BB Size Database

Bottom Bracket Size Database https://www.sheldonbrown.com/bbsize.html This page is a listing of various bicycle crank sets, and the bottom brackets that fit them. Sheldon solicited information from readers to collect this data but that project is on hold until we set up a new mechanism for collecting and posting additional data. This is the information he collected: Crank Make Examples: Campagnolo, Nervar, Shimano, Stronglight, SR (Sakae Ringyo) Sugino, TA, Takagi Crank Model Single-Double-Triple Spindle/BB Code and Size Examples: D3H, 68 ss 120, UN72 68 x 113, UN52 70 x 107, 344...See the section for your brand of crank for details of the measurement system used. As far as crank interchangeability is concerned, the most important thing is the overall length, and the offset if the spindle is longer on one side than the other (that's true of many older units.) Spec or Measurement "Spec" indicates that you got the information from a manufacturer's data sheet or other publication. "Measurement" indicates that you have measured a crank installed on a bicycle. Please measure everything in millimieters. Tapered square or splined? Most cotterless cranks use tapered square axles. Some newer models are splined. For splined cranks, it would be helpful to specify the spline pattern if known. Items above in red are essential. If you can't supply all 5 of these bits of info, don't bother submitting. If you can fill in any of the additional items below, it will make your submission more useful Chainline See the chart below for an explanation of how to measure chainline Chainring Clearance This would be the distance from the inner surface of the innermost chainring to the centerline of the seat tube or down tube. Right Crank clearance This would be the distance from the inside of the right crank to the centerline of the seat tube or down tube, measured at the centerline of where the pedal screws in. Left Crank clearance This would be the distance from the inside of the left crank to the centerline of the seat tube or down tube, measured at the centerline of where the pedal screws in. Sponsored Content PROWHEEL 7/8/9 Speed MTB Bike Crankset 24/34/42T 170mm MTB Bicycle Crank Set Hollow ChainwheelAliexpress Recommended by Tread (a.k.a. "Q factor") This is the horizontal width of the crankset from pedal mount to pedal mount. It is equal to the sum of the crank clearances above, plus the thickness of each crank. I can do the math if you provide the measurements. Bolt Circle Diameter This is a useful item if you know it. Accuracy Most of the size information on this list was provided by people like you. I have no way to check the accuracy of the data. It should be noted that frames can be reamed out to take a larger sized seatpost, and sometimes a replacement seatpost may be a slightly different size than the original. Japanese Bottom Bracket Spindles, Traditional Cup And Cone Type Note: India's standard copies this. See listing in PDF document Size Code Shell Width D Length Overall A Length Left End B Length Middle C Length Right End Symmetrical Equivalent 3H 68 113 30.5 52 30.5 113 3K 68 117.5 32 52 33.5 119 3P 68 119 32 52 35 122 3N 68 120 32 52 36 124 3S 68 121.5 32 52 37.5 127 3T 68 123 32 52 39 130 3NN 68 124 36 52 36 124 3U 68 124.5 32 52 40.5 133 3TR 68 133 42 52 39 130 3RR 68 136 42 52 42 136 5N 70 122 32 55 35 125 Substituting the "symmetrical equivalent" bottom bracket will preserve the position of the right crank and chainwheel, but the left side will often wind up farther out. These spindles are getting harder and harder to find. In many cases, it makes more sense to upgrade to an inexpensive modern cartridge bottom bracket. "3" series spindles normally fit 68 mm ISO/British/French bottom brackets. "5" series spindles normally fit 70 mm Italian bottom brackets, also 68 mm French with thin cups. "7" series spindles fit "oversized" 73 mm ISO/British bottom brackets, sometimes also work with Raleigh 