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ManualManiac
04-27-2016, 3:37 PM
Hi, i fancy building a springer fork. I want to use some Aluminium 883 XL883 Triple Trees as a base i dont have money for chrome so im tempted to use 39mm aluminium tube as rigid fork legs. Will this kill me?

Thanks.

slinginrods
04-28-2016, 1:52 PM
Maybe

shortpork
04-28-2016, 10:10 PM
Try to find some load testing on that material. I dont know shit about it but im sure you can find something. Like I said, I know nothing about 883 xl883 shit but my knee jerk reaction personally, is i dont wanna risk my life on aluminum over steel just because its shiny. Just build it with what everyone recommends, ride it til winter when you can get some mulah saved, and chrome that shit up while youre sitting idle

klondikekid64
04-28-2016, 10:36 PM
Stainless steel maybe? it comes in different grades and polishes up like chrome,

shortpork
04-28-2016, 10:49 PM
Stainless steel maybe? it comes in different grades and polishes up like chrome,

there you go, that sounds like several shitty hours of polishing. If you want that look though...

boomboomthump
04-29-2016, 6:26 AM
Stainless is typically not used due to the brittleness of it. For a short one with steep rake it might last but in general springer legs flex a LOT and stainless is not a good application. Also for the cost to build one in stainless, you could chrome one for way less money.

Springer legs are made from either solid round bar or very thick-walled (3/16"-1/4" wall thickness) tubing (mild steel or chromoly). The only exception to that would be a stock Harley springer which has elliptical tubing which adds strength and allows it to have a smaller wall thickness.


Here is a pile of my material...

https://scontent.cdninstagram.com/t51.2885-15/sh0.08/e35/11420698_910560022362798_1679218626_n.jpg?ig_cache _key=MTExNDgzNjExMzY1MzU1MTI5Mw%3D%3D.2

shortpork
04-29-2016, 7:47 AM
Stainless is typically not used due to the brittleness of it. For a short one with steep rake it might last but in general springer legs flex a LOT and stainless is not a good application. Also for the cost to build one in stainless, you could chrome one for way less money.

Springer legs are made from either solid round bar or very thick-walled (3/16"-1/4" wall thickness) tubing (mild steel or chromoly). The only exception to that would be a stock Harley springer which has elliptical tubing which adds strength and allows it to have a smaller wall thickness.


Here is a pile of my material...

https://scontent.cdninstagram.com/t51.2885-15/sh0.08/e35/11420698_910560022362798_1679218626_n.jpg?ig_cache _key=MTExNDgzNjExMzY1MzU1MTI5Mw%3D%3D.2

How much money worth of material would you say you put into a average front end build? And where do you shop for springs?

boomboomthump
04-29-2016, 10:27 AM
That material there (mild steel) for a roughly +12" over front end is around $150 and covers the legs, trees/bridge/perch, rockers and pivots welded into the rear legs. On top of that, $80 for the neck (if you have a lathe you can make one for $10), another $100 in misc hardware/bushings, $120 springs. That's $450. Most ballpark costs are $400-500 in materials all in.

The biggest cost is all the labor and the finishing cost.

shortpork
04-29-2016, 10:32 AM
Nice thats reasonable. And your spring source?

Sorry, not tryin to blow you up, Ive just heard a lot of spring manufacturers load ratings are inconsistent and not as stiff as labeled.

boomboomthump
04-29-2016, 12:52 PM
Oops. It's no secret, LOL. I'm using Colony springs on the one I'm making. There's only really 4 main sources for springs...

VTWIN MFG - repops of early OE Harley springs (China made)
Colony Machine - repops of early OE Harley springs (USA made) (also sold by 45 Parts Resto but made by Colony)
Paughco - slight length/width variances from early OE Harley springs but pretty close (USA made)
DNA/Hardbody/Mid-West - these vary greatly from OE Harley springs as they are narrower and thicker wire. Unsure what the spring rates equate to. (China made)


There's other places that sell springs but they are just one of these four. Basically you have the China or USA made exact replicas of early Harley springs, the Paughco ones which are high quality but vary slightly from the early Harley springs and then you have the ones used on DNA springers. I haven't seen any of those manufacturers list spring rates. It wouldn't surprise me if the China made ones are not consistent.

