I Need Gearing Change Help

[SJTaylor]

I’m sporting a new to me Serotta CDA that I took for a first ride yesterday. I like it a lot except for the gearing.
Here’s what it’s got:

Shimano Hyperglide CS-6500 12-27, nine speed cassette
Ultegra Rear derailleur with ~3” center to center on the cage sprockets
Ultegra triple crank with 52-42-30 chainrings
Ultegra Flightdeck brifters
Gearing is 30GI-117GI

I live in the Sierra Nevada foothills where nothing is flat, I’m not too fit yet and I have a gimpy aged knee that prefers cadence on up hills. I think I’d be happier at least for now with low 20s GI - 100 GI, I guess touring bike gearing.

I’m inexperienced with this gearing stuff so I’m looking for help how to best change the gearing without throwing lots of $$ at it. I don’t know how to figure out the capacity of the existing derailleur. I do have another Ultegra RD with 3-1/4” center to center on the cage sprockets.

I’d welcome any suggestions. Hope what I’ve written makes sense.

Thanks.

[Gummee]

Chances are, you won't be able to get much more than a 30t cassette on there without mods. If that.

If you switch to a mtn rear derailleur, you can probably get up towards 40-42t cassette on there. It'll depend on exactly how much the derailleur will wrap

Any mtn derailleur up to 9sp Shadow will work on your 9sp road stuff.

You'll need a longer chain to make it work

I much prefer the shift feel of 9sp shifters to the 10sp era, so keep running them till they die

M

[palincss]

Originally Posted by SJTaylor

I’m sporting a new to me Serotta CDA that I took for a first ride yesterday. I like it a lot except for the gearing.
Here’s what it’s got:

Shimano Hyperglide CS-6500 12-27, nine speed cassette
Ultegra Rear derailleur with ~3” center to center on the cage sprockets
Ultegra triple crank with 52-42-30 chainrings
Ultegra Flightdeck brifters
Gearing is 30GI-117GI

I live in the Sierra Nevada foothills where nothing is flat, I’m not too fit yet and I have a gimpy aged knee that prefers cadence on up hills. I think I’d be happier at least for now with low 20s GI - 100 GI, I guess touring bike gearing.

I’m inexperienced with this gearing stuff so I’m looking for help how to best change the gearing without throwing lots of $$ at it. I don’t know how to figure out the capacity of the existing derailleur. I do have another Ultegra RD with 3-1/4” center to center on the cage sprockets.

I’d welcome any suggestions. Hope what I’ve written makes sense.

Thanks.

For the cost of a rear derailleur (9 speed Deore XT, for example) which you could get for under $50 you would be able to replace that 12-27 cassette with a 12-36, which would cost you around $25. I suggest you plot your current gearing, then plot the same crank set with a 12-36 and compare them.

You also potentially could replace the 30T inner chain ring with one as small as 24T. I suggest you plot that with your existing cassette and see how that compares to both the original and to the one with the 12-36.

[cabriggs]

This gear calculator site (https://www.gear-calculator.com/) can help you work out which ring or cassette changes will get you to the range you want. Put in the rings, cogs, and tires you have now, set the Display to Gear Inches, then hit Compare and make some changes and you can view a new setup next to the current one.

[Ken Robb]

I had a similar set-up and I swapped for a TA Zephyr 48-38-28 crank. It worked well but engaging the middle ring required a half-click trim on the shifter and that was easy to do. The crank would have accepted a 24 tooth cog and, maybe, even smaller but I don't know how that would have shifted and these cranks would cost a lot more than the XT deraileur and 12-36 cassette others have suggested. A Sugino triple crank is almost as nice and costs much less than a TA. I had your cranks and a 7 speed 12-34 cassette with XT deraileur shifted by Suntour Power Ratchet friction shifters and that was a terrific shifting setup. I don't know that I could spin fast enough to use any lower gears than that.

[rccardr]

I would change out the crank to give you more gearing options. That 130/granny combo is very ,limiting fore true mountain climbing gears.

Something like a Sugino with a 110/74 bolt circle combination will let you get down to a 24 in front and literally anything you could want in the outer and middle rings.

Then like others have suggested, get a Deore 9 speed RD which will easily take up to a 34 out back and works with those shifters and the triple sizing mentioned above.

Works like this, with 48/36/24 chainrings and 13-32 cassette. This one uses down tube shifters, but would work fine with STI's:

[palincss]

Originally Posted by SJTaylor

Ultegra triple crank with 52-42-30 chainrings
Ultegra Flightdeck brifters
Gearing is 30GI-117GI

I live in the Sierra Nevada foothills where nothing is flat, I’m not too fit yet and I have a gimpy aged knee that prefers cadence on up hills. I think I’d be happier at least for now with low 20s GI - 100 GI, I guess touring bike gearing.

