Rear shock mount points conversion | Bobber style

Discuss all things 1970 & later Airheads right here.
Post Reply
User avatar
midwestoutreach
Posts: 2
Joined: Wed Apr 29, 2020 1:02 pm

Rear shock mount points conversion | Bobber style

Post by midwestoutreach »

Hi all,

I just found this forum, super excited to join and read all the available threads. I especially enjoyed the full on newbie resource guide aggregated over the years.

My current motivation to get an airhead was inspired by the classic bobber conversion seen everywhere online, which I am now persuing. Yes, I get that it may be impractical, but that's not the point of this build.

I've narrowed down my search on the seat pan, indeed this is the one that looks most appealing to me and is ready for installation without major mods.

Image
https://www.caferacerwebshop.com/en/bmw ... oeIVFBeFjw

My goal is to remove the entire rear subframe that supports the stock seat and fender. This is where I am stumped.

There seems to be a mounting point for the rear sub-frame right at the front of the seat near the tank, just at the 45 degree frame bar. (See pic below). I have seen multiple builds with custom brackets at that point. My questions is, can I mount the shock to this point or do I have to create custom brackets.
frame.jpg
frame.jpg (53.61 KiB) Viewed 1341 times
If the brackets are adequate for shocks, what do you suggest for a comfortable ride? I haven't measured the required length yet.

I've attached a few inspirations below. Thanks for your time and this amazing forum.
https://www.bikebound.com/wp-content/up ... bber-3.jpg
https://i.pinimg.com/originals/8d/d7/66 ... 0a4a98.jpg
https://caferacerforsale.com/wp-content ... 6img_1.jpg
2001 Eurovan | 2002 M3
Rob Frankham
Posts: 1214
Joined: Thu Aug 26, 2010 2:11 pm
Location: Scotland UK, 20 miles from civilisation up a dead end road!
Contact:

Re: Rear shock mount points conversion | Bobber style

Post by Rob Frankham »

FWIW, I wouldn't be at all happy about mounting top that point without significantly strengthening it. I know that the original sub frame mounts there and that supports the original shocks but the forces are quite different. In the original setup, the forces are mainly in compression whereas in the 'bobber' version, the forces are much more in the sheer plane. I know it's been done before... many times... but that doesn't make it a good practice.

Rob
ImageImageImage
User avatar
midwestoutreach
Posts: 2
Joined: Wed Apr 29, 2020 1:02 pm

Re: Rear shock mount points conversion | Bobber style

Post by midwestoutreach »

Rob Frankham wrote: Thu Apr 30, 2020 6:07 am FWIW, I wouldn't be at all happy about mounting top that point without significantly strengthening it. I know that the original sub frame mounts there and that supports the original shocks but the forces are quite different. In the original setup, the forces are mainly in compression whereas in the 'bobber' version, the forces are much more in the sheer plane. I know it's been done before... many times... but that doesn't make it a good practice.

Rob
Agreed, hence since I've posted this my inclination is to lean with a monolever set up that is already present on 84+ r series.
2001 Eurovan | 2002 M3
Post Reply