OK, I gotta ask: Is all that hanging off the 3 studs on the spare mount?
Need a side profile pic.
Need a side profile pic.
Builds The Guzzler - 2009 LX570 (4 Viewers)
- Thread starter grinchy
- Start date
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- Thread starter
- #923
- Thread starter
- #924
Exchanging intricate 1” x1/8” tube for phat 2” x1/4” tube. I’ll never worry about the rack base/vertical.
Buttressed by 2” by 1/4” angle.
Buttressed by 2” by 1/4” angle.
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- Thread starter
- #925
Six bolts closer. It’s sadly much heavier than before.
Stout though.
Even though I double bolted the cross it still wiggles a tiny bit. Going to add 2” angle 90s to make sure there is no wiggle.
just the bottom support and a couple stringers left.
Stout though.
Even though I double bolted the cross it still wiggles a tiny bit. Going to add 2” angle 90s to make sure there is no wiggle.
just the bottom support and a couple stringers left.
- Thread starter
- #926
Anybody have a spare tire hanger and associated bracketry they want to give up? I have a bunch of stuff for trade, including $.
- Thread starter
- #927
Almost done. Really.
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- #928
deciding if I need a vertical set of stringers too. Any thoughts on that? I can do pull-ups on it no problem, I weigh about what six bikes would.
Just the straps on the bottom left to install. 12 more holes.
It is super fast to load and unload. Love it!
next will be mounting it on top of the spare
Just the straps on the bottom left to install. 12 more holes.
It is super fast to load and unload. Love it!
next will be mounting it on top of the spare
I'll just say that there's a HUGE difference between static loading, and dynamic loading when bouncing down a bumpy road. And aluminum fatigues very quickly.
You might try to secure the bottom corners to the recovery points on the bumper, once loaded, so that the bottom at least can't twist and flex as much. Solid bar might be even better. Doesn't seem like that would require much material - maybe a 2" bar with a hole drilled on one side (which you could probably just attach with a basic nut bolt or even just a double wire safety pin that's the same size as the recovery point hole) and then bend the end 90 degrees and bolt it to the bottom corner of the rack
*I am not a mechanical engineer but I play one on the forum
*I am not a mechanical engineer but I play one on the forum
That's a lot of torque on that single attachment point, in the center. You need to at least have another brace as far away from that center as possible, top and bottom. And consider something more resilient, like steel or titanium. Which will make it heavier. Which will make it require more supports.
I would not put my bike back there, hanging like that, ever, I don't care how stiff it is or how well it's braced. Ignoring the obvious risk from a rear-ender, something is gonna give or fail and it will be ugly and expensive when it does.
My opinion, FWIW. I'm a civil engineer (PE), not a mechanical. I'll shut up now.
Yeah that is why airframes made of aluminum regularly drop out of the sky
More accurately, aluminum does not have a fatigue limit, that is after being loaded and unloaded repeatedly aluminum will fail regardless of the load. Whereas other materials such as steel have a fatigue limit and can be loaded and unloaded indefinitely if the load is below the fatigue limit. But I have not done any real Mech Engr in nearly 35 years after hucking stuff into space.
Grinchy, it is not so much you want more vertical support but as KLF notes you have a single point connection point with a lot of torque and want additional connection points. What I would do is have four soft connection points at the extrema. That is two connections at the bottom corners to the bumper (as suggested by LG) and two connections at the top corners to the roof rack. With a slight preload that will reduce left-right cycling as well as fore-aft cycling. Leaving only minimal rotational cycling and your cycle rack on the frame.
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- Thread starter
- #934
Thanks for all the advice. I’m not an engineer, just a physicist. Add more triangles is my solution to engineering. It’s not always suitable.
It’s meant to go on the tire, so it would then be resting on a 35” plate. However, it has been an interesting search for parts to fit it to the tire. Odd metric things aren’t really very available in the US. Not even grainger had what I was after. Anyhow that has shipped today.
I ran it around town for 10 miles with one bike on it. Nothing unusual happened, same amount of movement as the spare.
right now its snug against the tire plate, which Is 8” ish diameter of 3/16” steel. Which is connected to a steel 2x2. Which is connected to the swingarm.
the connecting members of the rack are 1/4” aluminum angle 2” and 2x2” 1/4” tube. Held together by 3 1/2” bolts.
but the whole swingarm itself is only connected at the spindle and via the latch. It hasn’t ever been a problem with the tire, I feel pretty safe at loads up to that mass.
