Several standards exist for chainrings. Depending on how many cogs the bike has on the rear wheel, the lateral spacing between the chainrings will vary. The more cogs in back, generally the closer together the chainrings are spaced, and the width of the chain must be narrower to fit the closer spaced rings. And rings are made to different standards for placement of the attachment bolts that hold the ring onto the crank.

Road racing bikes tend to use the highest range of gear ratios. So racing chainrings tend to be the largest used. So crank manufacturers use larger bolt circles for racing cranks than for touring or ATB cranks.

Touring bikes use many components from ATBs or mountain bikes. ATBs used to have cranks with 110mm outer bolt circles. But several years ago they switched to a smaller bolt circle to reduce the size of the rings and improve ground clearance since it's easy to grind a chainring over large rocks and downed trees.

The bolt circle defines the minimum number of teeth that can be had in a chainring. For example, if you look at the 130mm chainrings, you'll see that 38 teeth is the smallest number of teeth available. It's not possible to make a chainring with fewer teeth because the chainring bolts would get in the way. So there's little to be gained by looking around for a 37 or 36 tooth 130mm bolt circle chainring. They don't exist because they can't exist. 33 is the smallest number of teeth for 110mm bolt circle rings. 29 is the smallest for 94mm. 39 is the smallest for Campagnolo's 135mm bolt circle.

I stock replacement chainrings for a wide range of gearing combinations.

The quickest shifting on triple chainring cranks with Shimano's STI shifters can be had only with matched sets of chainrings. For example, the nine speed Shimano Ultegra Triple crankset 6503 comes with three matched rings; 52 - 42 - 30 teeth, and the later ten speed Ultegra 6603 comes with 52 - 39 - 30. The alignment of the teeth and the positions of the steel pins that lift the chain from smaller to larger rings are carefully positioned to make up-shifts as quick and smooth as possible, even under considerable pedaling forces. With a few exceptions, TA chainrings are designed to be used with many different adjacent rings. The TA rings have pins for lifting the chain, but since you can choose from many chainring combinations, the three rings you end up with won't be precisely matched for tooth position or pin position. That makes the shift a bit slower than if you use Shimano's matched chainring sets. But STI shifting still works. You just can't pedal as hard while shifting as you can with Shimano's rings and still get a smooth shift. Don't worry though, they still shift very well. This is only an issue with triple cranksets.

My most popular chainrings are 48 - 38 - 26 and 24 tooth replacements for Shimano's 9 speed Ultegra and 105 triple cranks. This makes for a much better range of gears if you're touring. Most of Shimano's 9 speed cassettes start with a 12 tooth cog, and some start with 11, which is wasted when your largest chainring is 52 teeth and you're carrying a heavy load. Reducing the size of all the chainrings lets you actually use all nine cogs in back. Why have nine speeds if you can't use them all? 48, 38, 24 shifts very smoothly with the Ultegra 9 speed front derailleur and STI shifters. When you change the size of the outer chainring, you'll need to change the position of the front derailleur. With every tooth reduction, the derailleur needs to be lowered by about 2mm.

Lowering all the gearing with a ten speed Ultegra triple crank is not really viable. The reason is the design of the front derailleur, and the 130mm bolt circle. The inner plate of the 6600 series triple FD is lower than the 9 speed version, to accommodate the 39 tooth middle ring on the ten speed crank vs the 42 tooth ring on the 9 speed crank. For the FD to properly control the movement of the chain from ring to ring, the sizes of the two outer rings must match the derailleur's shape. The relative size of the inner ring on a triple is less critical than the relative sizes of the middle and outer rings. So you could reduce the 52 - 39 - 30 to 51 - 38 - 29 and everything would work, but that's a bit silly. It's not enough of a change to warrant the expense of changing.

For chainrings compatible with Shimano road triple cranksets, like Dura Ace, Ultegra, 105 and Tiagra, scroll down to the TA Alize 130mm rings for the middle and outer positions. Then scroll to the TA Zelito 74mm rings for the inner (triple) position.

If you are using STI, you'll need to use a Shimano derailleur specifically designed for STI. The Ultegra Triple FD and the IRD Alpine clone of the Ultegra are designed for a 10 tooth difference between the outer and middle chainring. They're more flexible about the difference between the middle and inner ring. The Dura Ace 9 speed Triple FD is designed for a 14 tooth difference between the outer and middle ring. I get frequent requests for 38 tooth rings to replace the middle 42 tooth ring on the Ultegra Triple crank. But the shifting will be very poor if you do that. If you want a 38 in the middle, either change the outer to a 48, or change the FD to a Dura Ace Triple.