26 TPI cups in older Nottingham-built Raleigh bikes . Avocet - See Ofmega   Bontrager (Truvativ) Model Single/ Double/ Triple Length Type: Square/ Splined Chainline Chainring Clearance Right Crank Clearance Left Crank Clearance Tread (Q factor) BCD Chainring clearance more with steel inner ring, less with aluminum. All Square Type Triple/Single 113 Square 48.5 39.6/38.6 71 +/- 1.5 71 +/- 1.5 168 104/64 4-arm MTB Splined Type Triple/Single 113 ISIS 48.5 39.6/38.6 71 +/- 1.5 71 +/- 1.5 168 104/64 4-arm Road Splined Type Double 108 ISIS 43.5 130 Road Splined Type Triple 118 ISIS 45 130/74   Bulletproof Model Single/ Double/ Triple Length Type: Square/ Splined Chainline Chainring Clearance Right Crank Clearance Left Crank Clearance Tread (Q factor) BCD Notes BMX Single/Double 107 Square 43.4* 38.4 158 110 *43.4 chainline as double. 39.9 inner position, 46.9 outer position.   Campagnolo Sorry, no other data yet on this brand. Model Single/ Double/ Triple Length Type: Square/ Splined Chainline Chainring Clearance Right Crank Clearance Left Crank Clearance Tread (Q factor) BCD Notes Record 9 Double 116 Square 47 73 74 Edco Competition Cartridge BB (older model) bb spindle - 116 mm offset For more info on Campagnolo Models, see Martin Trautman's site   Coda Sorry, no data yet on this brand.   Mavic Sorry, no other data yet on this brand. Double 113 Square 130   Ofmega (Avocet) Ofmega cranks, including those branded "Avocet" use a non-standard spindle, thinner than either J.I.S. or ISO spindles. As far as I know, nothing else works.   Ritchey (Sugino) Sorry, no other data yet on this brand. Logic Triple 120 Square 122.5 mm UN-72 is the best Shimano replacement 118.5 mm Phil Wood barely fits Bridgestone XO-1 154 110/74 Logic Compact Triple 110-113 Square 154 w/113 94/58 Shimano Cartridge Bottom Brackets Shimano cartridge bottom brackets are typically coded with a model designation and two numbers: shell width and length. Model designations include: Square Taper: CT21, LP27, UN40, UN51, UN52, UN71, UN72, UN91. These are all interchangeable if the other numbers match. Listed in order of quality, CT21 is worst, UN91 is best. Octalink ® V1 Spline: 9 speed BB-M952 (XTR), BB-7700 (Dura-Ace), BB-6500 (Ultegra), BB5500 (105)    V1 BB spline grooves 5 mm long, ridges 2.2 mm wide. Octalink ® V2 Spline: 9 speed ES70/71, ES50/51 (Deore XT M571/572, Deore LX M751/751, M510-8, M440-8, also 2005 Tiagra FC4401 & 4404, 2005 Sora FC-3001 & 3004)    V2 BB spline grooves 9 mm long, ridges 2.8 mm wide. Note: Octalink ® V1 and V2 splined bottom brackets are very similar looking but if you use the wrong version you will ruin your crank! If in doubt, measure. The wider ridges of an Octalink V2 spindle plow into the grooves in an Octalink V1 crank. Thanks to David Richardson for the photo.   Hollowtech II ® Two-Piece Cranksets: Shimano's latest top-of-the line system is a two-piece crankset. One piece is the combined right crank and spindle, the other piece is the left crank. Hollowtech II uses separate bearing modules that screw onto the opposite sides of the frame. Since the spindle is part of the right crank, there's no issue of compatibility. All Hollowtech II cranks work with all Hollowtech II bearing units. Any crank that fits on one type of spindle will fit on all spindles of that type, but if the length is incorrect, the chainline/clearance will vary. Shell width in millimeters: 68 for standard ISO/British 70 for Italian 73 for oversized ISO/British. This dimension has to do with what kind of frame the bottom bracket fits, and has nothing to do with the crank. Length: overall spindle length in millimeters. This will determine the chainline and various clearance dimensions. Shimano sometimes specs two different lengths for the same crankset. This usually relates to the diameter of the seat tube. The shorter dimension is normally preferred, but bikes with fat seat tubes may require the longer size to accommodate the swing of the