I'm intending to put my front shocks inboard (for a few reasons) and am now wondering about bearing choices for the rockers. My build is mid-engined but this would apply to a "normal" Locost as well.

I've looked at several examples of inboards on the net and there's a variety of solutions. Is there any good reason why I can't just use PU bushes, the same as in the wishbone pivots?

This is attractive because:
- I already have some
- It's cheap to get more

My reasoning is that the PU bushes actually rotate on the crush tube, rather than distort like a metalastic bush, and the amount of motion is quite similar to the wishbones.

If this is a terrible idea, please tell me why and suggest an economically sensible alternative

Thanks in advance,

Dominic

although i have never taken them apart to examine them, my F27 has metro radius arm bushes pressed into a suitable sized tube, i think it is the redius arm repair kit and you need 2 per side (1 for each side of the rocking arm) so 4 kits in all.

Mine has done plenty miles and there is no wear on them yet.

Hope thats some help to you, sorry i cant give price info.

Hi Dominic

The early Strikers and fury's use to use poly bushes and tube, but it can sieze if not properly maintained

They now use needle roller bearings, have a look at :- http://www.thekitcarworkshop.co.uk/Parts.html
A bit pricey but has been proven on the track

Hope this helps

Adrian

I have bronze oil impregnated bushes on mine....very cheap, very easy to do, should be long lasting...

Hardened steel sleeves and needle roller bearings would be the belts and braces/most expensive route to take.
Alan's bronze bushes are a sound idea (as always from Alan). Oilite bushings spring to mind, as do Vesconite bushings.
Vesconite are in Victoria, Australia, so should be easy for you (Geko) to purchase. I'm not sure if they have a web site, but you can call them on (03)9796 4089.
From their catalogue:
"Replaces and outperforms: phosphor-bronze, white metal, oil filled porous bushes, steel and carbon, asbestos laminates, Nylon, HDPE, PTFE".
Tis goodly stuff, is easily machined, and comes in a tonne of sizes, or they'll even machine to your specs.

Col, thanks for the info although, being in Australia, I've got no idea what a Metro radius arm bush looks like and whether there's any easily available local equivalent.

Adrian, I've noted down the Striker methodology but, as Rorty says, needle rollers etc is hardly locost.

Alan, I had looked already at your design. The concern for me is to come up with something I can do with the absolute bare minimum of machining.

Rorty, thank you very much for your detailed reply. Veso do indeed have a web site and the product looks like a very good solution. Looking at their product list, there's a 36x22x90 bush that looks like it would be a good press fit into a piece of 32NB medium weight pipe (42.4x36). This is the goal - something that I can basically bolt together with the bare minimum of machining.

Thanks again to all for your replies,

Dominic

quote:

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Originally posted by Rorty......
Alan's bronze bushes are a sound idea (as always from Alan). Oilite bushings spring to mind...............

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Late to the party as usual.

My method required no machining either, some off-the-shelf oilite bushings (Ace Hardware) with flanges, some grade 8 bolts with nylock nuts, a drill press... Just used some of Alan's bright ideas and re-purposed them. No idea where he lifted them from...

Graber

I have been thinking about making an inboard system for the rear of the IRS locost chasy. Why because I thought it might be interesting and teach me a lot I also saw that some one has done a similar thing at the front using bike shocks. How do you go about sizing the rockers? And designing the lay out can any one-recommend a good web sight or other information.

Edited to add I think from looking at the picture that it was sgrabers front end with the inboard shocks that got me interested in the idea after having a look at some pics

[Edited on 10/2/04 by ceebmoj]

Bike shocks thread....

http://locostbuilders.co.uk/viewthread.php?tid=10705

Because the loads on these bushes are really high the rear trailling arm bearings from a mini or metro would be the most suitable for the job .