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Skittish Rear End


FlowerM

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Hi, I am new to 350Z having picked up 07 GT last Saturday.

 

Mainly great car, but on bumpy roads it is very skittish at the back, seeming to move laterally several inches and effectively changing direction.

 

I suspect it is because of the tyres, which are the standard fit Bridgestone RE040 with 12,500 miles on so only a few milimetres left. Presumably Bs are designed for smooth Japanese roads or tracks.

 

Having used Toyo Proxes T1-Rs on a GTR33 I was thinking of changing to them, but would be obliged if anybody could advise on cause of the problem and the choice of tyre.

 

Thanks for any help.

Mike F

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Hi, I am new to 350Z having picked up 07 GT last Saturday.

 

Mainly great car, but on bumpy roads it is very skittish at the back, seeming to move laterally several inches and effectively changing direction.

 

I suspect it is because of the tyres, which are the standard fit Bridgestone RE040 with 12,500 miles on so only a few milimetres left. Presumably Bs are designed for smooth Japanese roads or tracks.

 

Having used Toyo Proxes T1-Rs on a GTR33 I was thinking of changing to them, but would be obliged if anybody could advise on cause of the problem and the choice of tyre.

 

Thanks for any help.

Mike F

 

 

:welcome: to the forum

 

The Bridgestones are not one of the best tyres for the zed and they certainly sound like your problem with the symptoms you describe. Gone to Toyo T1-Rs on mine and noticed a big improvement. :)

 

Another tyre to consider that is popular is the Falken 452 :)

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Didn't '07s come with RE050s on? How many miles has the car done in total?

 

Worth checking your tyre pressures and alignment as well, either of those could cause the back end to feel extra lively.

 

 

Mine was registered 1st August 2007 and has done 12,500 miles. Currently fitted with RE040s all round with 34psi. Have tried reducing to 32psi all round but not noticed much difference. It is only lively when the road is bumpy, quite common in Gloucestershire, but on smooth roads it is fine, so I assumed that alignment was therefore OK.

 

Thanks for help from you all.

Mike

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Didn't '07s come with RE050s on? How many miles has the car done in total?

 

Worth checking your tyre pressures and alignment as well, either of those could cause the back end to feel extra lively.

 

 

Mine was registered 1st August 2007 and has done 12,500 miles. Currently fitted with RE040s all round with 34psi. Have tried reducing to 32psi all round but not noticed much difference. It is only lively when the road is bumpy, quite common in Gloucestershire, but on smooth roads it is fine, so I assumed that alignment was therefore OK.

 

Thanks for help from you all.

Mike

 

 

i wouldn't reduce, i'd pump them up, should be 35 psi all round. does help. ican tell when mine are dropping by just 1 or 2 psi as it handles differently. also if there is no heat in the tyres then the stones are slippery.

 

another tyre worth looking at is the vredestein ssantas, very good UHP tyre

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Also worth checking your shocks. I had an issue with mine twithcing to the side quite a bit when hitting a bump, or even on raised painted lines across the road, felt like quite a violent shift/twitch too.

 

It transpired one of the shocks wast kaput, which was causing the problem.

 

They were both replaced so as to make sure both sides were even.

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Also worth checking your shocks. I had an issue with mine twithcing to the side quite a bit when hitting a bump, or even on raised painted lines across the road, felt like quite a violent shift/twitch too.

 

It transpired one of the shocks wast kaput, which was causing the problem.

 

They were both replaced so as to make sure both sides were even.

 

 

Should shocks need replacing after only 12,500 miles though.

Mike

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:welcome:

I couldn't stand the stock 'stones. Felt really slippy, especially in wet. just couldn't get traction. Swapped for Toyo's - amazing. However the rear is very floaty on std set up in my opinion especially over fast bumpy roads. East Shore Racing advised me that the std set up is quite soft and is major casue of back end stepping out, especially over bumps. They had changed to full coilovers and the difference was absolutely amazing when I test drove theirs. ESR reckoned it was set up so well it was virtually impossible to get back end out without being completely reckless.

Coilovers will be my very next project when I have a spare grand - which might not be for quite a while !

