|
Most bicycle chainrings have holes spaced around a bolt circle to attach them to the crank,. The tables at the bottom of this page give bolt-circle diameters for major brands. Aftermarket and less prominent brands tend to use the same bolt-circle patterns as the major brands. Since approximately 2010, there has been a rash of new bolt-hole patterns with uneven spacings. This crib sheet does not necessarily guarantee compatibility, because it may depend on more than only the bolt-hole pattern. Details about other factors affecting compatibility are on a separate page. 
With our PDF templates -- example at right -- you can directly check the BCD for all chainrings in commercial production, old and new, of which we know. You identify the bolt pattern by laying a chainring down on a template printout and rotating the chainring until the bolt holes align. Then come back to this page to find out which common brands and models use the bolt pattern that you have identified. The templates also let you quickly determine a chairing's tooth count.
The table below on this page gives the dimensions to measure bolt circles using a ruler. Instructions have been moved to a separate page.
4-Bolt Cranks/Chainwheels, even spacing: For uneven spacings, see the next section of this table.Beware of near-matches! Measure! The BCD is 1.414, 1/sin 45°, times the spacing between adjacent holes. |
||||
|---|---|---|---|---|
| BCD (mm) | Smallest Ring |
Between adjacent holes (mm) |
Application | |
| 146 | 44 | 103.2 | Shimano XTR M960 Hollowtech 4-arm outer. | |
| 120 | 36 | 84.9 | SRAM 2 x 10 and XX. Threaded. | |
| 112 | 34 | 79.2 | Shimano XTR M950, M952 4-arm middle/outer | |
| 110 | 34 | 77.8 | FSA K-Force Light, Vero Pro | |
| 104 | 30 | 73.5 | Shimano XT, LX 4-arm outer 12 SPD, Sugino MX350. Some are threaded. See RaceFace compatibility table. | |
| 102 | 32 | 72.1 | Shimano 2003 XTR MX960 4-arm middle, | |
| 96 | 30 | 67.9 | Shimano compact triple cranksets models M782, M672, M622, M612 | |
| 94 | 30 | 66.5 | SRAM XO1, X1, GX, NX | |
| 90 | 30 | 63.6 | FSA: K-Force Modular Supercompact, Omega Pro, Powerbox Supercompact Stealth, Road Modular, Vero Pro | |
| 88 | 28 | 62.2 | Shimano M985 | |
| 68 | 22 | 48.1 | Shimano XTR M950, M952 4-arm inner, FSA Comet Modular | |
| 64 | 22 | 45.3 | Shimano XTR M960, XT, LX 4-arm inner. See RaceFace compatibility table. | |
| 58 | 20 | 41.0 | Sugino MX350 4-arm inner | |
4-Bolt Cranks/Chainwheels, uneven spacing: Measurements between adjacent holes of uneven patterns |
||||
| BCD (mm) | Smallest Ring |
Between adjacent holes (mm) |
Application | |
| 145 | 44 | 111.1, 93.2 | Campagnolo Super Record, Record, Chorus 2015- outer | |
| 123 | 38 | 93.9, 79.1 | Campagnolo Chorus, Ekar. Some also have holes at 96mm for inner chainring. | |
| 112 | 34 | 85.8, 72.0 | Campagnolo Super Record, Record, Chorus 2015- inner | |
| 110 | 34 | 90.1, 63.1 | Shimano Dura Ace 9000, Ultegra 6800, 105 5800, GRX outer, Tiagra 4703, 4700; Dura Ace with modification | |
| 110 | 34 | 89.0, 64.7 | SRAM Apex 1. 72/108 degree angles. Shimano is 70, 110 degrees. | |
| 110 | 34 | 84.3, 77.8, 70.7 | FSA Gossamer ABS, K-Force ABS, Powerbox, SL-K ABS | |
| 107 | 34 (?) | 86.6, 62.9 | SRAM X-Sync | |
| 100 | 32 | 92.7, 64.3, 58.8 | 3T Torno. Must use 3T bolts. Looks like a 5-bolt pattern with one bolt missing. | |
| 96 | 30 | 78.6, 55.1 | Shimano XT M8000, SLX M7000, Deore M6000, 10mm holes; XTR M9000 and M9020, M7 threaded holes. | |
| 96 | 36 | 73.5, 67.9, 61.7 | FSA 96/68 SLK MTB ABS | |
| 96 | 32 | 73.5, 61.7 | Campagnolo Chorus | |
| 80 | 30 | 65.5, 45.9 | Shimano GRX inner | |
| 76 | 26 | 65.8, 48.9 | FSA Afterburner, Comet, K-Korce, SLK MTB ABS | |
