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Plastic Balls in Bearings?

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Chris Trice26/02/2019 19:58:56
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Presumably because of the corrosion steel bearings would suffer in close contact with sea water. Plastic bearings are more than capable in non dimension critical situations.

Chris Trice26/02/2019 20:06:29
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Back in my car restoration days, I used to specialise in Triumph sports cars and the lower front bronze trunnions of the Herald/Vitesse/Spitfire/GT6 cars, that carried all the weight of the front of the car, had simple plastic bushes shaped like top hats about 11/16" OD and 9/16" I.D. with a steel sleeve inside that. Yes, they wore eventually but they were easy to fix and obviously deemed up to the job.

Edited By Chris Trice on 26/02/2019 20:07:33

Howard Lewis27/02/2019 17:07:00
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Following the comment from Chris, about suspension bushes.

In the 70s, Leyland Leopard buses and coaches with Dunlop air suspension, used two Glacier DU top hat bushes for the each of the shackle pins on the taper leaf spring which acted as radius arms to locate the axles.

The wear was not on the circular part of the bush, thanks to the automatic chassis lubrication, but on the side face (Brim of the Top Hat ) The side play on the front axle would eventually reach the point where there was wheel wobble ( presumably caused by the castor angle fighting the misaligned wheels ) One extreme case despite locking one's arms and shoulders, shook the powered doors open. A certain Vehicle Off Road until new bushes had been fitted.

A quick and nasty short term fix was to shim the side play with a large washer, to keep the vehicle running until the new bushes arrived, and could be fitted,;usually next day

Howard.

Excess word deleted

Edited By Howard Lewis on 27/02/2019 17:08:01

Jon Lawes27/02/2019 17:12:41
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Posted by Chris Trice on 26/02/2019 20:06:29:

Back in my car restoration days, I used to specialise in Triumph sports cars and the lower front bronze trunnions of the Herald/Vitesse/Spitfire/GT6 cars, that carried all the weight of the front of the car, had simple plastic bushes shaped like top hats about 11/16" OD and 9/16" I.D. with a steel sleeve inside that. Yes, they wore eventually but they were easy to fix and obviously deemed up to the job.

Edited By Chris Trice on 26/02/2019 20:07:33

Funnily enough I'm about to look at a solution to the trunnion design on my GT6. The high kerbs at some circuits does give it all quite a beating and someday I suspect a trunnion will make a bid for freedom. I see some based on a Caterham design are knocking around but I really would like a better solution. I could be tempted to start from scratch with rose joints.

Chris Trice27/02/2019 18:55:16
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Rose joints are great for racing but they tend to wear quickly. All the exotic kit cars like GT40 replicas use them but they wear badly and make the car a bit of a bone shaker on the road. Actually the Triumph front wishbone suspension units were very highly thought of. Lotus used them on their early Elans. The secret is to keep the threads on the bottom of the trunnion well lubricated. Better not to talk bout the rear end unless you have the rubber doughnut rear suspension.

Ian P27/02/2019 20:07:51
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Posted by Chris Trice on 27/02/2019 18:55:16:

Rose joints are great for racing but they tend to wear quickly. All the exotic kit cars like GT40 replicas use them but they wear badly and make the car a bit of a bone shaker on the road. Actually the Triumph front wishbone suspension units were very highly thought of. Lotus used them on their early Elans. The secret is to keep the threads on the bottom of the trunnion well lubricated. Better not to talk bout the rear end unless you have the rubber doughnut rear suspension.

'Better not to talk bout the rear end unless you have the rubber doughnut rear suspension.'

Why?

Ian P

Chris Trice27/02/2019 20:33:26
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Transverse leaf spring and a tendency for the rear wheels to tuck under. The system was tweaked to make it slightly better on later cars but still somewhat tail happy in the wet going around roundabouts. The rubber doughnut version used a lower wishbone rear rather than letting the axle shafts take the strain.

Chris Trice27/02/2019 20:41:40
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wheels-tucking-under.jpg

...... together with a sudden loss of grip at the rear end as the axles swing under the car pivoting at the UJ at the differential. There is no slow transition. It tends to go from grip to no grip very quickly.

Howard Lewis28/02/2019 16:20:24
3608 forum posts
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Closing the throttle, or braking, when cornering on any swing axle car i( such as the original VW Beetle, Triumph or Skoda 100 Series) will cause the rear wheel to tuck under. This usually precedes a visit to the the local countryside!

As Chris says, the transition from safe to Whoops! is pretty rapid, and not to be encouraged.

Howard

Ian P28/02/2019 16:41:17
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I thought you were referring to the Elan suspension (Doughnuts are in the drive train and not part the suspension). I got my Elan (I still have it) in the 60s and had two acquaintances with Spitfires, one of whom manage to flip his first car over on two occassions (on the same bend on the same road!) and then flipped his replacement car, but in a different place!

Ian P

Neil Wyatt28/02/2019 17:04:28
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I think most early Lotuses were 'bitsas'; the Esprit used Opel Ascona/Manta front suspension although I'd hesitate to call one a glorified Cavalier

Neil

<edit - added early!>

Edited By Neil Wyatt on 28/02/2019 17:04:56

duncan webster28/02/2019 20:39:14
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2795 forum posts
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Posted by Chris Trice on 27/02/2019 20:41:40:

wheels-tucking-under.jpg

...... together with a sudden loss of grip at the rear end as the axles swing under the car pivoting at the UJ at the differential. There is no slow transition. It tends to go from grip to no grip very quickly.

duncan webster28/02/2019 20:42:18
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Brings back memories of a certain not very popular teacher who had a Triumph Spitfire. Provided he had parked out of sight of the staff room we would lift the back end up and watch the wheels tuck in. Two or three big strong lads could easily lift the back end off the ground.

John McNamara01/03/2019 06:10:33
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When I was a lad one popular sport was carrying a small parked car up a set of steps and leaving it high and dry on a landing. Hmmm.......

Regards
John

John McNamara01/03/2019 06:10:44
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The double post bug got me...

Edited By John McNamara on 01/03/2019 06:11:34

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