What do you think of this homemade bike rack?
 

Well, not homemade exactly. I'm trying to see if I can avoid the nearly $500 it will take to put Yakima crossbars and a regular tandem rack on my Sienna. I took an old Rocky Mount single rack that is designed for factory crossbars, spent $29 to get a second tray and bolted them together to make a tandem rack. The factory crossbars are spread as wide as possible which still leaves the rear tire of the tandem about 1 foot behind the rear crossbar. It feels fairly stable and secure but it is not completely rigid. There is some flex in the tray at the rear tire and some flex in the factory crossbar at the front fork so the assembly will flex back and forth a bit.

I think this is certainly adequate for around town emergency type use. I'm just wondering how well it will do for long distance road trips and what issues I should think about. Any opinions? Any cheap ideas for beefing it up?

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If it works, it works.

I've used all kinds of hybrid roof mounts to carry tandems. Our triplet is basically secured using a single bike fork mount and a pair of suction cup mounts. It's not pretty, but it works and it only cost me $120 given I already owned all the other bits.

Just be sure that you've done your homework on the loads and keep an eye on your "farmboy-engineered" solution, as a $6000 tandem will be a pile of $20 junk if it comes off the roof at 60 mph, never mind any damage it does to your vehicle or anyone following behind.

Theres a reason that nice folks like Charlie Buchalter can make a living selling tandem racks...

Spend another $29 for a third tray and bolt it inside the second one to stiffen it up. Then spend $10 on a pair of motorcycle tie down straps from Home Depot. Attach the first one to the outside of the factory rails and to the stokers seatpost, and adjust it so it's tight when the bike is straight up and down. Do the other side the same, only cinch it down until you see the trays just start to flex. Done. The bike isn't going anywhere the car isn't. If you shake the bike you'll be rocking the car.

Me too. But wasn't it you that made a mount to carry your single on the back of your motorcycle? That I've never done!

I'm not sure bolting a second tray on top of the first one would accomplish that much because the trays have a channel on the bottom where the bolts slide in. So they don't actually nestle together tightly and two trays isn't going to provide any additional torsional rigidity. Although it will make it more rigid from downwards flex. But I do like the idea of using webbing straps to lash the bike down to the rails as an extra stabilizer.

I don't think I'm in danger of exceeding any loads. The factory rack on these Sienna's is pretty sturdy and I've driven all over the country with a Yakima rocket box mounted on the factory crossbar loaded down with several hundred pounds of gear. The fork mount is the factory fork mount from the single rack so it should be fine. The tandem isn't any heavier than a heavy single. I think the main concern is side to side flex.

If you are worried about the bending on the two rear racks... get a hunk of square aluminum tubing and bolt it to the bottom of both tracks across the joint. You should be able to find a carriage bolt that will fit the channel on the bottom of the racks and bolt to the tubing. Probably about a 5/16" I would say.

The side to side is controlled entirely by the front fork mounting. Some give will not hurt anything unless it begins to oscillate. If you need more there, add another cross bar tied on each side/end of the factory bar and to the bike rack head.

I have a Tandem Topper and A) it wobbles side to side a bit and B) there is some wiggle to the rear section. So it sounds like you are as good as the real stuff.

Yes, it was. Still have the rack, but sadly... I sold the R1150RT. It didn't rock my sweetie's world the way I'd hoped it would. Turns out she was a closet biker chic who had a thing for Harley's. Haven't been able to bring myself to making a rack for the Harley or my R1100S; that would just be wrong in both cases.

Actually, all these fork mount racks allow a tandem to wobble in the breeze dangerously. If you don't believe me, have your stoker drive your vehicle at highway speeds and you follow in another vehicle and watch. It's actually scary. Plus, this type of mounting system exerts an extraordinary amount of force from an unusual direction on the fork tips. Several HAVE failed over the years. Not to mention the owners who failed to tighten the skewer well enough.

Keep in mind that the fork tip rack was designed for a single bike, then adapted for a tandem. That's why I always use/recommend tie-down straps. Cinched down snugly, they stop all lateral movement and restore the downward force on the fork tips. Even if the skewer isn't tight, the bikes not going anywhere. Plus, they're $10. Too cheap not to use.

It's the downward flex that I was concerned about. You want to be able to cinch the tie-downs sufficiently. Not like you were compressing the suspension to strap down a motorcycle, mind you, but enough to make the bike feel like part of the vehicle. If that rear tray is too weak, it may bend. But you're the one looking at the setup, and you have to make that call.

If you're not comfortable with the single tray by itself, get a 4' strip of flat iron from the hardware store, paint it black and bolt it to the bottom of that section. Or replace the whole deal with a piece of heavier channel aluminum. Or figure out how to shift the mounting of the whole rack forward, etc.

Paraphrasing what TandemGeek said, the price of under-engineering your homemade rack is FAR greater than over-engineering it.

Yes, there's a certain level of decorum here that simply MUST be observed. Particularly with the Harley. It's hard enough for someone who actually knows how to ride a motorcycle to be seen on one that won't go around a corner, but to further call attention to yourself, well .... :lol:

That's what I was thinking. I guess I'll swing by my local home depot and see what kind of metal bar I can find to add rigidity. The rack really isn't for long distance driving. More for hauling the bike around town to local trailheads and that kind of thing. And for emergencies. Unfortunately I live in a location that requires some short stretches of fairly aggressive busy highway riding to get out of our neighborhood. Which is fine for me when I'm out on a ride by myself. But not so great when I'm out for a family ride with the wife and 3 girls.

Have you considered putting that tandem INSIDE the Sienna?

That's how I've been carrying it around before now. But I wanted to see if I could find a cheap way to put it on top for days when we take the whole family out biking. With the tandem inside I lose the whole 3rd row of seats and don't have room for my 3 daughters inside.

It worked fine this weekend when I drove out to a nearby trailhead. But for longer distances I'll either put it inside or do as onegun recommended and run tiedown straps from the seat rails to the crossbars

Isn't there an approximately 1" square hole under the channel on the trays? If so, you could insert a square steel or aluminum tube into both trays and butt them together.

It's not 1" square. It's more like 3/8" or maybe 1/2" square. It's where the mounting bolt heads slide. the whole assembly is already pretty stiff. However if I wanted to stiffen it up more I think it would make more sense to add another strap of metal (or even a length of wood) underneath and then run the mounting bolts through it.

try upside down
 

I used to put our tandem upside down and tie the handlebars to the roof rack. The rear saddle was adjusted so that it just pressed against the roof to give a fifth point of contact with the car (2 points of contact per handlebar). This is probably the cheapest option. It is also very stable (tested on many km on highways, never tried entering a parking garage, though :) ). My current car is too tall to easily load our triplet on top, so I went for S&S couplers and putting the triplet inside.

Note that for stiffness any flat metal underneath will not come close to matching a box section piece underneath.

A long time ago I had a bike come off a cheap rack at highway speed. Trashed a nice bike and dinged my car. Since then I have not taken any chances with bike transport. I use Yakima crossbars on my factory racks and a Sidewinder tandem mount. I check and double check when I put the bike up and give it a shake if I stop during my trip. Works great, keeps my tandem safe, and keeps my from worrying.