Bike Derailleurs Basic
Derailleurs are the mechanisms for “de-railing” or moving the chain from cog to cog and chainring to chain ring, allowing you to shift and change gears when you ride. The derailleurs don’t so much move the chain as they guide it from one side to the other, which is only possible if you’re pedaling forward and the chain is moving.
Both the front and rear derailleurs work through the use of an internal spring, which pulls the derailleur toward the bike or pushes the derailleur away from the bike, while the cable attached to the bike’s shifter opposes the force of the spring. When the shifter pulls the cable, the cable overcomes the spring and moves the chain toward or away from the bike. When the shifter releases the cable, the derailleur moves back to its normal position.
The fact that springs and cables are pushing and pulling on the derailleurs would be a problem if there were nothing stopping the derailleurs from moving the chain too far in one direction or the other. Fortunately, derailleurs are designed with a pair of stop-limit screws, which limit the movement of the derailleurs in both directions. These screws are usually marked with an H and an L, for high and low. The high-limit screw controls the distance that the derailleur can move away from the bike (toward the higher gears), and the low-limit screw controls the distance the derailleur can move toward the bike (toward the lower gears).
Limit screws physically limit movement as they’re screwed deeper into the derailleur. Turning the screws clockwise drives them in deeper and restricts the range of movement; turning the screws counterclockwise loosens them and increases the range of movement. If you were to tighten both limit screws to their maximum depth, you would limit the derailleur to a single position. This is good to know if you break a derailleur or chain and need to set the bike up for just one gear to get home.
Both derailleurs have difficult jobs when it comes to keeping up with the demands of a biker who is shifting to higher and lower gears. Moving the chain toward the frame puts the bike in a lower gear, whereas moving the chain away from the bike puts the bike in a higher gear. Just as with a car, lower gears are useful when you’re going slow (for example, climbing a steep hill), whereas higher gears serve you on the descent, when you’re riding at a faster speed.
The front derailleur has the unenviable task of moving the chain sideways as it’s under force. This part of the chain transmits power to the rear wheel, which is why when you’re applying a lot of power and moving slowly (such as climbing a hill) it’s hard for the front derailleur to shift. Rear derailleurs have the job of swinging their arm or cage back and forth under the freewheel, guiding the chain from one cog to the next. The rear derailleur cage has the familiar S shape, with two jockey wheels. The top jockey wheel guides the chain onto the cog and the bottom jockey wheel is designed to keep tension on the chain and take up slack.
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6 – Advanced Rear Derailleur Adjustment
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Shimano Altus Rear Derailleur, 7/8 Speed, M310, Black $25.99 |
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Sram Force mini group, shifters, front and rear derailleur, groupset 35 $340.00 |
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SRAM X0 XO 10SPD REAR DERAILLEUR LONG CAGE RED New $150.00 |
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MOUNTAIN BICYCLE BIKE REAR DERAILLEUR SHORT CAGE NEW $11.75 |
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Suntour XC Sport Derailleur Rear- Vintage $29.00 |
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[Bi_King] Shimano 105 RD-5700 SS Rear Derailleur Black Short Cage $49.00 |
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AL 7075 Sram Gold 11t Road mtb bike Jockey Wheel Rear Derailleur Pulley 1pc $14.90 |
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AL 7075 Shimano Gold 11t Road mtb bike Jockey Wheel Rear Derailleur Pulley 1pc $14.90 |
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AL 7075 Shimano Black 11t Road mtb bike Jockey Wheel Rear Derailleur Pulley 1pc $14.90 |
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***** VERY FINE ” DURA ACE ” RD – 7400 REAR DERAILLEUR – 7/8 speed ***** $59.99 |
