Stevethevet

Is it me or is this normal?

Just put the first 1000 miles on my STi Type UK. Have the optional 18" Prodrive 10 spoke wheels with Toyo Proxes T1-S tyres (225s).

The car seems very heavy to steer away from straight ahead and follows the camber of the road quite severely. In other words, it seems to take an inappropriate amount of effort to turn the car (almost the same feeling as when you have a flat tyre, but not as severe - tyre pressures are fine by the way).

Never experienced this with my old car (MY99 UK Turbo) but tyres were not so wide (Bridgestone Potenza 205s).

Is this just the wider tyres and more direct steering etc or could this be a problem? (almost seems as if the power steering is not working properly). I'd appreciate your comments.

(Am developing a larger right shoulder in order to stop the car pulling off to the left!!!!!!!).

Steve.

STI MAN

The steering is certainly heavier on the STi than the my01 it replaced, but I dont think that it's purely down to an extra 10mm of tread to turn.

Bearing in mind that i'm driving on manx roads which mean the car snakes all over the roads, no wonder so many people get away with drink driving, cos we all drive like we're pi$$ed

swaussie

Steve,
I have an MY02 with standard 17's and I get the same. I always seem to be fighting with the steering to keep it straight and it shows noticably under heavy breaking.

Stevethevet

Swaussie. That's interesting as I was convinced it was the 18s. My dealers STi demonstrator (on the standard 17s) does not show this behaviour at all (I took it out to try it yesterday). So is this a mechanial variation between different vehicles...........?

nom

Why not just take it to one of the cheapo places to get the tracking checked? They usually do the checking for free (presumaly with a mind that you'll get the tracking done as well ). Just for 'peace of mind'.

Stevethevet

Hi Nom.

Took it in for its first 1000 mile service yesterday actually and they checked the tracking and four wheel alignment etc then. Apparently all was AOK.

Just find it hard to believe that the rims would make such a staggering difference to the car (mine vs dealers on standard 17s). Effectively, with the tyre width being the same at 225 (between 17s and 18s) the only difference is the larger rim and slightly lower side wall (40 vs 45). However, they drive like totally different cars!

Steve.

nom

Oh well, that's it for ideas from me I'm afraid

MurrayZA

MY01---> STi 7 has a shorter steering ratio - not sure what,
but there are less turns lock to lock than a std MY01. This
might account for the difference.

russell hayward

tyre pressures ?

T5NYW

iTrader: (4)

The Sti7 has speed sensitive steering, I believe, but seems harder to turn at low speed than at high wrong way round you do have to have plenty of muscles on low speed tight bends, fighting torque steer

I believe although the Sit7 has less turns lock to lock but it's not a quicker rack than the WRX. Just reduced amount of lock due to the wider tyres (therefore turning circle is greater on STi7)IMHO

Tony

Stevethevet

Thanks folks. Tyre pressures are ok.

I'm concerned about the difference between my car and the dealers demonstrator more than anything. Maybe it is just individual variation between cars?

MurrayZA

I had my alignment checked and corrected this morning (may
be called geometry by the UK folk). This also affects the
way your car "feels" through the steering. Maybe your car's
needs to be checked ?

Stevethevet

Quick update. After having tracking, geometry etc, etc checked I decided to try the original (unused) 17s to see if it made much of a difference.

The difference is astonishing. The car behaves completely differently. The resistance to turning is much reduced and the car feels more "lively" at the front. It's actually encouraging me to drive harder and faster than on the 18s (Oh, God!!!!!).

I've only had it done this lunchtime so will reserve final judgement for a few hundred miles time but at the moment it looks like I will be sticking with the 17s.

Anyone else had this experience?

MurrayZA

I havent had that exact experience (as I only have 17"s on my car),
but what I can tell you is that on the same RR under simmilar
conditions, my OZ Super L 17's shod with SO3's gave 8 bhp less than I had achieve with the std equipment - once the gearing was
re-done, it achive a figure 1 bhp different, so the rRims and
tyres definitely affect our cars more than we think ? Just a thought.

Dave T-S

Steve
If your 17's are brand new, they will take a while to scrub in and are very skittish out of the box. We have two STi7's on original RE040's, one with 5500 miles and the other with 2200, and they have a huge amount of front end grip.

Reserve your judgement until you put at least 500 and preferably 1000 miles on the RE040's.

Stevethevet

Dave T-S.

