Wheel rate or Motion ratio

[TEGNO1]

Hi im trying to get the wheel rate or motion ratio if thats what you call it, for the honda double wishbone suspension, the info ive been reading is roughly 1.5 on the front, and 1.35 on the rear, however im not sure on this, can anyone answer this question with concrete evidence.
What is it:
If the tyre moves a certain distance: how much does the shock or spring move at the same time.
Another question what is the recommended droop to bump ratio on a street setup, race setup etc:
Thanks in advance.

[TEGNO1]

Anyone

[JasonGilholme]

Just buy some coilovers man!

I think your thinking too much about it.

If you've got adjustable suspension, jack it up, adjust it, test it and change it if neccessary.

its all about trial and error.

[Bayani]

No Expert, however, wouldn't those readings fluxuate in regards to the age of the suspension, and it's previous and current usuage?

[TEGNO1]

Tell me about it, ...but its interesting.

[bennjamin]

work it out for yourself.

Take out the shock / spring , and simply pivot the wheel on the hub up and down on its axis and take measurements from
0 load to max compression etc.

[TEGNO1]

Yeah i did that and measured 1:2 ratio, doesnt sound right thats why i was hoping someone would know, i'll try again. thanks.

[Muzz]

No Expert, however, wouldn't those readings fluxuate in regards to the age of the suspension, and it's previous and current usuage?

Wheel rate/motion ratio stays constant.
Why are you after the wheel rate? what are you using it to calculate?

[TEGNO1]

I was trying to work out the amount up and down movement of my wheel, in relation to how much the shock will move,
so if i have a range of say 80mm of up wheel movement before i hit stuff and the ratio is 1.5 to 1 my shock will compress 40mm, so then there would be no point in trying to get any more travel than 40mm.
Anyway im getting my shorter shocks soon so i'll see how they go, thanks.

[JasonGilholme]

isn't the wheel a child of the shock base anyway???

Seeing as tho they're both directly connected to the hub assembly?!?!?!

[TEGNO1]

No the shock travels less than the wheel on honda double wishbone,
The answers i found which im not sure of was 1.5 to 1 front, 1.2 to one rear.
Which also means if you have a 1000 pound front spring your tyre will see say 500 pounds, its a leverage thing.

[TEGNO1]

Integra Da motion ratios: (info sourced from G2ic)
Front: 1.5:1 (for one inch of shaft travel you get 1.5 inches of wheel travel.
Rear: 1.35:1

Wheel rate = (spring rate / (motion ratio squared))

Front wheel rate = spring rate / 2.25
1000 lb front spring gives a wheel rate of 444lbs

Rear wheel rate = spring rate / 1.82
1000lb rear springs gives a wheel rate of 550lbs

This means a car with strut suspension and 1:1 ratio would see a 1000lbs spring as 1000lbs spring at the wheel.
The wheel will travell the same distance as the shock.
A honda would see the same spring as 444lbs at the wheel....more than half the stiffness with the same spring.
And the wheel will also travell less compared to the shock.

I dont dont if it feels less stiffer but now you know.

[bennjamin]

I finally measured it the wheel moved 70mm and shock 50mm front and rear, so the ratio is 1.4 front and rear.

...after finding this ratio. How do you intend to use it ? Proper corner weighting or ?

[JasonGilholme]

No the shock travels less than the wheel on honda double wishbone,
The answers i found which im not sure of was 1.5 to 1 front, 1.2 to one rear.
Which also means if you have a 1000 pound front spring your tyre will see say 500 pounds, its a leverage thing.

What do you mean 1000 pound front spring and having the tyre only hold up 500 pounds??

If i understand correctly your saying that theres 1000 pounds right, and the spring holds 500 of it and the tyre holds the other 500.

If thats what your saying i believe your wrong. They weight cars by putting scales under each wheel which gives the weight of the entier car.

The suspension only suspends the weight, it doesn't reduce it.

[TEGNO1]

Sorry to confuse you they were just random numbers i used to give you an idea of the leverage effect.
Say you have 1000 pound spring the wheel will see 1000 divide 1.4 = 715 pounds.
Well its important to know the ratio because:
I have checked the maximum allowable bumb i can have by jacking up the suspension as high as it goes.
Maximum height the wheel will travel on a da is 285mm from centre before the upper control arm hits the top of the shock tower.
Thats without the tyres so thats another limitation.
I want my car sitting at 325mm from centre (About i finger gap). that means i have 40mm of bump clearance, now with the 1.4 ratio i would have to ensure that my maximum travel is 40 divide 1.4 = 28.5mm so i hit the rubber bumpstops before the upper control arms hit.
Then you would need a spring stiff enough not to allow alot more than that in compression.
So peaple who go really low say no gap around 300mm from centre, you would be 15mm from contact on the upper control arm and the maximum allowable travel would be 15mm divide by 1.4 = 10.5mm. (not enough and need super stiff springs and shorter shocks.)
If you go that low you got virtually no suspension movement left and your control arms drivshafts steering racks are pointing upwards.