Bicycle chain

The bicycle chain is part of the chain transmission used in the bike, the torque generated by the rider's pedaling force is transmitted to the drive wheel. The efficiency of a chain can be up to 98%. In derailleurs transversely shifted and with little further train running chain changed to a parallel sprocket or chainring. To improve this change, the outer plates of the chain are often specially shaped.

The bicycle chain can be with a special link ( master link ) is releasably closed. In derailleurs this broader term would collide with the switching mechanism, which is why closed chains are used here with a special tool called a chain tool permanently.

History

Nowadays almost exclusively used chains with sleeves ( IGH ) or bearing collar chains ( derailleur ) with a pitch of 1/2 ".

Dimensions and weights

Derailleurs require special circuit chains, where the multiplicity of the ability to switch the sprocket packets destined to the chain width. The usual Maßkennzeichnung for a bicycle chain consists of two dimensions in inches (dimension 1 × 2 degree ). The first dimension is the distance from joint to joint (chain pitch) is the same for the most commonly used today chains. The second dimension refers to the smallest internal dimension, ie the width between the inner links, exactly where the sprockets engage.

  • 5/8 " x 5 /32" for old touring bikes ( before 1945 ).
  • 1 "x 1/8" in block chain
  • 1/2 " x 1/ 8" for IGH, BMX and track bikes ( external width: 8.6 to 9.4 mm depending on the manufacturer )
  • 1/2 " x 3 /32" chain for circuits with up to 8-fold switchable sprocket assemblies ( External Width: 7.1-7.3 mm depending on the manufacturer ) (suitable for a Shimano InteractiveGlide chain ring and pinion thickness of 2.35 mm)
  • 1/2 " × 11/128 " for chain circuits with up to 9 -fold switchable sprocket assemblies ( Shimano Hyperglide external width: 6.8 mm and Campagnolo external width: 6.6 mm )
  • 1/2 " x 5 /64" chain for circuits with up to 10 -fold switchable sprocket assemblies ( Shimano Hyperglide Outside Width: 6.15 mm and Campagnolo external width: 5.9 mm)
  • 1/2 " x 9/128 " for chain circuits with up to 11 -fold switchable sprocket assemblies ( Campagnolo external width: 5.5 mm)
  • Modern IGH ( Rohloff / Alfine ) use as the 6- 8-fold derailleurs the incremental 1/2 " x 3 /32"

The weight of a chain varies depending on the application and length. Bike chains for derailleurs weigh about 300 to 350 g, hub gear chains 275-300 g per 100 links.

Catenary

In the plan view of the bicycle, the chain line is the line, as the chain which appears in its imaginary center position. It runs through the center pinion and the intermediate chainring or sprocket or chain with an even number of sheets in the middle between two sheets or sprockets. The distance between the center of the frame and chain line is also called short chain line and is standardized (eg 47.5 mm or 50 mm, with track bikes usually 42 mm).

The chain line determines the angle at which the bicycle chain runs between the front chainrings and rear sprockets. Ideally located chainring and sprocket in a straight line. In this case, the optimum power transfer is possible - the efficiency reaches its maximum, wear a minimum.

In derailleurs for all courses is theoretically not possible. The chain line should be such that the chain runs in the aisles most commonly used as straight as possible. In general, the chain line is determined solely by the length of the inner bearing shaft. In the modern, external bearings fewer variants are available.

Run-in

For new chains, bolts and chain sleeve / bearing collar linear contact. At first 100-200 km it comes to adjusting the radii and thus to high wear due to the small contact area of both parts. The Rohloff used in their chains trochoid - shaped bearing collar, the surface pressure - and thus the wear - much lower (Patent EP 0396701 ).

Chain maintenance and wear

The wear of a chain is formed, characterized in that during the movement of the chain slowly the connecting pins to be ground smaller. It comes to play in the joints, which manifests itself in an elongation of the chain. This wear should be checked regularly, see chain wear measurement.

The degree of elongation in operation (and thus the life of the chain ) depends largely on how much they polluted because of all residue has an abrasive effect. Fine sand - which is included in practically every kind of filth - acts like sandpaper and increases wear immense.

The most important part of the chain care is therefore to keep the chain clean on the outside, so that sand and other dirt particles only can not penetrate to the chain joints. Too much and too thin oil can wash the lubrication of the chain links, which also entails a high wear by itself.

For the lubrication of the outer chain parts, there are numerous means. One differentiates particularly between oil-bearing and oil-free products.

In oil-containing lubricants are categorized according to viscosity (thin or thick ). The lower the viscosity the oil, the better it gets into the cracks between the chain links and the less dirt will stick to the chain. However, low viscosity oils are easily washed out by rain. Generally you should wipe when using oil-based lubricant the chain regularly with a cloth, so that not too much dirt accumulates.

Lubricants silicone or PTFE-based ( polytetrafluoroethylene, DuPont trade name Teflon) are not sticky but will quickly rinsed from rain, making relubrication after each rain travel required.

The inevitable increase under load at derailleurs skew and switching the wear. Lowers wear on the other hand are large chainring and large sprocket. As the wear occurs only when moving chain links, keep the long chains of recumbents longer.

The mileages vary from 1000 km when using a derailleur in bad weather in the forest, about 3,000 to 5,000 km at derailleur with good care to around 6,000 km with chains without derailleur and good care. Long and largely protected chains, as in velomobiles can hold much longer; it is reported mileages up to 100,000 km.

The chain stay protector prevents hitting the bicycle chain to the frame and the chain stay, especially when driving off-road.

Chainrings and sprockets

By a lengthened chain, the teeth of the chainrings and sprockets are attacked, making them wear out faster than a new chain. You can optionally change the chain already at relatively low elongation to protect the chainrings and sprockets, or chain you go as long as possible and then change chainrings and sprockets along with the chain.

Synchronous chain on a tandem

Most tandems are equipped with a second chain, the synchronous chain. This usually takes place on the left side and connects the two cranksets with each other. This is an ordinary bicycle chain with an adjusted length.

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