Bicycles/Upkeep and Restore/Chain Rings – Wikibooks, open books for an open world

Bicycles/Maintenance and Repair/Chain Rings - Wikibooks, open books for an open world

A two-ring meeting. Discover the bolts with slotted nuts that fasten the chain rings to the spider of the crank, and the crank arm extending upward. When a guard plate is put in (not proven), it’s spaced from the biggest ring to permit clearance for the chain.

Two sorts of chain ring bolt. The silver bolt has a slotted nut to be used with a sequence ring nut wrench, and has no hex recess. The black bolt makes use of hex wrenches for each the screw and nut, 5mm and 6mm respectively.

At instances, for cleansing or to vary the chain rings themselves, the rings have to be eliminated. That is merely completed and in almost each case, needn’t have an effect on the crank arms themselves, or the underside bracket.


  • Chain Rings. These are the cogs (sprockets) which might be positioned close to the pedals. There’s at all times at the very least one sprocket and typically as many as 4 (see Thun quad chainring with 24t, 30t, 38t and 46t. Three units of sprockets are widespread on geared bicycles and 4 units are uncommon. The sprockets are bolted collectively or riveted onto the spider of the crank to type the chain ring set.
  • Chain Ring Bolts. These fasten the chain rings collectively, and repair the meeting to the spider of the crank. They exist in numerous lengths relying on their function, and might be fabricated from metal or softer alloys.
  • Crank Arms. The crank arms are the lengthy elements that be a part of the pedals to the principle shaft within the backside bracket of the bike. On the suitable aspect of the bike the crank arm extends right into a spider formed plate.
  • Spiders. The spider is an extension of the suitable crank arm, that the chain rings bolt onto. It has both a 4 or 5 bolt sample, relying on the design.
  • Pedals. These are screwed onto every crank arm. The left pedal’s attachment has a left-hand thread whereas the suitable pedal has a extra regular right-hand thread.
  • Chain Ring Guard. A steel or plastic half that protects towards injury from the rotation of the surface chain ring.
  • Chain Ring Nut Wrench. A particular wrench, typically used to help with chain ring bolts. It’s made to suit the slotted nuts of those fastenings, although is just not at all times wanted.
  • Pedal Wrench. A wrench sized to suit the nuts for pedal removing.

Removing of Pedals[edit]

It’s a reality that almost all chain rings and guards can’t match over the pedals of the bike, so if the intention is to fully take away them, the pedals should first be unscrewed.

  • Use a pedal wrench or a traditional 15mm wrench to UNSCREW THE RIGHT PEDAL ANTI-CLOCKWISE, whereas holding the work firmly to keep away from its shifting. The pedal is put in with a torque of about 360 in-lbs, (30 ft-lbs, 40.7 N.m), and this level ought to be famous throughout its substitute.
  • Though this process doesn’t require the removing of the left pedal, it’s completed by UNSCREWING THE LEFT PEDAL CLOCKWISE, and REPLACING IT BY SCREWING ANTICLOCKWISE, because it has a left-hand thread.

Take away or Slip the Chain[edit]

The removing of chain rings is finest completed with the chain fully eliminated although it’s not strictly vital for bolt substitute or different slight work. Take away the chain by breaking the grasp hyperlink, or simply derail it towards the within of the bike on the chain rings whereas shifting the pedal barely, relying upon the state of affairs.
Whereas derailing the chain, it helps to maneuver the rear detailleur cage inward to slacken the chain.

Removing of Rings[edit]

Some rings might be eliminated then changed in any place, however some others must have their alignment thought-about. This alignment requirement is extra doubtless for a number of chain ring units. The chain rings themselves usually bear a mark to indicate their supposed prime positions, however in case they don’t, it’s a good suggestion so as to add a mark to the highest of the rings with a marker pen or different technique to maintain issues clear.

The screws and nuts of chain ring fastenings are made with recessed allen key heads (hex wrench), and at instances the nuts is likely to be slotted as an alternative. They are often fabricated from metal or a softer alloy. Metal screws are prone to preserve increased torques than alloy, and the makers really helpful torque settings will replicate this. A standard becoming is a 5mm hex for the screws and a 6mm hex for his or her nuts. As a result of the strain on the bolts is pretty excessive, at the very least one long-shank hex secret’s most well-liked.

For single rings it should at all times be attainable to show the crank in order that each side of the screws are accessible with two hex wrenches, however in any case working solely from the entrance will often work for removing. For a number of rings, if there’s a tough thread, there won’t be house to get to the nuts with a hex wrench. On this case, slotted nuts come into their very own. The chain ring nut wrench has a slim profile that permits it to suit between rings and nonetheless have interaction the slots within the nuts.

For a number of rings the process is far the identical, beginning with the surface bolts, eradicating the guard and whichever rings as essential to reveal the following layer of bolts, and so forth.

Slide the chain ring guard and the varied rings over the crank with the pedal eliminated.

Putting in the Rings[edit]

Grease or oil the bolts earlier than assembling the rings once more, and pay specific consideration to the torque that’s really helpful for the ring bolts. Moreover, don’t apply full torque to anybody bolt in a set by itself, however somewhat carry as much as torque the entire set collectively, just a little at a time, to keep away from any distortions. A set right here means, the grouping of bolts in the identical airplane; the internal set, the outer set and so forth., ought to they exist.

If the producer’s knowledge is just not accessible, then consult with torque tables corresponding to Park Device: Torque Specs and Ideas for appropriate values to make use of.

Connect the pedals to the crank arms, and re-connect the chain.

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Few riders are fortunate sufficient to personal costly torque wrenches for his or her bikes, so it is likely to be as nicely to get the help of the bike store for work that requires their use. That stated, many are identified to approximate the required torques by judging the drive utilized to a wrench lever of identified size. That’s to say, torque is simply the product of drive and size. For instance, a 30 torque is utilized when a thirty pound drive is utilized at proper angles to the top of a one foot wrench. The accuracy of this technique is pretty much as good because the consumer’s ingenuity at judging or measuring the utilized drive.

Formulation for changing to different torque designations embody: = x 12 = Nm x 8.851 = / 1.15

Technical Be aware:


It has been dropped at the creator’s consideration that the hanger bolt that fixes the hanger of a rear derailleur to the body is similar to a sequence ring bolt, and in an emergency may clear up an issue.

See Additionally[edit]

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