DIY cargo roof rack -how to mount (Grumman Olson)

IndigoMarsh · Jun 12, 2019

Hey Step vanners and everyone else,

I would like to have a cargo rack fabbed for my 1993 Grumman Olson 'ROUTE STAR' and I'm puzzled when it comes to the mounting. I have a pic here of someone elses GrumOls that has a roof rack mounted to the drip rail or gutter. I have also found many, many universal mounting brackets that are used to mount roof racks to drip rails for various vehicles. My question is -is my drip rail sturdy enough to hold the weight of a hefty cargo rack? You see in the pic that the Grumman with the cargo rack on the roof appears to be a little thicker than mine. Mine is the pic without the rack and with my fingers sort of pinching the drip rail for size/thickness reference.

My optimism leads me to think that if I have a 7-8' long by the width of the box (6' maybe?) 1-1/4" tube steel roof rack with maybe 4 mounting brackets spaced evenly on each side of the van PLUS a few rubber soled 'feet' welded to the underside of the rack, placed over the reinforcing ribs in the ceiling of the van -I should be okay.

Anyone have any experience with doing this or advice for making it happen? Thanks

highdesertranger · Jun 12, 2019

rain gutters are usually strong enough. the more mounting points the better. since I am not there to see your gutters I am hesitant to give the green light.

what are the gutters made out of steel or aluminum?

I would be hesitant to mount to the roof, but I would mount it to the sides.

highdesertranger

bullfrog · Jun 12, 2019

What do you intend to haul in the roof rack and how much will it weigh? What is the wall thickness of your tubing and how much room between the rack and the roof will you have?

IndigoMarsh · Jun 12, 2019

bullfrog said:
What do you intend to haul in the roof rack and how much will it weigh? What is the wall thickness of your tubing and how much room between the rack and the roof will you have?

I havent purchased any tube steel yet so not sure. Load hauled would vary from kayaks, canoes and SUPs when going into the wilds and plastic storage containers of t-shirts when going to set up as a mobile retail store. Space between rack and roof is not something I've considered yet either but I wouldnt think it should be more than about 3-4" -this plan is just in the idea stage at this point...looking for answers to find out if it's even something I want to move forward with.

IndigoMarsh · Jun 12, 2019

highdesertranger said:
rain gutters are usually strong enough. the more mounting points the better. since I am not there to see your gutters I am hesitant to give the green light.

what are the gutters made out of steel or aluminum?

I would be hesitant to mount to the roof, but I would mount it to the sides.

highdesertranger

I think the gutters are aluminum. Someone in a facebook group posted this pic (i'll see if I can attach to this reply) of a torn/broken gutter and the shape and angle look a lot like mine -as seen in the pic in my original post above. Not like the thicker gutter shown in the pic I posted of someone else's roof rack mounted to the gutters. The guy who posted the pic said the gutter was in that condition when he bought the van so I'm not sure how it got like that. Not very encouraging...

bullfrog · Jun 13, 2019

The big problem is wind resistance and vibration with those type items, where as heavy items over an 8' length like a spare tire or battery would definitely cause some problems. I had the largest commercial rack on top of our old jeep Grand Wagoneer with 4 pretty heavy duty gutter clamps and 16 gauge 1' tubing with a double loop top and bottom and front to back rails every 6" which I carried 2 33" spare tires, a battery, and a bunch of recovery tools. Probably in the 300 lbs. range. I ended up putting rubber supports in four places that rubbed the paint off and dented the sheet metal slightly. Eventually it vibrated and stressed the mounts so badly they stress cracked the metal rack where they attached. The best kayak rack I ever built was of cedar wood to carry 2 30" wide kayaks. It was 5' x 8' with two cross pieces 4' apart with a piece of plywood 4' x 5' to hold it all together (sort of an H shape with a fat center) which mounted to the rain gutters of my vehicle and carried the kayaks side by side upside down. When we got to the water the kayaks would be set on the ground side by side about 8' apart and the rack removed from the vehicle rotated 90 degrees laid across the kayaks so the 8' pieces were just in front and behind the seating area and the 4' x 5' plywood area creating a platform between the two kayaks for an ice chest, camping gear and a transom for a small outboard motor. Eye bolts the width of the kayaks in the 8' pieces allowed cargo ratchet straps the secure the kayaks to the rack in front and behind the seating area. We could motor across large open water lakes and up smaller rivers to camp where the rack was removed and four legs attached with a tarp thrown over made a shelter for camp and allowed the kayaks to be paddled into the narrow slot canyons. Wood flexes where steel cracks.