Question: measuring up shock lengths

[80's_delirious]

Its time for new shocks on my 80series. I want to make sure I get shocks that are not gonna limit flex. to measure the lengths of shocks I need I am thinking I find somewhere to max out the flex. (driving one wheel onto the retaining wall beside my steep driveway should do that easy)
Unbolt the bottom end of the shocks all round
Unbolt swaybars (gonna make up disconnects later)
Flex it up
Measure full droop and full compressed lengths front and rear

Anything I need to look out for or consider to get the right lengths?
Will flexing it up with front or rear wheels on flat driveway and one wheel on a retaining wall get full flex or should I flex it up over a rut?
should I take shocks right out to do this?

[macca81]

take the shocks out, find a big ditch thats gunna keep ya front and back ends leval with each other, cross it up and measure away.

your wheels in the ruts should not be touching the bottom of the rut if you can help it, should just be ballancing on the 2 other wheels

[rover1]

you dont want the shock to lenghten further than your spring, otherwise you'll be picking up springs every time you go out.

[Gwagensteve]

Unless you lower your bumpstops or raise your top mounts, the longest shock you are going to fit in there is the one already sold by any major suspension seller.

Shocks can't be bought on extended length - that's not important. The compressed length is the important one because if the compressed length is too long you will break shocks/mounts when you hit hard.

For the extended length to get longer, the collapsed length gets longer too.

OME, Koni and heaps of others will sell a shock that has the longest possible compressed length for your car.

If you want to measure you own shocks (buying on dimensions not vehicle application), you will also have to determine what valving you require. valving is much more critical on a coil sprung car like an 80 than on a leaf car.

If you pursue measuring your own shocks up, remember you must leave 1" of shaft travel when fully compressed to prevent damage to the shocks or mounts in the case of a very hard hit.

Steve.

[PJ.zook]

If you did have to install longer shocks to stop limiting flex, and you had to mount them more on an angle, say close to 45deg to get them to fit, would that affect valving? Ie would you have to get stiffer valving the more the shocks are on an angle?

[troylux]

the more the shocks are inverted the less effective they work

so in short yes

or just buy some adjustable shocks, so you can set them up how u like

troy

[PJ.zook]

Sorry for hijacking but it seems smarter than starting new thread.

OK so what if you flex it up, say using 2 forklifts on diagonally opposite wheels, what if the diffs still dont touch the bumpstops, can you still use that measuerment for your shocks (+ 1inch), or should you weigh the vehicle down with it flexed till diffs hit bumpstops?

[Gwagensteve]

No, becuase that's only static load. If you jump the car ,(lets say accidentally) hit an unseen drain at speed or something The axle WILL reach the bumpstop. The forces at work here are very large. The bumpstops will compress heaps too.

I normally work on axle on bumpstop, + 1/2 the height of the rubber bumpstop +1" for safety.

I know this seems like a lot of lost travel, but broken shock mounts are a PITA to fix, especially if it then forces the shock through the floor etc.

Steve.

[80's_delirious]

Unless you lower your bumpstops or raise your top mounts, the longest shock you are going to fit in there is the one already sold by any major suspension seller.

Shocks can't be bought on extended length - that's not important. The compressed length is the important one because if the compressed length is too long you will break shocks/mounts when you hit hard.

For the extended length to get longer, the collapsed length gets longer too.

OME, Koni and heaps of others will sell a shock that has the longest possible compressed length for your car.

If you want to measure you own shocks (buying on dimensions not vehicle application), you will also have to determine what valving you require. valving is much more critical on a coil sprung car like an 80 than on a leaf car.

If you pursue measuring your own shocks up, remember you must leave 1" of shaft travel when fully compressed to prevent damage to the shocks or mounts in the case of a very hard hit.

Steve.

Good points Steve

was mainly looking at measuring to try to get the best off the shelf option. I know sometimes things need to be a compromise. I dont want to reinvent the wheel for no gain.
So an OME etc for a car with 4" lift is still gonna be made to suit fully compressed length with standard bumpstops. Correct?

