74 mm BCD Chainrings from Harris Cyclery
We stock a wide range of chainrings for modern and older crank sets.
For more technical detail see the B.C.D. entry in Sheldon Brown's Bicycle Glossary
This is the standard small chainring bolt circle used with:
Although "road triple" cranksets commonly come with a 30 tooth small chainring, it is very easy to replace this with something more reasonable, such as a 26 or even a 24. If you go with a 24, you would also be well advised to add a chain deflector such as the N-Gear Jump Stop.
- 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
Using one of these devices allows you to set the low-gear limit stop loose enough to provde positive downshifting, without the risk of the chain overshooting and falling off inward.
This is by far the cheapest and best way to lower the gearing of a stock bike with a road triple crankset.
See also our options in custom cassettes.
This will exceed the official "capacity" of your derailers, but generally works fine with original stock "road" derailers as long as you don't make a habit of abusing the small chainring by running it with the smaller rear sprockets. See the "Capacity" entry in my Bicycle Glossary for an explanation of this.
The French T.A. rings are expensive, but are very high quality.
Sizes: 24t | 26t | 28t | 30t | 32t | 34t | 36t
24t various brands $23.95 T.A. $43.95 26t various brands $23.95 T.A. $43.95 28t various brands $23.95 T.A. $43.95 30t various brands $23.95 T.A. $43.95 32t various brands $23.95 T.A. $43.95 34t T.A. $43.95 36t T.A. $43.95
T.A. chainrings are super-high quality, premium rings in Zircal 7075 aluminum. They have machined teeth, and a mirror-like finish.
T.A. triple conversion chainrings include the necessary bolts and spacers to attach a 74 mm granny chainring.
Classic T.A. Cyclotouriste cranks, chainrings and bottomm brackets are listed on our French Cranks Page.
There is a lot of confusion about the compatibility of narrow 9-speed chains with older cranksets. Shimano says you should replace the inner chainring(s) with specially designated 9-speed ones, but then they're all too eager to sell you stuff, whether you need it or not.
Shimano is also concerned about clueless users. The worst-case scenario is that you will be riding along with the bike in its highest gear (large front, small rear) and then for some bizarre reason shift down in front before downshifting in the back. (There is no shift pattern in which it is reasonable to shift in this sequence.) If you do shift this way, there's a small chance that the chain might "skate" over the edges of the teeth for maybe half a turn.
In practice this "problem" almost never materializes. Many, many cyclists are using 9-speed chains with older cranksets and having no problems whatever.
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