Fabricating your own Leading Links for a BMW 100RT

I know there is an article on SCT site in the file section.
I also know that members have fabricated their own leading link units.

Is the $400 you mentioned in your post the total cost(total parts & labor) or just for his labor for this project?

Sidecar Lenny: Hi! That Price was Total. The only question for him was the Price of the Shock and of course depending on what shocks you want to use, it would vary that price a little. That is a Ball Park Price because of the shocks. Been going to the Guy the last 10 years and he delivers on his word. 6 months ago, I had him make, for my '99 VW New Beetle Turbo Diesel, a Full metal Belly Pan(skid pan to ptotect the lower motor ect)and Metal Full length Rocker Panel Covers(3/12 feet long)-He fabricated these 3 items out of Diamond Plate Stock, 1/4 inch and installed them all for $250.The VW dealer wanted almost $85 alone for a cheap belly pan made out of 1/8 plastic so for the quality of the work and his accuracy, thats why I approached him on this deal with the Links.

I have a small weding shop. I imagine when he sees what the specifications are, the price may go up. Don't let him make it out of water pipe.
I don't think I'd low ball something as important as your steering. If he can deliver what your asking for, that price is hard to beat.

I have built a couple of them and i cant stress this enough.Make it out of high tensil strength stress proof steel.Years ago i had a earles fork that was produced by one of the sidecar companys (i wont say which one) it was made out of cold roll steel after a several thousand miles of use it snapped off at the down tube bend!The one i am building currently for my TRIUMPH ROCKET i am building the downtubes out of solid stock 150,000 tensil strength stress proof steel that is 2 3/8" in diameter.I put it on my lathe and drilled both ends out to 1 3/4" approx 10" deep from both ends which left the middle (where the bend is total solid stock steel)This may sound like overkill but believe me when you have had one break off on you you wouldnt say that.This is a item that if done properly will be the best addition to your bike,but if not done correctly can be deadly! hope this helps!

Something such as a leading link has a lot of varied forces acting on it. Bending forces from different directions that change on a constant basis trying to fold, twist and bend the downtubes. Harmonic vibrations are a factor as well. Some have utilized double tube construction I am told in an attempt to cancel these harmonics. Harmonics will cause metal fatigue which can create a failure after amany miles of usage.
It takes a competent welder, a knowledge of materiasls used and a knowledge of what a good connection consists of to make a link that can give true peace of mind. Keep in mind than nothing is any stronger than it's weakest point. Front end construction is not something to take lightly. If a sidecar mount fails one has a chance that the odds are in their favor ...if a rear suspension or even a sidecar suspension or the members they consist of fail the odds are not the best but still much much better than if the front end decides to fold up, bend , break, collapse or all of the above.
THIS IS NOT A PLACE TO MESS WITH UNLESS YOU HAVE NO DOUBT IN WHAT YOU ARE DOING.

I fabricated my own set up last winter, with the assistance of a machine shop doing the welding, and some of the machining necessary for the work.

This front end was made to overkill specs. 1 3/4" OD DOM tubing, .120 wall. Rather than bending the tubes to correct angle, I had them cut, bent, rewelded, with a 1/4" thickness gusset welded into the backside of the rewelded angle.

The bearing blocks mounting the downtubes to the swingarm are one-off, pillow blocks machined out of stainless. The other pieces machined include the axle blocks, and the brake arm/axle spacer bearings for the fully floating brakes.

I'm using Progressive Suspension 418 series shocks, meant for HD Big Twins. The reason for this choice is that there is a selection of replaceable springs available to fine tune stiffness/preload related to sidecar usage.

Not sure if your welder/machinist is quite clued up on what all is involved with putting a front end together - Mine was of my own design, made following my own plans - between parts outsourced (bearing supply houses, fasteners, metal stock), Powdercoating the completed project, all the welding involved, and the machining/turning required - I was on the hook for about $1800.00 CDN, for the project, not including the cost of the wheel itself, as well as the fender.

You are going to save money, and come up with likely a superior product, if you design and build it right - but i seriously question $400.00 being a reasonable goal for a LL front end design, even a basic setup using the stock bike wheel/braking components.

