Lowering Gurus wanted - The Gaz shock thread

[cunning plan]

I think that what's missing from your diagram is the "full extension" stop that exists within the damper assembly. You only get preload when you are butted up against that. Unless you are at full extension then the spring length will only adjust the ride height in relation to the adjustable platform (threaded ring).

You are right, but it is meant to show (not clearly), the shock with the bus weight on it.

So if you assume that both dampers in your diagram are NOT at full extension then what difference does the spring length make to your resting ride height? You'd just use your adjustable platform to move the spring up or down to the desired ride height once the weight or the bus is on it.

If you adjust 'up' / tighter, a 9" spring and 8" spring together, to exactly the same point, the 9" will hit preload sooner than the 8".

When you then place those shocks on a vehicle and allow the shock to take the weight, I assume the 9" will ride harder than the 8" and have a higher ride height as it is 1" taller.

If you use the 8", in theory, the ride height will not be effected as you would have to tighten the spring much further to affect the resting height of the bus and in doing so, you would likely go way past the comfort / hardness setting you want, which you are unlikely to do.

There are of course differences to spring length in dynamic use but that also depends on number of winds, damper rate etc. if I read this correctly this is just about ride height?

Yup!

 

[ozziedog]

That's exactly right, I've got very little adjustment left and on full drop I'm only just loading the spring. If you want that extra inch then you are going to have to use either lower profile tyres because any more than what we've mostly done will have you bottoming out regular or now we're getting into tubs and stuff, then notching etc etc etc. I've just measured from my tyre top to the tub is 2" just onsid the arch but three inches directly above the centre of the tyre into the seat tub. So you could squeeze another Inch by taking the edge of the tub out just where you the tyre hits and mine hits just halfway through this section. So we got 2"" of suspension travel left and that ain't much. So tubs or lower tyres for a bit more between a half and a full inch. Theoretically we could go eight and a half and a two hundred pound spring but then there would be little to next to none in the way of suspension and what little there is would firstly be mounted and stressed directly initiated through the shock towers which is less than ideal. :mrgreen:

Ozziedog,,,,,,,, go and chat to Graham :mrgreen:

 

[Zcat7]

OK I think I see what you're saying, its about the range of adjustment on the threaded stanchion. Fair enough!

 

[cunning plan]

That's exactly right, I've got very little adjustment left and on full drop I'm only just loading the spring. If you want that extra inch then you are going to have to use either lower profile tyres because any more than what we've mostly done will have you bottoming out regular or now we're getting into tubs and stuff, then notching etc etc etc. I've just measured from my tyre top to the tub is 2" just onsid the arch but three inches directly above the centre of the tyre into the seat tub. So you could squeeze another Inch by taking the edge of the tub out just where you the tyre hits and mine hits just halfway through this section. So we got 2"" of suspension travel left and that ain't much. So tubs or lower tyres for a bit more between a half and a full inch. Theoretically we could go eight and a half and a two hundred pound spring but then there would be little to next to none in the way of suspension and what little there is would firstly be mounted and stressed directly initiated through the shock towers which is less than ideal. :mrgreen:

Ozziedog,,,,,,,, go and chat to Graham :mrgreen:

No? oke:

 

[Zcat7]

Loving the diagrams!

 

[cunning plan]

Loving the diagrams!

:lol:

 

[Dani California]

Hallelujah !!!!!! I found somebody to help me Wheel arch rubbing for years to my Wife's disgust. Ive been looking to see who sells them in the uk. Found Demon Tweets. Are these the right ones, if so can anyone help me fill in the blanks, PLEASE, Does it matter what make Springs I have? I am running transporterhaus dropped spindles. Thanks

 

[ozziedog]

Hiya, when you have a week to spare, read through and yes it works and the custom coil overs along with slight tyre reduction was the answer. You can go extra low with extra low tyres but then you`re introducing speed bump aversion time. I can`t remember what shocks I used but it`s all in the thread somewhere. It dosen`t eliminate all rubs but possibly 99.9% are gone. I maybe get one or two a year and it`s usually with a load up and over forty and it needs a decent bend with a bump in it and usually a country road. To get any more than that you need to drive like you stole it. :lol: Maybe just read from page 15 to now mostly covers it. Graham L has got the spec, 16" shocks with 9" 150lbs springs just about perfect. When you say about springs , do you mean the original torsion springs in the beam ?

Ozziedog,,,,,,,,,,,,,,,,,your Mrs will love it :mrgreen:

 

[Dani California]

Thanks for getting back to me. I'm gonna read through the thread this week. I'm meant to be taking Dani camping this week. Have a new 1776 engine fitted last week, so I was trying to run the engine to change the oil and check the valves before I load her up. But the electric fuel pump gave up yesterday so the chances of getting a fuel pump for today is unlikely. The Coil over springs is what I was referring to. Demon Tweek sell the shocks separate to the springs. Sorry just reading what I wrote, I meant what brand of springs to go for?