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That is the exact same thing that was happening to me mate! I had the geometry readjusted and had the camber reduced in the rear and had them toe the rear wheels in a tiny bit.

 

No more problems with what used to feel like the rear of the car jumping a few inches side to side.

 

Hope this helps mate.

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I agree with Biscuit. Definitely 35psi, and make sure you check the pressure when the car is cold, ie not sitting in the sun even, straight out of the garage in the morning, as they'll pick up 2-3psi just sitting doing nothing in the sun quite easily, then go back down again.

 

What's the alignment like as well?? A bad alignment will really mess with the handling, as will the tyres most of us aren't fans of as previously mentioned.

 

The boys have also mentioned a few other possibilities.

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  • 2 weeks later...

Thanks to all for the welcome and for the advice.

 

I have had rear shocks replaced and rear wheel alignment checked this morning, and it is a different car. Still lively at the back, but that is OK, just what you expect and want in such a car, but not the scarry jumping across the road that the rear wheels were doing. On the concrete section of the M42 I had to slow down to 55mph it was so bad.

 

I can now start to enjoy the car as it was meant to be, and I will soon be changing the tyres, probably for Toyo Proxes T1-Rs, so should be even better then.

 

Thanks again to you all.

Mike :clap:

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Glad you got it sorted - it sounded exactly the same as the issue I had with mine. You hit a line in the road (such as the joins in the concrete section of a motorway), or those raised painted lines, and the car seemed to jump sideways about half a foot at the back.

 

It was a faulty shock on one side of mine too, had them replaced and its just like night and day. The sticky Toyos should make a further difference too. But at least you arent worried you have a serious issue anymore and you can get on with enjoying the car :thumbs:

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  • 4 months later...

As I mentioned before I had the shock absorber changed and the difference was amazing, completely different animal, very enjoyable.

 

HOWEVER - I have now had new tyres fitted, Toyo Proxes T1-R all round set at 36psi and it is not as good as with the old Bridgestones. Now done 400 miles since tyres fitted.

 

With the Bs it would understeer, but with the Ts it oversteers. Now obviously with more tread depth there would be more movement and more of a pendulum effect on turning, but at times, even in the dry it moves about a lot at the back. Not the shock absorber issue just a softer rear end I believe. One thing I have tried is to be more gentle with the steering, to allow the tyre time to move about, and that seems to help, but not always easy when you want to throw the car around a bit, and with the bad UK roads not always possible.

 

Does anybody have any ideas. I was thinking of increasing the tyre pressures but not sure how high you could go before you change the profile of the tyre tread area.

 

Thanks for any help.

Mike

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As I mentioned before I had the shock absorber changed and the difference was amazing, completely different animal, very enjoyable.

 

HOWEVER - I have now had new tyres fitted, Toyo Proxes T1-R all round set at 36psi and it is not as good as with the old Bridgestones. Now done 400 miles since tyres fitted.

 

With the Bs it would understeer, but with the Ts it oversteers. Now obviously with more tread depth there would be more movement and more of a pendulum effect on turning, but at times, even in the dry it moves about a lot at the back. Not the shock absorber issue just a softer rear end I believe. One thing I have tried is to be more gentle with the steering, to allow the tyre time to move about, and that seems to help, but not always easy when you want to throw the car around a bit, and with the bad UK roads not always possible.

 

Does anybody have any ideas. I was thinking of increasing the tyre pressures but not sure how high you could go before you change the profile of the tyre tread area.

 

 

Thanks for any help.

Mike

takes a while to bed tyre in so it is at peak performance? could be...

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Yeah, could be release agent on the tyres still. Do they look scrubbed over the whole of the tread? I hear Toyos can be very slippy when they arent yet scrubbed in. Can take 500miles or more depending on your driving style.

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my bet would be toyo's very soft sidewalls, had them on a previous car and you do get more lateral movement with them, but once your driving adjusts to them they're not to bad.

 

although not my choice of tyre these days alot of others run them on here and not really heard many complaints. the toyos dry handling wont be as good as the stones, but in the wet the toyo should out perform the stones.

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