Its me again..Refference tyre problem..

Hi Everyone.

About a month ago i put a post on here about the handling of my Supra since the rear tyres were changed.

I have had the car checked over and had it laser tracked and it still feeels and rides like a dog.

I am getting really frustrated with this and have decided to completley change all the tyres from the Dunlop that are on to Toyo...

This is the only thing i can think of doing and its a expensive excersise.

At the moment i have 235/45/17 on the front and 255/45/17 on the rear...The car does not feel like it has any grip or is in touch with the road..The sterring feels lose and all over the place and its hard for me to keep the car in a straight line.

My car drove like a dream untill i had new rear tyres and its the only thing i can think this problem is.

When my rear tyres were worn the car drove superb,Now with new tyres on its a joke....Someone on here pointed out to me that the rear tyre size on my car was the wrong size...255/45/17 and should be 255/40/17...Told the people who changed the tyres and they said they only changed like for like so unfortunatly i did not take any notice of what tyre size was on previous..

Its really getting me down and has been like this for 5 months now and its the only option i can think of doing,The guys at the tyre place suggested i just try changing the rear tyres to the correct size,But i have just gone right of Dunlop tyres and wanted a completly different tyre.

I really hope i have not wasted all this money and i hope when i get them fitted next week it gives me my car back as it was.

Cheers everyone for all your suggestions and help in the previous post.

Like i have said i have only had this problem since changing the tyres so any other advice would be welcomed.

I have even changed the tyre pressure as suggested down from 36 psi to 32psi all round and its still feels lose and crappy.

Sorry to hear this mate, can't think of anything to add from last time. Wouldn't have thought Dunlops would have made the handling so bad as you are finding though. Good Luck

Is it stock wheels?

Do you have any suspension upgrades, and have you checked your suspension components anti rollbars...e.t.c?

Is it a TT?

Bear in mind the supra will feel tail happy if your not used to driving it, but after 5months of ownership I'm sure you would be used to it by now

You did the right thing with your tyre pressures;)

I specialise in handling issues and suspension design and development, also in geo setup, why not leave the car with me for a couple of days and I'll tell you what's up with it, and then fix it if required?

On the Toyo front, I fitted a set of T1-R's a few months ago and they are WAY stickier than the Goodyears I had on previously. I'm getting less slides and more confidence all round.

Just out of interest what size tyres do you have on your car..Someone on these forums said i had the wrong size on the rear and when i opened the front door of the supra what he was saying was correct as there was a japanese sticker with tyre sizes on the sill.....

I got Dunlops sp sport on at the minute hardly used...

Front 235/45/zr17

Rear 255/45/zr17

I have completly gone of Dunlop and instead of going for a pair of rear Dunlops the correct size 255/40 i have opted to go straight in a change the lot to Toyo.

I know absolutly nothing about cars i just drive them,Ignorance is bliss untill you have issues like this.

I just hope that this cures the problem because its one expensive way to find out.

Are Toyo tryes any good as before this forum i had not even heard of them,I have heard from the tyre fitters that they are fitted to sporty type cars and they grip better but wear out even faster....Lol

And thanks Chris for the responce and i have sent you a direct email,Will be in touch if this fails thats for sure.

Stock is 235/45/17 front and 255/40/17 rear.

Oh and Toyo are top quality:)

Sorry what is meant by Is it stock wheels?

The car was imported from Japan,All i know was it was a dream untill the trye changes.

Its about a 1995 supra rz auto..

I have done nothing to the car whatsoever...Apart from having it serviced and changing the tyres..

Stock meaning origanal from factory. The supra came with 16" alloys or 17". The sizes I gave were the size of the tyre Toyota put on the supras with 17" wheels:)

There 17" alloy wheels mate and to my knowledge thats how it was when it left the factory.

What pressure so you use on your supra by the way if you dont mind me asking.

I am going to get these Toyo fitted tomorrow morning,I just wish i was more hopefull but i can not see this making a difference because the tyres i have on at present are not cheapo budget tyres...I only hope its because of the 255/45 on the rear which should be 255/40.

I dont know what else it can be because nothing else has changed only the tyres...What worries me is they are saying that there was 255/45 on the rear when they replaced them,Only thing i can think of is they were so worn that they felt more like 255/40....Clueless i am just trying to find a explanation...

And answering a previous post i have had the car 4 years mate and not only 5 months like you think i have..Its had originally Bridgestone tyres on when i first purchased the car and in between its had Goodyear and perrrili tyres .Had no problems with either untill these dunlop tyres .

I mean if the car drives like a dream and it comes back from a mot with new rear tyres then what else can it be.

i run 36psi on all 4tyres and never had a problem.

I use firestone za80 tyres and they are very good in the wet or dry.

What else did it have done during your last MOT?

Before you spend a load of money why not borrow all 4 wheelswith tyres off of some one else just to try?

Good luck.

Isn't there someone by you with a Supe whereby you can swap the wheels over an evening, take it out for a spin (soory I mean drive) and check if that sorts the problem before getting into more cost?

I specialise in handling issues and suspension design and development, also in geo setup, why not leave the car with me for a couple of days and I'll tell you what's up with it, and then fix it if required?