Beyond those, there's also longer springs which are found on late model Harley springers and Paughco springers with shocks. Lastly, some place in China is now making "square wire" springs which were around in the 70's. Probably comes from the same factory as the DNA/Hardbody/Mid-west stuff.

shortpork
04-29-2016, 1:12 PM
Right on, great information man. More than enough to get the ball rolling. Appreciate it!

Sorry OP wasnt trying to divert your thread. Sounds like mild or chromoly is your answer though. Aluminum sounds way sketch to me

bobscogin
04-29-2016, 1:14 PM
Before you investigate materials, investigate the geometry. Notice that most springers have the legs inline with the steering stem. The rockers work to provide the correct trail. The 39 mm trees have the legs moved forward of the stem to provide the correct trail when the axle is in line with the legs. Moving the legs forward of the stem by using the 39 mm trees, and then adding rockers at the bottom moves the axle ahead. I'm not saying this won't work. I'm just saying you should be aware of how the geometry is going to end up.

Bob

boomboomthump
04-30-2016, 12:33 AM
Very good point Bob. With the amount of offset in the trees, you would have to be running a large amount of rake in the neck to not end up with negative trail.

nofendertom
04-30-2016, 10:06 AM
check out Siouxicide Choppers---they sell a front end like you are thinking of making.

shortpork
04-30-2016, 2:28 PM
Premade front ends rarely ever work well. They try to make one setup for every bike, when in reality every bike really needs its own front end made for THAT bike. I wouldn't risk it/ waste the money. If you think you're capible of making one you'll be much better off.

nofendertom
05-01-2016, 10:14 AM
shortpork---didn't mean buy it---meant check it out for materials used and how they tackle the geometry issue that
bobscogin has already brought up.

bobscogin
05-01-2016, 2:57 PM
shortpork---didn't mean buy it---meant check it out for materials used and how they tackle the geometry issue that
bobscogin has already brought up.

Back to the geometry. I did some measuring to get an idea how using the stock trees would work. The offset is ~2 1/4". I measured the rockers on a Paughco springer at at about ~3 3/4" center to center for a total offset of 6", Making some assumption on wheel diameter, I used 26", and 28" on fork length which is about what a stock 39mm fork measures, and 30 rake. These numbers yield a trail figure of less than 1". Not safe. Plug in your own numbers and see what you get. You normally need around 4" of trail.

https://www.rbracing-rsr.com/rakeandtrail.html

Bob

shortpork
05-02-2016, 7:53 AM
Back to the geometry. I did some measuring to get an idea how using the stock trees would work. The offset is ~2 1/4". I measured the rockers on a Paughco springer at at about ~3 3/4" center to center for a total offset of 6", Making some assumption on wheel diameter, I used 26", and 28" on fork length which is about what a stock 39mm fork measures, and 30 rake. These numbers yield a trail figure of less than 1". Not safe. Plug in your own numbers and see what you get. You normally need around 4" of trail.

https://www.rbracing-rsr.com/rakeandtrail.html

Bob

good link

slinginrods
05-04-2016, 4:31 AM
check out Siouxicide Choppers---they sell a front end like you are thinking of making.

Damn it looks pretty legit to me .

ManualManiac
05-04-2016, 4:39 PM
i want to use aluminium triple trees and im afraid stainless, water and alu make a bad threesome

ManualManiac
05-04-2016, 4:44 PM
Im going to look into thick walled steel or chrome moly, I will cover that with aluminium tube so it looks all aluminium il weld in a sold aluminum plug at the end and drill rocker holes into that.

ManualManiac
05-04-2016, 4:47 PM
I can really get going now, Thanks a million for the info.

ManualManiac
05-04-2016, 4:49 PM
Right on, great information man. More than enough to get the ball rolling. Appreciate it!

