Converting 52/42/30 triple to 52/42/34.
#1
Farmer tan
Thread Starter
Converting 52/42/30 triple to 52/42/34.
Please help me find a 34 tooth 74mm bcd granny gear that works with 9 speed.
I have a "Sugino Comp" 52/42/30 triple (130/74mm bcd) that came standard on my 2008 Allez, which is a 9 speed. I'd like to replace the 30 tooth granny ring with a 34 tooth, but these seem to be difficult to find in 74mm bcd.
I've seen there is a TA 34t 74mm bcd available from Harris, but it's a bit expensive ($43). There are also some 34t made by Sakae available on ebay for $12, but I'm not clear if any of these will work with 9 speed chain. Any experience with this would be helpful.
From the listing:
This is a SR Sakae "300T" 34T alloy inner sprocket for triple chainwheels. The hole center to hole center is 43.5mm and the bolt circle diameter is 74mm. This sprocket fits SR FLC-T310, FXC-T310, SXC-T310, AXC-T310, CRC-T301, CXC-T300, SAC-T310, SXC-T200, Takagi Tourney GS & XT Cranks.
Here's another:
I have a "Sugino Comp" 52/42/30 triple (130/74mm bcd) that came standard on my 2008 Allez, which is a 9 speed. I'd like to replace the 30 tooth granny ring with a 34 tooth, but these seem to be difficult to find in 74mm bcd.
I've seen there is a TA 34t 74mm bcd available from Harris, but it's a bit expensive ($43). There are also some 34t made by Sakae available on ebay for $12, but I'm not clear if any of these will work with 9 speed chain. Any experience with this would be helpful.
From the listing:
This is a SR Sakae "300T" 34T alloy inner sprocket for triple chainwheels. The hole center to hole center is 43.5mm and the bolt circle diameter is 74mm. This sprocket fits SR FLC-T310, FXC-T310, SXC-T310, AXC-T310, CRC-T301, CXC-T300, SAC-T310, SXC-T200, Takagi Tourney GS & XT Cranks.
Here's another:
#2
Senior Member
Why? You will be lessening your gear range and won't gain much except more overlap between 2nd and 3rd ring.
#3
Farmer tan
Thread Starter
It's right for my cycling style. I'm changing up the cassette as well. Just didn't want to complicate my question by including the info.
#4
Over the hill
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If you only need a 34, have you considered switching to a compact double? Barring that, the Sakae should work fine with your 9s drivetrain.
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I second the compact double, a 52/34 would work better for you than a triple. Or else you could find some extra long chain ring bolts and make a 110bcd triple. I've seen some older cranks set up that way, but I have no idea where to get the bolts.
#6
Farmer tan
Thread Starter
I have considered switching to a road double, but i'm not ready to drop $200 on it. I only ever use the 42 and 52, which is noisy given the short chainline of this frame. The 30 is not used. The cassette is sram 12-26, so the 42/26 combo gives me 42.5 gear inches. I spend a lot of time in the 42, but wish it had the 11 cog, so I plan to put an 11-21 on the back.
My lowest gear will continue to be 42.5 gear inches (the 34/21 combo). Plus, I'll have a really useful range of 52.6 to 100.3 gear inches when in the 42. Perfect for the rollers around here. I'll also retain the 52 ring for flats and downhill.
Bonus: 16 tooth cog.
(thanks for the info about the Sakae !)
My lowest gear will continue to be 42.5 gear inches (the 34/21 combo). Plus, I'll have a really useful range of 52.6 to 100.3 gear inches when in the 42. Perfect for the rollers around here. I'll also retain the 52 ring for flats and downhill.
Bonus: 16 tooth cog.
(thanks for the info about the Sakae !)
Last edited by f4rrest; 03-23-09 at 01:32 PM. Reason: thx
#7
Bicycle Repair Man !!!
9 speed chain has the same inner measure of 3/32 as any other chain... any 74bcd 3/32 chain ring should work.
#8
Farmer tan
Thread Starter
I've attached the ratios of what I have vs. what I want (Sheldon's site).
#9
Farmer tan
Thread Starter
Great, thanks Sixty Fiver and Urbanknight. I've ordered the new "granny" gear.