TYRE Sises: Difference between 00 on 15s and 03's on 15/16s

[Anonymous]

Hi,

Just wondering. I have a 00 which came on standard 15"s, wasn't to keen on the look of them and then changed to 17"s with low profile tyres. However not sure, the car feels slightly understeery on them. i know the 03 Cars came with 15"s on front and 16" reers. Does this set up help and if so was there any other suspension up grade differences between the earlier and later versions.

Not Sure if the difference is only in my head, I only had the car about 3 weeks before I changed the wheels so maybe its just that I'm beging to exploit the car.

Also can anybody tell me how to work out correct tyre pressures. Am running 32 up front and 34 at rears. was running at 30 but ended up ruining a rear that a tyre guy told me was caused by low pressure.

[Two's Company]

When I was running Bridgestones I found 25f/30r the best compromise.

The understeer is probably due to the front tyres being overinflated.  The handbook figure is 26psi for font.  Officialfigures can be found inside the glovebox.

Hope that helps.

[Anonymous]

Are these still relevent considering I'm running on 17" rims with tyre sizes 205/40/R17

[Two's Company]

Erm no...I just need to learn to read the posts properly   s:oops: :oops: s:oops:

[markiii]

I'm not sure what to advise for pressures on teh same width tyres all round as I've never tried it.

I would say that having teh same tyre width all round is going to make teh it very easy to get the back end out though.

so be careful you don't end up in a ditch.

[kanujunkie]

i'd be finding a nice big empty car park if i were you, at first anyway

[Anonymous]

Funny I haven't noticed any oversteer at all (well unless I'm messin around in the Wet) instead I find the car a bit less pointy at the front but like I say this may be because I'm now gettin used to the cars handling. We've had torrential rain here the last two weeks and I even in that I have tons of Grip. But didn't the 00 version run on 15"s all round anyway?

[Anonymous]

Ok just noticed gapeing oversight, same radias wheels but different tyre widths though, Is this right?

[Anonymous]

'00 to '02 wheels are 15x6 front and 15x6.5 rear, tires are 185/55/15 front and 205/50/15 rear.

[aaronjb]

Ok just noticed gapeing oversight, same radias wheels but different tyre widths though, Is this right?

Yep - there's usually a width stagger from front to rear (20mm I think)

[Anonymous]

I'm guessing this is to make the front end pointier (not sure if I just made that word up!). i'm guessing thats what I'm missing on the corners. But Markiii and Kanujunkie seem to think running the same widths all around will make the car oversteer, whys that. Think they may be wrong though as the rear seems completely planted even in heavy rain.

Can anyone tell me how trye pressures are worked out.

[dieamond]

I had this problem with my S03 when they were new
195 front
225 rear

I had to use them for like 5000km to have them ok.

After 2 days on track, they are perfect  s:-D :-D s:-D

[so.simple]

I'm guessing this is to make the front end pointier (not sure if I just made that word up!). i'm guessing thats what I'm missing on the corners. But Markiii and Kanujunkie seem to think running the same widths all around will make the car oversteer, whys that. Think they may be wrong though as the rear seems completely planted even in heavy rain.

I use racing slicks with the same width on the front and on the rear whenever I take the car to a track day. I can guarantee that while the car may seem even better balanced, you will experience some violent snap oversteer if you don't understand and "respect" the car. Be prepared for that.

[dreambackup]

the stock MR-S understeers. I think you should feel a lot less understeer with wider wheels in front.

I haven't changed my wheel (stock 03) but I made some chassis upgrades and everything help handling and neutrality.

1- harder struts and springs
2- front sway bar
3- breast plate

note that the breast plate didn't take away any understeer but it makes the rear feel more attached to the rest  s:wink: :wink: s:wink:

[dieamond]

a "MR car" will always understeer at corner entry and oversteer at corner exit

this modification of balance is the trick part of MR driving

but

if you enter a corner with a speed below understeering, you'll generally exit at a speed below oversteer, and in the (small) gap between under and over, it's faster than any other car architecture : that's MR efficiency

plus, understeering allow you to use very late braking when entering the corder, which is another very good point

[Tem]

a "MR car" will always understeer at corner entry and oversteer at corner exit

I'd say that depends a lot from your setup. As an extreme example, say you put two spares at the rear and went driving, I doubt you'd see understeer at all. I believe you'd still have understeer with even tyre sizes all around, cause the nose is lighter. But it is very possible to get rid of it...

[dieamond]

you would not understeer because the rear tyres would give up very early, but this is not a livable setup

i'm speaking of a MR (MR, NSX, anything, maybe a F1 too) correctly setup, with rear tires according to its power, and front tires accorded to the weight

this car would always understeer at corner entry

[Tem]

correctly setup

this car would always understeer at corner entry

I agree with that. Just wanted to point out that you can change that, so someone doesn't get any ideas of changing the fronts to a very sticky and wide rubber and end up around some pole  s:lol: :lol: s:lol:

[dieamond]

 s:lol: :lol: s:lol:

[aaronjb]

sticky and wide rubber and end up around some pole  s:lol: :lol: s:lol:

It's very sexual in here these days....

*legs it*

[Anonymous]

So what I'm seeing is perfectly normal than? But what about tyre pressures. When the dealer fitted the alloys and tryes he left them at 30 all around, but a subsequent puncture caused by a screw in the passenger rear highlighted a problem.

When we took the wheel off we found a bump on the rubber. the trye guy thought he could repair this until he seen the the inside of the trye  and the bump had been rubbed away on the inside by the wheel rim. The guy told me this was caused by to low pressure. Im now running 32 up front 35 at the rear. but this is just a knee jerk guess.

Any suggestions considering Im running these tryes all around ( 205/ 40 R17)  s:?: :?: s:?:

[Anonymous]

Question for the group - 17s seem to be the optimum wheel size (both visually and what will fit in the wheel well), but I've never seen anyone discuss optimum wheel widths with the 17s (front to rear) or a good discussion on optimum tire sizes while running 17s.  Also, what about correct wheel offset?  Should that differ front to rear?  I think most buyers purchase a set of 4 wheels that are identical (and tires too) and maybe that's the wrong way to go.  Plus, what might be the best setup for the street, might be all wrong for the track......... except that I don't drive on a track, as I'm sure most MR2 don't.  As far as under or over steer go, almost all the OEMs set up their cars to understeer because it's the safer way to go for 99+% of drivers.  Mid or rear engine cars will oversteer, but it takes a trained driver to keep the car from ending up in a ditch.  Check out the number of bashed Porsches on  w www.wreckedexotics.com w  if you doubt me.

[dieamond]

i just bought hankook K107

front 195/40R17

rear 215/35R17

pretty good no ?

430Euros, less than 300£ on 123pneus.com

[Anonymous]

What size were the wheels?  And, how does it handle?  Do you drive just on the street? or do you imagine you're always on a track?

[kanujunkie]

i just bought hankook K107

arn't the Hankooks a background company for Toyo's???

a mate told me this but never heard it confirmed  s:? :? s:?