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Shimano Dura Ace 7800 Rear Derailleur $1.25 |
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SRAM XO rear derailleur 9 speed carbon X.O X0 Long Cage $9.09 |
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New TOKEN TK1711 Rear Derailleur Pulley / Jockey wheel, 11T, Green $33.96 |
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New TOKEN TK1711 Alloy Rear Derailleur Pulley / Jockey wheel, 11T, Silver $30.96 |
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New TOKEN TK1701 Alloy Rear Derailleur Pulley / Jockey wheel , 10T, Black $33.96 |
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Dura Ace rear derailleur RD-7700 short cage $0.99 |
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SHIMANO XTR M972 REAR DERAILLEUR CARBON FIBER SHADOW 9 SPD Mountain Bike XC RACE $40.00 |
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Shimano XT M750 Mega 9 Speed Rear Derailleur Bicycle Bike Spd XTR XC Race DH FR $5.50 |
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Shimano STX rear derailleur $1.00 |
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Campagnolo Super Record Titanium Rear Derailleur Patent 82 $1.00 |
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Campagnolo Super Record Titanium Rear Derailleur $1.00 |
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Shimano XTR M952 Mega 9 Spd Rear Derailleur Bicycle Bike Spd Road XC Race DH FR $5.50 |
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Campagnolo Nuovo Record Rear Derailleur Pat.82 Nice!! $1.00 |
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NEW Sram Rear Derailleur Pulley Wheels Road Bike Bicycle Cycling $9.99 |
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Campagnolo Victory Rear Derailleur $1.00 |
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Campagnolo Triomphe Rear Derailleur $1.00 |
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Shimano Dura Ace 9 speed rear derailleur – RD-7700 – very good condition! $50.00 |
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New Sunrace M30 Mountain Bike hybrid Rear Derailleur Long Cage Mega Drive $10.00 |
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Shimano 600 EX Rear Derailleur Classic Road 6 Speed Index Compatible RD-6208 $0.99 |
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2011 SRAM X-9 X.9 Rear Derailleur 10 Speed XC Long Cage Mtb Carbon White NEW $69.97 |
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New Sram Red rear derailleur Black Box w/ ceramic bearings $199.99 |
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SHIMANO 600 REAR DERAILLEUR FD-6207 $18.99 |
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7800 Dura Ace rear derailleur $1.00 |
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Vintage Campagnolo Record Gran Sport Road Bike Rear Derailleur Spring NOS NEW $9.00 |
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Brand New Shimano DeoreXT Rear Derailleur – # RD-M772 $0.99 |
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Brand New Shimano Ultegra 6700 Rear Derailleur – $0.99 |
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Shimano Dura Ace 10 speed rear derailleur NOS $200.00 |
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Simplex Prestige Rear Derailleur Parts for parts or repair $10.19 |
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Shimano XT RD-M772 Shadow Rear Derailleur – 9 Speed – SGS long cage $35.00 |
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Shimano Dura Ace Rear Derailleur Cable Stop $10.00 |
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2011 SHIMANO ALIVIO RD-M410 Rear Derailleur Mtb 7-8 Speed Aluminum 80mm Cage NEW $19.97 |
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2011 SHIMANO ALIVIO RD-M410 Rear Derailleur Mtb 7-8 Speed Aluminum 80mm Cage NEW $0.99 |
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SRAM X-9 Rear Derailleur // 9spd Speed Mountain Bike Long Cage Down Hill $0.99 |
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Shimano Dura Ace 7800 10 Speed Rear Derailleur $0.99 |
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SHIMANO ULTEGRA RD-6700 10 Speed Double Rear Derailleur Short Cage NEW $65.97 |
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2010 SHIMANO DEORE XT RD-M771 9 Speed Rear Derailleur Mtb Long Cage Alloy NEW $69.97 |
