Thread: Initial Flat Top Trailer Planning.

Finally, if you've towed before, but never with Electric Brakes, you will find the difference is like chalk and cheese. Mostly it's the control you have from the driver's seat rather than the trailer pushing you from behind to apply its own brakes.
I will never, ever, own a trailer with Over-ride brakes again.

Statement of the day.



Even if you are pushing close to 2 tonne, yep I know you can get away with 1 braked axle, but in my experience at least, go for brakes on both.

I have read with interest this build as it is very similar to my planned trailer.
Tandem 3200 kg , electric brakes 10 " on all wheels, break away system etc.
When I was getting a price from Yonnee's ex employer I was shopping through the components, 1600 kg per axle , parallel bearings and the salesman suggested 4 tonne springs.
I was puzzled a bit by this because I thought they maybe too stiff and not match the axle load capacity and overload it if loaded closer to the spring capacity.
Is my thinking awry?
I was tempted to go with the 3 tonne spring set up that Yonnee mentioned earlier in this thread.
Your advice please.

Originally Posted by MrSmith

I have read with interest this build as it is very similar to my planned trailer.
Tandem 3200 kg , electric brakes 10 " on all wheels, break away system etc.
When I was getting a price from Yonnee's ex employer I was shopping through the components, 1600 kg per axle , parallel bearings and the salesman suggested 4 tonne springs.
I was puzzled a bit by this because I thought they maybe too stiff and not match the axle load capacity and overload it if loaded closer to the spring capacity.
Is my thinking awry?
I was tempted to go with the 3 tonne spring set up that Yonnee mentioned earlier in this thread.
Your advice please.

You would be right to go with Yonnee's advise and go for the 3tonne set up, as the weakest link will be the axle set up at 3200kg, if using the "salesman's" recommendations, plus the extra cost of 800kg capacity that won't be capable of being used legally.
Kryn

Kryn's correct.
There's no point having 4000Kg of spring capacity and only 3200Kg of axle capacity. 200Kg is not going to overload a 3000Kg spring set.

I don't want to speculate on who you spoke to, but there's no training required to be a "salesman" in most fields of employment, and the information and advice given comes from experience in the field, and passion for the product and product knowledge. A passionate sales person will, in most cases, have the customer's best interest in mind and these people are difficult to find. Generally speaking, some sales people are purely interested in selling the product with the most profit margin, or up selling to the next sized item without a thought for the customer's long term requirements. Some are there just to collect a 9 to 5 paycheck...

Thank you gentlemen for your time in setting me straight.
I do want a set up that is matched in capacity as well as possible, is safe and legal.

Cheers.

I was doing a little research today while driving the tractor (autosteer can get a little boring) and while browsing a trailer parts website I came across this...

10 inch Electrics have a rating of 1600kg when using 13 – 14 inch Ford or Holden wheels and 1450kg when using 15 – 16 inch wheels. If you want 1600kg on 15 – 16 inch wheels then you will need to go to 12 inch Electrics and 2 tonne drums.

Is that correct? I wanted to use the same 17" 6 stud alloys that I have on my ute using 10" brakes. Why would the diameter of the rim impact the load rating like that? I would have thought that tyre diameter or rim offset would have an impact before rim diameter.

Anyone? ^^^

The old ratings come from the days when rims were small and tyre profiles were huge, so work on the OD of tyre. As for your springs, always have them lighter than the axle as the axle does all the work twisting and flexing.

I was planning on using 265/65/17 tyres with a load/speed rating of 112T. They have a diameter of around 776mm.

The wheels I was planning on using are 17x8" +42 and are rated to 1180kg each.


What would the load rating of parallel hub and 10" brakes with the above setup on a tandem trailer?

Go to Martins Trailerparts Trailerparts Home and download the catalogue, its got all the info you need. And they are most helpful by phone with any questions.

Originally Posted by naddis01

I was doing a little research today while driving the tractor (autosteer can get a little boring) and while browsing a trailer parts website I came across this...



Is that correct? I wanted to use the same 17" 6 stud alloys that I have on my ute using 10" brakes. Why would the diameter of the rim impact the load rating like that? I would have thought that tyre diameter or rim offset would have an impact before rim diameter.

Sorry naddis, I missed this earlier.
As Aufitt has touched on, those ratings/recommendations are from 30+ years ago when cars had 13" and 14" wheels, and 4WD's had 15's & 16". The rating for the Electric Brakes should not purely be based on the size or even offset of the rims alone, but the overall diameter of the tyre. You are correct in your thinking that the larger tyre diameter creates more torque in resistance to the braking effort of the drum and brake assembly. These days, the recommendations should now read;
"10 inch Electrics have a rating of 1600kg when using Passenger car wheels and 1450kg when using 4WD/SUV wheels. If you want 1600kg on 4WD/SUV wheels then you will need to go to 12 inch Electrics and 2 tonne drums."

This is also the consideration for the axle capacity rating as well, as it's the weight of the wheel and tyre combination, not the rim diameter that is the key factor. A light weight passenger car wheel & tyre, irrespective of the rim diameter, has much lees unsprung weight than a 4WD/SUV wheel and tyre and therefore puts less strain on the bearings.

Thanks for the reply guys.

So a 4wd rim/tyre on a 12"/2 tonne combo is actually rated at 1600kg - is that correct? O is it somewhere in between 1600kg and 2T?

Originally Posted by naddis01

I was planning on using 265/65/17 tyres with a load/speed rating of 112T. They have a diameter of around 776mm.

The wheels I was planning on using are 17x8" +42 and are rated to 1180kg each.


What would the load rating of parallel hub and 10" brakes with the above setup on a tandem trailer?

The load rating of the Parallel stub was designed with an "Off-road" wheel & tyre in mind, so should still be 1600Kg per axle, whereas the braking efficiency of the 10" Electric brake with the larger tyres is 1450Kg.
However... the rating of a trailer's registered capacity has never been anything to do with its braking capacity. Plenty of tandem trailer's are out there, legally registered at 2000Kg with only single axle brakes (good for 1300-1500Kg tops...)

So yours, depending on springs, 3200Kg with Rocker suspension, or with Slipper suspension 2666.66Kg.