Rear Frame Hoop De-Drooper

With the mudguard off for other work, decided to have a go at my droopy rear hoop. Noted the underside of mudguard was showing signs of tire rubbing.
Design requirements were to not require lashing bike down to floor since I do not have any lift or tie down points etc.

Pics worth a thousand words:



Was concerned how much force would be necessary and had a backup plan to place a bottle or scissor jack under the long stud and lift it up against the clamped section. But the nuts and thread did it easily. The hoop was roughly 28" from floor level at the rear most point beforehand. Was easily able to raise this a full 1 1/2" with a good sized Cresent wrench. No need to hold thread from turning etc. Releasing the tension gave a small rebound on the frame, ended up at roughly 29" off floor at rear most point, Dead even at each side and dead to nuts level with rest of frame, no more visible bend just rear of shock gussets.

Parts list:
8'x2"x4" lumber
4'x5/8" All Thread
4x 5/8" Nuts
4x 5/8" Washers
3' x 3mm Spectra high tensile strength line (1200 lbs SWL)

The line is wrapped 4x around 2x4 and frame spine...so that's easily 4000-5000 lbs load capacity.
Hope this helps someone else out.

Just goes to show, "necessity is the mother of invention"

Good work

Good job. The top of the rear loop should pretty much line up with bottom of the tank/coil mount? I've done a few of these...

dynodave said:

Good job. The top of the rear loop should pretty much line up with bottom of the tank/coil mount? I've done a few of these...

Click to expand...

So does that put it slightly up WRT the area above the shock gussets? I'm pretty much level to that area now...just eye balling. The visible bend is gone.

71 frame-assume undamaged and unrepaired (lucky they even changed the oil).
I have a 4 foot shear cut straight edge:
1. it's up against the bottom of the tank mount....
2. it's up level with top of tubing over shock mount...
All the way to the rear, the tubing even higher than the straight edge, but only by 1/4".
Sounds like you are very close... and recovered from fat chick syndrome...LOL

You should have seen my combat with a super sagging tail. I ended up surgically removing one from a donor frame and changing it out all together.

is this drawing relevant to Commando frame dimensions?
I found this drawing on another thread - Dimension blueprints of frames, parts etc?

Thank you for the photos and materials list, great job!

from the internet search, simply picture ref.

Set my Mk3 droop up with the 2x4 set up pictured here and had great success.
Pulled complete tail with fender and it was very easy and accurate.
Lowes supplied 5/8-11 x 3' all thread, washers, nuts about $14, 2x4 in my stock.
Oiled the top threads to ease the pull, very easy.

My tail was a visible ¾" droop.....now flat, perfect.

Thank you to Tornado



I used a bungee for temp hold, then strapped a ratchet tie down to clamp the long 2x4 down at headstock end.

p400 said:

Set my Mk3 droop up with the 2x4 set up pictured here and had great success.
Pulled complete tail with fender and it was very easy and accurate.
Lowes supplied 5/8-11 x 3' all thread, washers, nuts about $14, 2x4 in my stock.
Oiled the top threads to ease the pull, very easy.

My tail was a visible ¾" droop.....now flat, perfect.

Thank you to Tornado

View attachment 8981

I used a bungee for temp hold, then strapped a ratchet tie down to clamp the long 2x4 down at headstock end.

Click to expand...

Wow, thought I was looking at my rig for moment there! Well done Good Sir!

Very nice. My only concern would be bending the backbone. Tying to the backbone in two spots ( near the front and back) would eliminate that possibility.
It's kinda similar to what I did, but better as your method does not require major tear down.

XTINCT said:

Very nice. My only concern would be bending the backbone. Tying to the backbone in two spots ( near the front and back) would eliminate that possibility.
It's kinda similar to what I did, but better as your method does not require major tear down.View attachment 8988

Click to expand...

The length of the longer bit of lumber over the spine gives quite a lever arm to operate the clamp with. I'm pretty sure the tension on the wrapped line around the spine is only around a couple of hundred pounds at most. The hoop bent up with what seemed like minimal effort on the two nuts. Not creaking/bending of the wood members that I could notice. No danger of bending the spine as it is a very strong structure at that diameter for these kinds of loads. I'd suspect one could eliminate the lashing and just lean on the forward end of the lumber lever once clamped section was set up....even make the lever longer still for more MA if wanted. Things would get a little unstable though without the lash and without using the nuts to make the steady increase in force across both sides equally.

Many thanks to many posters. I finally got around to taking the "sag" out of the tail loop on my Commando. It wasn't that bad, but someone discarded a real estate for sale sign in the ditch next door and it was impossible to pass up a nice piece of 4x4 timber. Coupled with a few ratchet straps, a foot of all-thread and it was easy. As another poster mentioned, "you'd be surprised how easy the tail loop bends".

Peavey Jeltz said:

Many thanks to many posters. I finally got around to taking the "sag" out of the tail loop on my Commando. It wasn't that bad, but someone discarded a real estate for sale sign in the ditch next door and it was impossible to pass up a nice piece of 4x4 timber. Coupled with a few ratchet straps, a foot of all-thread and it was easy. As another poster mentioned, "you'd be surprised how easy the tail loop bends".

Click to expand...

I like the antigravity effect your stepup has!

Great. I had it down to the frame for a total re-do. Jammed the bar up to/at the bend point(s) of the rear loop , in between a huge industrial 5 ton pump for solid leverage. Held the main frame and lifted it up , total eyeball stuff but it worked first attempt.

Now weld the reinforcement plates in there.

Next time. There actually is a MIG welder just outside of the photo above, but the frame is in power coat and I'd want to put it on a table and get it "dead on balls accurate" before welding on it.

maylar said:

Now weld the reinforcement plates in there.

Click to expand...

Nah,just keep the big gals off the pillion

; -)