front derailer. Shimano Cranksets 105   200 | 200 | 300  600   700   Acera | Alivio | Altus   Deore   Dura-Ace   Exage   Hone Nexave   Nexus   RSX   RX100   Saint   Sora   STX   Tiagra   Ultegra   XTR Model Single/ Double/ Triple Length Type: Square/ Splined Chainline Chainring Clearance Right Crank Clearance Left Crank Clearance Tread (Q factor) BCD Notes  Shimano 105 Model Single/ Double/ Triple Length Type: Square/ Splined Chainline Chainring Clearance Right Crank Clearance Left Crank Clearance Tread (Q factor) BCD Notes 105-SC 1055 Double 113 (115) Square 43.5 130 7-speed 1990-92 105-SC 1056 Double 107 Square 43.5 130 8-speed 1993- 105-SC 1057 Triple 118 Square 45 130/74 8-speed 1996- 105 5500 Double 109.5 V1 Spline 43.5 130 9-speed 1999-2000 105 5501 Double 109.5 V1 Spline 43.5 130 Hollowtech, 2001-02 105 5503 Triple 118.5 V1 Spline 45 130/74 9-speed 1999-2000 105 5504 Triple 118.5 V1 Spline 45 130/74 Hollowtech, 2001-02  Shimano 200-700 (See also Exage and Ultegra) Model Single/ Double/ Triple Length Type: Square/ Splined Chainline Chainring Clearance Right Crank Clearance Left Crank Clearance Tread (Q factor) BCD Notes 200CX M202-C Triple 127.5 Square riveted 7-speed 1992 200GS M201 Triple 121 Square riveted 7-speed 1990 300EX A300 Double 115 Square 43.5 130 8-speed 1996-99 400CX C400 Triple 113-118 Square 45-47.5 110/58 7-speed 1993-94 700CX C700 Triple 113-118 Square 45-47.5 110/58 7-speed 1993-94   Shimano Acera / Alivio / Altus Model Single/ Double/ Triple Length Type: Square/ Splined Chainline Chainring Clearance Right Crank Clearance Left Crank Clearance Tread (Q factor) BCD Notes Acera M330 Triple 110-113 Square 47.5-50 61 mm 1999-2000 Acera MC19 Triple 110-113 Square 47.5-50 61 mm 8-speed 2001 Acera-X M290 Triple 110-113 Square 47.5-50 Recalled! Do Not Use! See Shimano dealer for free replacement. Compact 1995 Acera-X M291 Triple 110-113 Square 47.5-50 riveted 1996-98 Alivio MC10 Triple 110.5-113 Square 47.5-50 95 (!)/58 Compact 1994 Alivio MC11 Triple 110.5-113 Square 47.5-50 riveted Compact 1994 Alivio MC12 Triple 110-113 Square 47.5-50 Recalled! Do Not Use! See Shimano dealer for free replacement. Compact 1995 Alivio MC14 Triple 110-113 Square 47.5-50 67(!) 1996-97 Alivio MC16 Triple 110-113 Square 47.5-50 67(!) 1997-98 Alivio MC18 Triple 110-113 Square 47.5-50 104/64 1999 Alivio MC20 Triple 110-113 Square 47.5-50 104/64 8-speed 2000-01 Altus CT90 Triple 116-121 Square 47.5-50 Recalled! Do Not Use! See Shimano dealer for free replacement. Compact 1995 Altus CT91 Triple 116-121 Square 47.5-50 riveted 1996-97 Altus CT92 Triple 116-121 Square 47.5-50 riveted 1997-99 Altus CT93 Triple 116-121 Square 47.5-50 riveted 1999-2001 Altus C50 CT50 Triple 122.5 Square 47.5 riveted 1994-95  Shimano Deore Model Single/ Double/ Triple Length Type: Square/ Splined Chainline Chainring Clearance Right Crank Clearance Left Crank Clearance Tread (Q factor) BCD Notes Deore M440,480,510 Triple 110-113 Square 47.5-50 104/64 9-speed 2000-05 Shimano Deore DX Deore DX MT60 Triple 122.5 Square 110/74 1990-1993 Shimano Deore LX Deore LX M550 Triple 122.5 Square 110/74 1990-1992 Deore LX M560 Triple 113-118 Square 110/74 1993 Deore LX M563 Triple 107-113 Square 47.5-50 94/58 Compact 1994-96 Deore LX M569 Spiderless 107-113 Square 47.5-50 1997-98 Deore LX M570 Spiderless 110-113 Square 1999 Deore LX M571 Spiderless 113-118 V2 Spline 9-speed 2000-04 Deore LX M580, M581 Spiderless Hollowtech II 50 9-speed 2005 Shimano Deore XT Deore XT M730 Triple 122.5 Square 110/74 1990-1993 Deore XT M737 Triple 107-113 Square 47.5-50 94/58 Compact 1994-96 Deore XT M739 Triple 107-113 Square 47.5-50 Spiderless Compact 1997-99 Deore XT M750 Spiderless 110-113 Square 1999 Deore XT M751 Triple 113-118 V2 Spline 47.5-50 104/64 9-speed 2000-03 Deore XT M760, M761 104/64 Hollowtech II 50 9-speed 2004 and later  Shimano Dura-Ace Model Single/ Double/ Triple Length Type: Square/ Splined Chainline Chainring Clearance Right Crank Clearance Left