WHY do bigger alloys mean worse handling?

[jonb-]

I've got 18s on my Rev3 GT-S, handles great though I could do with more weight on the front wheels!. I've had Toyota do alignment and camber calibrations and checks.

I think you may be confusing roadholding with handling, they really are two different things.

And weight with downforce.

And great with awful. Just kidding.

[Gra_mr2]

ive got 225/40/18s on the rear and cusco coil overs ive neva lost a corner untill last nite in the rain i had 17 195`s on b4 n the handerlin was crap but u do need a back support its so hard it hurts ya kidneys

[Lauren]

ive got 225/40/18s on the rear and cusco coil overs ive neva lost a corner untill last nite in the rain i had 17 195`s on b4 n the handerlin was crap but u do need a back support its so hard it hurts ya kidneys

Again you are confusing handling with roadholding.

[jonb-]

ive got 225/40/18s on the rear and cusco coil overs ive neva lost a corner untill last nite in the rain i had 17 195`s on b4 n the handerlin was crap but u do need a back support its so hard it hurts ya kidneys

Again you are confusing handling with roadholding.

And English with gibberish.

Just kidding...

[luthor1]

Why would you put 225 40 18's on the rear? That's ridiculous.

215 front and AT LEAST 235's on the rear, probably 245's.

Handling is the cars ability to quickly, controllably and predictably change direction.

Grip is the point at which it will fail to maintain it's corner speed and run wide.

Low profile tyres improve the handling by speeding up the change of direction provided the centre of rotation of the wheel remains below the king-pin. However, lower profile tyres are prone to give up before higher profile tyres. Doesn't mean they won't go as fast, it's the rate of loss of grip with increased speed that people are commenting on.

Personally I HATE high profile tyres irrespective of their advantages. I run 215 40 17 front and 235 40 17 rear and they outperform the stock tyre sizes in every test I throw at them.

All IMHO of course

[tomwoodis]

Im about to change tyres and im still deliberating over what to go for.

At the moment the front of the car has 7.5j rims with 225 40 17 tyres on
The rear has 9.5j rims with 245 45 18.

Needless to say the rear tyres are well stretched on a rim of that width and i dont particularly like the way they feel, presumambly as i have very little sideways flex on a rim of that width.

The other thing i would liketo change is the profile as 40 is a little large for the rear and i keep catching my arches over bigger bumps and believe (although correct me if im wrong) that a 35 profile will:

1.) make me less inclined to catch the arches
2.) make the overal rolling radius closer to what it should be.

I have heard of the 20mm larger on the back compared to the front rule but would i be wrong to go for something like this:

225 40 17 as per existing arranegement but with new tyres on front

and

255 35 18 on the rear - slightly wider than before to account for the lower profile?

I realise this is 30mm diference front and rear but i cant really get a wider tyre on the front seeing as they are 7.5j wide

So.....

What to do?

[jonb-]

Most importantly you need a tyre that fits the rim as you've already identified.

Don't get too hung up on the stagger difference. I've tracked 225 and 245 rears with 205s at the front both times and in both sessions I wanted more REAR grip. In reality 245 to 255 is a very little different in rubber on the road as the footprint changes shape.

[Leon.]

Hi mate,

Usually, the problem going wider on the rears is that you are more prone to rubbing the arches and possibly coilover suspension depending on your offset. However seeing as you are dropping from 45 to 35 profile, you should be fine on a 255. A 30mm offset is actually what Toyota provided with the stock setup and I have it on mine with 245/215 and the balance really is very good - the extra width over stock removes understeer anyway I find.

So I think that sounds good, 225/40/18 and 255/35/18, or you could even go 35 profile on the fronts too. You might be even quicker with these fitted

[tomwoodis]

Good info, thanks guys

So I think that sounds good, 225/40/18 and 255/35/18, or you could even go 35 profile on the fronts too. You might be even quicker with these fitted

Your right I would look at getting a 35 profile on the front put the front rims are 17" not 18" like the rears so was going to stay with 40 profile on the front to avois the nose dive look

[tomwoodis]

Oh and jon i know you have had good experiences with the falken 451 tyres but was wondering if you knew what the 452's that are available were like?

