Drewmotty Posted January 19, 2018 Report Share Posted January 19, 2018 Dont laugh.....believe it or not Ive built a career as an aerospace engineer and made it to retirement ........... All our early cars were designed for use with cross ply tyres and now that we use radials they would benefit from a bit of negative camber. Had radals been an original fitment then the chassis would have been designed with a small amount of negative built in. Given that we are only talking about pulling the suspension towers in by about 10 mm a side and the chassis is not made of anything special and is pretty flexible has any one tried tweaking it a bit and making a shorter cross tube or even an adjustable one? Has Anyone ever made a chassis with revised geometry rather than mess about modifying the top fulcrums? Just thinking out loud.....,Ill get my coat???? Quote Link to post Share on other sites
Hamish Posted January 19, 2018 Report Share Posted January 19, 2018 I think that early racers shortened the cross tube to try what you suggest. But there was no guarantee that both side were drawn in equally. There is also a method of shortening the top wishbones (tr4 ones even if fitted to a 3) Moss do replacement vertices links (-1.5 deg) Or you could buy the camber systems off the likes of Revingtons. This is basically replacing the top fulcrum with adjustable ones that you then weld to safely set the desired camber. Others more technically minded will be along in a minute to put us both right. Im just a newbie at this TR malarkey. Quote Link to post Share on other sites
Motorsport Mickey Posted January 19, 2018 Report Share Posted January 19, 2018 (edited) Nope, I'd not do that. You are inputting a continuous stress into a pretty poxy mix of box sections and then inputting another on/off stress when cornering, I think material working and then hardening and cracking alongside welds is the way that would go. Crikey these are 50 + year old chassis, have a heart, nothing wrong with shortening the top wishbones 10mm which is the way it's been done over the last 30+ years without serious problems to the chassis (that I know of anyway). If you want to adjust the rear axle you could always remove and trim the axle tubes inputting 1 degree of negative camber into them...oh and then throw away the halfshafts and use a CV or U/J system inside the tubes to deliver the drive. See all the good stuff coming out now. Mick Richards Edited January 19, 2018 by Motorsport Mickey Quote Link to post Share on other sites
Nick Jones Posted January 20, 2018 Report Share Posted January 20, 2018 People have been cambering live axles for years without bothering with UJs/CVs. Apparently most axles can handle 0.5 - 0.75º before serious wear problems set in. 2.5º even if fully floating half shafts. Seriously doubt it's worth the aggro on a road car! Nick Quote Link to post Share on other sites
BlueTR3A-5EKT Posted January 20, 2018 Report Share Posted January 20, 2018 Dont laugh.....believe it or not Ive built a career as an aerospace engineer and made it to retirement ........... All our early cars were designed for use with cross ply tyres and now that we use radials they would benefit from a bit of negative camber. Had radals been an original fitment then the chassis would have been designed with a small amount of negative built in. Given that we are only talking about pulling the suspension towers in by about 10 mm a side and the chassis is not made of anything special and is pretty flexible has any one tried tweaking it a bit and making a shorter cross tube or even an adjustable one? Has Anyone ever made a chassis with revised geometry rather than mess about modifying the top fulcrums? Just thinking out loud.....,Ill get my coat My own car runs the neg camber V posts that Moss sell - it was the test bed car in 1990. Important too - Deal with the bump steer issues by moving the outer steering track rod end pick up centres outward as far as they will go - removing disc dust shield or boring hole in drum back plate is required. Revington do a kit of new reshaped steering levers for steering box cars - they work a treat - taking away that skipping on bumpy corners. http://www.revingtontr.com/product/rtr3314k/name/steering-geometry-imp-kit-tr2-3b Cheers Peter W Quote Link to post Share on other sites
TriumphV8 Posted January 21, 2018 Report Share Posted January 21, 2018 I do not like too much negative camber because although giving theoretically higher cornering speed it is nervous on the straight. Also when turning into the corner negative gives a somewhat unpredictable reaction making it difficult to turn the steering wheel correctly. It takes some time to make a perfect circle through the corner with a single set of the steering wheel and keep it than. It needs some correction.. I have the upper wishbones adjustable with long holes and custom washers. The four connections to the frame are pretty sufficient to get all the camber and castor setups that make sense. Without problems its possible to set 3 degree negative on a lowered car what is more than required. It only needs long holes at the top wishbones and shimming the lower. I have something special because in Germany we can go as fast as we want and I have the large V8 in the TR6. TR6 gets a little nervous beyond 200 Km/h and from 230 its not easy to keep the car on one lane on the highway. From that I had to increase castor about one degree. With that the car gets more stable on the straight and turning in the wheels do a more negative camber to inside of curve. That is a pretty good remedy for roadholding for the price that the steering gets pretty heavy when entering a parking box of leaving the garage. On my 215/55 16 I limited the camber to 0.5 degree negative. More was negative on driving behaviour and also on the rear I did not do more negative. -Negative camber is for racers- The higher the tire sidewalls the more negative camber is helpfull. Also they respond better on higher air pressure. Quote Link to post Share on other sites
DaveN Posted January 23, 2018 Report Share Posted January 23, 2018 I have something special because in Germany we can go as fast as we want and I have the large V8 in the TR6. TR6 gets a little nervous beyond 200 Km/h and from 230 its not easy to keep the car on one lane on the highway. . We can go as fast as we like too........the only problem being, is getting caught! Quote Link to post Share on other sites
Graham Posted January 23, 2018 Report Share Posted January 23, 2018 We can go as fast as we like too........the only problem being, is getting caught! Pot holes permitting ! Quote Link to post Share on other sites
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