| 76 | 25 | 62.3, 53.7, 48.9 | SRAM XX1 11-speed, Cannondale, Specialized Stout. Threaded for M8 bolts. | |
| 68 | 22 | 52.1, 48.1, 43.7 | FSA Comet MTB Modular, Comet triple, K-Force Modular, SL-K MTB Modular, V-Drive MTB Modular | |
| 64 | 22 | 52.4, 36.7 | Shimano XT, SLX, XTR 11-speed with the "X" shaped bolt pattern. | |
5-Bolt Cranks/Chainwheels: |
||||
| BCD (mm) | Smallest Ring |
Between adjacent holes (mm) |
Between non-adjacent holes (mm) | Application |
| 151 | 44 | 88.8 | 143.6 | Very old Campagnolo standard (pre '67) (Obsolete) |
| 144 | 41 | 84.6 | 137.0 | Old Campagnolo standard, still used for track; Sturmey-Archer FCT |
| 135 | 39 | 79.4 | 128.4 | Current Campagnolo standard |
| 130 | 38 | 76.4 | 123.6 | Standard Road double and triple (outer 2); Sturmey-Archer FCS |
| 128 | 38 | 75.2 | 121.7 | Nervar Sport, Star (Obsolete) |
| 122 | 38 | 71.7 | 116.0 | Stronglight 93, 101, 103, 104, 105 (Obsolete) |
| 118 | 36 | 69.4 | 112.2 | Ofmega, Takagi, SR (Obsolete) |
| 116 | 35 | 68.2 | 110.3 | Old Campagnolo Gran Sport touring, Victory, Triomphe |
| 110, 112 | 34 | 64.7, 65.2 | 104.6, 105.6 | Campagnolo CT inner/middle/outer with one bolt at larger diameter behind crank |
| 110 | 38 | 77.8, 70.7, 46.5 | FSA K-Force ABS: uneven pattern, 4 bolt with extra bolt behind crank | |
| 110 | 33 | 64.7 | 104.6 | Touring double, standard triple outer |
| 102 | 32 | 60.0 | 97.0 | Avocet triple inner (obsolete). Note, NOT same as Campagnolo. |
| 100 | 31; 36 | 58.8 | 95.1 | Merz adapter; Campagnolo triple inner (Obsolete) |
| 94 | 29 | 55.3 | 89.4 | Compact triple outer |
| 93 | 28 | 58.5, 52.7, 55.3, 54.0, 52.7 |
Wolf Tooth "CAMO", barely noticeable uneven spacing, requires Wolf Tooth spider and bolts. | |
| 92 | 30 | 54.1 | 87.5 | Shimano Dura-Ace triple inner |
| 90 | 30 | 52.9 | 85.6 | Edco, Mavic triple inner (old) |
| 86 | 28 | 50.5 | 81.8 | Stronglight 80, 99, 100, SR Apex (Obsolete). Chainwheels must be installed back to back, triple shifts poorly. |
| 85 | 28 | 50.0 | 80.8 | Old Shimano Deore, Takagi triple inner. (Obsolete) |
| 80 | 26 | 47.0 | 76.1 | Tevano (TA Campagnolo clone) triple inner. Bolts not interchangeable with others. |
| 74 | 24 | 43.5 | 70.4 | Standard ("full-sized") triple inner, used with 110 mm, 130 mm or 135 mm outer. |
| 58 | 20 | 34.1 | 55.2 | Compact granny |
| 56 | 20 | 32.9 | 53.3 | Sun Tour Compact granny (Obsolete) |
| 50.4 | n/a | 29.6 | 47.9 | TA Cyclotouriste, Criterium, Lambert, Shimano Deore, others: attachment for outer chainring; 7 mm holes. |
| 6- and 3-Bolt Cranks/Chainwheels: The BCD is: 2.000, 1/sin 30°, times the spacing between adjacent holes (6-bolt), 1.154 , 1/sin 60°, times the spacing between adjacent holes (3-bolt) or non-adjacent holes (6 bolt) |
||||
| BCD (mm) | Smallest Ring |
Between holes 60° apart (mm), 6-bolt |
Between holes 120° apart (mm) |
Application |
| 157 | 78.5 | 136.0 | Several very old Euro models | |
| 152 | 43 | 76 | 131.6 | TA Criterium bolts between outer chainwheel and others. |
| 143 | 42 | 71.5 | 123.8 | Lambert. Inner ring threaded. |
| 140 | 40 | 121.2 | Campagnolo Gran Sport inner | |
| 116 | 36 | 100.4 | TA Professional (10 mm holes), many old Euro steel cranks | |
| 116 | 36 | 58 | 100.4 | TA Randonneur: bolts are between outer chainwheel and others. |
| 112 | ? | 97.0 | Takagi | |
| 106 | 32 | 91.8 | Sugino Maxy, others w/8mm holes, SR Apex w/10mm holes. | |
| 95 | 30 | 82.3 | Shimano 600, 310 | |
| 88.9 (3.5") | 30? | 77.0 | Nicklin, Cross, Williams (very old) | |
| 86 | 28 | 74.5 | FSA Pro MTB 386, Comet 386 MTB | |
| 85 | 28 | 73.6 | SR Custom 3 | |
| 80 | 26 | 40 | 69.2 | TA Cyclotouriste, Lambert: bolts between outer chainwheel and others. |
| 70 | 24 | 60.6 | René Herse. 10mm holes. | |
Last Updated: by John Allen