For best shifting without STI, I recommend the Shimano XT front derailleur. It works best with a 12 tooth difference between the outer and middle ring on a triple to shift well. But the XT isn't compatible with STI road shifters. Use it with bar end or down tube shifters instead.

TA chainrings also have a few advantages. There's a huge selection available. Who else makes chainrings in one tooth increments? So you can get the gearing you want, rather than what Shimano thinks you should have. And TA rings are more durable than most Shimano chainrings, so they will cost you less to use in the long run. Only Shimano's Dura Ace and XTR chainrings are as durable as TA. And they cost much more.

TA chainrings for double chainring cranks work so similarly too original equipment Shimano of Campy rings that you would never suspect they weren't original. See the Hegoa, Syrius, Nerius, Nerius 11, Horus and Horus 11 chainrings below.

Modern chainrings are designed to be used either in the outer position, the inner position of a double, the middle position of a triple, or the inner position of a triple. Attemps to use a chainring in a position for which it was not designed are doomed to fail. Some people are desparate to make outer position rings work in the middle position of triple cranks, because chainring manufacturers don't make large enough middle position rings for the obsolete half-step gearing some people are determined to use. Outer chainrings don't work in the middle position of a triple crankset.

Shimano and Sugino tend to set the standards for chainring spacing. Unfortunately, they set different standards. For example, the inner chainring position of a Sugino triple crankset, the "triple" position, the location of the ring itself on the spider, is further inboard than on a comparable Shimano crankset. Sugino doesn't use loose spacers for mounting the inner triple rings on all of their cranks. They often have the inner ring mounted to a stud that's a part of the forged crank itself. Shimano often uses these studs too, but they are shorter. So the base of the inner chainring is further to the outside on a Shimano crank than on a Sugino. If you use Shimano rings on Shimano cranks, and Sugino on Sugino, it's no problem since each company positions the teeth on the chainring to accommodate this difference in the cranks. So, if you look at a Sugino middle position ring, the teeth will be roughly centered on the ring, and the Shimano teeth will be offset to the outside.

TA rings with Shimano compatible bolt circles are designed to work with Shimano cranks. The offset of TA chainrings are the same as Shimano's offset. So if you try using a TA ring with a Sugino crank, the inner ring on a triple ends up spaced further from the middle ring than it should. If you're running six speeds in back with a wide chain, you may be able to make it work by adding a spacer between the middle ring and the spider; I don't know for sure though. I intend to someday see how wide a chain has to be in order to allow TA rings to work well on these Sugino cranks. But for sure a 9 speed chain isn't recommended. Either the middle and outer ring are too far apart or the middle and inner ring are too far apart, depending on whether or not you place a spacer between the spider and the middle ring.

Lastly, if you see a chainring on the TA website that I don't have listed here, I can special order it for you. Can take up to two months.

Be Aware!

I personally do very little work as a bike mechanic these days. And since the introduction of 10 speed drive trains, I have done little customization of drive trains on bikes. The 9 speed stuff I can speak intelligently about based on many years of experience modifying these drive trains, but not 10 or 11 speed. So if you want to do something different with a 10 or 11 speed Shimano drivetrain, I'm afraid I can't give you much advice.

Bolt Circles

Chainrings are primarily categorized by their bolt circle. The bolt circle in the circle defined by the positions of the chainring bolts that attach the chainring(s) to the crank spider. The most common pattern is a circle of five chainring bolts. The center points of those five bolts define a circle, and the diameter of that circle, measured in milimeters is the bolt circle of the chainring, as well as the crank spider it fits. With an odd number of bolts, it can be difficult to directly measure the bolt circle. For a five bolt chainring, measure the distance between the centers of two adjacent bolts, and then multiply by 1.7. For 4 evenly spaced bolts as on the 104mm spiders, multiply by 1.4 .That will get you within a milimeter or so of the correct bolt circle. So you don't have to make an extremely precise measurement to know what the bolt circle is.

The two most common spider widths for 104mm chainrings are 18mm and 23mm. Shimano spiders are 23mm wide. SRAM and TA spiders are 18mm wide.

Here, I'm measuring the width of a TA Carmina 104 triple spider. As you can see it's 18mm. A Shimano crank spider would be wider at 23mm. So TA makes their 104mm chainrings in two versions to match these two sizes. If the chainring doesn't match, it's only a cosmetic issue. A 23mm chainring will work just fine, it just won't look as nice.