Crank Clearance Tread (Q factor) BCD Notes Dura-Ace 7200 Double 112-113 Square 43.5 130 6-speed 1980s Symmetrical spindle 112 for 68 mm BB; 113 for 70 mm (Italian) Dura-Ace 7400-7402 Double 112-113 Square 43.5 130 8-speed 1990-95 Right end of spindle 3 mm longer 112 for 68 mm BB; 113 for 70 mm (Italian) Dura-Ace 7410 Double 103 Square 43.5 130 8-speed 1996 Dura-Ace Aero BB-7300 (7500 AX) Double 107-109 Square 43.5 130 6-speed 1980s Symmetrical spindle 107 for 68 mm BB; 109 for 70 mm (Italian). Uses special cups, will not fit through hole in others. Dura-Ace 7600 Single 109 Square 43 40.6 56.3 56.3 139.4 144 Dura-Ace 7700 Double 109.5 V1 Spline 43.5 130 9-speed, 1997-2000 Dura-Ace 7701 Double 109.5 V1 Spline 43.5 130 Hollowtech, 2001-03 Dura-Ace 7700 Triple 118.5 V1 Spline 47.5 130/92 9-speed, 2002 and later Dura-Ace 7800 130 Hollowtech II 43.5 10-speed 2004 and later  Shimano Exage Model Single/ Double/ Triple Length Type: Square/ Splined Chainline Chainring Clearance Right Crank Clearance Left Crank Clearance Tread (Q factor) BCD Notes Exage 300X A300 Double 113 Square 43.5 130 7-speed 1990-92 Exage 300LX M300 Triple 121 Square 110/74 7-speed 1990-92 Exage 400X A400 Double 113 Square 43.5 130 7-speed 1990-92 Exage 400LX M400 Triple 121 Square 110/74 7-speed 1990-92 Exage 500X A500 Double 113 Square 43.5 130 7-speed 1990-92 Exage 500CX M400-C Double 122.5-127.5 Square 7-speed 1992 Exage 500LX M500 Triple 121 Square 110/74 7-speed 1990-91 Exage ES M520 Triple 113-118 Square 47.5-50 110/74 7-speed 1993 Exage LT M320 Triple 113-118 Square 47.5-50 110/74 7-speed 1993  Shimano Hone Hone M600 Hollowtech II 57.5 104/64 9-speed 2005 and later  Shimano Nexave Nexave T410 Triple 117.5 Square 47.5 104/64 2000 Nexave T411 Triple 116-121 Square 47.5-50 riveted 2000 Nexave T300 T300-S Triple 117.5 Square 47.5 riveted 2002 Nexave T300 T303 Triple 117.5 Square 47.5 riveted 2000-02 Nexave T400 T410 Triple 117.5 Square 47.5 110/64 2002 Nexave T400 T411 Triple 117.5 Square 47.5 79 2002 Nexave C600 C600 Double 117.5 Square 52.5 112 2000-02 Nexave C900 C900 Double 121 Square 52.5 112 2000-02  Shimano Nexus Inter C Model Single/ Double/ Triple Length Type: Square/ Splined Chainline Chainring Clearance Right Crank Clearance Left Crank Clearance Tread (Q factor) BCD Notes Nexus Inter C NX70 Single 116 Square 45 Swaged For internal hubs Nexus Inter C NX40 Single 116 Square 45 Swaged For internal hubs Nexus Inter C NX40 Single 116 Square 45 Swaged For internal hubs Nexus Inter C 510 Single 122.5 Square 45 Swaged For internal hubs  Shimano RSX Model Single/ Double/ Triple Length Type: Square/ Splined Chainline Chainring Clearance Right Crank Clearance Left Crank Clearance Tread (Q factor) BCD Notes RSX A410 Double 110 Square 43.5 110 36-46 1995-1997 RSX A413 Triple 118 Square 45 110/74 26-36-46 1995-1997 RSX A416 Double 110 Square 43.5 130 42-52 1999-2000 RSX A417 Triple 118 Square 45 130/74 30-42-52 1999-2000  Shimano RX100 RX100 A550 Double 113 Square 43.5 130 7-speed 1990-93 RX100 A551 Double 107 Square 43.5 130 8-speed 1994-2000 RX100 A550-T Triple 122.5 Square 47.5 130/74 8-speed 1996-2000  Shimano Saint Saint M805 Hollowtech II 57.5 104/64 9-speed 2004 and later  Shimano Sora Sora 3300 Double 110 Square 43.5 130 8-speed 2001-04 Sora 3303 Triple 113 Square 45 130/74 8-speed 2001-04 Sora 3301 Double 113 V2 Spline 43.5 130 8-speed 2005 Sora 3304 Triple 118 V2 Spline 45 130/74 8-speed 2005  Shimano STX, STX-ES, STX-RC STX MC30 Triple 110.5-113 Square 47.5-50 95 (!)/58 Compact 1994 STX MC32 Triple 110-113 Square 47.5-50 94/58 Compact 1995-96 STX MC34 Triple 110-113 Square 47.5-50 94/58 Compact 1997- STX-SE MC31 Triple 110.5-113 Square 47.5-50 95 (!)