette and chain, give everything else a clean up, fiddle with the b-screw, reset the High and Low stops on the derailleur, and job done?
Sort of ;-)
I went with a Shimano HG500 cassette in the new 11-42 size that they now offer, with an SRAM 1051 chain. I was very pleased with the SRAM 850 chain I used for a several years (when I bought Hoppy, it had an OEM KMC chain, and it seemed a pity not to just use it!), so, I thought to myself, a SRAM 1050-ish series chain will do me fine.
New bike bling for old folks? - Shimano's new-ish 11-42 10-speed cassette, and a new, shiny, so shiny, chain |
setting up a comfortable work area - the deck chair is essential ;-) The back of the car has a flat load area, so it also make a comfortable area to sit, as well as a place to lay out tools etc. |
which sprocket remover to use? the silver one is a "cheap" one, the black one is a Park Tools FR-5. Both fit a modern "Shimano"-style Freehub. |
I used the "cheap" one, as it has a 1/2" drive socket, so I can use a nice long tool to get the cassette lockring off. |
A great thing about the SRAM PG850 cassette is that the sprockets are held together with a very thin hex bolt, not a rivet, so ... |
... undo the hex bolt, and ... |
A magnetic tray is handy for small bits (in this case the long, thin, hex bolt from the cassette) |
The "working parts" of the RD591 derailleur come apart reasonably easily for cleaning |
The 10-speed HG500 cassette goes on nicely to replace the 8-speed PG850 cassette |
The crank all cleaned up. These are "Stronglight" branded. |
Yep, these really are 145mm extra-short cranks. tbh, they look like they are cut down from a Stronglight 175mm crank (and, yes, I do have a Stronglight 175 for comparison) |
Problems selecting the lower (bigger sprocket) gears ... |
I replaced the b-screw (original is the black one) with a longer one |
Still not enough, so I chucked a couple of nuts on the b-screw to further space it out from the derailleur stop |
1051 chain is 114 links - looks a bit short in the 37t rear gear (34t chainring) |
Still got a few niggles to work out, but the 11-42 setup as shown has already completed a 60 mile ride across the Chilterns, With a 13% hill at this end (Aston Hill), and a 14% hill at the far point of the ride (Rectory Hill, Amersham), I was sure glad of the lower gear ratio that the 11-42 provides.
(ride is on Strava here: https://www.strava.com/activities/2274995622)
So how low did I go?
34f/42r = a gear ratio of 0.81, pretty similar to the 26f/32r ratio I had before (0.8125)
Thus a "double" 34/48 with an 11-42 cassette has a similar overall gear range to a "triple" 26/34/48 with an 11-32 cassette.
As will be easily deduced from a Google search, there are a LOT more "double" chainsets than "triples", and in a LOT more variations, makes, and quality grades, too!
So there we have it.
an 8-speed steel 34t chainring driving a 10-speed chain, driving a 10-speed 11-42 derailleur, shifted by a 9-speed long-cage derailleur with a modified b-screw.
Just gotta sort out that chain length now!
Nice write up PP, I had no idea you could use a 42 tooth rear sprocket with a normal rear mech. I looked at a wide range 10 before I splurged on my alfine, but wasn't sure whether my rear mech would take it, only short cage though.
ReplyDeleteanother "bodge" that folks do is fit a "drop link" to lower the derailleur. Sunracee (iirc) do a well-priced one, and other brands are available, too. Dunno about short cage, but some folks use them with medium cage derailleurs.
ReplyDeletean alternative would be the special 3-speed rear hub that takes a 10-speed sprocket on it (Sunrace iirc), but with your super long chain length, you will still get a lot of chain "slap", i suspect.