Springer questions...

itrguy

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Ok Fellas I picked up an old narrow springer on a trade on craigslist, my research tells me it was made by a company called s.i.e. that existed back in the day in Oak Lawn here in IL. I plan on cutting it down to stock size to use on my 71 hard tail xs. The legs are square tube so chopping, slugging and welding shouldnt be too bad. My question is, how do You measure a springer?? Go from bottom of lower "tree" to the axle?? its 34.5", i want it 22" like stock. Im confused i guess with how wheel sits out a bit with the rockers....???? Any help is appreciated.
 
its a springer,2 lower springs and 2 upper springs.. the legs are square tube instead of round, old school radius rods or twisted square tube... back legs are 1" square tube and front legs are 3/4" square tube... Ill upload pics later... anyways do i measure same as forks?
 
Hey ItrGuy, just measured my 1Bs. From bottom of triple tree to center of axle:
Stock = 21 1/4"
10 over chop = 31 1/4"
That's fully extended. Do side view drawing of your springer, measure up, from the axle center, parallel with the legs, to where the bottom of your trees should be. If you're trying for stock street handling, adjust as needed to get 4 to 4 1/2" of trail.
Hope this helps...
 
Im not doing anything with the rake, are You saying that cutting the springer will change the trail?? I just disassembled the springer again so i can chop its legs...
 
Okay, stock rake, makes this easier.
Trail changes if the frame isn't level like the stocker, shorter/longer forks you know.
The springer's rockers will control your trail. Sometimes you make longer ones, sometimes shorter.
Lay your springer up against something, at the rake angle you expect to have.
Sight down the steering stem and visualize where the stem center (steering axis center) hits the floor.
Mark that spot. Mark the center of tire contact, 90 degrees straight down from axle center.
The distance `tween marks is your trail.
The springer may have been built for rake with extension, usually a longer trail.
When you chop down, you have to double-check this.

If I remember right (pause for senior moment...)
0" trail - neutral steer, speedway bikes
3 - 3 1/2" - dirt bikes
3 - 4 1/2 " - street bikes, racebikes
4 1/4 - 9" - choppers (highway stability)
Above 9" - (in Chongs voice) Wow, man that thing's smoooth on the hiway, but I keep falling down in town...

Good luck.
 
If it was me I would measure the springer from lower tree to the pivot point on the rear leg. Then measure from the lower tree to the axle of the stock forks. Now subtract the one from the other. Cut this much out of the legs on the springer.
Maybe cut a bit less. Tack weld the legs, assemble the springer, mount on bike, mount wheel.
See how it looks. If it's the way you want it finish welding the springer. If not cut some more out till it's what you want.
Leo
 
I was hoping the trail wouldn't be affected really if i cut springer to stock size..... wishful thinking?? Ill also do what xsleo said and see what the difference is. The bike still has whole stock front end on it, didn't want to take apart till springer was chopped and ready to install, then all i gotta do is figure out a brake stay so i can run my stock xs drum wheel...
 
On the trail, once you cut the springer to length the trail should be fine. Measure the trail once you get the cutting and welding done. If the trail is not at a comfortable spec you can make new longer or shorter rockers to adjust.
Leo
 
I talked to a guy running a similar setup on his xs chop.. He said 22" from bottom of lower clamp to the axle is perfect... looks like Im chopping 12.5" off of it! The next issue will be figuring out a slick brake stay so I can run the stock 71 xs drum brake! Any ideas??
 
Boy, I hope the Resto guys aren't reading this...
You'll probably have to fabricate a steel block to fit into the backing plate slot, drill holes, tap threads, etc, to attach that block in there. Then some kind of brakestay strap that to the springer leg, with pivoting ends. Ideally, the backing plate locks to the rocker, but that would mean rotating it clockwise 90 degrees, which makes cables coming out straight down. A strap going from that slot to the rear rocker pivot bolt would work, have to make a special pivot bolt.
Does it use flat plate rockers, or bushed trunnions?
 
Don't worry bout rest those boys, bikes been chopped for years...the rockers have bushings with grease fittings on the outside, there is about 2&1/4" inches between holes for axle and front leg on rocker, rockers are pretty long, axle sits lower... I need to upload some pics...
 
Okay, I think I have this back in my head, so hopefully it'll make sense.

Back in the days, if you look at stock springers (even new Harleys), you'll notice the rocker length, appropriately short. In the early days of extended springers, they were a bit wobbly, using stock length rockers gave them too much trail when raked. Solution? Lengthen the rocker, shortens the trail, improves handling. The better springer builders knew this, and incorporated longer rockers if it was intended for a raked front. If your springer was properly designed for extended/raked front-end, then it probably has longer rockers. If you shorten it, use stock rake, the longer rocker will reduce your trail, possibly to 1-2", creating a sensitive front handling.

There, hope I got that right...
 
motorcycle-rake-trail-offset-e1295912863770.png
 
Here are the rockers, before clean up....
 

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Fantastic, you got the good ones! Bushed pivots and clean flat plate between axle and front pivot.
If you have to move the axle back, simple hole drilling, cut-off excess, ready to go...
Yeah, do your set-up, measure it all out, decide on your trail length, measure twice, drill/cut.
Good luck.
 
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