Bengoh
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| posted on 23/4/02 at 12:33 PM |
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Rod end bearings
There are some rod end (spherical) bearings going cheap! A gent called James Mather of BRA cars has got some stock left over from the company (which
is closing down). His e-mail address is merlin@wizardsden.fsnet.co.uk.
I got 5 off 5/16" I/D male rod ends for £10!!
Can't say fairer than that.
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stephen_gusterson
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| posted on 23/4/02 at 09:31 PM |
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quote:
There are some rod end (spherical) bearings going cheap! A gent called James Mather of BRA cars has got some stock left over from the company
(which is closing down). His e-mail address is merlin@wizardsden.fsnet.co.uk.
I got 5 off 5/16" I/D male rod ends for £10!!
Can't say fairer than that.
Good price - but thats about 7 - 8mm isnt it?
The load rating for an average rod end that size is pretty low - might be ok on a track for a few miles, but a road car might break them.
I used 16mm rod ends on my suspension. 12mm looks a minimum to me.
I did use that size on my brake linkage tho.
atb
steve
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Liam
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| posted on 23/4/02 at 10:50 PM |
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I dont know why, but so many people (myself included) all seem to come to the same conclusion that 1/2" rod ends 'look about right' for a Locost.
I guess 1/2" is just a nice size.
Several months ago I just happened to be in the crash test place at Cranfield Institute when McLaren turned up with a couple of 2001 F1 cars. This
was great cos I got to fondle it to my heart's content and got some top inspiration for my next project. I even told one of the McLaren engineers I
worked for Arrows and he just chuckled. I'm surprised they let complete strangers anywhere near it, let alone examining every inch, bodywork
off...
Er, I digress...This F1 car had rod ends on the wishbones that were a mere 1/4" or 5/16" at the most. That's in a car that effectively weighs up
to 2 tonnes when it corners (due to downforce), and has cornering/braking loads up to 4.5g. The loads on the bearings must be phenomenal.
Sure they will be rather good quality rod ends in an F1 car, but you can see that 1/2" rod ends in a car weighing 600kg, with loads less than 1g is
probably overkill. So those 5/16" ones should be fine.
Besides, the biggest problem with rod ends is not breaking, but wearing. They'll never just break off (unless you clout a wall with your front
wheel) but they can quickly become sloppy. Apparently, F1 drivers can feel the slop develop in their suspension rod ends during race distance - so in
a road car doing thousands of miles on bumpy roads, the rod ends could become sloppy very quickly.
That's why I decided at the last minute to go for poly bushes instead of rod ends on my car. I'd be interested to know of anybody's experiences
with rod ends on road cars, though.
Taa
Liam
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Dunc
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| posted on 24/4/02 at 08:58 AM |
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It depends on where you mount them, the further apart they are the less load they see, generally. Liam were the wishbones on the F1 quite broad?.
I'm using a mix. Metalastic bushes onto the chassis and at the rear rod ends onto a fabricated upright. Because I might want to up the power quite a
bit I've made the wishbones rear quite hefty using 25mm square tube with 3mm wall thickness, and three 16mm rod ends to handle the torque. The rod
ends will also allow the adjustment of track and camber. I got some 8mm and 10mm and they looked a bit too small, would've done the job but wouldn't
have lasted too long.
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Bengoh
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| posted on 24/4/02 at 03:36 PM |
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I think the rod ends are being sold for use as gear linkages, and other less strenuous applications. Does anyone know whether they'd be suitable for
use in panhard rods, or track rod ends?
Ben
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Liam
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 posted on 24/4/02 at 06:39 PM |
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Yeah I suppose you're dead right about that, Dunc, and yes the F1 wishbones were very wide at the mounts - somewhere around 15 inches if memory
serves.
I too will be using rod ends on the rear uprights and poly bushes to the chassis all round. Also will have spherical bearings on the dampers as I've
heard many a time that makes A LOT of difference over dampers with rubber bushes (assuming the rest of the suspension is not on rubber). I feel
rubber bushed dampers would make nonsense of making my suspension so comprehensively and finely adjustable.
like you I will probably go big for piece of mind - probably 5/8".
Liam
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Dunc
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| posted on 24/4/02 at 08:41 PM |
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Spherical bearings on the dampers are a must if you are planning on having anitdive/ antisquat geometry built into the suspension.
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stephen_gusterson
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| posted on 25/4/02 at 06:43 PM |
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When I bought my bearings I had a good look around.
There are huge differences in the spec and construction. And price.
For instance, the static load of a bearing decreases by 50% under a slow cyclic load, and by 75% under pulsed loads.
Also, they are rated for pulling loads. If you use em with a sideways load, they derate to about 15%.
Now, my joints are 16mm, and rated to about 1800 kg load. As they are on front wishbones, and take sideways loads, then thats 15% of 1800kg per joint.
Thats 270kg a joint. I think most load goes into bottom joints, so thats 4 joints in the front with 1 tonne load capability. If you assume 1G braking
(not a reality) then thats bordeline - with 16mm joints!
12mm joints, according to my load tables, are less than half the capability.
A racing mclaren does 200 miles i suspect on a set of what are probably hyper expensive, aircraft quality parts - not the kinda thing we use.
Its my life so I decided it was worth using bigger joints on.
atb
Steve
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Liam
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| posted on 25/4/02 at 10:13 PM |
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quote:
Also, they are rated for pulling loads. If you use em with a sideways load, they derate to about 15%.
That's why you really should (and any F1,single seater,etc will) mount the rod ends so that the bolt is vertical. i.e. the biggest loads (braking)
load the joints radially and not axially.
Of course this means your suspension travel is limited by the 15 degree or so misalignment angle of the bearing. OK for a stiff racer but pushing it
on a road car. So I guess we are forced to use them the wrong way round, in which case it does indeed make sense to go large, or even supersize if
you can afford a whole 50p more.
Liam
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stephen_gusterson
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| posted on 26/4/02 at 07:07 PM |
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I paid fecking 16 quid each for mine
and there are 12 on the car!
steve
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bass
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| posted on 28/4/02 at 05:53 PM |
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i brought 20 at £1 each 10 lh and 10 r/hand
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