/58 Compact 1994 STX MC34 Triple 110-113 Square 47.5-50 94/58 7-speed 1996-98 STX-RC MC33 Triple 110-113 Square 47.5-50 94/58 Compact 1995 STX-RC MC36 Triple 110-113 Square 47.5-50 94/58 8-speed Compact 1996-97 STX-RC MC40 Spiderless 110.5-113 Square 47.5-50 1998-99  Shimano Tiagra Model Single/ Double/ Triple Length Type: Square/ Splined Chainline Chainring Clearance Right Crank Clearance Left Crank Clearance Tread (Q factor) BCD Notes Tiagra 4400 Double 110 Square 43.5 130 9-speed 2001-04 Tiagra 4403 Triple 113 Square 45 130/74 9-speed 2001-04 Tiagra 4401 Double 113 V2 Spline 43.5 130 9-speed 2005 Tiagra 4404 Triple 118 V2 Spline 45 130/74 9-speed 2005  Shimano Ultegra (600 Ultegra) Model Single/ Double/ Triple Length Type: Square/ Splined Chainline Chainring Clearance Right Crank Clearance Left Crank Clearance Tread (Q factor) BCD Notes 600 Ultegra 6400 Double 113 (115) Square 43.5 130 6-/7-speed 1990 8-speed 1991-96 Ultegra 6500 Double 109.5 V1 Spline 43.5 147 130 9-speed 1998-2004 Ultegra 6500 Triple 118.5 V1 Spline 45 156 130/74 9-speed 1998-2004 Ultegra 6600 Double Hollowtech II 43.5 130 10-speed 2005 and later Ultegra 6603 Triple Hollowtech II 43.5 130/74 10-speed 2005 and later  Shimano XTR Model Single/ Double/ Triple Length Type: Square/ Splined Chainline Chainring Clearance Right Crank Clearance Left Crank Clearance Tread (Q factor) BCD Notes XTR M900 Triple 107-113 Square 47.5-50 110/74 8-speed 1992-95 XTR M950 Triple 112-116 SV1 Spline 47.5-50 112/68 4 arm 8-speed 1996- XTR M950-HG Triple 112-116 V1 Spline 47.5-50 110/74 8-speed 1996-97 XTR M951 Spiderless 112-116 V1 Spline 47.5-50 8-speed 1998 XTR 952 Spiderless 112-116 V1 Spline 47.5-50 110/68 9-speed 1999-2003 XTR 960 Triple Hollowtech II 47.5-50 146/102/64 9-speed 2004 and later For more info on Shimano Models, see Martin Trautman's site   Sakae Ringyo (SR) Sorry, no data yet on this brand.   Stronglight See also: TA for older models.   Sugino Model Single/ Double/ Triple Length Type: Square/ Splined Chainline Chainring Clearance Right Crank Clearance Left Crank Clearance Tread (Q factor) BCD Notes AT Triple (Made for an asymmetrical spindle.) 127.5 + 2 mm spacer Square 150 110/74 Shimano UN-72 BB. 122.5 + 2 mm spacer Square 150 110/74 '80s Shimano UN72 w/2 mm spacer on right 115.5 + 2 mm spacer Square 42.5 139 110/74 Shimano UN-73 BB. 700CX 4-bolt Triple 110-113 Square 104/58 2001 EX 4-bolt Triple 110-113 Square 104/64 2001 '97 Impel 5-bolt Triple 110-113 Square 110/74 2001 XD 300 5-bolt Triple 113-118 Square 110/74 As short as 107 works with some road bikes. XD 500 5-bolt Triple 113-118 Square 110/74 2001 As short as 107 works with some road bikes. XD 600 5-bolt Triple 113-118 Square 110/74 As short as 107 works with some road bikes. 75 Track 109 ISO Square 144 Sugino BB-SG75 Alternate: Campagnolo 110.5 ISO Chain line will be 1.5 mm wider than normal, according to Sugino Alternate: Phil Wood 108 ISO Chain line will be 1 mm narrower than normal, according to Sugino RD 5-bolt Single 103 Square 42 130 2004   Sun Tour Model Single/ Double/ Triple Length Type: Square/ Splined Chainline Chainring Clearance Right Crank Clearance Left Crank Clearance Tread (Q factor) BCD Notes Cyclone 7000 Double Shimano 110 Square 43.1 38.1 30.5 30.5 146.2 130 Early '90s Superbe Pro Double Campagnolo 111 Square 43.5 39 59 60 143 130 Early '90s   T.A. Cyclotouriste (Generally interchangeable with older Stronglight) Ref.# Length Application #314 111.5 mm (track) #344 118.5 mm (double) #373 120 mm (road triple) #374 123.5 mm (road triple) #375 127 mm (tandem) #376 133.5 mm (MTB triple) Model Single/ Double/ Triple Length Type: Square/ Splined Chainline Chainring Clearance Right Crank Clearance Left Crank Clearance Tread (Q factor) BCD Chainring clearance more with steel inner ring, less with aluminum. Cyclotouriste Double Shimano UN52 115 mm Square 43 134.4 50.4 mm Sheldon Brown's Hetchins Zephyr Double 110 Square 43 36 61 59 147 130   Thorn Sorry, no other data yet on this brand. Tandem Triple 113 Square 113 spec, but 107 works a lot better. This gives a proper 47.5 mm chainline and lower Q-factor 162 110/74   Truvativ Model Single/ Double/ Triple Length Type: Square/ Splined Chainline Chainring Clearance Right Crank Clearance Left Crank