What thread pitch is this bolt

[Speedy1959]

Hi all,

A bit of a random question but what thread pitch is the bolt that goes into the rear shocks?
I have attached a photo which may help those of you in the know (or not).

I know the bolt is an M12 but as you may know there are several different thread pitches available.

Thanks in advance,

S.

 

[Redmonster]

Hi all,

A bit of a random question but what thread pitch is the bolt that goes into the rear shocks?
I have attached a photo which may help those of you in the know (or not).

I know the bolt is an M12 but as you may know there are several different thread pitches available.

Thanks in advance,

S.

02 07 12 9 907 435 ISA SCREW -
M10X80-10.9-MK

What year bike is it?

No bitchy remarks from me.

 

[Redmonster]

This one


03 33 53 7 686 734 FIT BOLT - M10X65X1,25MK

No bitchy remarks from me.

 

[ShakeyGS]

That nut certainly applies some “gronk” to those threads!

 

[knutk]

There is no mentioning of whether it is the top or bottom bolt. The most ordinary pitch for a M12 is either 1,25 or 1,5.
I think this is a 1,5 bolt.

If you plan to get a new bolt, I strongly suggest you go to BMW and get the correct one.

These bolts carry a hefty load, and there are requirements to the strength of the bolt. The Bolts in question is in the 10.9 class.

Given that you are asking such a basic question, (no offense) this means that your knowledge regarding bolts is limited. That's fair enough.
But with a limited knowledge level, it's quite easy to pick a bolt that is not strong enough, and this, in a worse case senario, may lead to a catastrophic failure.
Going to BMW and get the proper bolt specified, you are assured that the bolt meets the specs. And you may safely carry on.

Here is a link that shows the bolts and their part number. Same bolts for ESA and non-ESA.
https://www.realoem.com/bmw/enUS/showparts?id=0A51-EUR-03-2017-K50-BMW-R_1200_GS_17_0A51,_0A61_&diagId=33_1711

 

[Lowflyer]

There is no mentioning of whether it is the top or bottom bolt. The most ordinary pitch for a M12 is either 1,25 or 1,5.
I think this is a 1,5 bolt.

If you plan to get a new bolt, I strongly suggest you go to BMW and get the correct one.

These bolts carry a hefty load, and there are requirements to the strength of the bolt. The Bolts in question is in the 10.9 class.

Given that you are asking such a basic question, (no offense) this means that your knowledge regarding bolts is limited. That's fair enough.
But with a limited knowledge level, it's quite easy to pick a bolt that is not strong enough, and this, in a worse case senario, may lead to a catastrophic failure.
Going to BMW and get the proper bolt specified, you are assured that the bolt meets the specs. And you may safely carry on.

Here is a link that shows the bolts and their part number. Same bolts for ESA and non-ESA.
https://www.realoem.com/bmw/enUS/showparts?id=0A51-EUR-03-2017-K50-BMW-R_1200_GS_17_0A51,_0A61_&diagId=33_1711

Good answer, strong advice
Even better user name

 

[ianboydsnr]

It looks like 1.75 thread pitch to me, count 10 threads and it’s 17mm or so.

And it’s not a particularly hard screw, either, but why would it be, the sheer strength of a 12mm bolt is quite a few tonnes.

It’s defiinatly not a 10.9 with the wear on the threads like that.

 

[Winjar]

Like answer, if you not know thread, be safe buy from BMW.

 

[knutk]

It looks like 1.75 thread pitch to me, count 10 threads and it’s 17mm or so.

And it’s not a particularly hard screw, either, but why would it be, the sheer strength of a 12mm bolt is quite a few tonnes.

It’s defiinatly not a 10.9 with the wear on the threads like that.

Here is a copy from the parts list referred to in my previous post for the top/bottom bolts.

03 ISA screw M12X1,5-60-MK 1 46517688995
04 Fillister-head screw M12X75-10.9-MK 1 07119908207

 

[mrtee43]

I reckon somebody has got the top and bottom bolts mixed up and has used force hence the knackered threads on the bolt in the picture.
If I remember correctly, they are different threads.

