martinjohn Posted September 28, 2016 Report Share Posted September 28, 2016 Anyone got any ideas as to why my front tyres are wearing on the inside only on my TR6. Tyres are kept to the correct pressure, all wishbone bushes are ok and as far as i know the camber angles are ok. Could it be too much toe out wearing the inside of the tyre. I do notice that the steering seems quite heavy and when i brake the car has a tendency to pull to the nearside - coincidence. Have a look at the attached photo please. Quote Link to post Share on other sites
peejay4A Posted September 28, 2016 Report Share Posted September 28, 2016 (edited) Seriously bad toe out or excessive negative camber or both if all is well elsewhere. Edited September 28, 2016 by peejay4A Quote Link to post Share on other sites
Steves_TR6 Posted September 28, 2016 Report Share Posted September 28, 2016 Mine started doing that after i replaced the steering rack end ball joints. A quick reallignment at my local garage cured it. Steve Quote Link to post Share on other sites
stuart Posted September 28, 2016 Report Share Posted September 28, 2016 Definitely alignment, have the camber checked at the same time if they have the equipment. Are they both worn the same? Stuart Quote Link to post Share on other sites
martinjohn Posted September 29, 2016 Author Report Share Posted September 29, 2016 I think i will take it down to my local tyre place and have the tracking checked out, its most probably a process of elimination. I did replace the track rod ends a while back and tried to keep the original position unchanged but easier said than done. Also i am not convinced that these new poly bushes are all that they are cracked up to be. Quote Link to post Share on other sites
john.r.davies Posted September 29, 2016 Report Share Posted September 29, 2016 My mantra - the problem is the last thing you did on the car! John Quote Link to post Share on other sites
RogerH Posted September 29, 2016 Report Share Posted September 29, 2016 Hi Martin, critisise the poly bushes only after when all the geometry problems are sorted. Everybody agrees that the quality poly bushes (Super-pro etc) are very good. Where are about's are you based? Roger Quote Link to post Share on other sites
Clarkey Posted September 29, 2016 Report Share Posted September 29, 2016 (edited) My 1050 mile round trip to Le Mans this year did this to mine this year, only on the near side tyre, offside edge The tyre is well and truly knackered, i have had a good look around the suspension no signs of any nasty cracks around the chassis mounts but there is a lot of movement in the old bushes, so all new polybushes ordered and then off to get the tracking sorted. I did try to post video of the wear in the bushes but its not allowed in this forum Looks like there will be some more grown up word being used in the garage soon. Edited September 29, 2016 by Clarkey Quote Link to post Share on other sites
Peter Cobbold Posted September 29, 2016 Report Share Posted September 29, 2016 My 1050 mile round trip to Le Mans this year did this to mine this year, only on the near side tyre, offside edge The tyre is well and truly knackered, i have had a good look around the suspension no signs of any nasty cracks around the chassis mounts but there is a lot of movement in the old bushes, so all new polybushes ordered and then of to get the tracking sorted. I did try to post video of the wear in the bushes but its not allowed in this forum Looks like there will be some more grown up word being used in the garage soon. Martin, Yes wear on one tyre points to a supension fault on that side. Weak/rotten rubber lower w/b bushes tend to allow the tyre to sit back and wear the inner edge ( by toeing out) . Your wear looks like the tyre is being forced into a toed-in position that cannot be equalised across the rack with the other side tyre. Look for wrong angle of the upright, maybe upper wishbones fitted wrong, that then alters the castor trail. Does the steering tend to pull to the left ? Peter Quote Link to post Share on other sites
Clarkey Posted September 29, 2016 Report Share Posted September 29, 2016 Martin, Yes wear on one tyre points to a supension fault on that side. Weak/rotten rubber lower w/b bushes tend to allow the tyre to sit back and wear the inner edge ( by toeing out) . Your wear looks like the tyre is being forced into a toed-in position that cannot be equalised across the rack with the other side tyre. Look for wrong angle of the upright, maybe upper wishbones fitted wrong, that then alters the castor trail. Does the steering tend to pull to the left ? Peter Hi Peter If i could show the video you would see the wear on the the bushes and no it does run true when on the road . No signs of this issue before Le Mans also the car had been through the MOT just before. Quote Link to post Share on other sites
Andy Moltu Posted September 29, 2016 Report Share Posted September 29, 2016 Unless there is obvious play the likelihood it's going to be excess toe out or excess negative camber. Camber is unlikely to change unless you have put in extra shims on the bottom or had the top wishbone off and reversed it. The thing you have changed are the track rod ends so the tracking has to be the first port of call as putting back track rod ends the same place they came from is just a way of getting them "roughly right" so you can drive to somewhere to check them properly (& never a substitute for proper settling afterwards.) Toe out will tend to make the car oversteer & pulling under braking could jist be a reflection of that as the n/s wheel follows the camber of the road or the oversteer is highlighting brake imbalance. Quote Link to post Share on other sites
