Springer build with a difference...

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Prof
Founder, Choppers Australia
Posts: 5749
Joined: Sat Oct 22, 2005 3:54 pm
Location: Willunga, South Australia
Contact:

Springer build with a difference...

Post by Prof » Mon Aug 06, 2018 12:01 am

When I originally began my shovel build I planned a damped springer. To get it on the road, I extended its narrow glide front end. Later down the track, I swapped the disc brake for a twin leading shoe drum brake off a Kawasaki. Two years or so ago, Victor bought in a pair of Ford radius rods so I could finally get the front end I had planned and wished for for the last fifteen years and 140,000 miles.
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Well I've been staring at those radius rods, a wheel, set of shockers and full size drawing of the set since then. the other day, Victor announced he wanted to ride his reincarnated shovel to Shovel Fest in Victoria in October. That did it. My goal is to finally have the springer done for that trip...

Over the years, I've put in a lot of time researching everything I can find on springer design. So...
#1. Damped using standard (but short shockers) because although a well designed springer isn't unduly bouncy, damping is desirable for a comfortable ride especially in the rough conditions I like to travel. Also have adjustable preload.
#2. Shockers instead of a damper on a standard springer, because I carry gear (poor mans fairing) over the headlight especially when I travel and that top set of springs bouncing up and down against the bag is not ideal. As I love the look of the classic springer, I will run a set of dummy top springs. Should look close to classic when all done.
#3. Rake of 45 degrees. This will unfortunately put me outside the 550RidikulusRool, but I've been running 45 degrees for years now and really like the handling characteristics,
#4. Trail of 10". I ran 8" for quite a while, but the handling through the twisties is much nicer with the extra 2"
#5. Curved rockers. These allow the pivot point to be lower than the axle which greatly improves handling and steering. When turning actually gives the effect of much less trail. Took me a long time to find this out. Length of rockers determined by axle movement. Once doesn't want the axle hitting front legs in a big bump. Another benefit of the axle/pivot difference is that the movement of the wheel acts more in line with the force of the bumps it hits = better ride and less stress on the front end.
#6. I'm with a 19" front wheel which from personal experience and research is more stable on a road bike than 21". I'll use a Harley wheel which has a safety rim rather than the plain 70's Jap style.
#7. Twin leader. Yes, disc brakes work better and don't fade, but I do prefer a twin leader and have had one in the past that was a real stopper. My current Kwakka brake is not as good as I would like, but kept adjusted, is quite adequate for my style of riding. However, this time I am trying one off a Suzuki Titan. I know they were good, and have heard others who had them say the same.
#8. Construction. Classic springers were welded at the top and bottom of the bottom triple tree leading to cracking at the bottom weld. My back legs (Ford radius rods) will be longitudinally welded on the inside only with a fish mouth style gusset running 6" donw the inside as well. I've hit some nasty objects on the road and would rather a bent frame and staynig upright than having the front end fold on me. Time will tell...
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Setting up the Twin leader...
A drum brake on a springer, presents a problem. the brake anchor needs to attach to the back legs to prevent dive. Locked to the rocker it can twist the rocker under the pivot under hard braking... not good. However, with the brake plate anchored to the rear leg you can't tighten the axle or it locks the rockers and eventually will split the brake plate and put you over the handle bars!

Two solutions... the common Aussie 70's one of leaving the axle loose with some resulting wheel twisting or set up the backing plate to rock as the axle moves up an down. I'll of course do the latter which if one wants a lasting job takes some time and effort.