Clearance Tread (Q factor) BCD Chainring clearance more with steel inner ring, less with aluminum. Square Taper Models Firex Triple/Single 113 Square 48.5 39.6/38.6 71 +/- 1.5 71 +/- 1.5 168 104/64 4-arm FiveD Triple/Single 113 Square 48.5 39.6/38.6 71 +/- 1.5 71 +/- 1.5 168 104/64 4-arm Hussefelt Triple/Single 113 Square 48.5 39.6/38.6 71 +/- 1.5 71 +/- 1.5 172 104/64 4-arm Stylo Triple/Single 113 Square 48.5 39.6/38.6 71 +/- 1.5 71 +/- 1.5 168 104/64 4-arm X-Forge Triple/Single 113 Square 48.5 39.6/38.6 71 +/- 1.5 71 +/- 1.5 168 104/64 4-arm ISIS Drive Splined Models Firex Triple/Single 113 ISIS 48.5 39.6/38.6 71 +/- 1.5 71 +/- 1.5 168 104/64 4-arm FiveD Triple/Single 113 ISIS 48.5 39.6/38.6 71 +/- 1.5 71 +/- 1.5 168 104/64 4-arm Holzfeller Triple/Single 113 ISIS 48.5 39.6/38.6 71 +/- 1.5 71 +/- 1.5 172 110/74 5-arm Hussefelt Triple/Single 113 ISIS 48.5 39.6/38.6 71 +/- 1.5 71 +/- 1.5 172 104/64 4-arm Stylo Triple/Single 113 ISIS 48.5 39.6/38.6 71 +/- 1.5 71 +/- 1.5 168 104/64 4-arm A note regarding chainline: but there is currently confusion in the industry regarding how it is actually measured. For double road cranks and single speed cranks this is straightforward, but for triple cranks there are two current measurement methods: As Shimano, which is outlined on your web page, in which chainline is measured from the frame centerline to the INSIDE surface of the chainring teeth on the middle chainring. As most other manufacturers use, and is defined in the ISIS Drive standard, in which chainline is measured from the frame centerline to the CENTER of the tooth of the middle chainring. For typical 2mm thick chainring teeth, these two measurement methods differ by 1mm, even though the chainring ends up in the same physical location relative to the frame centerline. Hence, a Shimano 47.5 mm chainline is equivalent to an ISIS Drive 48.5 mm chainline. Further, the confusion that your table is attempting to help solve is the same confusion that we tried to address in the ISIS Drive standard. In the case of ISIS Drive, the standard spindle lengths are symmetric and vary in multiples of 5 mm. Thus, if you know the chainline is 48.5 mm with a 113 mm ISIS Drive spindle length, then you automatically know that if you use a 118 mm ISIS Drive spindle length your chainline will increase by 2.5 mm (each crank moves outward 2.5 mm, for a total of 5 mm). A note regarding these differences in chainline measurement on your web page may help some people better understand why a manufacturer claims a 48.5 mm chainline but when they measure it (per Shimano) it is 47.5 mm. Garrett Smith Truvativ International   Chainline Measurement Chainline is measured from the centerline of the frame to the center of the chain. You can measure the front chainline directly with a simple ruler. Simply hold the ruler against the seat tube or down tube and measure the distance to the middle of the chainring teeth. In the case of triple chainwheel sets, measure to the middle chainring. In the case of doubles, measure to the halfway point between the two rings. To measure rear chainline, the easiest way is to measure the distance from the inside of the rear fork end (or the outside of the axle locknut) to the middle of the sprocket. Double this, subtract it from the over-lock-nut dimension of the hub (or the frame spacing , which should be the same), then divide the result in half, and you have the rear chainline. This frame has a spacing of 125 mm Application Dimension Notes Road Double 43.5 Shimano spec, measured to the midpoint between the rings. with typical 5 mm chainring spacing, this puts the inner at 41 mm, the outer at 46 mm. Road Triple 45 Shimano spec, measured to the middle ring. MTB Triple 47.5-50 mm Shimano spec, measured to the middle ring. 47.5 preferred, but for frames with oversized seat tubes, the longer dimension may be needed, because the fat tube places the derailer mechanism farther to the right. Track/Coaster Brake Traditional