For the sake of comparison, your current gearing is this, I think:

114.3	92.3	66.0
105.5	85.2	60.9
98.0	79.1	56.5
91.5	73.9	52.8
80.7	65.2	46.6
72.2	58.3	41.7
65.3	52.8	37.7
57.2	46.2	33.0
50.8	41.0	29.3

Leaving the crank as it is and changing to a 12-36 cassette gives you this gearing:

114.3	        92.3	66.0
98.0	        79.1	56.5
85.7	        69.2	49.5
76.2	        61.6	44.0
65.3	        52.8	37.7
57.2	        46.2	33.0
49.0	        39.6	28.3
42.9	        34.6	24.7
38.1	        30.8	22.0

and changing the 1st position 12 to a 1st position 13 (around $10 for the sprocket, and it'll last virtually forever, just keep swapping it from cassette to cassette) changes that to

105.5	85.2	60.9
98.0	79.1	56.5
85.7	69.2	49.5
76.2	61.6	44.0
65.3	52.8	37.7
57.2	46.2	33.0
49.0	39.6	28.3
42.9	34.6	24.7
38.1	30.8	22.0

both of which in my opinion are more usable than the original and require relatively minimal effort and expense to achieve. You can do better with different chain rings and for sure, 110/74 touring triples are wonderful, but those are more extensive and expensive changes than a cassette and rear derailleur swap (especially since the crankset change would most likely require a rear derailleur swap anyway).

[AngryScientist]

pull the big ring off that crankset and replace the middle ring with a 46. leave the 30. replace cassette with 11-32 or 11-34. done and done.

[palincss]

Originally Posted by AngryScientist

pull the big ring off that crankset and replace the middle ring with a 46. leave the 30. replace cassette with 11-32 or 11-34. done and done.

Or, since the OP specified a top gear of around 100", doing your 30/46 chain ring conversion and replacing the cassette with a 12-34:

101.1	66.0
86.7	56.5
75.8	49.5
67.4	44.0
60.7	39.6
52.8	34.4
46.7	30.4
40.4	26.4
35.7	23.3

Doing the 1st position swap to a 13 instead of a 12 gives you this:

93.3	60.9
86.7	56.5
75.8	49.5
67.4	44.0
60.7	39.6
52.8	34.4
46.7	30.4
40.4	26.4
35.7	23.3

and using a 12-36 cassette instead of the 12-34 gives you this:

101.1	66.0
86.7	56.5
75.8	49.5
67.4	44.0
57.8	37.7
50.6	33.0
43.3	28.3
37.9	24.7
33.7	22.0

A rear derailleur swap would be required for all these options, because of the 34T or 36T large sprocket.

[smead]

XTR 9 speed RD and done. We have the same 6500 triple setup on our road tandem w/ XTR M952 RD. I swap rear wheels with 12-27 and 11-32 cassettes from time to time and just jumping to the 11-32 makes a huge difference.

With that said, on a single a 30-27 should be plenty of gearing for the sierra foothills unless you're doing something like Iowa Hill rd. on a regular basis. And if you're doing that, you'll be fit in no time!

[NHAero]

Was riding a 48-36-24 with a homemade 13-30 a la Sheldon for years on my Bob Jackson. Now same crank with 10 speed STI and I think 12-30 or 12-32.

[Ralph]

Depending on how low you want to go......if me....and I wanted to keep it cheap and simple.....would first attempt to use the derailleurs you have. And as many of the current parts you can. Your RD is a med cage....and will handle some more gears.

So.....again depending on how low you want to go....would first put a 28 tooth ring (74 BCD....bolt circle diameter) on the inner. Using same length chain....if it ran a little slack in small to small combo (s).....who cares.....as long as chain works on the bigger half of cassette. And a slightly slack chain will allow the RD cage to pivot forward slightly, and help clear a big cassette cog.

If you need more....would try to put a cassette with a 30 tooth cog on it. (or whatever 9 speed Shimano/Sram has) May have to play around some with B screw adjustment on RD for upper pulley to clear cog....and chain length. (don't go so short big to big won't work).

Would start here before I started to change out cranks and derailleurs. Your crank will take down to a 24 tooth ring on front....and the middle is 130 BCD. Would not be difficult to install 26-39 (or 38)-48 (or so) rings on crank you have now, and slightly larger cassette.....and it will work. Rings in 74 and 130 BCD not hard to find. Make sure the middle ring is designed to have a ring before it. (with ramps and pins) The only thing I'm not 100% sure about is if a 24 or 26 front ring will cause chain to rub on support brace at rear of FD when in smaller rear cogs....no issue if you don't use those combinations.

[bikinchris]

Originally Posted by rccardr

I would change out the crank to give you more gearing options. That 130/granny combo is very ,limiting fore true mountain climbing gears.

Something like a Sugino with a 110/74 bolt circle combination will let you get down to a 24 in front and literally anything you could want in the outer and middle rings.

Then like others have suggested, get a Deore 9 speed RD which will easily take up to a 34 out back and works with those shifters and the triple sizing mentioned above.

Works like this, with 48/36/24 chainrings and 13-32 cassette. This one uses down tube shifters, but would work fine with STI's:

Agreed. I had a 50-34-24 with a 12-36 gearing set for a while on my touring bike with a Suntour cold forged crank. I used barcons so I could use Dia Compe road levers and have XTR V Brakes on a full XTR bike, but there is no reason for the OP to not use STI levers.

[SJTaylor]

My LBS shop, friends with the owner, has a big box of rear derailleurs. Found just one long cage nine speed RD. It was a XTR missing a sprocket but added the missing pieces and gave $10 for it. I also bought a replacement chain and ordered a 12-36 cassette.

I did all this before I read many of the responses left here. It seems there are lots of options.

I had just purchased a new Giant Revolt Advanced 1 gravel bike before I stumbled into the Serotta. I’ve got to say the Serotta is comfortable ride and I’m enjoying having the Flightdeck brifters and the bike computer. My wife understood that the gravel bike was my last bike purchase. Wrong.

Thanks for all the suggestions.

[Ken Robb]

I don't know that all the more extreme ring swaps will work with his brifters.