1、自行车链条线设计参数自行车链条线设计参数Chainline This refers to how straight the chain runs between the front and rear sprockets. Ideally, both sprockets should be in the same plane, so that there is no sideward motion or stress to the chain. This constitutes perfect chainline. In the case of derailer geared bicycles,
2、 the chainline is not perfect in most gears. The worse the chainline, the worse the mechanical efficienty of the drive train. Correct chainline for a derailer system is a matter of opinion, and depends on the intended use of the bicycle. There are two simple answers to the question of what constitut
3、es proper chainline: 1. One view is that the middle of the cluster should line up with the middle chainring (or half-way between the two, in the case of a double. 2. From the parts manufacturers point of view, the chainline depends on the diameter of the seat tube where the front derailer mounts. Fo
4、r fatter seat tubes where the front derailer is farther to the right, derailer manufacturers want the chainline to be farther to the right also, because their main priority is shifting performance, and their front derailers have an optimal chainline with respect to the edge of the seat tube. This is
5、 particularly a concern in the case of bicycles with indexed front shifting. From the riders point of view, chainline is partly dependent on how you are going to use your gears. For instance, consider a road triple vs a mountainbike triple: , With a road triple, you mostly use the two bigger rings,
6、the granny is only occasionally used, and only with the larger rear sprockets. For a road triple, having the cranks close-in is good, because it increases the usability of the big ring. , With a mountain bike, the small ring is used much more often, and must often be used with fairly small sprockets
7、 to avoid having to shift the front under load. For mountain bikes, a more outboard chainwheel position is often preferable. Chainline Standards: Application Dimension Notes Shimano spec, measured to the midpoint between the rings. with typical 5 mm chainring spacing, this puts the inner at 41 Road
8、Double 43.5 mm, the outer at 46 mm. Shimano spec, measured to the middle ring. Road Triple 45 Shimano spec, measured to the middle ring. 47.5 preferred, but for frames with oversized seat tubes, the 47.5-50 MTB Triple longer dimension may be needed, because the fat tube places mm the derailer mechan
9、ism farther to the right. Track/Coaster Brake Older bikes with 110 spacing would be on the smaller end of Traditional 40.5-42 this range One-Speed mm Newer bikes with 120 mm spacing normally use 42 mm Most internal gear hubs Singlespeed Wider chainline need for chainstay clearance on MTBs. 52 mm MTB
10、 Rohloff 54 mm This is close to the chainline of the outer ring Speedhub (58 mm of a typical MTB triple w/13 tooth) White Industries ENO hubs use this chainline, which lines up Singlespeed with the middle position of a typical MTB triple. MTB 47.5 mm Its also fairly close to the outer position of a
11、typical road Alternate double. Chainline Measurement-Front 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 mid
12、dle 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. Chainline Adjustment-Front If you need to adjust the front chainline, there are several different options to accomplish it:
13、, Change the Bottom Bracket Most bottom brackets made since the mid-90s are symmetrical, they stick out the same amount on each side. If you replace your present bottom bracket with one that is, say, 4 mm shorter, it will move the chainline 2 mm to the left, because it will be 2 mm shorter on each s
14、ide. If you go this route to a narrower chainline, make sure that there wont be a clearance problem between the frame and the crank or chainring. , Bottom Bracket Spacer If you need to increase the chainline (move the chainring to the right) you can usually add a spacer washer between the right-side
15、 bottom bracket mounting ring (or cup) and Sturmey-Archer the bottom bracket shell of the frame. The usual spacer for this is a sprocket spacer. These fit all threaded bottom brackets except Italian size. Sorry, I dont know of any source for a spacer that will fit an Italian (36 mm) bottom bracket.
