Same sized tyres all around

[Tem]

I figured this might be worth a new thread entitled just for this.  s8) s8)

Here's my experience. I got to run on "streetable slicks" earlier this summer, which were from friends tracktoy and thus all the same size, 205/50/15. I run them on a parking lot with a track made of cones, so no major damage done even if I lose it and a good chance to really push them.

My first thought, after getting some heat into them, was that they grip like dried poop in your pants.  s:lol: :lol: s:lol:  Anyway, after getting a bit more familiar with the grip, I first felt that the same sized tyres work great. The front grips like never before and I get a nice little oversteer, just the way I like it. I've always liked oversteer anyway.

And then it happens, in a fastish corner. The car just snaps off without any warning and spins around and around close to dozen times.  s:shock: :shock: s:shock:  I didn't even realize what I had done wrong, was just glad it was on a parking lot. After that all goes fine for a while again and I'm enjoying the nice oversteer till SNAP...out of nowhere again. And again, I have no idea why. No sudden steering movement, not touching the brakes, not lifting the throttle, still can't figure it out. Maybe a bump on the surface or sand or...who knows, I don't.

I did play with them after that, but took it a lot slower and decided I'll never run same sized tyres on street. It's just dangerous, if you're ever on the edge of grip. And even if you don't plan to be there, it wouldn't be the first time there's dirt, sand, oil or whatever on the road.  s:? :? s:?

[Anonymous]

I picked up a spare set of standard wheels from a breakers that were fitted with the same size tyres all round. I guess Tem's experience explains why the car was in the breakers in the first place!

[enid_b]

perhaps u shud rename the thread tem, as

WHY NOT TO USE SAME WIDTH TYRES

made good reading, and only hope that recent posters and joiners get chance to read it before it costs money or injury.

carry on the good test pilot work, sounds like your parking lot could be the place for....

"i wonder what happens when i do this...." kinda questions


E

[Tem]

carry on the good test pilot work, sounds like your parking lot could be the place for....

"i wonder what happens when i do this...." kinda questions

It would be.  s:lol: :lol: s:lol:  It's not normally open for that kind of use though, so can't really just go there and have a go.  s:? :? s:?

[Anonymous]

Im not sure I agree - there are more factors at play than just size when it comes to grip and balance.

Currently running 15" Yoko Advan 195's all round on early model suspension. No mods. 8000 trouble free miles, driven hard on road, no spins, three trackdays.

Handling assessed by Jonny of Bookatrack and concluded to be safe for a novice like me, and also a friend who has a habit of crashing. No wet trackdays yet though, which may be a different matter and again hope to have wet handling assessed if possible.

By contrast, the Goodyear tyres fitted when I bought the car were in the normal sizes, but much more horrid, snappy, and likely to put you in the wall.

[Anonymous]

You're a brave person, that's all I'll say. I tried same size all round for about 40 miles, and swore I'd NEVER do it again. Way too unpredictable for my taste, especially when booting it.

[markiii]

well if all the posts on here don't convince you fair enough

so whats your next car going to be?

[loadswine]

If I understand the principles correctly, its not so much about the grip levels available so much as the snap oversteer behaviour when it does go.
That is what catches people out with this configuration and history has shown it isn't a myth.

[Tem]

If I understand the principles correctly, its not so much about the grip levels available so much as the snap oversteer behaviour when it does go.

That was my experience with it. First it feels great and predictable, then it bites you.

If you don't go near the limit, you could be fine. Not trying to judge anyones personal skills, but maybe a novice is staying away from the limit and will be fine? But no one will be a novice forever. Not in a car like this, which practically screams "find my limits" all the time.  s:twisted: :twisted: s:twisted:  

That is what catches people out with this configuration and history has shown it isn't a myth.

Yeah, sure seems to be a great way to crash the car.  s:? :? s:?

[edward.carter]

Currently running 15" Yoko Advan 195's all round

195's on the back, i loose traction in the wet with the standard 205's
195's... that is brave. Well good luck

[firepower]

the reason for fitting narrower front tyres is to provide early warning that you are approaching the limits of the grip and you feel this through the steering wheel as the front starts to push wide which is preferable to the rear snapping out, with same tyres all round no warning  s:shock: :shock: s:shock:

[Anonymous]

I tried same size all round for about 40 miles, and swore I'd NEVER do it again. Way too unpredictable for my taste, especially when booting it.

As I say, I've done 8000 miles so far without drama, most of which have been 3 hour runs from north wales to london or back on a-roads, middle of the night, often damp or wet, in a "press on" fashion.