One-Speed Most internal gear hubs 40.5-42 mm Older bikes with 110 spacing would be on the smaller end of this range Newer bikes with 120 mm spacing normally use 42 mm Singlespeed MTB 52 mm Wider chainline need for chainstay clearance on MTBs. This is close to the chainline of the outer ring of a typical MTB triple Rohloff Speedhub 54 mm (58 mm w/13 tooth) Singlespeed MTB Alternate 47.5 mm White Industries ENO hubs use this chainline, which lines up with the middle position of a typical MTB triple. It's also fairly close to the outer position of a typical "road" double. Axle/Crank Interfaces   Square Taper Traditional cotterless cranksets use a tapered square axle end. The sides of the end taper at a 2 degree angle compared to the centerline, 4 degrees compared to each other. While there is general agreement about the angle, there is no such agreement about the actual width cut off. ISO vs J.I.S. Standard Martin Trautmann posted on rec.bicycles.tech : L_right = 18 +0.5/-0 mm L_left = 16 +0.5/-0 mm Dimension across flat 1.5 mm from end: 12.6 mm +0.02-0.05 Spindle end to bolt seat: Loose: 3 mm Tightened: 1.5 mm min. Yet another source claimed that the squares of Campa, Mavic and Stronglight (ISO) are smaller than Shimano and Suntour (J.I.S.) with the result that J.I.S. cranks will move about 4.5 mm further in. This may conflict with the end of the square and result in a loose fit or breaking stress. For ISO cranks on J.I.S. squares there's less contact area between crank and spindle, since the crank does not slip perfectly onto the spindle. The result again is a higher risk of breaking the crank. But assuming those 4.5 mm and 2 deg, ISO is about 0.3 mm smaller than J.I.S. (2 * sin 2 * 4.5 = 0.3)? ISO cranks (Campagnolo, Stronglight, others) won't go as far onto J.I.S. spindles as they ideally should. J.I.S. cranks (most Japanese models) may bottom out if installed on ISO spindles. In practice, you can very often get away with mixing these sizes, as long as you select an axle length that gives the desired chainline. See also my Article on Bottom Bracket Tapers.   ISIS Drive Spline In the case of ISIS Drive, the standard spindle lengths are symmetric and vary in multiples of 5 mm. Thus, if you know the chainline is 48.5 mm with a 113 mm ISIS Drive spindle length, then you automatically know that if you use a 118 mm ISIS Drive spindle length your chainline will increase by 2.5 mm (each crank moves outward 2.5 mm, for a total of 5 mm). Garrett Smith, Truvativ International. Bottom Bracket Threading Bottom brackets come in different sizes, according to the nationality of the frame. The table below is for threaded bottom-brackets. For the Ashtabula and other unthreaded bottom brackets, see the unthreaded bottom-bracket cribsheet. Standard: Threading Adjustable (left) cup/cone direction Fixed (right) cup/cone direction Shell Width Applications/Notes British I.S.O. 1.370" X 24 tpi 1.375" X 24 tpi right left Standard 68 mm O.S. 73 mm The overwhelming majority of bicycles in current production. British and I.S.O. are interchangeable. Shimano Hollowtech II, FSA MegaExo, RaceFace X-type ISO right left 90 mm, 95 mm including cups External cups for cartridge bearings fit British/ISO threaded bottom brackets or unthreaded shell. 24 mm spindle, spacer to use 6805 bearings with 25mm I.D.. Bottom bracket shell must be faced so cups are parallel. Campagnolo Ultra-torque Italian or ISO       Spindle diameter 25mm. Chater Lea 1.450 x 26 TPI right left   Obsolete British size but available from Phil Wood & Co. French 35 mm X 1mm (25.4 tpi) right right (wrong!) 68 mm Obsolete, used on older French bicycles. Prone to problems due to the right threaded fixed cup, which tends to unscrew itself in use. ISIS Overdrive I 48 x 1.5 mm right left 68mm 100 mm   ISIS Overdrive II 48 x 1.5 mm right left 68mm 100 mm New proposed standard oversized system. Italian 36 mm X 24 tpi right right (wrong!) 