16、, Chainring Spacers For a single chainring, you can add spacers between the chainring and the crank spider. If your chainring is mounted on the outside of the spider, you can move it to the rigtht this way. If its mounteed on the inside of the spider, you can move it to the left as shown. This uses
17、the same 10 mm I.D. spacers normally used on rear hub axles. Suitable spacers are available in 1, 2, and 3 mm thickness. You may need to use longer double stack bolts, especially for the 3 mm size. , Phil Wood Bottom Brackets Phil Wood BBs are super quality, available in many different lengths, and
18、they also feature the ability to adjust the chainline over a range of several millimeters. Phil Wood stuff is expensive, but its the Very Best. Chainline Measurement-Rear (For bikes that do not use derailer gearing) To measure rear chainline: , Measure the frame spacing (or the over-lock-nut dimensi
19、on of the hub , which should be the same.) (Example: 120 mm) , Divide the result in half. (Example: 60 mm) , Measure the distance from the inside of the rear fork end (or the outside of the axle locknut) to the middle of the sprocket. (Example: 18 mm) , Subtract the dropout-to-sprocket spacing (Exam
20、ple: 18 mm) from the half-over-lock-nut dimension (Example: 60 mm) to determine the actual rear chainline (Example: 42 mm) For fixed-gear or other single-speed hubs, see below for a chart of different hubs and sprockets. With this chart you can calculate the rear chainline by simple addition. Fixed
21、Sprockets and Single Freewheels I have measured a selection of track sprockets, single freewheels and hubs with respect to chainline (units are millimeters.) The Chainline column is the distance from them mounting shoulder to the center line of the sprocket teeth. To figure the actual chainline for
22、a given combination, add the number from the chainline column of the sprocket or freewheel to the corrresponding chainline column of the hub chosen. Fixed (Track) Sprockets Model/Type Nominal Measured Total Thread Chainline (From Width width thickness Thickness Shoulder) 3/32 2.0 8.0 7.8 Campagnolo
23、7.0 1/8 3.0 8.0 7.2 Campagnolo 6.5 3/32 2.2 8.23 8.05 E.A.I. 7.13 1/8 3.02 8.24 8.05 E.A.I. 6.73 Miche Quick 3/32 1.9 7.72 7.3 5.85/5.15 Change Splined Miche Quick 1/8 3.0 7.72 7.3 5.85/5.15 Change Splined 3/32 2.3 7.01 7.01 Phil Wood 5.86 1/8 3.02 7.56 7.06 Phil Wood 6.05 Shimano 3/32 2.11 7.55 7.5
24、5 6.49 Dura-Ace Shimano 1/8 3.05 8.58 7.7 7.05 Dura-Ace 3/32 1.86 7.3 7.3 Soma 6.37 1/8 3.00 8.4 6.9 Soma 6.9 1/8 3.0 8.5 7.5 Sugino Gigas 7.0 3/32 2.26 7.35 7.35 Sun Tour Superbe 6.22 1/8 3.05 8.46 7.5 Sun Tour Superbe 6.93 3/32 2.0 7.4 7.4 Surly New (2005) 6.4 1/8 3 7.4 7.4 Surly New (2005) 5.9 3/
25、32 2.05 6.31 6.31 Surly Old 5.28 1/8 2.7 6.42 6.42 Surly Old 5.07 Single Speed Freewheels Chainline (From Model/Type Nominal Width Measured width Shoulder) 3/32 2.16 ACS 7.96 3/32 2.08 Shimano 7.89 1/8 3.0 Shimano 8.67 1/8 2.96 Tristar 7.71 White 3/32 2.17 8.73 Industries Single Speed and Fixed Gear
26、 Hubs ChainliOLD Model/TyTrack/MAdjustableLeft Right Drillinne SpaciCenter to peTB?*SideSidegs ng Shoulder Ambrosio large Track 120 ? 36 Fixed Fixed 32 flange Campagn28, 32, Track 120 Yes 36 Plain Fixed olo small 36 flange 2002 Campagnolo 28, 32, C-Record Track 120 Yes 35.9 Plain Fixed 36 Large flan
27、ge 120, 130, Gold Tec Track Yes 39.5 Fixed Fixed 32, 36 135 Fixed/FrI.R.O. Track 120 No 36.0 32 ee Kogswell MTB 135 No 45.3 Fixed Fixed 32 28, 32, Miche Track 120 Yes 36.3 Plain Fixed 36 On-One Full MTB 135 No 43.3 Plain Free 32, 36 Monty 120, Plain Phil Wood 28, 32, 126, Fixed Track No 36.75 Fixed
28、Track36 130 Free Phil Wood Plain/FrFixed/FrK.I.S.S. MTB 135 No 45.35 32, 36 ee ee Off Shimano 28, 32, Dura-Ace Track 120 Yes 35.3 Fixed 36 7700 Shimano 28, 32, Dura-Ace Track 120 Yes 35.3 Fixed 36 7700 Small Flange Shimano Dura-Ace 28, 32, 7600 Track 120 Yes 35.4 Fixed 36 Large Flange Sovos Track 11
29、2 Yes 33.5 Free Fixed 36 28, 32, Spot MTB 135 No 47.25 Plain Free 36 Surly Track 120 Yes 36.22 Free Fixed 32 Track Surly 1 x Fixed/FrDrillinMTB 135 Yes 46.5 Free 1 ee gs Suzue 117-1228, 32, Track Yes 34.74 Free Fixed Basic 0 36 Suzue Promax 28, 32, Track 120 Yes 35.0 Free Fixed (cartridge36 ) Suzue
30、28, 32, Promax Track 120 Yes 35.0 Fixed Fixed 36 NJS Van MTB 135 No 45.9 Free Fixed 32 Dessell White 126, Track/M28, 32, Industries 130, No 39.1 Free Fixed TB 36 ENO 135 Chainline Adustement-Rear There are a number of options for adjusting rear chainline on bikes with a single rear sprocket: , Axle
31、Re-Spacing/Re-Dishing This is the usual way to go for converting bikes from a multi-speed derailer setup to a single-speed fixed-gear or freewheel drive. The spacers are located just behind the outer locknuts, between the locknuts and the cones (or the bearing mounting nuts, if your hub uses cartrid
32、ge bearings.) You will need cone wrenches and a general understanding of hub bearing adjustment to do this job. Assuming the rear hubs spacing already matches your frames spacing, you can take spacer washers from one side of the hub and move them to the other side, thus shifting the entire hub from side to side. In the c
