Gearing advice

10 replies [Last post]
Anonymous's picture

"A friend of mine has a 34/50 compact FSA crankset (ISIS) combined with a 10-speed Dura-Ace 12-27 cassette, 10-speed STI shifters, and D-A rear wheel, and would like to get some lower gears for climbing.

I'd like to see at least two lower gears, but - wow! - to switch over to a triple is on the spendy side. Plus I'm not completely enamoured of the new Shimano 10-speed 30/39/52 Ultegra chainring combination. Even with a 12-27 cassette, that's not going to produce the gears I have in mind.

Here are some other options, in no particular order:

- get a Campy wheelset and 13-29 cassette, and keep the compact crank.

- get an IRD ""triple-lizer"" ring for the crank, new bottom bracket and derailleurs, and keep the cassette and D-A wheels. Chainrings with the triplizer might be something like 26/36/50.

- take out an equity loan and go all Shimano for the triple, but get a smaller granny ring, and maybe a 13-25 cassette.

What other options might we consider?

Many thanks!

Anonymous's picture
Neile (not verified)

"I think the ""triple-lizer"" + new bottom bracket.

Does the left shifter support a triple? You sure he'd need new derailleurs?

The Campy option seems a lot of $$ for little difference.


What gear inches you shooting for?

FWIW, a 48/34 on a 11/32 rear cassette gets you 114.7-27.9.
Rowing the front rings closes the rear gaps nicely -- if he's touring not pacelining.

Also, article on full gearing/ half step gearing"

Anonymous's picture
Tony Rentschler (not verified)

"Agreed, I like a triple - one way or another.

I'm looking for at least a 27-inch Low, with 30 gear inches above that. I think my friend will find that she can spin up the hills at the same speed she climbs now and have lots more energy left over at the top. If she can spin up a little faster, then all the better. But the main focus right now is to increase enjoyment, not speed. With the right gears, there's no hill too long or too steep!

I'm generally not super keen on the wide-range cassettes for road bikes because I find the gaps awkward on group rides. Riding by myself - no problem.

The fly in the relish here though is the 10-speed D-A wheel and shifters, which can't use the 11-32/12-34 cassettes.

I like Sheldon's 13-30 Century Special cassette, which I'm running to good effect on my ""pass hunter,"" but that cassette is 9-speed only. I've combined this cassette with a 26-tooth granny for a 22-inch Low. What a gas!

Anonymous's picture
"Chainwheel" (not verified)
12-32 rear

"""I'm looking for at least a 27-inch Low, with 30 gear inches above that. I think my friend will find that she can spin up the hills at the same speed she climbs now and have lots more energy left over at the top.""

Unless this is for heavily loaded touring in the mountains, I think a 27"" gear may not be necessary. I would first try a 12-32 cassette with an MTB rear derailleur. With a 39T chainring that gives you a 33"" gear and doesn't cost much.

Remember, there's nothing magical about super low gears. You still have to generate enough power to maintain ~4 mph to keep the bike upright.



Anonymous's picture
Tony Rentschler (not verified)
I'll buy that, but...

The key is the 10-speed D-A hub and shifters. I don't see 12-32 in 10-speed and we're trying to avoid a wheel and shifter swap.

Anonymous's picture
Evan Marks (not verified)

Reroute the cable to the opposite of the fixing bolt and the derailer works as a 9-speed (with one extra click).

But but but ... I can't remember if the 10-speed hub is backwards compatible for 9-speed cassettes.

(BTW, 33t is the smallest chainring for compacts, from peter white cycles and probably sheldon brown/harris as well.

12-30 can be cobbled together and will *probably* work with a double RD, 12-32 can *possibly* work with a double RD depending on the chainstay length and derailer hanger location.)

Anonymous's picture
Tony Rentschler (not verified)
It's not

The D-A 10-speed hub is 10-speed only, according to Sheldon anyway. The Ultegra can take 9-speed cassettes.

Anonymous's picture
Steve (not verified)
More relish

I am missing those low gears as well. With a 50/36 compact crankset and a 9 speed 12-25 cassette, the hills are making sure I remember that I am no longer 20.

I was thinking that I could change the cassette to a 9 speed 11-32, which would allow for a little more cadence on the inclines.

Good luck to you.

Anonymous's picture
<a href="">Peter O'Reilly</a> (not verified)
SRAM Dual Drive

Replace the front shifter and rear hub with a SRAM Dual Drive system. That will give you 54 (9*2*3) gears to choose from:

Anonymous's picture
Pete jackson (not verified)
smaller granny ring for Shimano? Who makes it? (nm)
Anonymous's picture
Neile (not verified)
"""Who makes it?"""


74 mm BCD (bolt circle diameter) is the standard small chainring bolt circle used with:

110 mm ""touring"" cranks, older mountain bikes, most everything that has a 46 or 48 tooth big ring.
130 mm ""road triples"" including Shimano Ultegra, 105, Tiagra, Sora.
135 mm Campagnolo triples

Chainrings for 74 mm BCD + 5 bolt pattern made by FSA, Salsa, Shimano, Sugino, Truvativ, Raceface, T.A:

[So even trolls can make it up the big hills.]


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