 

[ozziedog]

You'll get more of an idea when you wade through the thread. The coil over shocks we are using and most of us have gone for are custom built items with the shock and spring included so you just unbolt your old ones and bolt on the new unless you have a narrowed beam then there is a bit more involved. The empi ones seemed to just about manage to assist your regular suspension but very few lasted more than a hundred miles or so, some a lot less. So you just ring the company up and tell them exactly what you want and depending on how busy they are they should be there delivered to your doorstep somewhere up to six weeks. The spec you need or if you copy what has been trialled and works is the spec I wrote above.

Ozziedog,,,,,,,,,,,,, trial and error, now sorted :mrgreen:

 

[Dani California]

Thanks Ozziedog, I've just ordered a pair, and should be with me in 4 weeks time. Can't wait

 

[ozziedog]

:shock: Dani, I forgot to tell you the downside :shock: . This will knock out about 99.9% of your rubbing issues. BUT ! You will however have to paint the underside as it will start rusting now if it don't get its regular dose of tyre contact smooching up to your arches.

Ozziedog,,,,,,,,good luck and let us know when they're onbud :mrgreen:

 

[Igotaholeybus]

This is a great thread, really helpful and informative.

I have transporterhaus 3 1/2" dropped spindles on my bus so i understand i should go for 160/105/B12 to suit 1.9" ID RD1.9/150/10 - 1.9", 150 Rate, 10" Free Length springs is this right?
Found them on Rally Design for a good price i think.

Thanks for reading my post. Dan

 

[Igotaholeybus]

Or should I go for the 9" spring?

 

[cunning plan]

Or should I go for the 9" spring?

It looks like 9" raises the ride height, so 10" certainly would.

I was considering an 8", but the bus is still not ready to have them ordered yet.

 

[Moseley]

Or should I go for the 9" spring?

It depends on how the spring sits on the shock once you have set up your desired ride height. Ultimately, a 10” spring and a 9” spring with the same rate will give no difference in ride quality - they both compress the same length per unit of weight added.

Where spring length comes into play is if using too long a spring, the coils become ‘coil-bound’ as the damper compresses, I.e. the coils all end up touching whilst the wheel still has room to travel. So in this scenario, logic tells you to pick a shorter spring, but then this can lead to there not being enough adjustment on the threaded damper section before you cannot set enough preload on the spring.

Not sure if that makes sense, but ultimately you want as long a spring as possible (as this gives the most adjustment options) but not so long that it becomes coil-bound when the suspension is fully compressed - either when bump stops are hit, or tyre contacts wheel arch.


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[Igotaholeybus]

Or should I go for the 9" spring?

It looks like 9" raises the ride height, so 10" certainly would.

I was considering an 8", but the bus is still not ready to have them ordered yet.

Thanks for your advice 🖒 I'll go for the 9" I think

 

[Igotaholeybus]

Or should I go for the 9" spring?

It depends on how the spring sits on the shock once you have set up your desired ride height. Ultimately, a 10” spring and a 9” spring with the same rate will give no difference in ride quality - they both compress the same length per unit of weight added.

Where spring length comes into play is if using too long a spring, the coils become ‘coil-bound’ as the damper compresses, I.e. the coils all end up touching whilst the wheel still has room to travel. So in this scenario, logic tells you to pick a shorter spring, but then this can lead to there not being enough adjustment on the threaded damper section before you cannot set enough preload on the spring.

Not sure if that makes sense, but ultimately you want as long a spring as possible (as this gives the most adjustment options) but not so long that it becomes coil-bound when the suspension is fully compressed - either when bump stops are hit, or tyre contacts wheel arch.


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Thanks for your explanation it made perfect sense. I'll be ordering the 9" ones

Thank again Dan

 

[jude7789]

So, the thread returns!
I’ve recently bought some secondhand but as new condition lowering gear for my ‘72.
I’ve got the following...

2x T/Haus 3.5 spindles
2x T/Haus rear adjustable spring plates c/w rubber donuts
2x Gaz adjustable coilovers (9inch springs)
2x disk backing plates with cutouts

Sounds like the previous owner had been following this post
Anyway, I am about to embark on fitting all these bits to my as yet standard bus in the following days/weeks so seeing as there’s a good few folk done this conversation now, is there any pointers or pitfalls I should be aware of?
I’ve been advised by Graham(midlands earlybay) that I’ll be needing to replace my rear donuts and also the spring plate cover bolts for longer ones.
Is there any other bits I’ll definitely need so I can be forearmed with them, rather than making good progress and then getting held up with daft little parts.
Thanks.

 

[67westy]

Been a while since I did it but I believe you need 2 adjustable track rods, you probably have one adjustable and one fixed at the moment

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