Bosch gen 4 bolts

Bigred123

New Member
Jul 6, 2024
10
0
Middlesborough
Just been checking bolts on motor , then found this bolt not so tight, anyone know torque settings and iam also guessing the more bolts like this under the casing, ( do I have to remove crank to get to remove casing?

IMG_1111.jpeg
 

RustyIron

E*POWAH Elite World Champion
Subscriber
Jun 5, 2021
1,851
2,901
La Habra, California
There is no shortage of torque tables on the interwebs. Let google be your guide. After you figure out the fastener size and thread pitch, you're probably going to be safe assuming Grade 5 or Class 8.8. Use either thread locker or anti-seize; don't assemble dry.
 

Gareth

Member
Apr 20, 2024
114
141
Ayrshire
That looks similar to my new Mondraker Crafty. The head you have circled is not a motor screw. Don’t know what it is, but I’d just nip it up, I wouldn’t put much torque on that. I haven’t removed the covers from mine. But the screw head on the right looks like motor mount screw. There should three each side about that size, they are torx heads.

Yeah I would think you need to remove the cranks and pop the covers off to see what’s what. Again I haven’t poked about my Mondraker much, but on my Cube with the Bosch motor to remove the crank you first removed the plug with a 8mm allen key then used a good old fashioned taper style crank remover. Like this,

Park Tool CWP-7 Crank Puller

The motor mount screws are usually 20Nm into aluminium, but as to what the figure is for carbon frames nobody seems to know. Cranks go back on at 40Nm, though I usually just go to 35Nm.
 

steve_sordy

Wedding Crasher
Nov 5, 2018
9,047
9,508
Lincolnshire, UK
20Nm into aluminium! Yikes. That seems a lot for a bolt of that size. I wouldn't go more than 14Nm, but if I genuinely didn't know, I would use the correct size Allen/Torx key and tighten with one hand only until it felt right. Then I'd keep my eye on it until I found out the correct torque setting.
The absolute last thing you want is to shear off the bolt, or shear the threads in the motor. :eek:
 

Gareth

Member
Apr 20, 2024
114
141
Ayrshire
20Nm into aluminium! Yikes. That seems a lot for a bolt of that size. I wouldn't go more than 14Nm, but if I genuinely didn't know, I would use the correct size Allen/Torx key and tighten with one hand only until it felt right. Then I'd keep my eye on it until I found out the correct torque setting.

Which is exactly what I just said.
 

Gareth

Member
Apr 20, 2024
114
141
Ayrshire
Very difficult to tell what is what from your picture. But this is a Bosch Gen 4 motor. You want to find the screws that go into those threaded holes in the two brackets. There are 6 screws altogether, 3 on each side. And again this is off my Cube, so I don’t know if there are variations on the mounting bracket.

P1150001-Edit.jpg
 

Gareth

Member
Apr 20, 2024
114
141
Ayrshire
If that is a schematic of your bike (what is it that you have?) then it is definitely as I said. You can see the same brackets that are in the picture of my knackered motor.

Two screws into one bracket, one into the other. It is the same both sides.
 

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