Granny gear option on road bike?
05-30-22, 01:49 PM
#1
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Granny gear option on road bike?
I have a Shimano 105 10 speed compact crankset (50-34) and I was wondering if I can put on a smaller chainring, 30-32, or is a 34 as small as I can go?
Would like a smaller granny gear if possible. I have a 32 in the rear with a Shimano 105 long cage derailleur currently on my road bike.
suggestions?
Would like a smaller granny gear if possible. I have a 32 in the rear with a Shimano 105 long cage derailleur currently on my road bike.
suggestions?
05-30-22, 02:04 PM
#2
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Shimano 105 10 speed is the old 5 spoke spider isn't it? You might find a smaller ring. However the rings are paired at those sizes partly to give you optimal shifting. What you might do is look for a new crank entirely. Likely both of the rings will be smaller.
32 rear and a 34 front is pretty low already for the hills on most roads in the midwest and deep south where I'm at.. Perhaps you just need to ride more and build up some leg muscle and endurance.
And don't rule out a new bike. That might be the best way to get the range of gearing you think you need.
32 rear and a 34 front is pretty low already for the hills on most roads in the midwest and deep south where I'm at.. Perhaps you just need to ride more and build up some leg muscle and endurance.
And don't rule out a new bike. That might be the best way to get the range of gearing you think you need.
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05-30-22, 02:13 PM
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A sixteen tooth jump is kind of pushing it already. But I grew up in the "half step" days of chainrings. And the chain wrap specs of the rear derailleur are probably at their limits, so you'd probably need to get a smaller large chainring too, as mentioned above. Or be very careful about shifting large-small.
05-30-22, 02:27 PM
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Check to make sure your front derailleur can accommodate that size chainring and the jump from 50 to 32. If so, find out what the BCD for the small chainring is, and see if there are 32T chainrings with that BCD. Another route would be to get a 11-36 or 11-42 10-speed cassette and a Deore rear derailleur (or another that can handle the larger cog size). I think the 105 rear derailleurs top out at 32T.
05-30-22, 02:43 PM
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Here's another option. bikinGreen CNC Road Chainring 46/30T BCD 110mm 5 Bolts 10/11 Speed Cyclocross | eBay They also offer other gear combos and in black or silver. I have no personal experience with them but met one rider who was very happy with durability and shift quality. Shop around on Ebay for best prices.
05-30-22, 07:22 PM
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The 10-speed 105 compact crank (FC-5750) has a 110 mm bolt circle and a 33T chainring is the smallest that will fit but 34T is far more common. The 10-speed 105 triple (FC-5703) had 130/74 bolt circles and the granny position would take down to a 24T chainring but good luck finding one of these now days.
