compatible UK trailers

You don't need a tilting trailer.  What you need are sufficiently long ramps to reduce the ramp angle so that your front diffuser does not hit the ramp.  A little bit of scraping the ramp will not hurt the diffuser, but you do not want to support a significant amount of the car weight on the front of the diffuser.

You can determine the max angle between the front tire and the front of the diffuser with a little bit of trigonometry.  The height of the front diffuser is typically 40mm to 45mm.  Likewise, you can then use the height of your trailer and some trig to determine the required length of your ramps.  The question then becomes can you purchase or make ramps for your chosen trailer.

Edit: the maximum angle (I believe) would be 2.9 degrees for an SR3.  I used a height of 45mm and a distance to the bottom of the front wheel center of 889mm.  arctan(45/889) = 2.9°

So if the height of your trailer is say 30 cm, then you would need ramps that are at least 5.922 meters long.  20 cm, then 3.948m.  10 cm, then 1.974m.  (my total length ramp in the picture above is about 4.6 meters)

A trick that can help is to get the front wheels elevated before starting up the ramp.  For example, placing two pieces of wood one meter long, 15cm wide, and 4cm thick in front of the ramps will do this. 

Finally, if you do select a tilting trailer, you still need to make sure that the loading angle is not greater than 2.9°.  

(try that again ...)

G'day Rojid,  I agree with almost everything that David outlined in his post above.  It seems like he and I have been on parallel approaches - albeit that I went through this about two years ago.

I'll post some photos of my set-up below, as well as some detailed engineering drawings of the ramps I designed that might help you.. at least I hope so!

Before doing that 'll just reflect a little on some points in the above posts.

I did exactly what you are planning to do, and didn't initially go with an enclosed trailer.  Of course you can do that, and maybe available finances mean that's the only option for you.... but I wish in retrospect I had bitten the bullet earlier and purchased an enclosed trailer up front.

In terms of a 'tilting trailer' - as David says, you absolutely don't NEED one, but it certainly helps a lot.  To be clear though, the trailer doesn't need to have a hydraulic (or even winch based) tilt system... you can simply force the trailer brakes on, unhitch the trailer from your tow ball and crank the front of the trailer up to cause the rear end to be lower when loading and unloading.  On my Brian James Race Sport Trailer (not 'tilt' mechanism) I do exactly that and can get the rear end of the trailer deck easily to within 150mm (6") off the ground.

... when loading at home my hitch ends up around 670mm off the ground.... works perfectly

I don't like the front splitter to take almost any load when loading or unloading, but as David mentions they will 'touch' the ramp surface at different points during the loading/unloading process.  My car runs 39mm ground clearance under the front wear strip (in the middle of the splitter) and slightly higher on each edge (its and RSX splitter)

I would recommend you design your set-up with 2.5 degrees (or less) approach angle.  David suggests 2.9 degrees but that would cause my splitter to rub fairly heavily I suspect....?

David's suggestion of using strips of 4cm thick wooden planks under the front wheels leading onto your ramps is a good one, although I'm not sure how easy it will be to get up the first 40mm step unless you put as slow taper onto the leading edge. I effectively did the same thing in the ramps I have detailed below, but the step on mine is only 30mm (1" rhs and some aluminum tread plate) and the aluminium plate hangs over and forms a nice ramp up onto the 30mm step.  I can push the car up onto this section on my own when loading the car (on flat ground) so it works really nicely.

If you look closely at the Race Ramps (that the brand) of David's set-up you might notice they have a 2 piece 'compound slope' rather than just a 'straight incline'.  This is important as it can fairly significantly reduce the overall length of ramps you need.  I couldn't afford the Race Ramps (the ramps themselves were a good price, but the freight from the US to Tasmania was prohibitive).... so I copied the idea and designed/fabricated my own.  I think from memory the 'compound slope' reduced the overall length by about 600mm.

My total ramp length is 4.2 meters including the 1.8 meter long rear door which forms part of the overall ramp surface. (this compares top David's as shown in his post of 4.6m, but I note he hasn't tilted his trailer at all either... when I'm loading/unloading the rear of my trailer is probably at least half the height shown in David picture)

Here is some initial sketches of my trailer ramps.... these were concepts that I was starting to design around when I purchased my Brian James trailer and I had to modify my existing ramps that were designed originally for a non-enclosed trailer....  