Sorry OP wasnt trying to divert your thread. Sounds like mild or chromoly is your answer though. Aluminum sounds way sketch to me

Your asking the things i didnt even know i wanted to know, you thinking about building your own springer? (Man i love this site)

ManualManiac
05-04-2016, 4:53 PM
Before you investigate materials, investigate the geometry. Notice that most springers have the legs inline with the steering stem. The rockers work to provide the correct trail. The 39 mm trees have the legs moved forward of the stem to provide the correct trail when the axle is in line with the legs. Moving the legs forward of the stem by using the 39 mm trees, and then adding rockers at the bottom moves the axle ahead. I'm not saying this won't work. I'm just saying you should be aware of how the geometry is going to end up.

Bob

i was thinking it might work in my favor since its going to be a short fork and i want my 21 inch wheel to stay well away from my headers. 69377

ManualManiac
05-04-2016, 4:55 PM
check out Siouxicide Choppers---they sell a front end like you are thinking of making.

Wish i could, ive already been making bar talk that im going to make one myself, Thanks for the link

ManualManiac
05-04-2016, 4:59 PM
Back to the geometry. I did some measuring to get an idea how using the stock trees would work. The offset is ~2 1/4". I measured the rockers on a Paughco springer at at about ~3 3/4" center to center for a total offset of 6", Making some assumption on wheel diameter, I used 26", and 28" on fork length which is about what a stock 39mm fork measures, and 30 rake. These numbers yield a trail figure of less than 1". Not safe. Plug in your own numbers and see what you get. You normally need around 4" of trail.

https://www.rbracing-rsr.com/rakeandtrail.html

Bob

Thanks Bob, i didnt even consider the science behind it.

ManualManiac
05-04-2016, 5:03 PM
check out Siouxicide Choppers---they sell a front end like you are thinking of making.

looks bitchn. that is the look im aiming for

ManualManiac
05-04-2016, 5:05 PM
Back to the geometry. I did some measuring to get an idea how using the stock trees would work. The offset is ~2 1/4". I measured the rockers on a Paughco springer at at about ~3 3/4" center to center for a total offset of 6", Making some assumption on wheel diameter, I used 26", and 28" on fork length which is about what a stock 39mm fork measures, and 30 rake. These numbers yield a trail figure of less than 1". Not safe. Plug in your own numbers and see what you get. You normally need around 4" of trail.

https://www.rbracing-rsr.com/rakeandtrail.html

Bob

I fear those are my numbers. damn i really am building a death trap

bobscogin
05-04-2016, 8:48 PM
I fear those are my numbers. damn i really am building a death trap

Dude, I hope you don't think I'm throwing cold water on your plans, but you did say in your first post "Will this kill me?". I've been at this over 50 years, and I find front end geometry to be widely misunderstood, or in some cases totally unfamiliar to the builder. Again, I'm not saying it won't work, but the numbers don't support it.

Bob

slinginrods
05-04-2016, 9:27 PM
Bob how do you think the souixcide springer works? They don't have any trail numbers on the website. I think that's the design he wants to build .

bobscogin
05-04-2016, 10:03 PM
Bob how do you think the souixcide springer works? They don't have any trail numbers on the website. I think that's the design he wants to build .

I looked at it, and if it retains the trail of the stock fork, I can't see how. The springer leg is in the same position as the stock leg and the rocker appears to pivot from the same position as where the axle would be would be in the stock set up. The rockers move the wheel ahead, and that reduces the trail. Trail could be increased by using de-raked trees, but that defeats the whole intent of using the stock ones. Am I missing something?

Bob

slinginrods
05-05-2016, 9:44 AM
I watched the install video ,they use the same triple trees. Id like to talk to some one who has ridden one of these

boomboomthump
05-05-2016, 11:20 AM
They would probably tell you it rides great. I wouldn't believe them for a second.

bobscogin
05-05-2016, 6:41 PM
I watched the install video ,they use the same triple trees. Id like to talk to some one who has ridden one of these

I just watched the video too, just to make sure I wasn't misunderstanding anything in the design. I'm not that curious, but maybe someone here would be interested enough to ask them their thoughts on trail theory. In the absence of a plausible explanation, to me they're Suicide Choppers instead of Siouxicide Choppers.:D

Bob

ManualManiac
05-06-2016, 6:02 AM
I looked at it, and if it retains the trail of the stock fork, I can't see how. The springer leg is in the same position as the stock leg and the rocker appears to pivot from the same position as where the axle would be would be in the stock set up. The rockers move the wheel ahead, and that reduces the trail. Trail could be increased by using de-raked trees, but that defeats the whole intent of using the stock ones. Am I missing something?

