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Post by Zed. on Jul 10, 2019 22:06:22 GMT
So, anyone have any experience with a suspension bushing that is NOT poly or rubber - ie. nylon / delrin / acetal / ptfe / spherical-bearings (metal, 'Rose-Joint') I'm looking into bushing materials BUT I hate poly & would prefer to not go oem rubber (Cost!!!) I have a lathe so machining profile from material stock is no issue (except time & effort) and have some 'stock' plastics, ph/Bronze & spherical-bearings  the easy option would be nylon (or one of the many engineering plastics), - easily machined but has a 'life' and can deform. then ptfe, - bitch to machine as a thin section as it 'bends' but not too bad if thick section. self lubricated or 'slippery'. either of the above would need internal sleeve-tubes, possibility to add bronze bushings to complicate matters? as to spherical's, this is the most complicated (if using standard wishbones) as adapter-tubes would need making to suit. plus side is 'loose' suspension movement BUT gets 'rattly' when worn. spherical's would be the most expensive for initial setup costs but when worn would be cheap to replace the bearing while keeping the adapter-tubes & spacers from the initial assembly. sorta. Rich. |
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Post by wannabe on Jul 11, 2019 8:13:26 GMT
Wouldn't rose jointed suspension be basically unbearable on the road if you're driving to/from events? lol
IIRC one of the latest uber-911s has RJd suspension, but I've always thought having zero or very little rubber/poly/whatever in the system must put components at increased risk of impact stress when dealing with bomb craters potholes, speedhumps, etc.!
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Post by Zed. on Jul 11, 2019 11:14:06 GMT
Wouldn't rose jointed suspension be basically unbearable on the road if you're driving to/from events? lol IIRC one of the latest uber-911s has RJd suspension, but I've always thought having zero or very little rubber/poly/whatever in the system must put components at increased risk of impact stress when dealing with bomb craters potholes, speedhumps, etc.! I've been using rj suspension components on rallycars for years, mostly as a method of adjustbility (using 'rod-end' type joints) and a rally tarmac or gravel / forrest stage can be sorta rougher than UK roads  iIrc, Mitsubishi use a 'pretend' rubber bushing in their evo suspension, basically a spherical bearing encased in rubber to Look like standard suspension bushing (a group N cheat?) - probably done by other manufacturers as well  I admit that spherical bearings bring a measure of setup cost & also rattle (the Ohlins on my car have minimal rubber bushing on their lower mounts & slightly worn spherical / aluminium top mounts so already have 'Noise'  ) but tyres will absorb a lot of road surface issues? I'm thinking for less than £100 + my time I can re-bush my cars suspension, a little cheaper than buying OEM rubber or various poly offerings... then theres engine & diff mounts, another story (but something I'm working on ) Rich. |
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Post by wannabe on Jul 11, 2019 13:22:55 GMT
If they rattle/wear, does that mean they have some 'play'? And if so, would that 'play' create, er, 'interesting' handling while the bushes take up the slack as weight is transferred during a corner?? If you could create a set of solid bushes that work for the road for that sort of money, I'm sure you would have some potential buyers  |
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Post by Zed. on Jul 11, 2019 15:59:49 GMT
If they rattle/wear, does that mean they have some 'play'? And if so, would that 'play' create, er, 'interesting' handling while the bushes take up the slack as weight is transferred during a corner?? If you could create a set of solid bushes that work for the road for that sort of money, I'm sure you would have some potential buyers the 'play' is measured in thousandths of an inch not milimeters as to making bush-kits, unless the materials were bought in bulk & there was a definate market then I dont think it's worth the effort Rich. |
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Post by howardb66 on Jul 11, 2019 19:44:20 GMT
Check the blue book. If you change bushes it might lead up the modified class road...
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Post by dickie on Jul 11, 2019 20:10:08 GMT
Hi Zed,
You could look at delrin, its hard tough and slippery.
Machines easily and resists oil.
Not sure how expensive bar stock is as mine comes out of the scrap pile from work.
I use Delrin as engine mounts for the Austin Seven.( IL Motorsports bushes on the project car )
You have to remember that the OEM rubber is part of the overall suspension package and has to be set up with the suspension under the weight of the car.