Thinking of giving them a go as they can be had for a good price at the moment and in the right sizes im looking for

[jonb-]

Oh and jon i know you have had good experiences with the falken 451 tyres but was wondering if you knew what the 452's that are available were like?

Thinking of giving them a go as they can be had for a good price at the moment and in the right sizes im looking for

I've never driven on any falken so i don't knwo where you got that idea, I did do a lot of research into the FK452 to see if it's rating ( http://www.tyrereviews.co.uk/Tyre/Falken/FK452.htm ) was fair on the site and i found nothing but praise.

The best overall rated tyre for the mr2 turbo is the s02 http://www.tyrereviews.co.uk/Tyres_For/ ... -Turbo.htm ,great tyre if you have a budget.

[Leon.]

In that case then yeh, 40s on the fronts

[tomwoodis]

I've never driven on any falken so i don't knwo where you got that idea, I did do a lot of research into the FK452 to see if it's rating ( http://www.tyrereviews.co.uk/Tyre/Falken/FK452.htm ) was fair on the site and i found nothing but praise.

Sorry thats kind of what i meant. was looking at the site earlier thats why.

Will have a look at the S02's

[Harry]

Here are the rims and tyres used over years i can comment on:

Volks-Rays two piece split rims 7&8" 35or38 offset? 20mm spacers-rays
Tyres Michelin Pilot Sport 205-45-16 225-50-16
Verdict tyres grip well too bouncy rims not stable enough at speed good cornering good wet and dry
traction but not enough to
compensate for lack of stability.

Enkei RS-Evo two piece deepdish rims 7&8" 35or38 offset? 20mm spacers
Tyres Falken GRB 451 215-40-16 225-45-16
Verdict excellent, outstanding-traction, grip ,handling,braking and acceleration
Also here the smaller front radius in relation with taller rear made turn in great.

Advan-RG Gold Forged(Special type material light weight?) 7.5&8.5" offset
29&37
Tyres Falken GRB 451 225-35-17 245-35-17
Verdict very flat track feel handling very hard due to material/design of rims but one way function only
mind boggling performance 10/10 all departments.

Here is the best...

Enkei RS two piece split rims 8&9" 38&42 offset
Tyres Falken GRB 451 225-35-17 245-35-18
Perfect really really great also the smaller front radius along with the
slightly taller rears makes the ideal set up

All above with full track suspension Tein HA coilovers set 6 front 10 rear.
Tyres pressures 32-33&33-35 rear.All camber/toe laser alignment settings
along with balancing full service with print out.

Oh also on ALTEZZA RS200 BEAMS engine in front rear wheel drive with
lsd and traction control using factory 17" rims 225-45-17 Falken GRB 452
a size up from 215-45-17 again smooth quiet with directional grip 10/10.


Getting a set of ENKEI EVO TARMAC rims for track only 8" all round with
35offsets 215-40-17&245-40-17.Here i would have preferred 225-35-17
front as this is about an inch less tall than the 215-40-17 but at least the
rear is still taller with 245-40-17 with in mm. of the 245-35-18" size.
(Oh again FALKEN GRB 452)

Found SO2 Bridgestone noisy and rough good dry grip not good wet grip
not my cuppa.

See my garage for any ideas or set up spec per (ROGUE-MOTORSPORT*)

Soon as the track rims are on Jonb will be testing

[spaner]

The tyres are designed to use the sidewall to turn.

Hence when you change to big wheels (which are heavier than air) and low profile tyres you lose the amount of traction they can give at the limit. (Slip angle)

Basically it'll mean if you push your car to the limit on 18s with 35 profile tyres the grip will feel great until a point where it'll throw you off the road with no "known" warning. Whereas a greater sidewall will give you more slip angle and a much more progressive feel whilst on the limit - so you can almost "feel" when the car is going to lose grip etc.

Along with what lauren said about the camber - although if you add wheels and lower your car you really should get everything checked and adjusted accordingly.

I've got 17s on mine with a 45 profile tyre. I seem to prefer this over the 40 profile.. but haven't really ever pushed to what it is capable of, I'll wait for a track day and then comment!

u do that with the arseof ur pants

[Matty_GTS]

Mattys fun sunday on the M25...

17's all round, lightweight Enkie rims, 8j and 9j staggered.

