Thread: is someon using dual rear shocks in his 110?

Originally Posted by 85 county

Heat mainly

The constant small movements in a shock say like when driving over corrugations, heat the shock up. Then shock fade sets in. I have even seen a Prado on fire due to a shock over heating.

With two the load is shared.

Or look at motorbikes, dirt bikes, they went from two vertical shocks. to twin shocks at about 45 deg, which halved the travel on each shock thus halving the heat. to rear link setups with very short shocks, do at 1 inch movement of the wheel = 1mm of travel in the shock. less movement less heat

Actually the less shock shaft movement the greater the potential heat generated as the forces have to increase to damp the spring and chassis.

So, as you lay a damper down relative to vertical axle movement you need heavier valving to damp the same forces as the piston and shaft isn't moving as much and so will generate more heat. (and the less sensitive it becomes to wheel movement)
You do reduce friction (and therefore heat from friction) when you decrease shaft travel, but you increase the internal pressures needed to control the forces and so increase heat.

Dirt bikes went to laydown dampers to get increased wheel travel with little weight gain and compact mounting, race cars started to do the same thing with inboard suspensions and bellcranks but lost damper sensitivity, these days motion ratios are back well over 1:1 to gain sensitivity with minimal wheel movement.

All a damper does is convert kinetic energy to heat, generally through forcing hydraulic fluid through shim valves and pistons.
Increase the piston size and you reduce the internal forces of the damper, or use a multi damper setup, but the current 2.5, 3 and 4" bore off road race shocks are aimed at reducing internal forces without needing multiple shock setups at the expense of a little increased friction.

Originally Posted by rick130

Actually the less shock shaft movement the greater the potential heat generated as the forces have to increase to damp the spring and chassis. .

yes as i said, like driving over corrugations. a lot of short movements. so a lot of heat

Originally Posted by rick130

So, as you lay a damper down relative to vertical axle movement you increase the load on the damper. (and the less sensitive it becomes to wheel movement) .

You also increase the load on the spring, and port the damper accordingly. however travel is reduced.

Originally Posted by rick130

You do reduce friction when you decrease shaft travel, but you increase the internal pressures needed to control the forces and so increase heat.

Originally Posted by rick130

Increase the piston size and you reduce the internal forces of the damper. .

and is this not what adding a second shock not doing? But dubbing the size of the piston??

Originally Posted by rick130

All a damper does is convert kinetic energy to heat, generally through forcing hydraulic fluid through shim valves and pistons.

Originally Posted by 85 county

yes as i said, like driving over corrugations. a lot of short movements. so a lot of heat


You also increase the load on the spring, and port the damper accordingly. however travel is reduced.



and is this not what adding a second shock not doing? But dubbing the size of the piston??

If you have x amount of vertical wheel and spring movement and you have a shockie laying over at 45*, the shock piston is only moving half the distance of the spring, and so it needs to be valved twice as stiff as another damper mounted vertically.

The shockie laying over at 45* is also only half as sensitive as the vertically mounted one.

The reason for laying over a shock is packaging, you can get away with a shorter damper for a given amount of wheel travel but there aren't really any other positives.

I was agreeing that using two shockies per wheel halves the forces needed, but was also pointing out that increasing the piston size does the same (and is the same) thing.

spoke to Bendan from Ultimate Suspension and he said no benefit for a 110 unless carry's extremely heavy loads he said his single shock set up would be more then adequate so will settle with that for time being.

Originally Posted by Steve223

spoke to Bendan from Ultimate Suspension and he said no benefit for a 110 unless carry's extremely heavy loads he said his single shock set up would be more then adequate so will settle with that for time being.

Well that’s how it is with the vast majority of 110, but it also depends on the sort of trips you do, rock climbing and screaming over a few sand dunes, probably not. But punting around for hours on rutted and corrugated tracks then yes they do

Yep, magic damping control over corrugations with no fade and good shock temps even with heavy loads. Ie good for desert travel, particularly as a normal touring load in Oz is often a heavy load compared to elsewhere (due to fuel and water needs).

My mate is very impressed with his Ultimate set up (on his Hilux) and I've heard lots of good things, but I'd still be inclined towards dual shocks or the Konis if your focus is heavy desert work.

Originally Posted by 85 county

easy to fit with the exception of one hole you have to drill wich is a pain as the flange on the diff is in the way

Originally Posted by 86mud

There are 3 x 12mm holes to drill on each side of the lower shock mount.

The one hole 85 county is talking about is when he helped fit the twin shock kit to my county. Defenders have a hole drilled on the wheel side of the original lower shock mount that matches the new bracket, my county did not.

Yes I am happy with the twin shock setup,I have terrafirma prosport +50 shockers and airbag kit from the airbag man.

Jim.

What do we all think of running two different shocks on a duel shock set up ?

I have recently fitted a set of Raids, but still getting "seemly" uncontrolled bounce over the "whoop-t-doo's".

The TF Expeditions that were replaced are still fine, sitting on the shelf.

Really want to bring this bounce under control before the Simpson is 10 weeks, but a $1000 a pair for the Raids it's a bit exy to run twin Raids, but it may be the only way.