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Shimano Deore XT RD-739 rear derailleur long cage 9 speed $9.99 |
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Shimano Deore XT RD-750 rear derailleur long cage 9 speed $9.99 |
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2011 SRAM X-9 X.9 Rear Derailleur 10 Speed XC Long Cage Mtb Carbon White NEW $1.25 |
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Sram X7 rear derailleur 9 speed med cage. Flawless. x9 x0 xx $25.00 |
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Shimano RD-6700 Ultegra 10 sp Double Rear Derailleur $0.99 |
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SHIMANO SIS RD-TY15 Bike Rear Derailleur 5 Speed NEW $3.97 |
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NEW BICYCLE REAR DERAILLEUR HANGER PARTS 88 $0.99 |
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Shimano XT M772 Rear Derailleur Shadow SGS No Reserve! $1.00 |
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SHIMANO ULTEGRA RD-6700 10 Speed Triple Rear Derailleur Medium Cage NEW $64.97 |
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Campagnolo Super Record Rear Derailleur,1st Generation,Titanium,PAT.76, RARE! $0.99 |
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New Token TK1701TBT Ceramic Rear Derailleur Pulley 10T $52.99 |
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2011 Campagnolo Record Carbon 11-Speed Rear Derailleur $370.00 |
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Bicycle Replacement 10 Teeth Jockey Pulley Rear Derailleur $11.86 |
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Shimano Ultegra 9 Speed TRIPLE Rear Derailleur, RD-6500 $0.99 |
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Shimano XTR M900 front and Rear Derailleur $19.99 |
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Rare 1967 / 1st Edition Campagnolo Nuovo Record rear mech / derailleur $18.03 |
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Campagnolo Chorus 8 Speed Rear Derailleur, Excellent Condition! $59.00 |
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SHIMANO ULTEGRA RD-6700 10 SPEED REAR DERAILLEUR NEW NEVER MOUNTED $0.99 |
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Shimano RD-6700 SS SILVER ULTEGRA SHORT CAGE 10 Speed Road Bike Rear Derailleur $87.20 |
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Shimano RD-6700 GS ULTEGRA GRAY MEDIUM CAGE Rear Road Bike Derailleur 10 speed $89.35 |
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Campagnolo 2007 Veloce middle cage 10speed rear derailleur (NOS) $75.00 |
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Shimano RD-6700 GS ULTEGRA SILVER MEDIUM CAGE Rear Road Bike Derailleur 10 speed $89.35 |
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Campagnolo Specific Red Anodized Sealed Bearing Rear Derailleur Pulley Wheels $24.95 |
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Vintage 1976 Campagnolo Super Record Road Bike Rear Derailleur Rare!! $499.95 |
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Shimano RD-M580 Deore LX GS Medium Cage Rear Derailleur Rapid Rise NEW $0.99 |
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Campagnolo chainstay cable stop for rear derailleur p.n. 636 vintage, new NOS $8.50 |
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HURET JUBILEE REAR DERAILLEUR VINTAGE MADE IN FRANCE 140gr $249.00 |
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Shimano Dura Ace 7700 9-speed rear derailleur $4.99 |
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SRAM X9 MTB REAR DERAILLEUR 9 SPEED MOUNTAIN BIKE 29ER HYBRID X.9 LONG CAGE NIB $73.85 |
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Campagnolo Veloce 8 Speed Road Bike Rear Derailleur $119.99 |
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SHIMANO XT MEGA 9 FRONT & REAR DERAILLEURS 9spd M750/ M760 NO RESERVE $0.99 |
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2011 Shimano XTR RD-M980 Dyna SGS Shadow Rear Derailleur 10 speed $11.50 |
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Vintage Campy Campagnolo nuovo record rear derailleur 100% Working $84.99 |
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New Campagnolo Xenon Rear Derailleur 9 speed $22.00 |