If you don't go near the limit, you could be fine. Not trying to judge anyones personal skills, but maybe a novice is staying away from the limit and will be fine? But no one will be a novice forever. Not in a car like this, which practically screams "find my limits" all the time.

3 trackdays with 3 different drivers of various ability. A complete beginner, myself, and Jonny. All found it very forgiving. Gives the impression it feels unstable in high speed corners, probably a result more of the soft std suspension, but winding off a little lock is all it needs.

If I understand the principles correctly, its not so much about the grip levels available so much as the snap oversteer behaviour when it does go.

Actually I would have thought that narrower tyres at rear are less likely to snap out on you, and more likely to start to slide early on.  On the mystery Goodyear tyre, 205 at back, is only time I've had it snap off in the other direction. Fortunatly, was on track, ran across dirt, fitted Advans a few hours later and difference/improvement was astounding.

195's on the back, i loose traction in the wet with the standard 205's

Traction isn't bad at all, no oversteery moments, but I have been cautious in the wet. Once had an AO32R shod westfield, so as far as traction goes MR2 is going to trounce that regardless of tyre and conditions.

Jonny concluded there was not enough power to get the back out in the dry even with the narrower tyres.  Engine light keeps coming on, despite only 30000 miles, so if it turns out its due to fail would love the Celica engine and hope to get the back out on demand then. I presume this may horrify some of you on this board, but not used to a RWD car where you cant nail the throttle at will for sideways action.

the reason for fitting narrower front tyres is to provide early warning that you are approaching the limits of the grip and you feel this through the steering wheel as the front starts to push wide which is preferable to the rear snapping out, with same tyres all round no warning

Have had next to no understeer in this car, which I am led to believe is a trait of the car. That's on both the wider Goodyear and current Advans.

One thing I will say is that I am still running the pressures at 26F,32R as per the toyota manual, I have not lowered them as it seems you should for the Advan tyre.  From reading this board it seems common to knock the front down a PSI to reduce understeer, but as I'm experiencing little understeer as is.  I may reduce 1 or 2 PSI all round, as I feel overall grip levels fall slightly shy of what I was expecting, though maybe this is simply the perception of such progressive tyres. Seem to be wearing evenly so far though - maybe need a pyrometer to optimise this!

Should point out, only reason am running 195's at rear is because car is an early model on 15's at rear with original suspension, and Advans not available in 205 for 15" wheels. So far, it's working out well, and see no reason to pop 16" on just for wider rubber.

Anyway, link to a photo proving it does go round corners, sideways (lap after lap as it happens), without crashing! :

 m http://batpics.myphotos.cc/e/660/jules/ ... 478_Fs.jpg m

[markiii]

Jonny concluded there was not enough power to get the back out in the dry even with the narrower tyres. Engine light keeps coming on, despite only 30000 miles, so if it turns out its due to fail would love the Celica engine and hope to get the back out on demand then. I presume this may horrify some of you on this board, but not used to a RWD car where you cant nail the throttle at will for sideways action.

I'm just not buying that, since I and many other can get the arse out at will n/a on 205 rears. Hell I've even done it on Stus with 225 on teh rear


likewise he agreed MPHs was lethal on 195 all round when we tried it an Anglesey


of course teh opposite of teh previous post copuld also be true, that rather than a novice going slowly your actually an expert  :-) :-) :-)

either way it's a risk that is just daft to take when you don'thave too.

Which model Advan by the way?

[Anonymous]

I'm just not buying that, since I and many other can get the arse out at will n/a on 205 rears. Hell I've even done it on Stus with 225 on the rear

Maybe in the wet.  In bone dry needed extreme provacation around the hairpin at anglesey, 1st gear, scandinavian flick, floored throttle, etc.  Probably a goer on suitable roundabout, but going in too fast and lifting off seems to be far easier way to do it, but then thats a shame in a RWD car.

either way it's a risk that is just daft to take when you don'thave too.

Believe me, I was very nervous about having them fitted, but it was Jonnys idea, and both of us concluded some experimental laps would be wise. But there was actually an improvement at the rear end, it entering and coming out of a state of oversteer much more gracefully, whereas before it would snap back quite violently. I was particulary aware of this because I had a broken collarbone at the time, and was able to scientifically measure this via the medium of pain.  s;) s;)

I finally concluded they were safe when I asked him to try entering Anglesey's School corner, too fast, turning in quite violently, as perhaps, a beginner would or a clueless idiot like myself might. Despite successive attempts to tempt it to bite back it never did, hinting at near disaster but again, nothing more than winding off lock was required to stabalise things once more.

