thanks Pin-Head for clearing that up,very much app.
can too hard a springs in it cause a few problems, aas my springs are made for constant weight but most of the time its empty. theres not much give in the springs if any at all
regards peter
Caster Correction Question
- Thread starter LFD2037
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can too hard a springs in it cause a few problems, aas my springs are made for constant weight but most of the time its empty. theres not much give in the springs if any at all
regards peter
i rang pedders today to ask about the springs as there doesnt seem to be any bounce in them
the springs 7745 C rear 450mm high
front 7702 B 510mm high
both are 18mm thick and 8 coils each
the springs had a date of 2009 on them and when i spoke to pedders they said that they should be that strong as i can fill both tanks up with fuel about 170 lts pluss 5 people and all our gear and the rear only drops about 25mm
saying all that, could they be too strong and not compressing when i hit bumpy roads and only flexing at the tyres causing the 4wd to bounce over the road
interested in what your thoughts may be, would like to know if any one else is running the same springs as i am and if they have the same hassle as i do
Regards Peter
the springs 7745 C rear 450mm high
front 7702 B 510mm high
both are 18mm thick and 8 coils each
the springs had a date of 2009 on them and when i spoke to pedders they said that they should be that strong as i can fill both tanks up with fuel about 170 lts pluss 5 people and all our gear and the rear only drops about 25mm
saying all that, could they be too strong and not compressing when i hit bumpy roads and only flexing at the tyres causing the 4wd to bounce over the road
interested in what your thoughts may be, would like to know if any one else is running the same springs as i am and if they have the same hassle as i do
Regards Peter
The informative spring parameter to know would be the spring rate (Newtons/mm or Kg/mm) and the sprung weight at each wheel. You need to make compromises and decisions. A spring that can handle an extra 600 kg in fuel, people and gear is going to ride rough when the truck is unloaded. A spring that rides nice unloaded is going to bottom out when loaded with an extra half ton. Your choice, but you can't have both unless you want to change springs for different circumstances.
yeah, thats what i was thinking. as we wont be travelling for awhile i might just keep the std ones in for the time being
I believe its because they had smaller tires?
Tyre size does change caster, but most of the time its hardly measurable.
In the very early FJ80's there was a 15mm Hieght difference. But the housings are the same, the chassi spring perch's are the same. So the conclusion was 15mm difference in coil height. Coil manufactures have the same coil height across all 80 models.
On another note. The 105 series spec's different caster again even though 80/105 housings are the same.
In the very early FJ80's there was a 15mm Hieght difference. But the housings are the same, the chassi spring perch's are the same. So the conclusion was 15mm difference in coil height. Coil manufactures have the same coil height across all 80 models.
On another note. The 105 series spec's different caster again even though 80/105 housings are the same.
I think his point was that the need for caster changes because the rolling resistance is less with smaller tires.
Can someone provide a link or an explanation as to the washer method? This is the first time I have heard of it. Thanks
There is a link posted in the first half of this thread.
Just a little tech hint to anyone without a calculator with an inverse sine function: Wolfram alpha.
http://www.wolframalpha.com/input/?i=invsin(.0765) (don't scroll down too far--it may scare you...)
Alpha can solve just about any formula you want to throw at it, and all it requires is a web browser.
Geof
http://www.wolframalpha.com/input/?i=invsin(.0765) (don't scroll down too far--it may scare you...)
Alpha can solve just about any formula you want to throw at it, and all it requires is a web browser.
Geof
Ha! Hiding in plain sight. Thanks!
I hate to add on this thread but how do you find the caster and why do you need to know the degree? Does it effect what direction you place the bushings in the control arms?
If you're at stock height there is nothing to worry about or to do.
If you're running a suspension lift you should get the alignment checked, so they can calculate your caster. On an alignment machine its not a measured angle, but an inferred or calculated angle. It's done with a process called a caster sweep, where they measure the camber change and whatnot to come up with the caster angle.
Once that's done, you can figure out how much caster correction you need.
My truck has 2deg caster, 315 tires, and handles pretty good at freeway speeds. I don't tow heavy loads though, and don't haul bricks or stuff, just people and camping gear.
I worked as an front end alignment mechanic for 3 years with a Hunter Laser aligner machine and it read the caster angle right off the machine. We measured the caster angle. I never heard of a caster "sweep" until I started reading this forum. Sweeping was what the grease monkeys did to the shop floor at closing time.
Well I worked at a Firestone back in the very early 80s and we hung mirror assemblies on the tires and would have to move the tire from lock to lock and then compare the two readings to calculate caster and camber. I think the sweep comes from that long ago practice.
sleeoffroad
Supporting Vendor
I think so too, pretty much any machine requires you to turn the front wheels through a set angle range to get the caster read / calculated. I think that is why people call it a caster sweep.
So I Googled "caster sweep" and ih8mud 80s forum came up #2 on the list with no alignment machine vendors listed on the first page. Yes, you do turn the wheel side to side on many alignment machines, but I don't remember the manufacturers calling this a caster sweep.
Being an alignment guy was one of the top jobs in the shop. You got to lie down on the job and if the car didn't need any adjustment (50% or the time), you just listened to music and banged on the frame every once in a while. You didn't even get dirty. The shop policy was that every car on the rack paid for an alignment and we guaranteed it was aligned when it left.
Being an alignment guy was one of the top jobs in the shop. You got to lie down on the job and if the car didn't need any adjustment (50% or the time), you just listened to music and banged on the frame every once in a while. You didn't even get dirty. The shop policy was that every car on the rack paid for an alignment and we guaranteed it was aligned when it left.
Pin head you had it easy. Try doing an alignment if a 74 VW bug after 7 years in New England. Hours of torch work!