... and here the ramps are in their final form (note that in this next photo that the trailer is in my home driveway which is on a 5 degree slope... so definitely not flat ground!.  This was a complication for me when designing the ramps as I've got to get the car into and out of my trailer when it is at the bottom of a sloping driveway.)

.. and here is the detailed design drawings that they were made from... (although these were the original ... I modified them when I purchased the Brian James enclosed trailer, but the shape is essentially the same - it's just that now the aluminium fold down ramps that are an integral part of the Brian James trailer rear door form the support for the last 600mm of the ramps I made, and the original 1" rhs steel structure was cut away to suit....)

.. and the pdf of the same in case it's hard to see the detail.

(Please note that the lines shown on the side rails of the ramps in these drawings aren't really welded joints - they are simply lines to show that this is where the ramp rails should be bent into the compound shape that I desired to keep the ramps as short as possible... and each point has a height noted from the horizontal 'datum' (ground level) which makes it really easy to get the bends in exactly the right place and at the right level)

These ramps fold up (around a central hinge joint) into my trailer for easy stowage and that limits the total length of the ramp assembly to around 1200mm (the width of a standard aluminium tread plate sheet, so that there are no joins required in the ramp surface)

Here is one of them (there is one stored in each side of my trailer) as stored and transported in my trailer.  I designed and fabricated the aluminium storage rack and the ramp storage rack to make iot use the trailer space efficiently.  There is only one 'ratchet strap' that holds each ramp securely in place for transport - it's really easy to pack up and get out. 

Here's some 'renderings' of the final design...unfolded

... and folded (upright as stored)

I really hope that helps you out... !?

Regards

Rod

thanks for the detailed responses, much appreciated.

The issue i have though, is in both your examples your ramps are leading onto a large flat area which hinges onto the bed which the car sits on. The angle between the hinged door and the trailer bed is pretty flat. 

The sort of non-tilt trailers i'm looking at are these, which i can pick up relatively cheaper second-hand: 

And my concern is this: 

if I go for a non tilt one - ok as you guys have said, i can fashion or buy some extra long ramps which have a gradual angle to get the car onto the Trailer ramps, but once its there, the 2nd angle will surely be too large and the car would bottom out?

 

In terms of a 'tilting trailer' - as David says, you absolutely don't NEED one, but it certainly helps a lot.  To be clear though, the trailer doesn't need to have a hydraulic (or even winch based) tilt system... you can simply force the trailer brakes on, unhitch the trailer from your tow ball and crank the front of the trailer up to cause the rear end to be lower when loading and unloading.  On my Brian James Race Sport Trailer (not 'tilt' mechanism) I do exactly that and can get the rear end of the trailer deck easily to within 150mm (6") off the ground.

... when loading at home my hitch ends up around 670mm off the ground.... works perfectly

this could be the answer... i did think about whether this was possible but wasn't sure how the trailer would be held up at that angle whilst the car was being loaded on. 

@rojid … that’s definitely a BIG part of the answer…. I was worried you had missed that point when reading your initial reply above.

I purchased one of these that bolted directly onto the trailers A-frame, and hooks into the trailers on board 12v battery (installed to operate the electric winch) via an Anderson plug. It takes all the manual winding up/down that a standard jockey wheel requires out of the equation….

… but you are still going to have to use an extra set of ramps… effectively making up for the fact that your trailer does not have a rear door.
I had this exact issue on my original trailer (non enclosed without the rear door that acts as part of the ramp) and I had a pair of 2m long galvanised ramps made that hooked onto the rear of the trailer bed, and that sat into the fabricated ‘notch’ that’s shown on the design for the ramps I included details of in the previous post. The ‘fabricated notch’ (and the short leg that is under that end of the ramps in my drawing) are required to ‘prop up’ the end of these extra ramps off the ground. This is needed to get the angles consistently around no more that 2.5 degrees increase (the point beyond which the front underneath edge of your splitter will hit your ramp)
… trust me… I modelled this using CAD software two different ways, and there is no way you will do it without ramp length totalling 4.2m to 5m long depending on three main factors;

