Bicycle Mechanics - 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:
http://i16.ebayimg.com/06/i/001/3b/e7/0fa5_2.JPG

Why? You will be lessening your gear range and won't gain much except more overlap between 2nd and 3rd ring.

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.

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.

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.

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 !)

9 speed chain has the same inner measure of 3/32 as any other chain... any 74bcd 3/32 chain ring should work.

I've attached the ratios of what I have vs. what I want (Sheldon's site).

Great, thanks Sixty Fiver and Urbanknight. I've ordered the new "granny" gear.