This is about the best advice you can get. If there's a problem then Chris will find it and your car will feel alot better as a result.

(usual fee applies Chris )

I have emailed Chris and i will take the car to him to check out if this tyre issue is not resolved in the next few days.

Refference the Mot...It was a straight forward Mot and they dont do anything to the car do they.It just failed on Rear tyres which i new it would as they were well worn.

Apart from the obvious regarding driving supra,like been really twitchy on the back end if you give it to much power then the car has always driven like a dream.

I mean all this issue has only reared its ugly head since the change of the tyres,Now i suppose being a realist something could have broken without my knowledge,But i can only assume at present that its the tyres that have caused the concerns.

might just be that you have a dodgey tyre fitted? I have known it happen before..... for some reason the tyre has some form of defect... such as the curing process when the tread is added didn't work right and it has affected the compound.

Or there has been an impurity fallen into the compound when being made.

Not all tyres are quality tested, only a certain number on the production line and maybe one has slipped the net.

I'm sure Chris Wilson will be able to sort you out... he'll be able to tell either way whether it is geo or chassis related or if it is tyre related.

Update..

Had new Toyo proxes T1 R Fitted today...

Front 235/45/zr17

Rear 255/40/zr17

finally my problem is cured and the car now drives like a dream once again,What a huge relief and i am well pleased as this could have turned out to be a expensive trial and error had it not worked...

Thanks all for all the help and suggestions.

Not wanting to be a harbinger of doom, but you haven't exactly gone from some Korean no name tyre to a market leader. I respectfully suggest you *MAY* have a serious geometry issue that new tyres of any brand would hide until the geo problem wore them down a bit. Hopefully you have acquired that rare beast, a sub standard tyre from a nationally known maker, but I do have my doubts...

Update..

 

Had new Toyo proxes T1 R Fitted today...

 

Front 235/45/zr17

Rear 255/40/zr17

 

finally my problem is cured and the car now drives like a dream once again,What a huge relief and i am well pleased as this could have turned out to be a expensive trial and error had it not worked...

 

Thanks all for all the help and suggestions.

Glad you got it sorted.

If in the short term the problem returns, take it to the one who knows best 'Chris Wilson'. I can meet you there and you can stop at my house while Chris is sorting it out. Free food and board.

Food for thought anyway.

Gaz

Sorry Chris i thought Toyo tyres was a good brand and many supra owners on here seem to have suggested them and used them.

If i have any trouble rest assured the car will be booked in for you to check out,But in the mean time its running fine.

Not up on the technical side of things so when you go on about geo and the rest it means nothing to me .

Would like to know what you mean by geo settings and all the rest you are going on about.

Be good if you could explain exactly what you mean and what do you do to put these right and how do you find out if they wrong in the first place.

Thanks SilverMachine i will take you up on your offer if i end up at Chris place for sure.

No worries.

Happy to help a fellow supe dude.

Chris's head is full to bursting with technical info that you or I could only achieve if we spent 30years doing advanced maths at the leading university.

Chris may not be able to explain in 'common petrol head speak' but his hands do the talking (equipped with techno tools). LOL

Gaz

I have probably missed your first thread on this, but exactly what dampers and springs do you have fitted? These can have an enormous effect on the handling of the car (Mine had RSR race springs when it came over, they were incredibly stiff - and low -and made the car very, very twitchy).

Toyo's are recommended by some, but not me I've found Goodyear Eagle F1's a great all round tyre for a daily driver and the wear is only very minor (around 12k miles all round, though the fronts do wear quicker on the inside edge)

As already mentioned, I'd highly recommend you visit Chris Wilson and have him check the car over. He's relatively close to you too.

geo - basically reffering to the geometry as in the alignment of the wheels in relation to the chassis and the drive of the rear wheels or whats called the thrust angle. This is the effective line of thrust your rear wheels make on the car.

If this is not centralised then your rear wheels will be pushing the car at an angle.

Other things such as front wheel tracking, this is to ensure your front wheels are not 'fighting' each other and can also be set up to reduce tyre wear.

Then there is castor and camber. Castor affects the self-centering of the front wheels if you were to let go of the steering wheel. Camber affects the loading of the tyre in a corner but also has a big effect on tyre wear (aswell as the toe in/out settings).

But all the above has a big effect on car handling. Always a good idea to have alignment checked every few years.

Sorry, I put that badly, I didn't mean that you have fitted a rubbish tyre, i meant you didn't have rubbish tyres before, that may have been suspect, they were a good named brand, same as the Toyos.

Thanks aj for the information and that explains it a little clearer,And thanks Chris also for the answer.Thanks everyone for there imput and help.

I am not sure Chris if you picked up on the fact that i did have the wrong size tyres on the back,I also had the car lazer tracking done which was a few degrees out on the rear.

But changing these tyres for the moment at least have made a massive difference to the handling,Also you mentioned that this could be short term ,But the dunlop 9000 i had fitted previously were crap from day 1 and felt totally unstable and twitchy.

This was not a gradual thing that happened as time went by and the tyres wore in.

What i am saying is the dunlop from day one produced a very unstable problem with how the car drove and how it felt,Putting these toyo tyres on and the correct size on the back has made the car once again the car i used to know and love.