andrew-theasby
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| posted on 2/4/09 at 08:31 AM |
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eye bolt strength
How strong are eye bolts with a side loading (i understand only certain types can be used in this application)? Do they bend or snap first? The
reason i ask is that the underside of my car will be completely sheeted and i thought of welding 2 bits of internally threaded tube vertically on the
chassis either side just behind the diff to just protrude through the floor so i can screw a couple of eye bolts in for trailering, rolling road,
recovery etc Ive found some tables which give sideways ratings but the numbers mean nothing to me. And when the eye bolt bottoms out the eye might be
pointing lengthways or sideways but it would be almost a 90deg pull on it. Is it just a bad idea to start with or are they well over rated for the
kind of load im talking about? Other idea i thought of was similar but a bolt and a flat plate lug like a seatbelt mount.
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Howlor
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| posted on 2/4/09 at 08:40 AM |
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I think you'll find the chassis will give first before the eye bolts even pulling in that direction.
They tend to bend first from what I have seen.
Steve
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Mr Whippy
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| posted on 2/4/09 at 09:20 AM |
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You could easily hang the car off one, their high tensile after all, your chassis would give in first
might be nasty if one clips a pothole, speed bump etc personally I'd fit them horizontally to the ends of the chassis
I tend to tie down cars with the straps going through the wheel spokes as that prevents any movement
[Edited on 2/4/09 by Mr Whippy]
Fame is when your old car is plastered all over the internet
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will121
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| posted on 2/4/09 at 11:54 AM |
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how about use of the new type of flexable towing eye straps, only need a 7/16" bolt fixing
demon tweeks tow strap
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Mr Whippy
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| posted on 2/4/09 at 12:20 PM |
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quote:
Originally posted by will121
how about use of the new type of flexable towing eye straps, only need a 7/16" bolt fixing
demon tweeks tow strap
looks quite cool
Fame is when your old car is plastered all over the internet
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andrew-theasby
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| posted on 2/4/09 at 12:38 PM |
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quote:
Originally posted by Mr Whippy
You could easily hang the car off one, their high tensile after all, your chassis would give in first
might be nasty if one clips a pothole, speed bump etc personally I'd fit them horizontally to the ends of the chassis
[Edited on 2/4/09 by Mr Whippy]
Id remove them for driving, thats the idea of using eye bolts. Also they wouldnt be in tension, which is why i asked.
Those straps are pretty much what i was thinking of with a falt plate lug, not seen them before, i think thats probably the route ill take now.
Thanks
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Nick Skidmore
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| posted on 2/4/09 at 01:08 PM |
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If you buy quality ones they have the SWL marked on them.
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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andrew-theasby
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| posted on 3/4/09 at 10:11 PM |
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I know, but thats in tension, not pulling at at angle
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907
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| posted on 3/4/09 at 11:28 PM |
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Half it.
I used to have a proper job that often involved turning a vessel from the horizontal to the vertical.
On something weighing 5 tonne the minimum eye bolt I would use is a 10 tonne.
When bending metal half the thickness is under compression and half under tension.
That theory will be near enough for your purpose anyway.
To orientate an eye bolt a shim washer is used.
Say the thread has a 2mm pitch then a washer that is 0.5 or 1.5mm will turn it 90deg etc.
hth
Paul G
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andrew-theasby
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| posted on 4/4/09 at 03:23 PM |
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OK thanks. How many tons can i expect to be applied to it on a rolling road for example?
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nstrug
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| posted on 6/4/09 at 04:51 PM |
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You can calculate the force applied on the rolling road quite easily if you know how much torque your engine produces. The formula is:
F=T * R1 * Rp * Rf / rr
Where:
* T is the maximum engine torque in Nm
* R1 is your first gear ratio
* Rp is your primary reduction ratio (1 on a car engine)
* Rf is your final drive ratio
* rr is the rolling radius of your driven wheels in m
This will give you the maximum propulsive force on the car in N. The actual force will be a bit less than this due to transmission losses.
As an example, on my R1 5PW powered car this is 5052N (or 1135 lbf if you prefer).
By the way, I'm not sure if its a wise idea to tie down a car to its trailer via the chassis - in order to stop it moving around you would have
to seriously compress the suspension, which might not do it any good if you have a long drive - much better to just use tiedowns through the wheel
spokes.
Nick
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