The Chopper Compendium

I need some insite on building a girderfront end PLESE??

Here is the parts I have and plan!! For what it is worth???



A set of shocks off a Yamaha SR250!
11.5 eyelet to eyelet centers!
Not known spring rate? Pushing down with body wieght I can get 1in movement! I wiegh considerably so guessing 200 to 300 psi rating???
About 2.5 in travel to rubber stops on shock shaft? So around 3in with the stops compressed??
Adjustable!!










Two blocks of Alloy to hopefullly make trees out of!











Somewhat of a plan for the front linkages???
I thank this site and membershere [RueDOG] for helping me with this tool!!!
It has been of great help!!!











One or two designs to play with???
















Plan for neck shaft?



Thread the bottom tree and shaft 1in 14tpi and thread shaft to protrude out bottom to put lock nut on!!

Turn the shaft to length of assembly untill out top tree then thread to 1in 14tpi and install a lock nut!!!

Drill and set screw top tree or clamp by splitting aluminum and installing thru bolt??? Not sure if needed?



Questions??

1.I want to use 1/2 grade 8 sholder bolts and cut head off and thread one end so both ends threaded on lathe to bolt thru trees and girder legs and for linkages??
2.I want to run locknut, washer, girder leg, nylon bushing, bronze oilite thrust washer, bronze oilite flange sleave bearing, nylon washer and then tree on bolt???
3.Can I run one shock with this shock?
4.Do I need tofind different shock or just run two?
5.Is the design valid?
6.Do I need to fix top tree to shaft?

Any Help greatly Appreciated!!!
I hate just slapping something toghter without planning it but, I am not scared to have to do it over!!!

Here is a print and I belive the final linkages layout???

Anyone see any problems???

I know I am getting anoying with all of this!!!

I went to check the simulator and found it did not really match???


I rendered this in a 2d cad???

See any problems or want any measurements???

check out "Dkilliam" and "concreteguy" s girder builds in the " girder , springer , spirder" section !

here is the link to the front end rules

http://www.choppercompendium.com/ccforu ... f=34&t=494

Rule of thumb for setting trail of hydraulic and girder frontends:
First use the tire width formula (T=(((rear tire width/front tire width)*100)-100)*0.01) to find the needed adjustment trail.
I.E.: 90/90/21 front tire and 250/35/18 rear tire
T=(((250/90)*100)-100)*0.01
T=(((2.778)*100)-100)*0.01
T=((277.778)-100)0.01
T=(177.778)*0.01
T=1.778" of trail adjustment needed

* remember this equation results in American Standard Measuring not metric so you would have to do one more little conversion for metric: simply multiply answer by 25.4 to get mm answer
* i try to round to three decimal places as that is a common amount when machining.

So now using a baseline trail of 2" I will add the trail adjustment to the 2" baseline and come up with my needed trail.
I.E.: 2" + 1.778"= 3.778" of needed trail or round to nearest 1/8" so 3.75" of trail.

- I do not concentrate on wheel flop for these front ends as they respond better to the trail numbers rather than the wheel flop numbers. Frontends with a rocker system at the axle, I use my wheel flop equation and shoot for .125" of trail as the axle travels in an arc about the fulcrum point.






Hello krymis have I done this right???



3-21in front = 80/100/21
4-18in rear = 100/100/18
http://www.cb450stuff.com/tires/




So

T=(((100/80)*100)-100)*0.01=19
T=(((19)*100)-100)*0.01=18
T=((18)-100)0.01= -0.82
T=(-.082)*0.01= -0.0082
T=- -0.0082 of trail adjustment needed????????



So I need to be shooting for 2in instead of 3.5in????

gearhead1951 wrote:check out "Dkilliam" and "concreteguy" s girder builds in the " girder , springer , spirder" section !

Thanks for the Help!!!

It may be because I am blonde but having problems finding the threads???

I looked in the girder section and build sections??

Can you post links PLEASE????

Here is my flop number if I did it right at 3.5 trail??? This is actual trail not ground trail???


(((3.5 * sin(45°)) * cos(45°)) / 90) * 40 = 0.777777778


And the flop for 2in???

(((2 * sin(45°)) * cos(45°)) / 90) * 40 = 0.444444444

Customize IT wrote:...I went to check the simulator and found it did not really match???...

I'm glad you've double checked the numbers in CAD! If the numbers are off by more than 0.1", you may need to double check your 2D CAD. I had the same problem and had not transfered the offsets properly to CAD.

When you build, use your CAD numbers only. You drew it, you know what the numbers are.

Customize IT wrote:

gearhead1951 wrote:check out "Dkilliam" and "concreteguy" s girder builds in the " girder , springer , spirder" section !

Thanks for the Help!!!

It may be because I am blonde but having problems finding the threads???

I looked in the girder section and build sections??

Can you post links PLEASE????

Sorry 'bout t hat I forgot that everything prior to the big crash/hack job was lost !!

rudog wrote:

Customize IT wrote:...I went to check the simulator and found it did not really match???...

I'm glad you've double checked the numbers in CAD! If the numbers are off by more than 0.1", you may need to double check your 2D CAD. I had the same problem and had not transfered the offsets properly to CAD.

When you build, use your CAD numbers only. You drew it, you know what the numbers are.

Thanks for the program it got me going and troubleshooting and theroizing in the right direction!!!

My using a angle over 45 degrees may have thrown it off????

I have triple checked my CAD but will do again??

The only thing that was really off was the offset of links inward on lower girder leg linkages!!!

It said 1.5 in would do but,in the cad it was over 2in????

gearhead1951 wrote:

Customize IT wrote:

gearhead1951 wrote:check out "Dkilliam" and "concreteguy" s girder builds in the " girder , springer , spirder" section !

Thanks for the Help!!!

It may be because I am blonde but having problems finding the threads???

I looked in the girder section and build sections??

Can you post links PLEASE????

Sorry 'bout t hat I forgot that everything prior to the big crash/hack job was lost !!

I thought I had read everything in that section??

Thanks for looking for it for me thou!!!