martinjohn Posted September 29, 2016 Author Report Share Posted September 29, 2016 Well at the moment with all of the questions and answers i do think i have to take Mr Spocks logical approach and that is to get the tracking looked at. Its true to say that generally nine times out of ten it is the last thing that one replaces that upsets the balance. Regarding poly bushes versus conventional rubber bushes is a contentious issue as they both work but in different manners, I guess you ether love or hate them. One of the great joys of driving a car like the TR6 is when everything is running smoothly, the fact that I am scrubbing tyres out makes it less attractive and then of course there is the cost. Next stop will certainly be the tyre shop. To some degree I find it slightly disconcerting when most of the staff at the tyre shop are a lot younger than the car itself using modern equipment that either cant be used on old cars or nobody knows what the camber angles or toe in/out should be. Martin Quote Link to post Share on other sites
Motorsport Mickey Posted September 29, 2016 Report Share Posted September 29, 2016 Oh...and don't let the youngsters at the tyre firm tell you to put your new tyres on the front,. swap the rears onto the front and replace with new tyres on the rear. Mick Richards Quote Link to post Share on other sites
Peter Cobbold Posted September 29, 2016 Report Share Posted September 29, 2016 (edited) Well at the moment with all of the questions and answers i do think i have to take Mr Spocks logical approach and that is to get the tracking looked at. Its true to say that generally nine times out of ten it is the last thing that one replaces that upsets the balance. Regarding poly bushes versus conventional rubber bushes is a contentious issue as they both work but in different manners, I guess you ether love or hate them. One of the great joys of driving a car like the TR6 is when everything is running smoothly, the fact that I am scrubbing tyres out makes it less attractive and then of course there is the cost. Next stop will certainly be the tyre shop. To some degree I find it slightly disconcerting when most of the staff at the tyre shop are a lot younger than the car itself using modern equipment that either cant be used on old cars or nobody knows what the camber angles or toe in/out should be. Martin Martin, Not difficult to rig up a simple trammel bar to do the toe-in at home: https://enderw88.wordpress.com/2008/12/05/diy-front-end-alignment-make-the-trammel-bar/ Plumb line for camber. All done on a level surface. Castor is not adjustable. Standard settings are here: http://vintage.mitchell1.com/PClubData/chassis/chis73/V2I738042.pdf Peter Edited September 29, 2016 by Peter Cobbold Quote Link to post Share on other sites
martinjohn Posted October 1, 2016 Author Report Share Posted October 1, 2016 Thanks Peter I will print off the charts that you attached and give a copy to the tyre shop. Regarding the camber ,i bought a magnetic angle finder some time ago and will use that to check the camber, i will also check the top wishbone pivot to make sure that they (on both n/s and off/s) are the right way around. Regards Martin Quote Link to post Share on other sites
Peter Cobbold Posted October 1, 2016 Report Share Posted October 1, 2016 Martin, Mine are the wrong way round as I find a bit of negative camber works a treat to reduce understeer in hard cornering. Peter Quote Link to post Share on other sites
martinjohn Posted October 1, 2016 Author Report Share Posted October 1, 2016 Interesting chart from Peter showing the front wheel camber angles, it does not show a minus sign. I have attached a chart from my intereurope workshop manual that states the camber angle as 1/4 deg negative +/-1/2 deg. If its 1/4 deg negative this means that the top of the tyre is leaning inwards to the body (this is with 68 kg in each front seat). If we apply the plus 1/2 deg then this must mean the total neg camber could be 3/4 deg. If we apply the minus 1/2 deg then theoretically the neg turns into a positive camber by 1/4 deg. Confusing to say the least. The best thing to do is to load up the front seats apply my angle finder and set the camber angle to 1/4 deg neg if possible. Quote Link to post Share on other sites
Motorsport Mickey Posted October 1, 2016 Report Share Posted October 1, 2016 Martin, it's not a watch, Bang 1/2 deg negative onto each wheel, don't bother with the 68kg on each wheel (they were made with an anticipated 70kg "fat" Uk driver and passenger anyway). As long as the wishbones top and bottom are the correct items and fitted the correct way around run it down to tracking shop and see what they get when setting it up. Mick Richards Quote Link to post Share on other sites
martinjohn Posted October 2, 2016 Author Report Share Posted October 2, 2016 Thanks Mick Anything for an easy life , ill stick 1/2 deg on each wheel and then take down to the tyre shop. Martin Quote Link to post Share on other sites
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.