Trailer Axle Travel

[gxl_d4d Advanced Member Find all posts View Profile Close gxl_d4d]

Hi,

I want to fit a water tank under by 7x4 off road box trailer. I was thinking about install a 80 or 100l slim line to spread the weight more evenly and maximise ground clearance. If I do this, 2/3 of the tank would be behind the axle and 1/3 in front. How do I work out how much the axle travels up under spring compression? My trailer has a beam axle on 1500kg eye to eye offroad rebound springs.

Between the top of the axle and the under side of the trailer chassis with the trailer empty there's 190mm of clearance. The water tank I'm planning to use is 115mm thick.

Thanks,

[Bushbasher Out of control poster! Find all posts View Profile Close Bushbasher]

Have a look at the clearance above the tyre and below the mudguard. I have 9 leaf HD springs and there's 90mm clearance above the tyre. I know on my CT the springs barely move 50mm.

[gxl_d4d Advanced Member Find all posts View Profile Close gxl_d4d]

Thanks Bushbasher. Just had a look there's around 140mm of travel between the top of the tyre and the wheel arch. The rear shackle plates are around 90mm centre to centre so the axle will be able to move upto least 90mm. If the springs moves any more rearward it's going to hit the top shackle bolt. Not sure if it will bind or bend the spring.

[mjrandom Out of control poster! Find all posts View Profile Close mjrandom]

What you can do to get an idea of spring compression is to put a tarp in the trailer and slowly fill it with water. Based on the depth and length and width you can load the trailer to maximum load and see how much the springs compress. I did this with my box trailer that I built last century. I have a chart somewhere that plots clearance under the guards against load which can be useful too. Obviously under dynamic loading the springs will compress more but it gives you an idea.