Shimano
UN55 Square Taper Bottom Bracket

Question 1

Q.

asked by: a guest
I own a Cinelli vigorelli Caleido Frameset- Which bottom bracket will fit? Thanks!

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mhutch · Answer

This bike should use 68mm, but to be sure you can measure the width of the bottom bracket shell in millimeters. The spindle length will depend on your particular crankset and is dictated by the manufacturer.

Question 2

Q.

asked by: a guest
OEM spec for a trek 820 calls for 68/116 Shimano Bb-ct91. Would the 115 or 118 be the better replacement?

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canteau · Answer

The 115 would be a better fit because it's actually 115.5mm

Question 3

Q.

asked by: a guest
can this work as replacement for fsa 68 x 110.5?

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canteau · Answer

The Shimano UN55 should work as a direct replacement for an FSA JIS square taper bottom bracket.

Question 4

Q.

asked by: a guest
So you have the crank bolts for this BB?

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canteau · Answer

The Shimano UN55 is compatible with any M12 crank bolt

Question 5

Q.

asked by: a guest
Is this BB compatible with Sugino 75 cranks?

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canteau · Answer

The Sugino 75 cranks require an ISO (Campagnolo) tapered bottom bracket and are not compatible with Shimano (JIS) square taper bottom brackets.

Question 6

Q.

asked by: a guest
What spindle length is needed with Origin8 150mm cranks and an Alfine 8 hub for proper chainline? Origin8 specs 107 but don't know what chainline that gives.

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canteau · Answer

Unfortunately, we do not carry Origin8 so this would be best answered by them or one of their dealers, but most likely if the Origin8 cranks call for a 107mm spindle, it most likely has a 42-43.5mm chainline with 42mm being for a road single speed and most internally geared hubs and 43.5mm being road double.

Question 7

Q.

asked by: a guest
Will the un-55 fit a 1978 schwinn competition scrambler bmx bike.Sugino super maxy cranks

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kristenkey · Answer

If the crank uses a JIS squared tapered bottom bracket, than it will work. If you're local, bring the bike by and we'd be more than happy to take a look!

Thanks!

Question 8

Q.

asked by: a guest
Can i run this with the White industries eno crankset

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canteau · Answer

Yes, the White Industries ENO crank uses a JIS square taper bottom bracket.

Question 9

Q.

asked by: a guest
Just got a bike with a BB-UN55 70 X 116. What cranks fit that Bottom Bracket?
thanks

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canteau · Answer

You will need to find a crank that works with the rest of the drivetrain (proper number of chainrings, proper chainring sizes and chain size) once you find the crank that checks all of those boxes you will need to get an Italian threaded bottom bracket with a spindle that meets the needs of that crank.

116mm spindles are used on some track and road double cranks that require a JIS square tapered crank.

Question 10

Q.

asked by: a guest
I want to use a 127mm. What Derailleur will work with this extra width? Mtn or Road is ok

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canteau · Answer

The front derailleur is determined by the style of the crank, size of the chainrings and shifter, not the bottom bracket width.

Question 11

Q.

asked by: mic...@....com
Hi Which of these BB length for Sugino XD 600 crank (triple) on Surly LHT? thanks

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canteau · Answer

Sugino recommends that you use a 110mm spindle with road front derailleurs and 113mm spindles for mountain front derailleurs.

Question 12

Q.

asked by: a guest
What size are the crank fixing bolts? length, diameter and thread?

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canteau · Answer

These Problem Solvers bolts should work with most cranks: http://www.treefortbikes.com/product/333222342814/1213/Problem-Solvers-8mm-Hex.html

Question 13

Q.

asked by: a guest
Can this one replace my VP-BC-73T? Its for my Specialized Rockhopper (2015)

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mlewis · Answer

Shimano doesn't list weights for either of these bottom brackets, so we don't have a good basis for comparison.

mlewis · Answer

We can't find any specific info on the crank you're referring to, you may need to take it to a local shop for further identification.

mlewis · Answer

Yes, chainline is measured from the center of the BB shell, there's some great info about chainline at sheldonbrown.com/chainline.html

tnelson32 · Answer

Thanks!, Is 43.5mm chainline you mentioned measured from mid-point of bb shell?

canteau · Answer

Square taper XT cranks were made to be used with bottom bracket spindles from 113-122.5mm in length depending on the chainline required.

With a 9-speed cassette the middle gear on the back should line up with the middle chainring.

If the frame is using a 130mm rear road hub and a 43.5mm chainline, I would start with something in the 113mm range and go from there.

canteau · Answer

It will work, but won't be ideal, the Miche uses an ISO (Campagnolo) taper and Shimano bottom brackets are JIS (Japanese International Standard). You can interchange the 2 but the chainline won't be right.