Ride Height

[Longboarder]

Not so fast. You need to do some practical and sums. When you wind up the spring platform things happen in order. Firstly the spring does not compress. The two parts of the shocker are simply extended. The lower half is bolted to the wishbone which is attached to the hub and wheel and can't move down. Therefore the top half of the shock moves up and as it is bolted to the body of the car, the car rises with it. If that corner of the car weighed 170kg before adjustment of the shock and compressed the shock half an inch it will still weigh 170kg after adjustment and will still compress the spring half an inch.

However if you keep winding the spring platform up the shocker will eventually be fully extended and the car will have risen to the maximum ride height you can dial in.(Not drivable in this state!) If you continue to wind the spring platform up the spring then start to compress adding preload but not raising the car any higher. If you needed a higher ride height you would need a longer shocker.

You can calculate the ideal length of the shocker you need.

Jack up the car with the wheels on.

Remove shockers and springs.

Lower the jack till you have the ride height you want.

Measure the distance between the shocker mounts. This is the length the shockers will be when you are driving on a mythical bump free road.

Now the sums. (fingers and toes only needed!) Your shockers will need to have this length as their two thirds extended length. So lets say this distance is 10 inches you would want a shocker that is 11 inches fully extended and 8 inches fully closed. (Because you need twice as much available compression as extension from the ride height position.)

Now look at shock manufacturers catalogues and find something close to an 11" open/8" closed (3" travel) shocker. OK you may not find this precise shock but try to find one that has your desired length at ideal ride height at 2/3 extension.

Check your new shockers. Are they the right length? If not talk to your supplier. For springs choose your desired poundage and fit the longest ones that will mechanically fit without fouling (behind the hub or on a wishbone.). Don't forget to take into account a bump stop on the shock if fitted (should be!) when reading the specs of the shock. They use up some of the movement.

 

Nigel

Edited October 12, 2014 by Longboarder

[Guest chris brown]

Another point if you have the 2B plus standard wishbones when using 2.25 shocks you will have to fit them the other way up and not like Ian's as his after market wishbones have much more room. Coilovers don't have a correct way up so fit the way to get the most clearance. (Been there several years ago ). Longboarders advice on how to work out lengths is a must.

[agent_zed]

just to add even more confusion into the mix (sorry) you also need to be aware which part of the setup is taking the force at full droop.

 

Lets say you go a bit quick over a bridge and you leave the floor. The wheel will obviously drop until it stops on the suspension. The question is which part of the suspension is it stopping on? you ideally want the shock to be doing the stopping as it will have an internal bump stop and will take some of the force out of the wheel dropping.

 

The RH's are often setup with the top balljoint locking before the shock reaches its full length so the force is being taken on the balljoint. which is not the best situation, as it could fail.

 

Mine was like this to be honest for years, until i changed shocks and realized this was not a good thing.

 

What i did was have the wishbone all setup with the shock loose at the bottom mount then dropped it to full droop until the balljoint stopped it then lifted the wishbone a bit (so the balljoint isn't locked) and fixed the lower bracket for the shock at that point. I now know that my shock will be the first bit to stop the wheel dropping.

[Guest Ian & Carole]

When I put my conversion together I built it up without the springs and ran it from full droop to the tightest compression to make sure nothing was binding or locking up.

Once I was happy I fitted it with the springs and that was when the ride height problem arrived.

A quick call to Dave at Dampertec and a new pair of springs arrived by return of post at no charge.

Great service as always from this guy.

[Guest Nik]

Thanks guys I think!! Will do some more checks. The new shocks are identical lengths to the old ones but what I won't do now is assume that makes them right. 9" springs will be the maximum length I can get on. After checking the shocks I'm going to order 9" 350lbs I think. The bottom wishbone is in my opinion strong enough although i appreciate this takes more of the forces,it is the top mount I'm more worried about. Once it is set up and I'm happy with it I think I will beef them up. I have had to enlarge the bolt hole and this doesn't leave a lot of meat around the rest of the mount. Won't get a chance to look at it till the weekend now then I'll take my socks and shoes off and start counting. Back in the day we just used to fit check straps to the off road cars!

[Guest Nik]

Back again. 9" 350lb springs fitted, ride height good. i have the bottom box section cross member level, the bottom platforms at the excat same settings and there is 5mm difference in the measurement to the top of the head light mount one side to the other. seems shocks and ball joints arrive at the end of their travel at the same time. Coils are very tight for room in the top wishbone, have tried turning them upside down but then have no room to adjust platforms. Have taken it up the road and all feels good with nothing binding.have only run it round our lane so not tested at speed. Camber not looking great although cant remember what it was like pre alterations. Wish I'd bought 1.9s now, who said bigger is best!!

[agent_zed]

just a thought as i made a stupid mistake when i fitted my new shocks as i had long bolts to hold the top of the shock. The end stuck out enough that when the suspension bounced really hard the wishbone tube made contact with the sticky out bit. Lucky i noticed before anything serious happened but just something to check if you've changed the bolts.

[Guest Nik]

Think I'm ok there Zed, will have a look later. And one day I will learn how to up load photos, It would be nice to show you all my shiny bits!