Toyo Proxy's on front and Yoko's rear (not sure on number).

Apexi N1 99' spec coilovers... solid as hell.

Lots of surface water and serious rain... hit a big puddle at 40 and pulled a complete 360 spin!! Argh

Think i'll be putting my lowered bilsteins back on as i have had enough of the solid ride and after this it has just topped it!! lol

Anyone in the market for some coilovers? lol

[benstevensuk]

sorry to bring an old subject up again, but like you say this is a big'un.

I've always thought that as toyota spent millions on developing a car that was tested and decided that ran better on 195/55/15 and 225/50/15 tyres, that was enough for me.

im on my 4th mr2 (third turbo) and every one of them has had a different setup when i bought it. this latest, bought this week, has 17s (215 and 235 if my memory is right) and handles / holds very badly. hence why im loking again.

my last turbo i put 15s with new standard sized tyres. it was amazing. and id stick with it. but some of you are saying you've been getting really good results with various other setups.

i am a little confused about the profile number though, because ive been told that it is a percentage of the width and not a measurement (mm), which means changing the width also changes the profile anyway.

where to know? any advice on my new set?

[Leon.]

i am a little confused about the profile number though, because ive been told that it is a percentage of the width and not a measurement (mm), which means changing the width also changes the profile anyway.

Correct.

where to know? any advice on my new set?

17s won't 'handle' as well as 15s on a Mk2 MR2 due to the loss in tyre profile and progressiveness etc (assuming both are the same rolling radius). However, on the road at least, with good tyres and a good wheel alignment, you certainly shouldn't have a car which handles "very baldy". I suggest you look at tyre choice and alignment as first port of call.

After this, wear in components such as balljoints, topmounts, struts, bearings, track rods ends etc can affect handling so something to look at if good tyres and alignment don't improve things.

[Tarmaxx]

I have a 1991 SW20 on standard 14s (for the minute) and a few years back I had a 1990 version of the same car (only not a T-Bar)

I noticed earlier that someone mentioned the Toyota engineers being paid a lot of money to ge the handling spot on, which is correct in general but missed one point:

Although the MR2 is designed as a sports car the target market included a large number of "middle-aged-wives-of-rich-men" excuse my obvious generalisation. This meant that the handling was "softened" up to make it more controllable, one of the things that they did was put 185 tyres on the front and 205s on the back, making the car understeer a LONG time before it oversteers as understeer is more controllable to a relative novice.

The new one I have has had 205s fitted front and rear and the handling is noticably more enjoyable, a little like a go-kart. It still understeers before it oversteers but the margin is greatly reduced. I found that I could put it into a corner a lot harder than the old one without the "oops I am going straight on" moment. Ok there is less time to compensate for oversteer, but to someone who is fairly experienced at handling these things that isnt too much of a problem!!

In my workshop I also have a set of 17" Lexus wheels which I want to try. I know that it will make the handling a little less progressive but I think the initial increase of rubber-on-tarmac will improve the handling over the current set-up, then it is just a matter of carefully finding the limit so that it doesnt catch me out later... and yeah.. the 17s look a LOT nicer than the 14s

[gts 400]

Well think we all need to gather for handling set up day.....? so many factors, so many different cars...? i've had two mark2's three suspensions, four or five wheel types and s~~t loads of other stuff!

16's were good 17's changed things a lot and lowering car can mess up set up! first thing you need to do is get yourself down to wheels inmotion and talk to tony and get the camber and the car set up properly!

i run 215/40/17 front and 245/35/17 rear on rota slip stream lightweight wheels with tein super street and the edfc + trd anti roll bars and strut bars all round! it's not to harsh on bumps and handles well, but you do have to catch it sometimes!

When it was on 16's wheels with TRD adjustable rear shocks and standard front shocks with lowering springs all round it was decked and amazing!like a go kart!

but it depends on so much now the car has shed loads of power i need give to lay down power! or she spins! T1R rubber hepls grip much more than goodyear.

i have used poly bushes but to be honest did not see anything but more feed back through wheel!

it also depends on corner weight, brakes, carbon parts changing balance, t-bar roof models etc etc!!

you can really chase your tail with this! as i said above if we could come together and try other peoples cars we could all pick the set up we liked! but i guess thats not so easy....?