1. Are you using compound incline ramps (as mentioned, these do make a measurable difference)

2. What is the height and angle of the rear of your trailer bed when it is TILTED (using the A-frame jack and pivoting around the tandem axles - no need for a pivot in the trailer frame)

3. Are you able to load and unload on pretty level ground?  In my case the angles of my driveway work against me - there’s a 3 degree difference in the part of the concrete outside my garage and the concrete driveway where the wheels of the trailer park…. Which makes this more difficult for me in that location…. Hence the hours and hours I spent thinking/modelling and fabricating a solution. 

nice solution and engineering Rod

@davidf …thanks David. It’s obvious we were on similar paths. 
Have you tried tilting your main trailer bed by jacking the front up vertically  off the tow hitch? (While you have the trailer brakes on) It makes an enormous difference. 

@rjbender Yes -- I get some tilt from the slope of my driveway, but at the track I am always hitched up to my truck when I load, and on a flat/level surface.  The trailer has a gentle down slope in the back, and the ramps are progressively sloped.  It is a beautiful solution which I received from Charley and Reverse Logic Limited.  

On that note, sadly, Reverse Logic is no longer a designer/reseller for Race Ramps.  One can still purchase several standard ramps, but I think that custom made race ramps are now a thing of the past and I got the very last set that was tailored for my Radical and my Featherlite trailer.  

I've been using ordinary two piece RaceRamps with my Featherlite enclosed trailer with good luck. My front diffuser gently rubs on its way in, but it's not concerning. I tuck them in the trailer (long ways up) with a single quality bungie cord. Even my wife and her twig-arms can secure them in the trailer. (though she does complain from time to time)

due to the weight distribution of the car, wouldn't i have to load the car in backwards?

@rojid - I’ve done it both ways, and checked ball/hitch weight…. but now always load ‘front first’ …

It probably depends a bit on whether you carry anything else on/in your trailer and where that is loaded. For instance if you have spare wheels/tyres mounted up front (like in my Brian James Race Sport and like in the photo you shared in a previous post) and you make sure the SR3 is on the trailer as far forward as it can go, then that will make enough difference to balance the load forward enough to give correct ball/hitch load. that’s what my measurements proved… I also store about 80kg’s of tools, trailer spare tyre and race fuel right at the front of my trailer… that also helps…

These cars aren’t like most other ‘sedan based’ race cars which tend to be very ‘front axle heavy’…. The SR3’s are only 100kg heavier on the rear axles (without driver weight) compared to the front axles - that’s a tiny difference compared to most other cars. 

when it comes to trailer widths, how narrow can i get away with?
I know the car is 1.8m. When winching up, is the tow hook dead center? Does the car winch up in a straight manner?

i ask because there's a reasonable used trailer going on ebay but it's 1.85m internal width....which is certainly tight. 

Any recommended space i should aim to have either side of the car?

@rjbender 

hi Rod, 

with my first event being on 31st march, my attention is back on this subject...

my towcar is... a relatively low car (4 series coupe). And my concern now is whether, if using a non-tilt trailer - if i tilt the bed as much as i can using the jockey wheel, I would have to load the radical on without the tow car attached?   

i'm guessing that if i have the trailer already hitched to the towcar, and then try raising the trailer using the jockey wheel to its highest point to get the shallow angle i need - the rear of my car would be pulled up a fair amount until presumably the hitch would break or something horrible would happen?!

in which case...any recommendation for how to safely load the trailer whilst unhitched?

@rojid … Hi - Sorry for the late reply as I’ve been travelling. 
You are correct that you will need to tilt, then load your trailer with the tow ball raised and unhitched…. As shown in this photo from my previous post

How high you need to raise it depends on your trailer and the shape of the ground under the car/trailer. 
As described previously, I load mine on a driveway that has a relatively steep slope and have absolutely no issues. 
For safety I leave the safety chains attached to the car, put the trailer handbrake on and always chock the trailer wheels.