 

[Speedy1959]

Thank you all for your advice.
The bike is a 2015 LC (GS)
The bolts are definitely M12.
I had removed the rear shock (well partially removed it) to clean it and the coil spring.
The bolts seemed very worn and not crisp if you know what I mean.
Lowflyer I did know about different tensile strengths of bolts. I was actually looking at some 12.9 bolts from a UK supplier.
I did NOT know they would use different threads on the same application M12 bolts. That’s almost perverse !

Thanks again for all your replies.
S.

 

[ianboydsnr]

Here is a copy from the parts list referred to in my previous post for the top/bottom bolts.

03 ISA screw M12X1,5-60-MK 1 46517688995
04 Fillister-head screw M12X75-10.9-MK 1 07119908207

The bolt he posted a picture of is a 1.75 pitch thread, regardless of what the part list says it matters not that it is a high tensile bolt in the list, the picture is not of a high tensile bolt.

1.75 is probably standard pitch for M12 I forget, maybe someone replaced the original bolt, with the wrong one, if they have and it screws into the swing arm then the thread will be mullard, if it has a nut on the end then just replace with a new one of the correct dimension and length.

 

[knutk]

The bolt he posted a picture of is a 1.75 pitch thread, regardless of what the part list says it matters not that it is a high tensile bolt in the list, the picture is not of a high tensile bolt.

1.75 is probably standard pitch for M12 I forget, maybe someone replaced the original bolt, with the wrong one, if they have and it screws into the swing arm then the thread will be mullard, if it has a nut on the end then just replace with a new one of the correct dimension and length.

There is no nut showing in the partslist.
I find it strange if BMW introduced two bolts with different pitch, but I'll keep an open mind.

Like you suggest, if someone mounted a bolt with the wrong pitch, that would explain the damaged threads.
Let's just hope on OP's behalf that a new bolt will enter the treads and tighten properly.

 

[Neil W]

I have just changed the rear shock on my 1200 gsa , both top bolt was M12x1.5 x60 and it goes into a captive nut in the frame , lower bolt was M 12x1.5x75 and it goes into the threaded portion of the swingingarm.
Picture of the bolt looks like whatever thread it is that it has been mated with the wrong pitch nut, I would assume that as it is not covered in bits of alloy threads from the swingingarm that this is from the upper mount and would be looking very carefully at the threads in the captive nut before trying to fit a new pivot bolt

 

[knutk]

I have just changed the rear shock on my 1200 gsa , both top bolt was M12x1.5 x60 and it goes into a captive nut in the frame , lower bolt was M 12x1.5x75 and it goes into the threaded portion of the swingingarm.
Picture of the bolt looks like whatever thread it is that it has been mated with the wrong pitch nut, I would assume that as it is not covered in bits of alloy threads from the swingingarm that this is from the upper mount and would be looking very carefully at the threads in the captive nut before trying to fit a new pivot bolt

Let's hope for the OP's sake that you are right.

I have been succsessful in cleaning up damaged threads with a tap. Usually, whenever a bolt with the wrong pitch has been forced into whatever, merely entering a proper sized bolt will also be damaged since the 'receiving' end has become deformed.

 

[JohnnyBoxer]

Dumb job

 

[mrtee43]

When I removed and refitted my ESA shock from my 2013 LC for repair, my top and bottom bolt definitely had different pitch threads. I know because I accidentally did try the wrong bolt in the wrong hole and knew something was not right when the bolt started to bind when trying to tighten it up.

I then realised I had got the bolts the wrong way round.

The bolt in the original picture has probably been forced in the top mount where it goes into the captive nut in the frame.

 

[Bem]

Having had mine out to replace both shocks I can confirm that they are different lengths - at which point I carefully positioned them back where they came from (and so not necessary to consider thread pitch).
As for the bolt in the picture from the op -

Buy a new pair from BMW as Knut suggests, and hope there is enough thread left in the retainer.

 

[harry]

Dumb job

You'll be the man who never made a mistake, eh Johnny?

 

[JohnnyBoxer]

You'll be the man who never made a mistake, eh Johnny?

Oh yes, lots
I meant it’s a dumb job to have to sort out