So to be able to increase the extended length, and achieve max articulation shock towers need to be modded? with shock hoops?

For the rears in an 80 to go longer, top shock mounts need to be inboarded? Is this feasable?

[ozy1]

in the rear of the 80 id also be checking tyre clearance, in the guard, no point having lots of up travel if your tyre is going to slam your inner guard if landing hard, also no point in tearing a tyre on a sharp guard lip, it may also be wise to adjust your bump stops to suit,

having a slighly longer bump stop, will give you a longer compressed length, which will give you that longer shock,

inboarding the shocks on your 80 may soften the rear up too much, which will have your suspension working more in the rear off road, and also inducing aot more body roll, your sway bars will only help to a point, they wont stop it all,

[Gwagensteve]

Do OME offer shocks for an 80 with 4" of lift? If so, I wasn't aware of this. It might be a side effect of the LTR shocks allowing more shaft length, so an LTR for a nominal 2" of lift will still work acceptably on a 4" lifted car. I don't think a stock OME shock would be long enough to allow acceptable droop. (LTR's have the foot valve in the reservoir so the shaft can be longer for the same collapsed length.

It is a compromise for sure. For me, lowering bumpstops is an excellent way of fitting a larger tyre without excessive lift, and the end result is more wheel travel because a longer shock can be fitted.

I agree, inboarding the rear shocks would be a bad idea on an 80 - getting the shock length in without cutting into the floor would result in the shocks laid over too far to achieve decent damping. I think the only useful gains in the rear in shock length will be through bumpstop spacing, which is a happy coincidence, because any tyres over 34" tall will catch the guards on compression anyway.

In the front, sure, taller top mounts could be made up, but the limiting factor on articulation of an 80 is the radius arm design, not the shock length. X-link equipped 80's prove this.

Personally, I'd bumpstop to suit the tyres and then with LOWER my top shock mounts to match the amount of bumpstop spacing added, or run a longer shock to suit the new spacing.

PS, I'm suspiscious that some of the aftermarket shocks sold for 4" lifted cars should be sold with bumpstop extensions, but many 4" lifted springs are stiff enough that the car can't reach the bumpstop when articulated so they sort of get away with it.

Steve.

[Gwagensteve]

Sorry, wasn't clear in my first reply - to move the top mount further inboard on an 80 would be very complicated. even a small move inboard will add a lot of length to the shock and it would be likely that that length would be wasted, either through the springs going loose, or the shock never compressing that far.

It would also reduce the effective damping, so stiffer valving would be required. It would be a major task to maintain proper drivability.

This is not the same in the front, because the shocks are vertical a 2" more shaft travel equals 2" more wheel travel, no ratios to worry about and no wasted shaft length because of the angle.

Steve.

[80's_delirious]

Cheers fellas

Steve, Im not aware of 4"lift OME's either, I refered to them and "etc" more as an example of an of the shelf product than anything else sorry for confusion.
I know not all 4" springs and shocks are created equal, so mainly wanting to be certain I get the best result 1st up.

So for best results, check tyre clearance at full compression, look at lengthening bumpstops, then measure compressed length + 1", look for a product with suitable compressed and extended length already valved for the 80series?

[Suspension Stuff]

If you are trying to measure the front, reverse up somthing steep so you put more pressure on the front and then get one of the front wheels off the ground. I always sell 26.5" extended length shocks for the 4" coils that I sell for an 80 series.

Shane.

[me3@neuralfibre.com]

http://neuralfibre.com/paul/?p=89
For measurement methods

Jamie at GSA Wholesale for shocks.

Paul

[Suspension Stuff]

http://neuralfibre.com/paul/?p=89
For measurement methods

Jamie at GSA Wholesale for shocks.

Paul

Jamie and the team at GSA Wholesale are great and they sell top stuff. I use him as a supplier myself but they aren't going to help you with anything over a 2" lift.

Shane.