Trailer mud guard setup

Submitted: Saturday, Sep 10, 2011 at 21:42
ThreadID: 88946 Views:10614 Replies:6 FollowUps:4
This Thread has been Archived
Hi,

I am in the middle of designing an off road trailer with a hinged lid (we use 2 rv5 oztents) and was wanting to know how much clearence to have betwen the tyre and guard. I will be using either 5 or 7 leaf rebound springs (most likley the latter) rated at around 1300 to 1550 kg and was wondering how much they will sag at their max. loading.

Also what size tyres are you using, I could use 31x10.5 15 but that will make the trailer sit a lot higher and could cause problems with putting a tent on it in the future or I could use 30 x 9.5 15 but then it wont match the tug but will keep the center of gravity a bit lower.

Any thoughts would be appreciated befour I launch into it with the grinder and welder

Thanks
Trev6
Back Expand Un-Read 0 Moderator

Reply By: Member - Tony H (touring oz) - Sunday, Sep 11, 2011 at 01:55

Sunday, Sep 11, 2011 at 01:55
This may be of assistance
http://www.infrastructure.gov.au/roads/vehicle_regulation/bulletin/vsb1/vsb_01_b.aspx#17

AnswerID: 464662

Follow Up By: ozjohn0 - Monday, Sep 12, 2011 at 20:24

Monday, Sep 12, 2011 at 20:24
Tony H has given you the link to VSB1. The legal trailer design requirements.
Check it out as it includes just about everything you need to know about building a trailer including mudguard design.
Cheers, ozjohn.
0
FollowupID: 738794

Reply By: Thinkin - Sunday, Sep 11, 2011 at 07:37

Sunday, Sep 11, 2011 at 07:37
Hi Trev6,

I would go for around 130mm to 150mm clearance with no load at the wheels on the shed floor, you've got to allow for the bumps. Check with your spring supplier. I've seen many new camper trailers at shows without being loaded with 60mm to 100mm clearance. I don't know how they get away with it.

You mention tyre size affecting trailer height, slinging the axle above the spring will lower trailer height.

Happy grinding and welding.
Alpero
AnswerID: 464666

Reply By: Michael ( Moss Vale NSW) - Sunday, Sep 11, 2011 at 09:36

Sunday, Sep 11, 2011 at 09:36
1500kg spring set are fairly stiff so 125mm would be plenty. You need 25mm minimum between the tyre and the chassis rails. I used to have 1100 kg a side springs and 7 leaf and only 710mm between the eyes so were really stiff and bounced much of the time so recently after my trailer mishap,(read my blog) I changed the entire axle and springs to 650kg a side and six leaf. It has internal guards and 150mm mudguard clearance.. I bought a complete Alko offroad axle 50mm square and parallel bearings with off road electric brakes. Around $1100 with 6 stud Landcruiser bolt pattern. If you are fitting brakes be careful if you buy bits and pieces off the internet, some brake drums and back plates have different offsets so it could be a problem if you bend or brake something when you are out and about and new parts from somewhere else may not fit or want to overlap others. I have GU Patrol steel standard rims with 265 x 75 x 16' BFG A/T,s to match my Patrol. Try to get 5/8" U bolts, if not get 1/2" High tensile, they are more expensive but worth it. If you need any other info, let me know. I have just been through the whole exercise. regards Michael
Patrol 4.2TDi 2003

Retired 2016 and now Out and About!

Somewhere you want to explore ? There is no time like the present.

Member
My Profile  My Blog  Send Message

AnswerID: 464683

Follow Up By: Trev6 - Sunday, Sep 11, 2011 at 16:22

Sunday, Sep 11, 2011 at 16:22
Thanks for that Michael,

The tyre size is the same as my cruiser, can you tell me what size chassis rail is under the trailer and how high the trailer floor is off the ground that way I could get fairly close to how mine will sit if I go with the bigger wheels, I am presuming that the springs go under the axle. thanks Trevor
0
FollowupID: 738706

Follow Up By: Michael ( Moss Vale NSW) - Sunday, Sep 11, 2011 at 16:46

Sunday, Sep 11, 2011 at 16:46
Trev, The bottom of the chassis where the spring hangers are welded on is 560mm to the ground. The trailer is home made and the chassis is made of 50x 50mm SHS tube, 3mm wall. So the flooring inside the trailer would be 560mm plus the 50mm tube plus the flooring thickness. The axle is inside the spring, the conventional way, not placed underneath.. Michael
Patrol 4.2TDi 2003

Retired 2016 and now Out and About!

Somewhere you want to explore ? There is no time like the present.

Member
My Profile  My Blog  Send Message

0
FollowupID: 738707

Follow Up By: Trev6 - Sunday, Sep 11, 2011 at 19:38

Sunday, Sep 11, 2011 at 19:38
Thanks for that Michael it was just the info that I needed

Trevor
0
FollowupID: 738715

Reply By: Crackles - Sunday, Sep 11, 2011 at 13:54

Sunday, Sep 11, 2011 at 13:54
Lots of variables in your question Trev as the wheel travel will depend on spring length, rate & load. Not only will you have to allow for the max load but also the up travel when hitting a pot-hole etc. Measuring my box trailer it has 130 clearance but for offroad 150 would be closer to the mark. My coil sprung offroad gear trailer has 170mm space to the guard but that was worked out using full compression of the spring & shock resting on the bumpstop.
The tyre size ideally would be the same as your tow vehicle but if looking for something standard then a Hilux 205/16 would be tough enough, give reasonable clearance, easily found outback & not too tall for unpacking the trailer.
Cheers Craig...............
AnswerID: 464715

Reply By: splits - Sunday, Sep 11, 2011 at 16:11

Sunday, Sep 11, 2011 at 16:11
Trev

Below are a couple of links that are always worth reading when building off road trailers. The man using the Jeep springs also mentions Falcon ute springs. He is not the only one I have heard talking about them on 4wd forums. Hilux rear springs are also popular. Be careful of short stiff trailer springs. They are often far too hard.

Try not to mount shock absorbers like he did. There are on too much of an angle to be affective which is why he had to use four of them. They still worked ok for him but standing them up straighter is much better. 30 degrees off vertical is about as far as you should go with tubular shocks.

http://www.caravanandmotorhomebooks.com/articles/why_wheels_fall_off.html

http://www.go.jeep-xj.info/HowtoTrailerPlans1.htm
AnswerID: 464724

Reply By: Trev6 - Sunday, Sep 11, 2011 at 16:12

Sunday, Sep 11, 2011 at 16:12
Thanks for all the replies so far I thought when i put the question to you all that it wouldn't be easy to answer but I thought it would be worth a try.....and it was.

What I am thinking of using is a spring and axle setup sold online by "Huntsman" trailer parts, there off road backing plates are the ALKO brand I think the rest is from somewhere overseas. My tyre delema is I already own 4 six stud rodeo rims with 2 tyres that would be good enough for a while all I need to do is get another second hand one for the spare, the prospect of not having to fork out extra $$$ for another set is quite an atractive one, but it wont fit the cruiser hence the question on what others do with their wheels and tyres.

Trev6
AnswerID: 464725

Sponsored Links