I want him or somebody of similar ability to repeat this exercise in the wet, however!  s;) s;)

What I would say is that I think it's a nature of these tyres they behave poorly in very cold conditions, as did the AO32R's on the westfield, but I guess it's all a case of warming them up on track, which is why posts on this board suggest they are a poorer road tyres amongst other reasons.

Which model Advan by the way?

Elise jobbies: Neova LTS.

[markiii]

hmm Neovas will be better as they give a lot of qwarning when they are going, however the comment about getting the arse out with 225, was on a warnm sunny dry day on teh road   s:D s:D

[juansolo]

I was there as the discussions were going on as to whether this was a daft idea or not, hence the J5/Jules experimentage.  

On the fat rears it has too much grip at the back IMO.  You haven't got the power to kick it out so you have to result to lifting/trail braking to get some sideways action regardless.  This is also reflected in the fact that I used to run the rears hard and fronts soft to make it fun.  Either way it was worth a punt and it works ok on the Neovas as he's said.

What I would also add is that in the wet the width of a tyre wont have as much impact as the water dissipation properties of the tread and the compound of the rubber.  Indeed a greater surface area can be a bad thing in low grip situations...

The Neovas in question are going to give you plenty of warning, it's the nature of the tyre.  The semi-slicks won't because of their nature.  Too much emphasis in this thread is being put on the width being the only factor which is nonsense.  Different tyre, different properties, different operating temperatures, etc.

[markiii]

theres also a huge difference between whats good for hanging the arse out on a track and what is going to be sensible for your average Joe on teh road.

to infer that just because this worked with neovas on track means don't worry about your tyre stagger on the road is both irresponsible and dangerous (Juan, not aimed at you particularly)

[juansolo]

Though on a track you will find out far more about the nature of a tyre than you ever will on a road and it'll give good idea how it's going to behave, certainly when it's cold on the first couple of laps.  Also bear in mind that this was tested by people who aren't going to let their web developer go out there on the road and kill themselves with a dangerous tyre combo...

[markiii]

and you've got a lot more space on track to recover it. if and when it all goes pearshaped.

[kanujunkie]

can you lot stop talking about trackdays, i'm getting an urge!

[juansolo]

and you've got a lot more space on track to recover it. if and when it all goes pearshaped.

Which is the same regardless of what rubber you run.  I would argue that slapping wider and bigger rims on all round as people commonly do, is equally as risky as you're dramatically altering the way the car is going to handle and more than likely not for the better.

[markiii]

agreed,

however the issue at stake is the pro/cons of the same width rubber all round.

I'm all in favour of what gives you teh most fun on track, and 225 neovas for example are too good if it's hanging the arse out your after. as they just grip and grip.

but for teh road, keep as close to teh stock stagger as you can manage. or it's going to end up in a ditch

also bear in mind on track you shoudl be giving 100% concentration on teh road you rarely do, and when they bite, it's too late.

[firepower]

i agree completely balancing the tail end of a mid engined car like the mr2 and drifting the tail out on the road is not something to be attempted intentionaly, its difficult and if you overstep the limit of grip only slightly you'll feel like your on the waltzers  s:oops: :oops: s:oops:  as the weight bias of the engine over the rear wheels spins you round  s:( s:(

[juansolo]

also bear in mind on track you should be giving 100% concentration on the road you rarely do, and when they bite, it's too late.

Not the tyres fault that you're driving too fast and not paying attention   s:wink: :wink: s:wink:  

Blaming the tyres is like blaming a diesel spill for a sudden running out of talent.

How did people ever survive driving an original Lotus Elan?  Front engined, lighter than a MR2, respectable power and 145 section tyres!   Must've been LETHAL!   s:wink: :wink: s:wink:

[juansolo]

i agree completely balancing the tail end of a mid engined car like the mr2 and drifting the tail out on the road is not something to be attempted intentionaly, its difficult and if you overstep the limit of grip only slightly you'll feel like your on the waltzers  s:oops: :oops: s:oops:  as the weight bias of the engine over the rear wheels spins you round  s:( s:(

It must just be me then that found the Mr2 really quite forgiving in this department...    s:? :? s:?

Note:  I deleted the original content that he's responding to because I felt I was being a bit harsh.  It was something along the lines of "if you lose the backend unintentionally, you're driving too fast for the conditions" blah, blah