Cycle Carrier Mounting

[Guest Roy Hamilton]

I have a Lunar Roadstar 720 second hand with a Fiamma Cycle carrier on the rear. I notice that the top mountings are bolted right through the rear panel with a plastic cover over the nuts inside but the lower mounting appears to be only bolted to the outer GRP panel as it flexes this. The weight of the cycles will tend to push the lower mountings against the solid rear panel but I am sure that in transit the carrier will bounce up and down to a degree. Before I remove the lower bolts and refit them right through to the inside (no problem as the inside is accessible) does anyone know of any technical reason for the present fitment.

[Guest PeteC]

I wold think that the top boltsare through a strut. If they are bolt right through And that the lower ones are just into the outer skin If that is the case putting bolts right through the lower fixing points , you would be thightening them onto the inner & outer skins without anything of substance between them, you may thus pulling both skins towards each other. ie. compressing the insulating material You would be advised to contact the people who fitted the bike frame initially and/or Lunar - they are probably the best to advize

[Guest JohnP]

You could fix the bottom brackets (I take it that there are two) as follows. Drill through the panel from the outside using a drill slightly larger that the shank of the bolt that you intend to use. Obtain some ali tube (B and Q) through which the shank of the bolt will just pass. Open up the holes you have drilled from the inside (using a drill which just gives clearance for the outside diameter of the ali tube)but do not go through the outer skin. Insert a length of the ali tube through this hole (from the inside) until it butts up against the outer skin. Cut it accurately to length so that is is flush with the outside face of the inner skin.. Make up two metal spreader plates approx 75mm x 50mm. Drill two clearance holes for the bolts in these spaced across the plate. When you assemble this arrangement the bolts will pull up on the ali spacer which will prevent the skins from collapsing inwards. The spreader plates will help spread the load across the inside skin. To check that the holes you are drilling are of the correct size - practice in a piece of wood Remember! 1. Measure twice and cut once. 2. Seal the holes on the outside with suitable sealant. Fiamma do sell mounting kits separately for most of their bike racks. A number of vans are only screwed at the bottom.eg Hymer 584 but they use a long mounting bracket at the bottom. Hope this helps

[Guest Derek Uzzell]

You say that the fixings for the lower mounting-points on your cycle-carrier don't pass through your Lunar's rear panel. It would be unusual (though technically possible) to use "bolts" in this way, but it's more likely that these fixings are actually "coach-screws" - sturdy, coarse-threaded screws with hexagon heads. Using coach-screws for attaching a motorhome cycle-carrier is simpler and cheaper than employing 'through-bolts', though their normal advantage comes when the inner face of the body panel is inaccessible. Coach-bolts need something substantial to screw into and, as Lunar uses traditional wood-framed panel-sandwich construction for their bodywork, I would expect the fixings to screw into the wood framework between the inner and outer skins. However, your mention of the outer GRP panel flexing suggests the framework at this point may be insubstantial or only attached to the outer skin. JohnP comprehensively describes the process of replacing the lower fixings with through-bolts. When the holes through the body-panel are drilled you will immediately discover whether or not the present fixings screw into a wood frame. If so, you may be able to avoid the need for anti-compression spacers, but only if the frame spans the full distance between the body-panel's inner and outer skins. The choice of different top or bottom attachment methods is probably because the fitter recognised (like you) that the carrier's upper fixings will partially be in tension and the lower in compression, and through-bolts are preferable to screws in the former case. (Another possibility is that the fitter knew that using lower through-bolts would be more problematical and time-consuming, so just decided not to!) If it's just the outer GRP skin that's currently flexing, then changing the lower attachments to through-bolts (using spacers if necessary) should help. If, however, it's the whole panel that's moving, then you would also need to make the panel itself more rigid by gluing wood or metal reinforcing to its inner surface. To introduce a general note of controversy to this, it's comfortable but risky thinking to assume all new motorhomes are designed to accept cycle-carriers, tow-bars, awnings, etc. I recall a letter in MMM several years ago from a Compass owner whose coachbuilt 'van had developed a yawning gap between the rear of the kitchen work-surface and the inner wall. It was clear this was being caused by the weight of bikes on a rear carrier deforming the motorhome's rear body-panel and the owner accordingly complained to Compass. The reply was that this particular model was not designed to carry bikes on the back and that's why a cycle-carrier was not a brochure option. My feeling is (when choosing a new motorhome) that it's always worth checking what accessories the manufacturer does, or does not, offer. If a cycle-rack, tow-bar, etc. are on the options list, then it's reasonable to assume the vehicle can be easily and successfully retro-fitted with such items and there will probably be fitting instructions available on how to do the job properly. Nothing on the options list may be an omen of a fundamental problem (as with the Compass example) or indicate the need to rely subsequently on educated guesswork on how the desired accessory should be installed. A few right-thinking manufacturers (eg. Chausson/Challenger) fit cycle-carrier 'mounting-blocks' as standard to their new motorhomes. This practice may not enhance a 'van's prettiness, but I'd definitely prefer factory-installed visible cycle-rack mounting-points on a motorhome to an elegantly sculptured rear panel with absolutely no clue what's beneath to enable a secure fixing to be obtained.

[Guest Roy Hamilton]

Thanks everybody for the detailed replies. It's only the outer skin that is flexing. The upper "bolts" are coach bolts with a small round head on the outside and presumbably a square which has locked to the Fiamma bracket to stop them turning and nylon locking nuts on the inside, the lower "bolts" are round flat headed with a cross for a screwdriver. I have contacted Lunar to see what reaction I get from there and will let you know what they say. Also I intend to contact the previous owner to try and find out who fitted the rack.