De-dion tube fun (and a warning for folks like me)
Discussion
Well... changed the old rotting spax rear dampers on the back of the car for some new AVOs fitted with stiffer 150lb springs.
Took the car round the block, ride was beautiful, seemed great.
Took it for an extended test ride, it was going beautifully, riding well, then as the speed increased it got twitchier and twitchier form the rear, nearly binned into the scenery on a fast sweeper, felt like the from wanted to tuck under the car.
Pulled over, kicked tyres, checked wheel nuts were on properly, checked the bearings for play... nothing.
Drove home very carefully, car felt like the rear was on a skid pan, wanting to shoot out either way, noticed both rears were squealing when going straight ahead, gave me my first clue, I've somehow altered the toe.
Got home, rears were red hot (driving at 30mph), definitely a load of toe . Sure enough, got my metre rule out checked the alignment, they were toed maybe 5-10 degrees :0.
Wheels off, checked id bolted everything together right, all nuts and washers on tight. No problem.... hmmm.
Wheels on drive down the road, felt like the car wanted to kill me, like the rear was on flat tyres on ice. Got 100 yard turned around, wheels off....
AHHHHH, socking great bend in the dedion tube, which I hadn't noticed... obviously, recent work on the rear, new stiffer springs etc. had been a push too far for the fatigued tube and it bending was causing the massive toe in!
An unlucky coincidence for the new AVO dampers, which otherwise seem very good.
Anyway did a bit of research and found this fantastic thread.
http://www.blatchat.com/t.asp?id=94283&pn=1&am...
If like me you were previously blissfully unaware of de-dion failures, give yours a check... I believe I was quite lucky that I didn't bin it.
Apologies as I am sure it had been discussed before but a bit of awareness for people newer to caterhams such as myself is not a bad thing.
Took the car round the block, ride was beautiful, seemed great.
Took it for an extended test ride, it was going beautifully, riding well, then as the speed increased it got twitchier and twitchier form the rear, nearly binned into the scenery on a fast sweeper, felt like the from wanted to tuck under the car.
Pulled over, kicked tyres, checked wheel nuts were on properly, checked the bearings for play... nothing.
Drove home very carefully, car felt like the rear was on a skid pan, wanting to shoot out either way, noticed both rears were squealing when going straight ahead, gave me my first clue, I've somehow altered the toe.
Got home, rears were red hot (driving at 30mph), definitely a load of toe . Sure enough, got my metre rule out checked the alignment, they were toed maybe 5-10 degrees :0.
Wheels off, checked id bolted everything together right, all nuts and washers on tight. No problem.... hmmm.
Wheels on drive down the road, felt like the car wanted to kill me, like the rear was on flat tyres on ice. Got 100 yard turned around, wheels off....
AHHHHH, socking great bend in the dedion tube, which I hadn't noticed... obviously, recent work on the rear, new stiffer springs etc. had been a push too far for the fatigued tube and it bending was causing the massive toe in!
An unlucky coincidence for the new AVO dampers, which otherwise seem very good.
Anyway did a bit of research and found this fantastic thread.
http://www.blatchat.com/t.asp?id=94283&pn=1&am...
If like me you were previously blissfully unaware of de-dion failures, give yours a check... I believe I was quite lucky that I didn't bin it.
Apologies as I am sure it had been discussed before but a bit of awareness for people newer to caterhams such as myself is not a bad thing.
Edited by jackh707 on Monday 12th August 14:28
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