Due to the fact most of the FI road network is unsurfaced gravel and I want to trailer the rib to other parts of the islands this summer, I had to do something about the ride as the boat would be bounced around on the standard 13" tyres. It was also a problem on one of the beaches I launch on at very low tide as the trailer axle could get physically hung up on rocks on the beach. Both a function of the location rather than the trailer, but with no proper slipways to launch from, I needed to fix it.
I ordered the trailer with Land Rover stud pattern rims (5x165 PCD) and have had a couple of old Land Rover wheels waiting to go on for a while, with carefully steptoe'd nearly-bald tyres so they don't pick up stones.
First job was off with the mudguards as they were nowhere near big enough. I have to get some large mudguards made up to protect the boat from stones as it will be trailered on gravel roads for any trips further afield, and gravel is not very tube friendly. I'll also have to move the wheel carrier further forwards - at the moment I've got 235/70R16 tyres on there as a good all-rounder but can easily fit bigger flotation sizes if I need to trailer it off road - I've got a pair of old 31x10.50R15 tyres and rims available if I need them, but as you obviously need more water for launching with bigger tyres, I don't want them on there all the time.
The other issue I had was that due to the shape of the Vipermax planing pad which slopes up from the keel, the boat was only supported at the stern by the side bunks which worked, but I was not entirely happy with it. Sometimes the simplest solutions are the best
- after toying with a few complicated ideas (needed to be something that supported the boat solidly but was easily removable without too many tools) I decided that an offcut of 2x4 cut down and shaped to fit along the top of the rear trailer beam and be a tight fit against the planing pad, tight enough so it needs to be tapped in gently. With the boat strapped down tight to the back of the trailer, it cannot fall out, and the boat now rides perfectly with a good support across the widest part of the planing pad - much less movement on the trailer especially if you hit a pot hole.
The biggest difference though is the way the whole thing rides - the old tyres are 185/50R13 and had 60psi in them, I am running the new 235/70R16 at 25psi at the moment and the way it tows is transformed - no bounce, no crash if you hit a pothole, in fact you hardly notice there is anything there. With a set of flotation tyres on it should be really good - all I need now is mudguards. Not sure if this would be a legal modification anywhere else (may be OK with mudguards?) but it has certainly transformed it for what I need
Summer is on the way