Newbie Trailer Design Help

[Strop]

Hi Frank,

Busy weekend and just got to your post. The bench height of 900 is not absolute but optimal for a few reasons. Wife is only 5' 2", sorry 5' 2.5" :-) Very important that 1/2 inch. Not a problem for me. The height is compounded a bit by having to lean in as the bench edge will be in a bit back from absolute trailer rear edge.

The second part of this is looks. I would like it to be squat not high. I am not intending going anywhere that a normal car can't get (unless I am being ultra careful). My son has a 4WD so some very strict rule setting will go on if he borrows it. The axle will be a 4" drop axle lowering it even more so ground clearance will be a factor.

The wheels (205/60R15) was to get a very similar look to the tow vehicle. It is intended to be a 1987 Citroén CX. The Citroén has a PCD of 98 so there is no way I am going to get a trailer hub that I can use the Citroén's spare with, hence the need for a spare. My other car has 19" rims so not even going to consider matching them. I could go for a 14" rim and still retain the look really. Too skinny with the tyres will take away from the look though. A 195/75R14 is not that different in overall size. There is not a lot of difference when you look at a variety of them.

205/60/R15
Diameter = 24.7"Width = 8.07"Wheel = 15"Sidewall = 4.84"Circumference = 77.5"Revs/Mile = 817.4
205/60/R14
Diameter = 23.7"Width = 8.07"Wheel = 14"Sidewall = 4.84"Circumference = 74.4"Revs/Mile = 851.9
205/75/R14
Diameter = 26.1"Width = 8.07"Wheel = 14"Sidewall = 6.05"Circumference = 82"Revs/Mile = 772.9
205/70/R14
Diameter = 25.3"Width = 8.07"Wheel = 14"Sidewall = 5.65"Circumference = 79.4"Revs/Mile = 797.6
195/75/R14
Diameter = 25.5"Width = 7.68"Wheel = 14"Sidewall = 5.76"Circumference = 80.1"Revs/Mile = 790.8
195/70/R14
Diameter = 24.7"Width = 7.68"Wheel = 14"Sidewall = 5.37"Circumference = 77.7"Revs/Mile = 815.4
185/70/R14
Diameter = 24.2"Width = 7.28"Wheel = 14"Sidewall = 5.1"Circumference = 76"Revs/Mile = 833.9

At a push I could get away with the 185/70R14 - it might not take the bumps as well that's all but better than the 205. Time to visit some build journals to have a look.

I have never had a puncture on my box trailer but I know what will happen when I don't have it with me. Thinking of putting on 4 corner stands so I can get away without carrying a jack but I will have to price a jack first just in case there is a HUGE cost difference. I wonder how many people out there who have a spare for their trailer carry a jack or even a tyre lever so they can change it if they get a flat?

I have found a bloke who can build me a water tank that will sit over the spring axle. That is why I am using a drop axle. To give me some vertical space but have the trailer sit lower. The tank will have enough space for vertical and lateral movement with a 50-75mm piece joining two drop down tanks on either side. Should give me perfect balance so not adding any tongue weight when full empty or whatever - or minimal weight change really as you will get a bit of splash from one side to the other. I could add two tanks equal distance back from the axle for the same effect but not quite as elegant and will actually cost more than a custom tank.

Keep the comments coming - it makes us think. Good all round.

Laurie

[Strop]

Frank,

A couple of photos to illustrate my concerns. I think this first one looks like the tyres are too small. 12" x 5.3" Not sure of the actual size like we use.

Progress.jpg (71.54 KiB) Viewed 258 times

The next one has tyres 205/70/R14

Tyres 1.jpg (138.78 KiB) Viewed 258 times

And finally the tyres from one of my favourite threads. I think David said they were 205/75R14

Atma.jpg (103.47 KiB) Viewed 258 times

The bigger mudguards also help but I am going to put on the mudguards the same style as the second photo using the same methodology as he did. Will show in next post as only allowed 3 attachments

[Strop]

Mudguard design and attachment method planned.

Mudguards 1.jpg (135.6 KiB) Viewed 257 times

Mudguards 2.jpg (169.71 KiB) Viewed 257 times

Mudguards 3.jpg (126.86 KiB) Viewed 257 times

Just need to place some felting between mudguard and body. I am thinking the welding should keep them in place. The only problem would be is someone sat on them so maybe a light on the top to stop people thinking about that.

Laurie

[Sheddie]

Hi Laurie,
Good to see some detailed planning going on there. My wife is 5'3". My Mum was 5'2.5' and she always made sure to claim the extra 1/2". You can get your bench at an easier reaching distance by curling the back under a bit and there by bringing the bench back nearer to the floor length.
I can see that the Citroen would not be easy to match up with, that is 2mm under a lot of Japanese stud patterns.
I have 50x50x3 frame and a torsion axle. The axle centre line is about 1/2" below the bottom of the frame with the TD sitting at rest. The axle we bought had a stud pattern to suit Falcon or Hi Lux. We went with the 14" Hi Lux because a guy in town here had a pair for sale on Trade Me for $20, and I have 195/60R14 tyres on them as I had some in the shed left from my tyre shop days. I just went over to the shed and put a tape over them, to give you a comparison, diameter measured horizontally 22.5". The distance from the centre of the axle to the ground is 11" and the frame is 11.5" from the ground. I assume that when you were working the calculations for your bench height that you worked on half the difference of the diameter of the tyres?
I have guards very similar to the ones you are looking at. They don't have the inner guard piece like those ones have and I haven't as yet seen the need for them. To mount them I welded a length of 40x5mm flat bar on its edge to the bottom of the frame with a couple of m6 bolts set well apart. The guards sit only about a couple of mill off the walls and don't vibrate enough to touch them. Also they are strong enough for me to stand on top of them when I am washing it.

Frank