Jump to content
Sign in to follow this  
Ron-M

Fork bridge screws

Recommended Posts

Ron-M

I replaced the front tire on my 1250.  As I was reinstalling the front wheel, I noticed the instructions in the manual direct you to, once the wheel is back on, take the motorcycle off the front wheel stand, compress the forks, install the front wheel stand again and then tighten the fork bridge screws.  I wanted to get the thoughts on whether this is a necessary step, or if I can just reinstall the wheel and button everything back up without messing with the fork bridge screws.  

BMW manual.jpg

Share this post


Link to post
duckbubbles

That is to align the forks and eliminate any side load that would cause binding when the forks have to move in compression.  Improves ride quality.  I would do that even if they didn't list it. 

 

Frank

Share this post


Link to post
AndyS

That is curiously interesting.

 

In the riders manual I have for the 1250 shiftcam (2019) pages 165 and 166 make no mention of this procedure (and neither do the rider manuals for the R1200 2014 - 2018).

Share this post


Link to post
9Mary7

Procedure has been standard for aligning forks that use a clamp on one side of the axle. Don't know why they haven't included it in BMW owner's manuals before.

Share this post


Link to post
Ron-M

I was looking at another manual that I found on line. It was a manual for the 1250 RT in Europe, and it had no mention of this procedure either.  I am wondering how important it is if it is not mentioned in some manuals and mentioned in others.  

Share this post


Link to post
9Mary7

Smooth fork action is important to me so........ I always do it. When you do your own work you get to decide what shortcuts to take....:5146:

Share this post


Link to post
Dann

The repair manual for my R1250Rt mentions compressing the forks but there is no mention of doing anything to the fork bridge in the procedure.

Share this post


Link to post
AndyS

+1

Share this post


Link to post
dirtrider
23 hours ago, Ron-M said:

I replaced the front tire on my 1250.  As I was reinstalling the front wheel, I noticed the instructions in the manual direct you to, once the wheel is back on, take the motorcycle off the front wheel stand, compress the forks, install the front wheel stand again and then tighten the fork bridge screws.  I wanted to get the thoughts on whether this is a necessary step, or if I can just reinstall the wheel and button everything back up without messing with the fork bridge screws.  

 

Morning  Ron-M

 

This one is difficult to understand. My gut feeling is that the BMW riders manual (that mention the fork bridge screw tightening) is incorrect.  Pumping the forks before final wheel axle tightening IS important but tightening the lower bridge clamp bolts seems out of place on JUST a tire change service. (especially if there is no request to loosen the fork bridge bolts prior to pumping the forks with the wheel on the ground) 

 

It is possible that BMW just wants those lower bolts checked for being (remaining) tight at each tire change interval.

That 6x or 3x per bolt is a requirement at fork re-installation to neutralize fork tube loading but that also assumes starting with loose bolts (as I mentioned above I see no mention of loosening those bolts first so it doesn't seem to be an alignment or neutralizing thing). Just a tightening (tightness verification)  thing. Of possibly just a riders manual miss-print  driven by incorrectly using the fork tube installation information from the BMW service manual.

 

I see no mention of LOOSENING those bolts at any point during the tire change service so it doesn't seem to be an alignment or fork tube neutralizing  thing. So, (IF) that fork bolt  bridge bolt torque is actually a requirement it seems more related to "verifying" the lower bridge bolt torque is correct than actually neutralizing  the fork tube side loading.

 

In my mind, it is a toss up between the riders  manual being incorrect (possibly when the riders manual was assembled the fork tube replacement procedure was incorrectly inserted into the the simple tire change procedure). (OR),  BMW just wants to assure that the lower fork bridge pinch bolts are remaining tight after seating in.    

 

Personally, I would do the 6x (alternating) 3x per bolt   torque check (would NOT loosen first) at first tire change. If you get to 19 nm on each bolt & they don't move  then that would be it for life (or until a fork tube was removed), If by chance one or more bolts moved at or before 19nm  then I guess I would check them at each tire change. 

 

My one suggestion on things like this is to simply call your local BMW dealer & ask them what "they" typically do during a normal tire change (they might have a service bulletin, either explaining the WHY, or possibly telling them to disregard, or possibly a further explanation anyhow.  

 

  

  • Like 1

Share this post


Link to post
AndyS

Well DR, I personally don't think that fork bridge needs touching.

However, a light tighten of the axle and axle pinch bolts then remove the bike from the centre stand and back on a couple of times before a final torque up of the axle and axle pinch bolts. With a check of the discs to make sure they aren't rubbing. 

I am open to being corrected if someone has a valid reason why anything should have changed between wheel removal and wheel replacement.

Share this post


Link to post
dirtrider
48 minutes ago, AndyS said:

Well DR, I personally don't think that fork bridge needs touching.

However, a light tighten of the axle and axle pinch bolts then remove the bike from the centre stand and back on a couple of times before a final torque up of the axle and axle pinch bolts. With a check of the discs to make sure they aren't rubbing. 

I am open to being corrected if someone has a valid reason why anything should have changed between wheel removal and wheel replacement.

Morning Andy

 

That is pretty well what I said above, the riders manual has NO MENTION of loosening those lower bridge pinch bolts before taking motorcycle off wheel stand, bouncing, then putting  back on wheel stand  so there is no way it could a fork alignment or neutralization deal. 

 

To me it is either a  mis-print in the riders manual (possibly someone looked up the pinch bolts & referenced the wrong pinch bolts). OR, it is simply a torque verification on those lower  bridge bolts after neutralizing wheel axle attachments to be verified at every wheel removal/tire change. 

 

My SWAG it that it is just a manual mis-print.  

  • Like 1

Share this post


Link to post
Ron-M

D.R. and Andy,

 

When reading the manual, it mentions this fork bridge screw tightening almost as if it is an after thought,or mistake.  There is no lead up to the instructions picture showing the fork clamp and the sequence to tighten the screws, such as "Next, tighten the fork bridge screws."  The instructions go from "Tighten left axle clamping screw 2 to specific torque," to "Tighten right axle clamping screw to specific torque,"  with the tightening fork bridge screw sequence picture stuck in between those two instructions with no reference.  I checked the screws and they a tight.  I am going with that it was a misprint by BMW.  

Thank you to all that have commented.

  • Like 1

Share this post


Link to post

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×
×
  • Create New...