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Old 08-17-14, 12:32 AM   #1
spectastic
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motorcycle bike rack (will this work?)

update: see below for new design..

http://i.imgur.com/7pow0py.png

Last edited by spectastic; 08-23-14 at 03:51 PM.
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Old 08-17-14, 06:29 AM   #2
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They way the diagram looks, I don't think so. The steering head of the bicycle needs to be more vertical for the rear wheel to track behind the front. With it nearly horizontal as shown in the diagram the wheel can swing left or right but not turn left or right...see what I mean?

Also, as the suspension of the motorcycle works the fork dropouts will have to rotate in the fork clamp. I can't tell if that clamp rotates, but many do not. Notice the serrated surfaces in the picture of the clamp? If the clamp doesn't rotate, these will grind down your dropouts.

Last edited by Looigi; 08-17-14 at 06:34 AM.
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Old 08-17-14, 08:33 AM   #3
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Just get this or something like it. I have seen one in Eureka Springs, it was a solid setup. Owner of it likes to mountain bike and the GS gets him to the trail in high style.

Motorcycle Bicycle Rack | 22 Cycles

Rod
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Old 08-17-14, 08:39 AM   #4
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Note how Team support for the European spring classics figured it out.
its more like the above rack so no rear wheel miles until you ride the bicycle.
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Old 08-17-14, 02:45 PM   #5
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Quote:
Originally Posted by Looigi View Post
They way the diagram looks, I don't think so. The steering head of the bicycle needs to be more vertical for the rear wheel to track behind the front. With it nearly horizontal as shown in the diagram the wheel can swing left or right but not turn left or right...see what I mean?

Also, as the suspension of the motorcycle works the fork dropouts will have to rotate in the fork clamp. I can't tell if that clamp rotates, but many do not. Notice the serrated surfaces in the picture of the clamp? If the clamp doesn't rotate, these will grind down your dropouts.
I'll put in lubricated washers between the skewers to make the joint mobile. what if I put a swivel joint between the skewer and the spoiler?

I don't really want to spend $300 on a bike rack. I'd rather go with something simpler that's easy on easy off
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Old 08-18-14, 07:58 AM   #6
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I'll put in lubricated washers between the skewers to make the joint mobile.
It would depend on the details but as long as it allowed the skewer to rotate about its axis and not allow the fork to accidentally come free, it could work.

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what if I put a swivel joint between the skewer and the spoiler
That would allow the rear wheel to steer left and right, which is needed. However, with the fork being able to rotate on the bike frame, the combination would allow the bike to just flop over instead of staying upright. You'd need to fix the fork to the bike such that it couldn't rotate, perhaps with straps from the frame to the bars or something.

FWIW: This is something I'd be very thoughtful and careful in doing and testing as there is a possibility of bodily harm to yourself or others if things go wrong.
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Old 08-18-14, 09:18 AM   #7
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yea, I do plan on doing some testing before doing any serious riding with it. I was thinking I could lock the handlebar/fork by bungie strapping part of the front wheel to the handlebar/stem, and the rest of it to the toptube and downtube. I'll have to deal with the different diameters of the tubes, and the cables, but I think it will work.

And if it doesn't work, the next best thing imo is to rig up a couple of extension bars to lower the bicycle fork and make that head tube more vertical. like this guy http://www.justxr.com/cycbycyc/cycbycyc2.jpg

just hope there won't be any 4x4's on the road

Last edited by spectastic; 08-18-14 at 09:28 AM.
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Old 08-18-14, 09:40 AM   #8
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you actually like the plan to be wearing out your bicycle tires dragging the rear one behind your motorcycle on the street?
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Old 08-18-14, 09:52 AM   #9
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Originally Posted by fietsbob View Post
you actually like the plan to be wearing out your bicycle tires dragging the rear one behind your motorcycle on the street?
my take is the wear will be minimal. there's only about 15 lbs of weight on that tire, and it's being dragged. there's basically no shear stress on the tire because there's no load.
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Old 08-18-14, 09:55 AM   #10
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good luck then ..
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Old 08-18-14, 09:59 PM   #11
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Not a good idea. As has been mentioned, wear on the rear wheel/tire will be excessive.


If you don't want to spend 300$, find a buddy with a welder and give him a case of beer. Then spend 3,000 when your bike falls off on the highway.





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Old 08-18-14, 10:14 PM   #12
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Drivers will be terrified to be anywhere near you (rightfully so) and you will stopped by every single police car that see's you (good luck proving the units structural integrity). As far as wear (tread and mechanical), remember that if you put a "lubricated washer" to pivot vertically for your suspension, every bump and crack in the road is going to send the bicycle jumping off the ground and crashing back down again, which at 40mph will be devastating.
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Old 08-18-14, 11:32 PM   #13
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You should also check that your motorcycle insurance provider will still cover you if you actually use your self-fabricated design on public roadways.

-j
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Old 08-19-14, 06:24 PM   #14
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Out of concern for the OP's safety, other drivers on the road and the bike I would agree with the other posters that this is a very bad idea for all the reasons mentioned and at least one other I can think of. If you don't want to make a proper rack, spending the $300 for a manufactured rack would be very cheap insurance.
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Old 08-20-14, 09:26 AM   #15
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Your original idea seems unsafe, for the reasons outlined by others. The commercial rack linked above looks like a safe design.

But, if you can't spare the $300, plus shipping, for that rack, then maybe imitate it?

You could find the mounting rail from a roof rack, and then mount that rail to your motorcycle with inexpensive hardware. I've seen Thule roof rack rails going for <$100 on craigslist.
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Old 08-20-14, 09:54 AM   #16
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Old 08-20-14, 09:56 AM   #17
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Wear is not the enemy,heat is.You run the risk of the tire coming apart from heat.

Bicycle tires are not made for extended high speed.

If a wheel touches the ground,your making a trailer,it's suppose to have tags,lights and DOT tires,ect.

If you must:


Look up Johnny Racks for a style that carries the bike off the ground.

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Old 08-23-14, 03:27 PM   #18
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what about this one? it's sloppily drawn. I put the bike on there today to make sure the dimensions check out. the top tube is going to be more parallel to the passenger seat, and the center of gravity of the bike is a lot closer to the tail lights than the picture shows.

http://i.imgur.com/7pow0py.png

I was thinking about hooking up the handlebars to ratchet straps connected to somewhere around the frame near the passenger footpegs, and hold up the top tube by modifying the spoiler into a hinged clamp that secures it in place. on the passenger seat, I'll put a piece of support that allows me to tighten the straps without the head tube being jammed into the bike passenger seat.

what do you think?

what should I use to secure the top tube?

Last edited by spectastic; 08-23-14 at 03:37 PM.
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Old 08-23-14, 04:00 PM   #19
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Go with 2x2 cycles as linked above. I will attest after 5k miles it's a solid setup. Although..... I did drop my front wheel on the George Washington Bridge and by the time I got back to it, it was a smashed taco. But that was no fault of the bicycle rack, it was a combination of NYC potholes and my inability to further secure the front wheel.
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Old 08-24-14, 06:17 AM   #20
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I doubt the tire will assplode from speed as it's so lightly loaded. Heat comes from repeated flexing of the rubber and high speed flexes the rubber more frequently which heats it but with so light a load there's very little flexing going on.

And not withstanding all the other reasons not to do it, note in the photo post 17 that the front fork is supported so that the bike is more level. This orients the steering axis more vertically which is necessary for the bike to trail properly compared to your first proposal where the fork's steering axis was nearly horizontal.
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