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Campagnolo rear derailleur, Nuovo Record, vintage, 5-6 speed? $25.00 |
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New Campagnolo Record Titanium 10 Speed Road Bike Rear Derailleur Carbon Cage $399.00 |
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Shimano RD-M310 Altus 7/8 Speed Rear Derailleur Silver NEW!! $24.98 |
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SRAM X7 Rear Mech Derailleur 9 Speed spd Long Cage Aluminum Storm Gray MTB Bike $61.99 |
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Campagnolo Croce d’aune rear derailleur $0.99 |
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Campagnolo Daytona 9speed rear derailleur $0.99 |
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Vintage Huret Rear Derailleur (French made) ’70s $1.55 |
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CAMPAGNOLO RECORD TITANIUM 9 SPEED REAR DERAILLEUR $1.55 |
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Shimano 200GS long-cage direct-mount rear derailleur RD-M200 7s-14s-21s SIS $9.00 |
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Shimano xtr rear derailleur for parts 9 speed $5.99 |
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Shimano Deore LX rear derailleur RD-M570 8s/9s Mega-9 SIS long-cage MTB/Touring $17.45 |
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NEW SRAM APEX White rear derailleur short cage FREE US SHIPPING $67.99 |
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SRAM X.9 10sp Rear Medium Cage Derailleur Carbon/Gray $151.80 |
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KCNC REAR DERAILLEUR PULLEY JOCKEY WHEEL 11T BOLTS GOLD PAIR $39.60 |
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2011 SHIMANO ALIVIO RD-M410 Rear Derailleur Mtb 7-8 Speed Aluminum 80mm Cage NEW $26.97 |
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New Bicycle Rear Derailleur Campagnolo Chorus RD11-CH1 11 Speed 2011 $244.99 |
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SHIMANO DURA-ACE RD-7800 SS 9/10 SPEED ROAD BIKE REAR DERAILLEUR $125.00 |
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New Bicycle Rear Derailleur Campagnolo Record RD11-RE1 11 Speed 2011 $319.99 |
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Shimano XTR M960 Rear 3×9 Speed Rear Bicycle Derailleur $49.99 |
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New Bicycle Rear Derailleur Campagnolo Super Record RD11-SR1 11 Speed 2011 $479.99 |
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Sunrace Index Hanger Plate With Nut and Bolt, Shimano Compatible $1.67 Derailleur Hanger Plate with Nut and Bolt…. |
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Shimano XTR RDM970/971 Upper Bolt and Spring Assembly $17.28 Shimano Miscellaneous Rear Derailleur Parts… |
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SRAM X.0 10spd Hanger Bolt Assembly $25.50 SRAM Miscellaneous Rear Derailleur Parts…. |
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Shimano RD-4500 Tiagra Rear Derallieur (SS Short Cage, 9-Speed, Silver) $39.99 Shimano Tiagra Rear Derallieurs.High-precision action for 7-, 8- or 9-speed systemsLarge 11-tooth pulleys run more quietly and wear evenlyItem SpecificationsColorSilver/BlackWeight265gIntended UseRoadCassette SpacingShimano/SRAM 9Shifter/Derailleur CompatibilityShimanoLargest Cog27teethChain Wrap Capacity29teethDerailleur ActionTop-Normal (Traditional)Cage LengthShort… |
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Invention Rear Derailleur Shirt L/S Sports Long Sleeve T-Shirt by CafePress Invention Rear Derailleur Shirt Bike Parts… |
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D95 Derailleur Hanger – Fits: Marin Pioneer Alpine Bayview Trail, Hawk Hill, Bolinas Ridge $20.99 Fits MARIN models: Alloy hardtail: Comfort (26″): Please compare… |
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Pacific Chromium Boy’s Dual-Suspension Mountian Bike (20-Inch Wheels) $151.99 Pacific Chromium Boy’s Dual-Suspension Mountian Bike (20-Inch Wheels)… |
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Shimano Acera SL-M310 Rapid Fire Shifter, Right (Black, 7-Speed) $13.59 Shimano Shifters, Flat Bar-RightItem SpecificationsCassette SpacingShimano/SRAM 7Shifter/Derailleur CompatibilityShimanoEnd TypeShimano/Sram… |
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