Replacement bottom bracket for Shimano XT FC-M785 crankset

Asked by: Amber Gordon

What is a hollowtech bottom bracket?

HOLLOWTECH technology is an ultra-lightweight hollow crankarm created by SHIMANO with the company’s own proprietary forging technology that also maintains rigidity.

What size are Shimano bottom bracket bearings?

Shimano developed its press-fit standard using 41mm diameter bearing cups with an 86.5mm wide bottom bracket shell for the road, and 89.5 or 92mm for mountain bike.

What size spindle is Shimano?

Crankset Standards

When did hollowtech 2 come out?

Shimano’s Hollowtech II cranks, unveiled in 2003, essentially ushered in the current era of crank design by integrating the axle into the design of the crank. From that point on, the weight, stiffness and reliability of cranks improved, plus, they were easier to install and service.

How do I know which bottom bracket I need?

Quote from video: Found at any point here by hitting the information icon in the corner. The bottom bracket is the bearing system between your bicycles cranks.

How do I know what size bottom bracket I need?

To find out the size of bottom bracket needed, measure the inside of the bottom bracket shell in your frame, it will be 73mm, 70mm or 68mm. Some older frames may have Italian threaded bottom brackets, instead of the more modern English.

Are Shimano bottom brackets interchangeable?

All Shimano Hollow-Tech II road bottom bracket cups are interchangeable, that is they all have the same bottom bracket shell threads, fit in same shell width, have the same axle diameter and overall width.

What is the difference between BB30 and BSA?

BSA is English standard and have screw thread inside the hole ,usually use in shimano,while BB30 is Italian standard and don’t have screw thread, usually use in CP.

Is BB92 the same as PF92?

The frame’s bottom bracket shell inner diameter is 37mm. A bearing with an OD of 37mm is pressed directly into the frame. Trek is moving away from the BB90/95 system to what they call PF92, which is the same as a BB92 (41mm ID shell and 92mm width).

What is a 68 73 bottom bracket?

The 68mm and 73mm dimension measure the width of the bottom bracket on the frame of the bike with no BB installed, simply the width of the shell. Most road bikes that use a threaded bottom bracket measure 68mm wide and most cross country/trail mountain bikes measure 73mm.

How do I know if my crankset is compatible?

In most cases three-and two-piece cranksets are compatible with the same bottom brackets so long as the axle is the same diameter. They are commonly used in conjunction with the mid-style bottom bracket standard. One-piece: This is where the axle and crank arms are a single piece of steel.

Does spindle length matter on bottom bracket?

The critical thing is your spindle length: as long as you can set up the correct chainline you will be good to go. But, again, best never to mix standards if you can at all avoid it. If you are looking to replace a cottered crank setup with a square taper setup, then look no further than a cartridge bottom bracket.

Will any bottom bracket fit?

To a certain extent which bottom bracket you end up buying is up to what kind of frame you have. Certain frame materials and drivetrain options only support one type of Bottom Bracket. There are two main types of bicycle bottom brackets in today’s market, namely, threaded and press-fit BB’s.

Does changing bottom bracket make a difference?

(Click here to read BikeRadar’s complete guide to bottom brackets.) According to Friction Facts’ latest report: “No statistically significant difference exists showing a general advantage or disadvantage of a standard type under similar loading conditions.

Do I need to grease the bottom bracket?

In the case of the bottom bracket, you will use the grease when you install it, whether it is threaded, press fit or similar, and in the same way when you install or clean the cranks. The point of contact of the cranks with the bottom bracket should be greased too.

What is the difference between hollowtech and square taper?

What is this? Conclusion: When we compare the bare units, Hollowtech models are about 3.4 times lighter than square taper bottom brackets. However, it’s necessary to take into account that square taper bottom brackets come with a spindle whereas in the case of Hollowtech models the spindle is part of the cranks.

How do you install a Shimano hollowtech 2 bottom bracket?

Quote from video: Place the required o rings on the spindle. Next apply lubricant to the thread in the frame of the bank. Slide the bottom bracket into the frame and thread it into place in a counterclockwise.

How do you measure hollowtech bottom bracket?

Quote from video: Part of the bottom bracket. So you get a caliper on it. And you measure it and then you take a look in this case it's 73. So well the most common sizes are 68 and 73.

How do you remove hollowtech cranks?

Quote from video: You're gonna unscrew it and then you can put an actual 5 millimeter tool right here if that plastic cap is a little tight. You could even stick a screwdriver in one of these holes.

How do you remove a Shimano XT crank?

Quote from video: And maybe a plastic mallet or rubber mallet to tap. Out the cranks. If they're tight. And as with most jobs it is easier if you have a work sand.

How do you remove a hollowtech bottom bracket?

Quote from video: Move the ring spanner to the right side. And start it moving clockwise. Keep going until the unit comes.