What does the B-tension screw do?
Simply put, the B-Tension screw is there to control the gap between guide pulley (the upper pulley on the derailleur) and the bottom of the cogs.
Where is the B-tension screw?
B-Tension is an adjustment using that mysterious third screw on the back of your rear derailleur. Its proper adjustment is the final step to clean and quiet shifting. It also provides a degree of chain tension assuming: Chain is properly installed and the right length.
What does B-tension mean?
The B-screw is for “Body screw”, since it affects the body angle of the derailleur. B-Tension is Shimano’s term for B-screw — as Sheldon points out, on Campagnolo, the screw behaves the opposite of Shimano. See Sheldon Brown and Park Tool for more details. Also, see the answer here for more details on what it does.
What is the B screw on a derailleur?
B-Screw. Most derailleurs have some form of adjustment for the spacing of the guide pulley to the cogs. This spacing is controlled by the B screw, or body-angle screw. This adjustment is check when the chain is on the smallest sprocket up front, and the largest cog in back.
What is the B gap?
The B Gap is the space, or split, between the offensive guards and offensive tackles on either side of the offensive line. Gaps can be widened by blocks, used as holes or lanes by running backs, and/or targeted by defenders as an entry point to the backfield.
How Do You Measure B screw?
You can measure B-gap with a pair of calipers. For smaller B-gaps (e.g. in the 4-10mm range), you can use an appropriately sized hex wrench as a measuring tool. Use your calipers or hex wrench to check the distance from the upper guide pulley of the rear derailleur to the lowest point of the large cog of your cassette.
Why is it called B screw?
The B-screw is for “Body screw”, since it affects the body angle of the derailleur. B-Tension is Shimano’s term for B-screw — as Sheldon points out, on Campagnolo, the screw behaves the opposite of Shimano.
What size is a Shimano B screw?
M4 x 17.4 mm
The Shimano B-screw for XT RD-M8000 11-speed rear derailleur is an adjusting screw in the size M4 x 17.4 mm.
Where is the B Tension screw?
How do I adjust the B screw on my bike?
If the bike is shifting well, the B screw is probably within acceptable adjustment range. To increase the gap, tighten the B screw. To decrease the gap, loosen the B screw. If you do make significant changes to the B screw, double check the indexing adjustment.
What is the B-tension screw on a bike?
The B-Tension Screw almost always contacts the frame directly or indirectly. The part of the frame it contacts is called the derailleur hanger or derailleur tab. Photo by Eric Ramirez If the jockey pulley sits too close to the cogs, it will struggle to shift.
Are the limit screws on front and rear derailleurs the same?
It’s easy to forget as this is not done very often and there are so many different models of front and rear derailleurs. Even similar models; for instance on the FD-M590 and FD-M591 font mechs the limit screws are different ways round.
How do you adjust the B tension on a rear derailleur?
From this point progressively turn the B Tension screw 1/2 turn at a time clockwise, or in. Pay close attention to the B-Gap. As the derailleur starts to pull down and away from the cogs, try shifting again. Sometimes, it requires the smallest gap.