The Titan backing plate has a steel insert which first must be removed. You can see it drilled it out here and the inner piece loose. I forgot to take a pic, but I then make an alumimium bush to fit in the gap. After this I take the backing plate to an ally welder I use to fill up the speedo passage and weld in the bush...
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You can see the bush here welded in. It is protrudes further in than needed and will be trimmed to allow the backing plate to have the correct clearance in the drum. The backing plate is in a four jaw chuck (what a pain this was) and the centre now bored out to a final size to take a new and larger steel liner...
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Steel liner here made (blue arrow) and sitting on the partially machined brass bu sh on which the backing plate will pivot...
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Steel bush pressed in with some retaining compound as it was not as tight as I would have liked...
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Bronze bush is a top hat style and inserts from the inside. Rim of 'hat' will bear against the bearing. It is now tested in the wheel hub for clearance...
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Now put in the mill and 3mm machined off. This allows the backing plate to sit perfectly in position and gives a broad smooth surface for the top hat to bear against reducing any tendency to wobble and to wear...
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Backing plate fitted with axle. Top hat bush protrudes three mm and will bear against a bronze washer held in place by the axle spacer...
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The ally welder also filled in the stock anchor slot with weld. I drill this out and insert a 3/8 UNF recoil thread for the new brake anchor...
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Next step is setting up axle spacers and speedo mount on right side. It's been done but my bedtime. Tomorrow maybe...
Chopit'nrideit... Prof

Prof
Founder, Choppers Australia
Posts: 5749
Joined: Sat Oct 22, 2005 3:54 pm
Location: Willunga, South Australia
Contact:

Re: Springer build with a difference...

Post by Prof » Thu Aug 09, 2018 12:36 am

So now for final set up of axle spacing. I will run a HD speedo on the right hand side. HD axles are 19mm while this axle is 15mm. So speedo needs a bush as a part of the spacing. The axle bearing is also exposed to the weather, so I need to incoporate a seal which will be an 'o' ring squeezed between the speedo and hub...
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Cut and drill a couple of pieces of 25mm square tube bolt onto the axle and work out centering of wheel between rockers and make sure we have sufficient clearance between the legs and braking mechanism. Here measuring the brake plate side from centre of tyre to extended 'rocker'...
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Calculations working out required spacing between legs and therefor the spacer sizes we will need. Internal measurement on a narrow glide is 130mm. For a WLA springer it is 180mm and for the DNA springers it is 190mm. My legs are 30mm wide so I compromise and and settle on an inner measurement of 140mm...
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Now I can make the brake side spacer. Bottom right diagram is the final version...
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Spacer machined out of stainless and installed. I experimented with an indent in the spacer to the axle plate bears directly against the stainless spacer with 1mm clearance, but I think ally against stainless will wear too quickly so will go back to original idea of a bronze washer...
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Now to measure up for speedo side spacer. Measure edge of hub to wheel centre...
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Calcs again...
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Spacer turned on the lathe and a slot made (red arrow) with the mill to lock it into speedo (blue arrow) and prevent it from turning..
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Spacer in place with a large 'O' ring installed...
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After work tonight I had a bit more of a play. Set the chopper up on a jack so both tyres are both just touching the floor (ie no spring compression due to the chopper's weight. Height of steering head and rake are measured as well as distance the wheel is forwards of the steering head (605mm) from the centre of the steering head Oops Mr Plod; 55mm over the RidikulusRool!
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Now set this all up on my jig. I machine up a steering head and pop in a couple of bearing cups, bearings and a headstem. This is now set up at the same angle and height as the shovel.
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Close up...
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Wheel set up and one of the 25mm tubes is angled down so the pivot (+) is the required 90mm below the axle
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Here's the approximate location of the rear leg. Because I want to keep the same trail as I have, the leg will actually angle back slightly to the headstem angle... Ie. Rake is 44 degrees but leg is only around 40 degrees...
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Next job will be to make the curved rockers and intall them. Then I'll machine up the tabs that hold the rear pivot bolts. More on that when it is done...
Chopit'nrideit... Prof

Youngblood
Posts: 371
Joined: Wed Oct 24, 2007 1:48 pm
Location: North-Eastern suburbs- Adelaide

Re: Springer build with a difference...

Post by Youngblood » Thu Aug 09, 2018 11:02 pm

8) 8) 8)
Youngblood

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