I'm really glad you mentioned that. The car is much easier to turn in now (which was my original complaint with the 18s) but as you say the 17s do feel very skittish which I was a little concerned about.

I will do as you recommend and get some miles on them before drawing any conclusions. Overall, I think I will stick with the 17s as I much prefer the way the car responds now even with this initial skittishness which, as you say, will hopefully settle down.

johnfelstead

these new 18" wheels, what offset are they? Are they the same offset as the 17" wheels? If you have gone from OEM offset to a lower ET this will affect the handling in the way you describe.

Dave T-S

JF
The Prodrive wheel is ET46 IIRC.

Stevethevet

Hi guys. Sorry, what does this mean? I'm not familiar with this technical stuff.

Cheers Steve.

johnfelstead

this is what Mike Wood posted elsewhere.

"The latest WRX also has ET55 wheels as std but after testing we decided to carry over our existing wheels to avoid confusion. The new 18" P-FF7 wheel is ET51, mainly so that it gives us maximum tyre clearance without compromising the steering in any way. We did however protect this design so that it would clear the Brembo calipers at ET55 if necessary"

If the STi7 is the same OEM offset as the normal WRX then it sounds like the prodrive 18" wheels are running less offset, which will increase tramlining and make it more darty. If i understand what mike is saying, he is saying that the design could be manufactured in ET55 if they found the ET51 caused problems. Interesting?

If they are ET46 then !!! LOL I have ET45 on my STi5 and does that thing dart about! Its got great response, but its harder to drive than if it were on ET52.

johnfelstead

oh, these ET numbers are the measurement of how offset from the centre of the wheel looking from above the hub face is machined to. Basically, you can move a wheel inwards or outwards in relation to the suspension and body by changing this offset. This has the effect of making the wheel more or less of a lever to forces that try to move it sideways so it affects the handling. Imagine you pack a big spacer between the wheel and hub, thats makes the wheel sit out more, that makes the wheel a bigger lever for left/right movement, and vise versa. In practice its more complex than that, but you get the idea.

mutant_matt

I've gone from the OE 17" with 650 miles on them (so just about run-in) to the new Prodrive P-FF7 18" wheels with Toyo's on them, which have currently done about 400 miles.

I would say that tramlining is no better or worse from one to the other and that it is very difficult to tell them apart, performance and feel wise. I would say the steering is a lot heavier than a standard MY01 but not as firm as my old MY00 with proper Geometry, Bump Steer Mod, Eibach's and the Anti-Lift Kit.

I would say that the Geometry is way out on my car, as it was on the STi demo car I also drove and will be visiting Powerstation soon to get this sorted out. Judging by first visit to PS when my last car was 1100 miles old, the Geometry can make an amazing amount of difference. Until I've had this done, I'll reserve judgement on how my STi handles other than to say, I like firm steering, lots of feedback and an "alive" car which requires some proper input and concentration.

BTW, I don't think the car does torque steer, it's just what it feels like when the front diff is trying to find some grip

Also, as the Toyo's have more mileage on them, they are starting to give more grip and are firming up the steering feel nicely

Matt

MikeWood

Further to John's comments, the ET46 wheel when used with a Pirelli PZero Nero DOES NOT give the characteristics you are experiencing if the geometry is correct.
This sort of issue is quite common in respect of mixing different specifications. The ET46 wheel is OK if the tyre is suitable for it (like the Nero) but it could be a totally different story with a different tyre. Similarly the tyre could be OK on a different offset of wheel. It's all about testing the options and making sure it works.

Mike

russell hayward

Having my geometry done at PS tomorrow

7,000 miles and no sterring issues/uneven tyre wear so we will see if it makes any difference.

Mike, what is the recommended tyre for the 17 and 18" wheel please ?

mutant_matt

P-Zero's right Mike?

Matt

MikeWood

Russell

Did you need to ask really?

We recommend the PZero Nero in 18" but that doesn't mean that another tyre wouldn't work as well. It's all down to trying them but are most people in a position to try a tyre and get rid of them if they don't suit the car, the wheels they have, the geometry they are running, their driving style, the roads they are used on etc

Mike

russell hayward

Thanks Mike

When are we going to get the figures on the PPP ?

Dave T-S

Russell
LOL - try asking for the meaning of life instead

Dave T-S

PS - I have them and i'll tell you providing you pay for my PPP for me

johnfelstead

Can we have a list of all the tyres you have tested on this config please mike? Are you contracted to use Pirelli only on anything you sell?