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LH Ride Height with 18x10 Rears

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#1 Eagle75au


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Posted 30 June 2019 - 05:06 PM

Hi all,


Regarding ride height on an LH fitting 18x10 rears and using the original trailing arms.


To me the height of the car from bottom of the sills is too high and I want it lower, but my panel beater mentioned the lowest point of the car is from bottom of the trailing arm mounts.


Does anyone know what the factory height and minimum height is allowed from the bottom of the arms? Assuming people have got the car lower whilst still having enough clearance, has anyone got any ideas what i can do to get it lower? Has anyone moved / modified the mounts and arms?

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Edited by Eagle75au, 30 June 2019 - 05:07 PM.

#2 dattoman


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Posted 30 June 2019 - 08:33 PM

100mm is usually the lowest allowed

Whether it be sump , diff centres or whatever 

#3 Bigfella237


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Posted 01 July 2019 - 04:31 PM

Firstly, unsprung mass isn't counted when measuring ground clearance, so diff housings, hubs, swingarms, etc. don't count. Everything attached to the body does, including suspension mounting points.


NCOP6 - Section LH, page 8/LH73 says a vehicle must have a ground clearance of:


 - at least 100mm at any point within 1 metre of an axle; and

 - at least one-thirtieth of the distance between the centres of adjacent axles at the midpoint between them (for a Torana with a wheelbase of 2593mm this means a minimum clearance of 86.4mm at the centrepoint between the axles); and

 - at any other point — at least the distance that allows the vehicle to pass over a peak in the road with a gradient on either side of 1:15, if the wheels of one axle of the vehicle are on the slope on one side of the peak and the wheels of the next axle are on the slope on the other side.


That last one is kinda redundant, to figure out the height of the peak they're referring to you divide the wheelbase in half, then divide that half by 15, which comes out the same as one-thirtieth of the wheelbase mentioned earlier, so the height of the peak is again 86.4mm but in real terms they're saying a Torana must be able to drive over a hump with a radius of 9.77m (don't ask me how to calculate that, I did it in CAD).







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Posted 01 July 2019 - 07:00 PM

I was lead to believe it as Datto's post above  ......100mm to lowest point but i could be wrong 

#5 77lx308


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Posted 01 July 2019 - 07:42 PM

In Perth they have the can test - roll a can of coke under the car - if it stops anywhere you fail.

Seriously though (and the can test is the recognised at home test) its 100mm everywhere.

#6 neglectedtorana


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Posted 01 July 2019 - 08:44 PM

Engineer I am doing my LS conversion with says 100mm

About 18 months ago RMS had a road side inspection after a car show and were using a 100mm block on a stick to test for clearance

#7 ozyozyozy


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Posted 01 July 2019 - 09:35 PM

So that said about ride heights you also want minimum 50mm compression travel on the suspension from rideheight, more is better, or else it will probably be a pig to drive.

#8 Heath


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Posted 02 July 2019 - 12:14 AM

I've certainly never gotten off a defect because the low part of my car was part of the suspension or not... whatever the books do or don't say, they enforce it as 100mm regardless of what part it is, or whether you've got a flat tyre or your three of your fat cousins in the back seat.

Your rolling diameter looks kinda massive. Reduce it so that you can get your car sitting nice and low.
No, it won't be legal.
Yes, it is the only way to make it look good.

Edited by Heath, 02 July 2019 - 12:14 AM.

#9 Bigfella237


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Posted 02 July 2019 - 08:43 AM

The 100mm test might be what's enforced by your typical mr plod on the side of the road, but that doesn't make it right.


I've just been through all the legislation for trailer design (which is basically the same as outlined in NCOP6 above), and if I had 7.5m between the last tow vehicle's axle and the first trailer axle, and only 100mm ground clearance in the centre, I'd be dragging it's guts over every bump in the road!

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