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Post by Zed. on Jul 11, 2019 21:10:16 GMT
Check the blue book. If you change bushes it might lead up the modified class road... I'm presuming to be in road modified, especially if I get the ford sccr gearbox bit sorted  Hi Zed, You could look at delrin, its hard tough and slippery. Machines easily and resists oil. Not sure how expensive bar stock is as mine comes out of the scrap pile from work. I use Delrin as engine mounts for the Austin Seven.( IL Motorsports bushes on the project car ) You have to remember that the OEM rubber is part of the overall suspension package and has to be set up with the suspension under the weight of the car. all good points especially re. the oem rubber being part of the 'suspension' I've quickly priced Acetal / Delrin on ebay (its a lazy 'baseline' pricing, can search for cheaper later) www.ebay.co.uk/itm/White-Natural-Acetal-Delrin-Hollow-Bar-Plastic-Tube-Engineering-Plastic/17361334560440mm od, 20mm id & 1200Long (need ~ 1200mm to do most of a '5, the largest id of the wishbones 'tubes' is 40mm and the 20mm id allows for metal tube-sleeve for the bushing to run on / saves the smaller diameter of the bolt) maybe 50mmod would be a better option to machine to an exact size (& maybe a 'sholder' to stop the arm sliding down the bushing?) BUT untill I strip all the wishbones I have then I will not know their exact sizes OR condition Rich. |
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Post by wannabe on Jul 11, 2019 22:04:35 GMT
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Post by Zed. on Jul 11, 2019 22:31:09 GMT
maybe I should have proof-read my post....... although my link ran to the sizes not options Rich. |
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jimb
New Here
Posts: 27 
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Post by jimb on Jul 12, 2019 11:47:34 GMT
From the blue book, for roadgoing modified
11.7.6. For Road-going Series Production Cars bushes
may be changed for similar polymer materials but not
to spherical or similar metal joints
nb road going modified also needs an original gearbox casing. |
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Post by Zed. on Jul 12, 2019 12:02:00 GMT
From the blue book, for roadgoing modified 11.7.6. For Road-going Series Production Cars bushes may be changed for similar polymer materials but not to spherical or similar metal joints IF they can be seen  in the 5's suspension it's easy to 'hide' metal joints as they would be 'inside' a tube, also, it's possible to 'seal' with a rubber disc that could 'look' loke a rubber bushing the above is an honest comment, it's possible that some competitors use similar 'tricks' (every second counts?) but either don't speak about it OR nobody notices? - do scrutineers actually climb under the wheelarch to inspect bushings? (definately not the ones I know OR have been 'victim' to in the past ) going back a few years, I worked on a Talbot Sunbeam rallycar (one of many) and this had the 'PTS' rear axle 'bushings'... basicly these were nylon adapter tubes that fitted into the rear axle bush-tunnels and would allow a metal / spherical joint to be used. far easier articulation and the axle almost felt 'loose' with the car on axle-stands (well, supported by the sills / jacking-points!) I've always liked that 'feel' since  if i do go R/j then it's easily re-converted to a rubber bushing so not the end of the world..... then theres rack-spacers to counteract bump-steer? OR cut & re-weld the rack-mount in a higher vertical position on the crossmember to 'keep' close to the as designed 'Ackerman' angles? - another discussion & thoughts maybe Rich. |
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Post by wannabe on Jul 12, 2019 14:04:56 GMT
then theres rack-spacers to counteract bump-steer? OR cut & re-weld the rack-mount in a higher vertical position on the crossmember to 'keep' close to the as designed 'Ackerman' angles? - another discussion & thoughts maybe I've picked up a set of the rack risers from Moss - I'm not 100% sure I need them as my setup is not that low, but I believe it's slightly lower than standard and it would be nice to remove some of the kickback through the steering when under compression (hopefully...). I'll get them added when I get the replacement rack put on - another job to do  lol |
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Post by howardb66 on Jul 13, 2019 12:35:58 GMT
Zed
10.1.3. Road-Going Specialist Production, Modified Series Production Cars and Modified Specialist Production Cars must comply with K.1.6.1 or K.1.6.2
Which is all about the spec of cages, but I guess you knew that already. You also need a FHR device too...... more ££££££!
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Post by Zed. on Jul 13, 2019 23:10:50 GMT
Zed 10.1.3. Road-Going Specialist Production, Modified Series Production Cars and Modified Specialist Production Cars must comply with K.1.6.1 or K.1.6.2 Which is all about the spec of cages, but I guess you knew that already. You also need a FHR device too...... more ££££££! Nylon / PTFE it is then  Cheaper I suppose Rich. |
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) but tyres will absorb a lot of road surface issues?
lol
le sigh