Hollowtech II bottom bracket spacers explained
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- čas přidán 4. 07. 2024
- Should you put spacers on both the right and the left-hand side cups? How many spacers and which thickness?
I tried answering those questions along with explanations why.
CONTENTS:
00:00 Introduction
01:34 3 notes
03:07 3 goals
06:54 BB shell width and diameter
12:05 Threaded bottom brackets
15:47 2.5 mm "default" right spacer
18:17 Road bike BB cups
21:18 MTB BB cups
23:54 How to check if it's all good
27:17 Wider (boost) frames and press-fit
29:21 Catches and gotchas
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How to install Shimano Hollowtech II bottom bracket - video:
• How to install Shimano...
What is a bicycle chainline and how to measure it? - video:
• What is a bicycle chai...
Bicycle chainline - article:
bike.bikegremlin.com/1755/bic...
Accurate vs precise, digital vs analogue - Calipers, how to use them? - video:
• Accurate vs precise, d...
Accuracy vs Precision - article:
bike.bikegremlin.com/8374/acc...
Threaded bottom bracket standards, thread pitches, and diameters - article:
bike.bikegremlin.com/1634/bic...
Threadless (press-fit) bottom bracket standards and dimensions - article:
bike.bikegremlin.com/1652/pre...
T47 threaded bottom bracket standard:
bike.bikegremlin.com/1672/new...
Anti-seize (mounting) pastes and greases - video:
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Mounting and anti-seize pastes - article:
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Shimano SMBBR60 bottom brackets made for frames with a 68mm bottom bracket shell DO NOT require any spacers. This video is wrong. For example, if you have a road bike frame with a 68mm shell and you buy the 68mm version of the Shimano SM-BBR60 bottom bracket then Shimano does not supply spacers with it - because NONE are needed! If anybody followed the advice above and put in spacers that they had laying around, in the example given in this video, then that would be wrong.
Fair point - though it does depend on the particular frame and cranks. Sometimes (not rarely enough) you need a spacer before the right hand side cup in order to get the axle protruding just the right amount (there is a bout +-1 mm "wiggle" room for the left crank fitting) and have them be symmetrical relative to the frame's centre line.
Relja
Great video! Love the way you convey the reasoning and logic behind every decision!
It's easier (for me at least) to learn and memorize that way. When you understand the logic, you can always work out the needed details. That helps a lot when something is non-standard or out of the ordinary.
Awesome and incredibly informative video. Thanks!
Super useful - Thank you!
Learned a lot. Thanks!
Glad to hear that.
I enjoy making videos and articles, and knowing that it helps at least one person makes it worthwhile - knowledge multiplies when you share it. :)
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Relja
Thx
Great video. Relax too my friend it is difficult when your first language is not English. Really great information...
One question....I have a 68mm bottom bracket (cyclo cross bike). I bought a Hollowtech Road style Bottom Bracket (BB52 I think). It didn't come with any spacers.. So I should add 1 2.5mm spacer on the chainside crank ...Thanks if you get this !🙏👍👍
Hi,
Thanks. :)
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Relja
thanks a lot for sharing. i need to increase my chainline by 2-3mm but my spindel is in the bracket and not attached to the pedal. how to add a spacer on this case?`or do i need a longer spindel`? thanks
Hi,
Please use the BikeGremlin forum for any questions & answers:
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Relja
Hello Sir,
Can you tell me,
I have 68mm BB on Cube mtb hardtail, is it always 2 spacers on the right and 1 spacer on the left? No matter what crankset? If I change from triple crank to one by crank is the spacer still the same on bottom bracket?
Hi,
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Relja
Nice video. I have a pressfit BB92 and my bike manual says that 2.5mm spacer is not needed.
I’ve replaced the BB and bike shop fitted 2.5mm spacer on drive side. Everything is working smooth now.
Why did they say that the spacer is NOT needed ?
One good measurement beats a thousand expert opinions.
You could measure the front and the rear chainline, and check your crank arm symmetry to see if it's all good.
For example:
Different cranks have different chainring positions, so maybe the bike shop concluded that the spacer will help get the chainline closer to optimal.
But, more imporant than that: is the bike working and shifting fine?
Relja
Nice video, but little too complicated for me. 😅Can you tell me, if the BB is 68/73mm and the width of the shell is 68mm, and I am using the triple front crankset, do I need to install 2 spacers of 2.5mm, and where, one on the left and one on the right or somewhere else? I tried with one spacer on the right side and it looks like I could fit another one (my crank is able to move left and right just a little bit).
In most cases, with Shimano BBs and cranks, that would be 2.5 mm on the left, and 5 mm (2 x 2.5 mm) on the right.
Relja
My width is 86,5 mm and I am installing T47 BB which is 48,5 mm wide (16 teeth). Crankset will be GRX600 10 speed. With BB I received 3 spacers 1/2/3 mm, and can not find info what is proper way to install it (which spacer, on which side)
Hi,
Please use the BikeGremlin forum for the technical questions:
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Relja
@BikeGremlinUS what is the proper chainline triple chainring hallowtech Bottombraket non-boost frame??
If best you make a video about it❤🎉😊thank you so much new biker.
As I like to say, one correct measurement beats a thousand expert opinions.
So, the safest route is to measure your rear chain line and try to match that with the front chain line.
Generally it is about 50 mm for most Shimano MTB triple cranks, and about 45 mm for Shimano Road triple cranks.
Relja
@@BikeGremlinUS thank you soo much sir🥰❤️
#2 on you list is not critical and will no effect pedaling. Chain line is most important. In my situation I have a 73mm with the one 2.5mm on the drive side. I have a 141 boost QR frame using a 142 TA hub with adapter. My front chain line is 48mm my rear is almost perfect at 49mm. I'm using a knock off 24mm Hollowtech II crank Teyssor branded similar to the iXF one.
I have an "emptyB" bike according to this video! lol (bad joke - or my hearing is going - or both).
Some times you need spacers….
Русский что ли?
Čto.
:)
Novi Sad. :)