I get that for off-roading there might need to be more supporting. For that I’d need to move the whole thing up to get ground clearance too.
in my mind the 12” stub out to clear The seats from the spare tire is the design issue. Unfortunately dropper posts make seat removal troublesome.
i am on the lookout for a spare tire winch and crossmember, then I could go to a simpler vertical only design.
It’s meant to go on the tire, so it would then be resting on a 35” plate. However, it has been an interesting search for parts to fit it to the tire. Odd metric things aren’t really very available in the US. Not even grainger had what I was after. Anyhow that has shipped today.
I ran it around town for 10 miles with one bike on it. Nothing unusual happened, same amount of movement as the spare.
right now its snug against the tire plate, which Is 8” ish diameter of 3/16” steel. Which is connected to a steel 2x2. Which is connected to the swingarm.
the connecting members of the rack are 1/4” aluminum angle 2” and 2x2” 1/4” tube. Held together by 3 1/2” bolts.
but the whole swingarm itself is only connected at the spindle and via the latch. It hasn’t ever been a problem with the tire, I feel pretty safe at loads up to that mass.
I get that for off-roading there might need to be more supporting. For that I’d need to move the whole thing up to get ground clearance too.
in my mind the 12” stub out to clear The seats from the spare tire is the design issue. Unfortunately dropper posts make seat removal troublesome.
i am on the lookout for a spare tire winch and crossmember, then I could go to a simpler vertical only design.
- Thread starter
- #935
Pretty much finished v2 last night.
Maiden voyage today to local MTb park. I watched it the whole way there with much trepidation. About 45 minutes, 20 on city roads and 25 on freeway.
All good. Some jouncing and bouncing, but it seems to be in the swingarm, not the carrier so much.
It’s sadly not Offroad worthy.
It bounces more at low speed on city streets than freeways.
The city streets where I live aren’t very smooth and have a lot of surface variations and level changes.
Anyhow, three bikes transported 90 minutes. All made it there and back. No drama.
Maiden voyage today to local MTb park. I watched it the whole way there with much trepidation. About 45 minutes, 20 on city roads and 25 on freeway.
All good. Some jouncing and bouncing, but it seems to be in the swingarm, not the carrier so much.
It’s sadly not Offroad worthy.
It bounces more at low speed on city streets than freeways.
The city streets where I live aren’t very smooth and have a lot of surface variations and level changes.
Anyhow, three bikes transported 90 minutes. All made it there and back. No drama.
Check out recon racks. Locally made to you and bulletproof.
- Thread starter
- #937
Thanks. The issue with an off the shelf rack (hitch style) is that they are not compatible with my aftermarket tire swingout.
The swingout is around 42" long. There is no way I'm going to put a 48" extension on my hitch. I could make it so I can't get into the rear of the car with a hitch rack and a shorter extension, but that isn't a great option either.
The swingout is around 42" long. There is no way I'm going to put a 48" extension on my hitch. I could make it so I can't get into the rear of the car with a hitch rack and a shorter extension, but that isn't a great option either.
- Thread starter
- #938
Another 180 minutes on the rack last weekend. Watching other vertical racks (hitch mount) on the road, this one moves just like they do, if a bit less even. No worries so far.
finished up another fsr build today. Now have three of these classics. This 2000 sworks build reused a bunch of extra stuff from the first two builds, so I didn’t have to buy much more than the frame. It’s the lightest as well.
finished up another fsr build today. Now have three of these classics. This 2000 sworks build reused a bunch of extra stuff from the first two builds, so I didn’t have to buy much more than the frame. It’s the lightest as well.
- Thread starter
- #939
So the rack is done. I’ve been taking on feedback and think it can connect up to the hitch if I extend the main down about six inches. To that end I got some more 2x2 and have it in the hitch.
Any recommendations on a 1/2” pin that is quick release for this purpose? It’s a horizontal joint (already ran some 2” angle to the hitch, not pictured).
I can find lots of qr vertical pins, and the typical hitch pins, but I kind of want something like a large bicycle skewer.
For the short term I’ll just put a bolt thru.
What about two ball detention pins, one vertical and one horizontal? I could cook that up.
Any recommendations on a 1/2” pin that is quick release for this purpose? It’s a horizontal joint (already ran some 2” angle to the hitch, not pictured).
I can find lots of qr vertical pins, and the typical hitch pins, but I kind of want something like a large bicycle skewer.
For the short term I’ll just put a bolt thru.
What about two ball detention pins, one vertical and one horizontal? I could cook that up.
- Thread starter
- #940
Here’s the vertical, it aligns with the side of the hitch member.