Bob

I swapped my steering head its only tack welded in at this point, So i can still change the rake. its 30deg i could make it less than that.

bobscogin
05-06-2016, 6:38 AM
To increase trail, you need to increase the neck angle. Using the same numbers (except neck angle) that were previously plugged into the calculator, working backwards to get around 4" of trail shows a neck angle of 42 yielding 3.63" of trail. I'd consider that to be a minimum. Trouble is, the previous number of 28" for the fork length is probably going to have the bike sitting flat on the ground unless the forks are lengthened. Then you do the calculations over again for the new fork length. You need to get out your drawing board and drafting tools (I'm old, don't do CAD.) and figure it out on paper.

Bob

ManualManiac
05-07-2016, 8:54 AM
To increase trail, you need to increase the neck angle. Using the same numbers (except neck angle) that were previously plugged into the calculator, working backwards to get around 4" of trail shows a neck angle of 42 yielding 3.63" of trail. I'd consider that to be a minimum. Trouble is, the previous number of 28" for the fork length is probably going to have the bike sitting flat on the ground unless the forks are lengthened. Then you do the calculations over again for the new fork length. You need to get out your drawing board and drafting tools (I'm old, don't do CAD.) and figure it out on paper.

Bob

il figure something out, Thanks for the effort.

IronheadVic
05-07-2016, 10:14 AM
based on the picture of the front end, I don't think that rocker is 3.75" from back leg to axle hole. The axle is pretty much right below the front leg. I'd say that is 2 inches max, maybe less from the back leg to the axle. Adding that to the 2.25 offset in the trees, the trail is 3 inches minimum, still twitchy, but not certain death.

bobscogin
05-07-2016, 12:06 PM
based on the picture of the front end, I don't think that rocker is 3.75" from back leg to axle hole. The axle is pretty much right below the front leg. I'd say that is 2 inches max, maybe less from the back leg to the axle. Adding that to the 2.25 offset in the trees, the trail is 3 inches minimum, still twitchy, but not certain death.

Your point about shorter rockers increasing trail is right on target. I measured a set of Paughco rockers because they mimic the dimensions of the stock Harley rocker, which has sort of become the de facto standard of the chopper industry. Going shorter than that would be beneficial from a trail viewpoint, but shorter also reduces the suspension's effectiveness, shortening travel, and throws a wrench into the spring choices because the rates for those are based mostly on original Harley springs for longer rockers. As I stated in my first post, not necessarily a deal killer, but be careful and go in with some knowledge.

Bob

ManualManiac
05-09-2016, 2:06 PM
Your point about shorter rockers increasing trail is right on target. I measured a set of Paughco rockers because they mimic the dimensions of the stock Harley rocker, which has sort of become the de facto standard of the chopper industry. Going shorter than that would be beneficial from a trail viewpoint, but shorter also reduces the suspension's effectiveness, shortening travel, and throws a wrench into the spring choices because the rates for those are based mostly on original Harley springs for longer rockers. As I stated in my first post, not necessarily a deal killer, but be careful and go in with some knowledge.

Bob

What if i add a steering damper?

slinginrods
05-09-2016, 2:26 PM
I email souixcide about the trail on the springer conversion.they said it does infact reduce the trail on a bike with the stock rear shocks , but if you lower the bike with 2" shorter shocks it brings trail back to the 4.9 original spec. That a hartail conversion that drops the rear 4" would increase it further and they recommend a shorter front end . What do you guys think about that ? I know jus by playing with my project by raising and lowering the front of the frame you will definetly change the rake angle ,which does influence trail. Just food for thought . Oh by the way the rockers extend the axle 1.5 to 1.75 inches further out they said.