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Looking at exploring my options with my shock setup. Originally i was going to put them laying horizonal towards each other. With the position and angle of the pushod suspension i would need to mount the shock about 15-20* from horizontal. So the pushrod end would be lower then the ends at the middle. This is the only way to mount them without going down into the footwell (this is for a Middy!). So il thinking of running them up the frame like the Ar-i-el At-om... just researching ideas on the bearing setup ill need to run to achieve this. My first thought is to weld a threaded stud to the frame press bearings into a rocker arm, and then drop the rocker arm on the stud...

Just looking for ideas on setting this up!

heres some thoughts on bearings so far... sizes havent been explored.
http://bearingsdirect.com/store/index.p ... ail&p=3816

One pressed into the top and one pressed into the bottom of the rocker:
http://bearingsdirect.com/store/index.p ... ail&p=3469

Thoughts? Experience? I want to go the simple non angled way but i just dont know if its possible and no im not going outboard

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2007 R1 Powered Mid Engine Street & Track Car
Build Log: viewtopic.php?t=4970

Have you checked out combined needle/ball roller bearings? for example NKIB 5901. http://medias.ina.de/medias/en!hp.ec.br/NKIB

It's a standard bearing, so most manufacturers have it in their product line.

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I used spherical bearings.

Because the rocker arm moves very little, larger ball or cylinder bearings will get pounded into the bearing race by shock loads unless they're small and/or roll more than a diameter in normal use.

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Midlana book: Build this mid-engine Locost!, http://midlana.com/stuff/book/
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Why not use large bronze bushings?

Also, the amount of movement you'll have is completely determined by the size of your rocker arm and how much wheel travel you expect. A smaller rocker with more wheel travel would probably warrant using good bearings. There is naturally less movement with less wheel travel and a larger rocker.

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+442E, SR20det, Thunderbird/Markviii IRS with clutch lsd, R1 suspension all around, Mustang II 2" drop spindles, Woodward steering rack

I used bronze bushings, I have about 2k miles and no problems yet.

These are nice but expensive.
http://www.pegasusautoracing.com/produc ... oduct=3080

Rod

Edit: Now 15K miles, no issues!

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Those are nice, but I'd rather have a inner race with a sleave between bearings to tighten up on. Thrust loads should be virtually non-existant.

A large roller (versus needle) bearing seems to be a good compromise between ball friction and plain load.

The load is spread across a greater contact area than a ball but less than a plain (bronze, plastic) bearing, with lower friction than plain but probably slightly more friction than ball.

With a single seal on each outboard side of the bearings, rapid wear from contamination shouldn't be the issue it would be for plain.

The rate of rotation caused by suspension movement would be equivalent to an rpm. Needle bearings in ohv roller rocker applications hold up well despite not actually turning a full 360 degrees. Cam profiles and spring loads can be very agressive for the size of these bearings.

A plastic bushing should rattle less than bronze. A twisting rubber oem type bushing would not rattle. It would also act as a damper. When tightened at ride height, it would resist both rebound and compression.

I don't know if you guys have this link for universal plastic bushings:

http://www.suspension.com/4-bar.htm

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On our FSAE cars we always used "nadella bearings" which is a brand name but commonly refers to a bearing with two sets of needle rollers, one for radial and one for axial loads, you would use two on each rocker.

Sorry to resurrect an older thread but I am currently trying to source out some bearings for my build and I was wondering what kind of dynamic load capacity they should have. I am using a 1/2 inch shaft (bolt) and they need to be double sealed. The ones I have found so far have a dynamic cap. around 1500-lbs. but I am not sure if that is going to be enough for the loads being placed on the rocker bearings by the rest o the car and the suspension.

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More than you would think.

The actual load really depends on the bellcrank geometry but off hand I would say 1,500 lbs is too low. That pivot can have some high forces going through it.

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-Andrew
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You can buy bronze bushings with a nice collar on them at home depot and menards in the little pull out bins by the hardware.

Figure 5G inpulse loads at the ground. However, the rocker bearing will possibly see a lot more depending upon geometry, made worse depending how stiff the shocks are adjusted. I'd go for something like 10,000 lb. load capacity bearings.

I do Not advocate using large diameter roller bearings. As I posted earlier, large ball bearings litterally won't turn more than a fraction of a revolution, so pothole impacts will hammer the bearings into the race, denting them. Either use needle bearings, bushings, or spherical bearings.

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Midlana book: Build this mid-engine Locost!, http://midlana.com/stuff/book/
Kimini book: Designing mid-engine cars using FWD drivetrains
Both available from https://www.lulu.com/

I am just going trough the selection process and the loads are quite shocking..

I got something like 25000 N (let's say 5000 pounds.? )... The shocking bit was the price of the combined needle/roller bearing combo.. and do not forget, you need two of those per crank..
I will investigate the possibility of using separate bearings... one wide needle + two side axial roller bearings for axial loads.. might be cheaper.. as is a more common kind..

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Building a single seater middy BEC with GSXR 1000 power
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I'm glad I'm not the only one trying to figure this out, I thought about using 2 spherical bearings per rocker but then I wasn't sure on how to package it up with the width of my rockers not being much. I also though about just getting some oilite bushings and running those but not sure yet. I find that it is much harder to work on the car when it is on a different continent (I'm currently doing a semester in Germany) and you can't just go measure things out real fast

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Might help but it might not, probably just keep you awake at night. ... Tapered roller load formula's are on page A31.


http://catalog.timken.com/WebProject.asp?CodeId=7.4.4.3&BookCode=tmk09flx#

I suppose this would help too

http://www.timken.com/en-us/products/Documents/BearingSpecGuide7534.pdf

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after seeing the prices for the combined bearings I decided to try using more common, two separate needle radial bearings and two needle thrust bearings.. which should give me the load rating I need..

anyway,... the whole package, that uses 16mm ID needle bearings, which when using 16x12x20 inner race is then compatible with a 12mm bolt running trough it, is about 40 mm wide... My rocker will be, if in steel, something like 24 mm wide... which leaves some space for a 5 mm wide lip seal..

pics to follow when I get the component prices and decide if it is worthwhile..

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Building a single seater middy BEC with GSXR 1000 power
build log: http://locostusa.com/forums/viewtopic.php?f=36&t=5899

day job: http://smg.photobucket.com/albums/v723/turbolimac/portfolio/