My advice, re-do your cost estimations, then apply the project maxim of taking the estimate, and triple it 🙂

Bill i appreciated your post and the pictures!I am the earlier post re:the leading link that broke.I just wanted to pass on some helpfull information.My suspension had a gusset welded at the bend as well.After the break the front end was taken to a metal specialist to determined why it failed,his conclusion was it failed because of the gusset.If it wasnt there the joint or bend would have continued to absorb the flex but because of the gusset it concentrated the flex to the area on either end of the gusset.And that is where it broke.I just thought i would share this with you.Dont want anyone to get hurt!! safe riding!

A Correction to my earlier posting - I checked my records, and i used .188" wall thickness DOM tubing - This is why i didn't have the tubes simply bent.. 1 3/4" DOM x .188 wall thickness was beyond the abilities of the machine shop i utilised for portions of the project, to accurately bend using one of their mechanical benders. 1 3/4" translates to 44.5 mm diameter, and i needed to machine down the tube tops to fit into 43 mm headstocks while still leaving plenty of material, and transitioning the tube flair back to 44.5 mm to prevent a stress focus in a sharp-cut. The tubes were 3/4 angle cut, at the point of 'bending', stop drilled, and welded. The gusset itself is a 1/4" plate section welded into the corner. All welding was professionally TIG'd.

When i designed this, i did consider the upper fork tube flexure issue.. Hence the large gusset, as well as the tapered .188" wall tubing hopefully being strong enough in the long term to serve it's purpose well - On the short term, so far is so good, it's got through it's first 15,000 km season with flying colours. I'm not in the industry, or even technically familiar with many of the processes involving tube welding and fabrication - I bugged lots of people in the know, and everyone i involved with this did indicate i was building to overkill 🙂 I can only trust in their collective experience, and improve my own knowledge on what works and what doesn't, when i go on one of my project larks..

Honker,
Just curious but did the tubes break right at the weld or away from it. Did both sides break? Was it a full break of a crak and fold type deal? Also do you know if the matrial was chromoly and if so was it condition 'N'? Sorry for all the questions.

IT HAS BEEN SEVERAL YEARS AGO NOW,BUT AS I REMEMBER IT WAS WAS COLD ROLL STEEL,I WAS COMING BACK HOME FROM A 6000 MILE ROUND TRIP FROM CALIFORNIA WE HAD BEEN RUNNING HARD ALL DAY,IT WAS 3:00AM AND WAS 2 MILES FROM MAKING IT HOME.I HAD NOTICED THE LAST 30 MILES OR SO THE RIG WAS HANDLING FUNNY.I STOPPED TO CHECK BUT COULNT FIND ANYTHING IN THE DARK.SO I WENT ON AT A REDUCED RATE OF SPEED WHEN THE FRONT END COLLAPSED DROPPING IT DOWN ON THE MOTOR.FORTUNATLEY WE WERE OK.IT BROKE AT THE BOTTOM OF THE GUSSET RIGHT WHERE THE WELD FOR THE GUSSET ENDED.IT TOOK ABOUT 30,000 MILES OF USE BEFORE IT HAPPENED.BELEIVE ME WHEN I SEE THESE THREADS ABOUT HOME MADE UNITS, THAT EXPERIENCE IS STILL FRESH IN MY MIND!AND EVEN THOUGH SOME HAVE SEVERAL THOUSAND MILES OF USE WITH NO PROBLEMS.IT MAKES ME WONDER WHICH ONES ARE TIME BOMBS? I JUST DONT WANT ANYONE TO GET HURT!

i have built several LL using dom 1 5/8 x 3/16 wall and bending tubes

i guarantee if you get one for $400 u either got junk or the man did it for nothing

by the time you finish with bearing mounts for the swing arm, pinch yokes for the axle, the mount for the caliper and all the related brackets you will be looking at about 20 or more hrs time especially if its the 1st one
plus the materials about $80 - 100 guessing
at best only looking at about $15/ hr nobody works for that LOL

i usually figure about $1500 or so installed

stacy