70 mm Italian and some high-end French bicycles. Prone to problems due to the right threaded fixed cup, which tends to unscrew itself in use. Raleigh 1 3/8" X 26 tpi right left 71 mm 76 mm Older British-made Raleighs, 3 speeds and others from the Nottingham factory. Swiss 35 mm X 1mm (25.4 tpi) right left 68 mm Same thread as French, but fixed cup is left- threaded for reliability. What happens if you try to mix different sizes: Bottom Bracket Shell Threading (Below) BritishI.S.O. 1.37/1.375" x 24 tpi CUPS R-L (34.8/34.9 x 1.06 mm) Italian 36 mm X 24 tpi CUPS R-R (1.417" x 1.06 mm) French 35 mm X 1mm CUPS R-R (1.378 x 25.4 tpi) Swiss 35 mm X 1mm CUPS R-L (1.378 x 25.4 tpi) Raleigh 1 3/8" X 26 tpi CUPS R-L (34.9 x 1.06 mm) British/I.S.O. 1.37/1.375" x 24 tpi (34.8/34.9 x 1.06 mm) Made to Fit 36 mm Cup diameter is too large, thread won't even start. Cup diameter is slightly too large, usually won't start. Right (fixed) cup threaded in the opposite direction. Cup diameter is slightly too large, usually won't start. Diameter matches, but thread pitch does not. Will bind after only a few threads are engaged. Italian 36 mm X 24 tpi (1.417" x 1.06 mm) British/I.S.O. cups fall through Made to Fit Italian shells are larger diameter, all other size cups fall right through, threads will not engage. French 35 mm X 1mm (1.378 x 25.4 tpi) 35 mm = 1.378". Shell is slightly larger, thread pitch slightly finer. Left side may seem to fit, but will be loose. 36 mm Cup diameter is too large, thread won't even start. Made to Fit Left (adjustable) side is interchangeable. Right (fixed) side is threaded in the opposite direction, won't fit. 35 mm = 1.378". Shell is slightly larger, thread pitch slightly coarser. Left side may seem to fit, but will be loose. Swiss 35 mm X 1mm (1.378 x 25.4 tpi) 35 mm = 1.378". Shell is slightly larger, thread pitch slightly finer. May seem to fit, but will be loose. 36 mm Cup diameter is too large, thread won't even start. Left (adjustable) side is interchangeable. Right (fixed) side is threaded in the opposite direction, won't fit. Made to Fit 35 mm = 1.378". Shell is slightly larger, thread pitch slightly coarser. May seem to fit, but will be loose. Raleigh 1 3/8" X 26 tpi (34.9 x 0.977 mm) Diameter matches, but thread pitch does not. Will bind after only a few threads are engaged. 36 mm Cup diameter is too large, thread won't even start. Cup diameter is slightly too large, usually won't start. Right (fixed) cup threaded in the opposite direction. Cup diameter is slightly too large, usually won't start. Made to Fit Chainline Application Dimension Notes Road Double 43.5 Shimano spec, measured to the midpoint between the rings. With typical 5 mm chainring spacing, this puts the inner at 41 mm, the outer at 46 mm. Road Triple 45 Shimano spec, measured to the middle ring. Note that this results in the middle chainwheel's being to the right of the chainline for the middle rear sprocket. MTB Triple 47.5-50 mm Shimano spec, measured to the middle ring. 47.5 preferred, but for frames with oversized seat tubes, the longer dimension may be needed, because the fat tube places the derailer mechanism farther to the right. Track/Coaster Brake Traditional One-Speed Most internal gear hubs 40.5-42 mm Older bikes with 110 spacing would be on the smaller end of this range Newer bikes with 120 mm spacing normally use 42 mm Singlespeed MTB 52 mm Wider chainline need for chainstay clearance on MTBs. This is close to the chainline of the outer ring of a typical MTB triple Rohloff Speedhub 54 mm (58 mm w/13 tooth) Singlespeed MTB Alternate 47.5 mm White Industries ENO hubs use this chainline, which lines up with the middle position of a typical MTB triple. It's also fairly close to the outer position of a typical "road" double. Thanks to those who helped by providing data points for this survey: Evan Marks, Andrew Muzi, Joel Stern, Martin Rockwell, Martin Trautmann, Alex Wetmore... For more info on Campagnolo and Shimano Models, see Martin Trautman's ssi