Best R tire for a no camber adjustment application?

[Gord]

Hi all,

I see there are other threads regarding best R tire (I agree with most of what I saw there), and I have read the shootouts that GRM did a few issues ago. I'm looking for something a bit different, something a bit more application specific.

What is the best R tire for a car with no camber adjustment available?

Specifically I am interested in the Mk4 VW's (which have no camber adjust) and don't have very agressive negative camber to begin with. This would also be for a stock car.

I know that a wider wheel will help any tire, and I plan to stuff some 15x8" wide wheels in there (225 in a 45 or 50 profile). That should help some as would suspension improvements to limit the camber change caused by body roll, but that is not an option for a stock car.

Is there one tire that works better than the others?

Thanks,

-Gord

[haniforama]

Toyo's will work since they tend to be able to handle more abuse that most other R-compounds, and when you find the outer edges are worn, you can flip them on the rims to use up the inner edges.

The Kumho with it's stiff sidewall (and assymetrical construction) will likely be the best performer but once the outer edges are worn, you cannot flip them.

The late BFG R1 was the best in this situation but alas, BFG decided to bring us a useless replacement.

Hanif

[Marsh]

Originally posted by haniforama
Toyo's will work since they tend to be able to handle more abuse that most other R-compounds, and when you find the outer edges are worn, you can flip them on the rims to use up the inner edges.

The Kumho with it's stiff sidewall (and assymetrical construction) will likely be the best performer but once the outer edges are worn, you cannot flip them.

The late BFG R1 was the best in this situation but alas, BFG decided to bring us a useless replacement.

Hanif

I find it funny that people say the Kumho has a stiff side wall. I first had BFG G-Force R1s and they were so stiff they were neary undrivable below 100km/h. I found the Kumhos a nice soft and predicable relief. The new V70A Ecstas are so disgustingly soft they simply will not work with out at leas -3 deg of camber. The victoracer seems moderately happy at -1.8 to -2

[haniforama]

My Kumho comments are based on the Victoracers only.

But maybe i should change that from stiff to stable...

Hanif

[andrew1984]

im gonna be trying the victo's on my bug this year, hopefully that will turn out good.

may i suggest 225/45/17's as a good tire for auto-x.

falkens are a good comprimise for street/auto-x applications.


also, you may (highly recommended) want to invest in a rear swaybar (neuspeed 28mm).

i did so, and there was a gigantic difference in my cars handling abilities.

and- i have some shine race springs for sale if your interested. slightly used, like new of course. PM me for details.

[Gord]

It's interesting to see peoples feelings on the differences between the two Kumho tires. Everything I have seen (and heard locally) has had the Victo being stiffer on the sidewall, but the Ecsta being grippier overall. GRM's findings seem to indicate this as well.

I know having a stiff sidewall will help keep the tire from rolling over, but a wide wheel will help this as well. Since there is so much positive camber (roll induced), would a somewhat softer sidewall on a wide wheel keep a bigger contact patch on the ground than the stiff wall. Kind of like how the old R1 had the stiff inner wall and soft outer wall to get some camber gain (or do I have it backwards?).

I have run the Toyo's before, and so have a lot of others here, and the feeling is that the Ecsta is similar, but better in every respect except wear. These will be slalom only tires as tracking a tire ruins it for slalom in my experience. Wear (within reason) is then not an issue, except for the wearing down the outside edges because of limited camber (nice to be able to flip them).

Andrew, I want to run 15" since it is lighter, cheaper, and has better gearing. Plus, you get some lowering as well. If I do any bar at all, it will be a big front bar. It's the only way to get some roll stiffness in a stockish modern VW. The body roll is the main contributor to the camber problems at the front, and hence the understeer problem.

There seems to be two camps. The "Shine" club with the rear bars and or no front bar, and a small group that says go front bar. I sit in the front bar camp since the theory makes more sense (rear bar is a bandaid fix to remove grip from rear to get the car to turn, and does not fix the grip problem at the front), and more importantly the only successful front runners in modern VW's in the SCCA swear by the big front bar method.

-Gord

[andrew1984]

i have never heard anyone say to go with a front bar.

thats insane, the car already pushes WAY too much.

you could also get a torsion bar from shine.

shine is supposed to be one of the best set ups, maintaining stock ride height - and creating a neutral car.
i chose a neuspeed setup, and im never looking back.

my car is almost neutral. i have only noticed myself being able to oversteer it - which is what id rather have.

IMO, with oversteer you could at least continue to put some power down and while with understeer, you HAVE to brake.

which is faster? well, from my very limited experience (19 years old in march)... i drive MUCH quicker with the way my car is currently setup.

also, with my suspension on the track - i keep my foot on the gas through corners... i want to see you do that with a big front sway.

with a rear bar, theres no middle speeds.. you either go fast or slow. when you attempt otherwise, your back end WILL step out on you.

BTW, i found some camber plates for mk4s. i believe they allow you to go from 1.5-3.5* of camber, available from volkswagen racing (bildon). i am disputing if i should install it or not, and i may choose to install them with my new victo's.

anyone have an idea of victo's preferred camber settings?

[roooo]

Adding a bigger front bar will help keep the tires planted and maintain a good contact patch which is especially helpful when you don't have much camber. It is also a free mod so you don't have to worry about switching classes while experimenting.

[Gord]

Like I said, it's a pretty small group that follow this philosphy, and it applies mainly to the later VW's. But, the results alone speak for themselves.

And yes, it is very conuter intuitive, at least based on what everyone says and not looking a bit deeper into the technical details of what is going on.

I'm very sure that you are faster in you car now with the rear bar. But, like I said before you are compensating for the front not turning as fast as you want by making the rear break loose and slide, causing the car to turn. Looking at it though, it is exactly as I said. You are removing grip from the rear to get the car to turn. You are not adding to the front. The net overall grip is being reduced.

It is also as you mention, a very fast or slow approach, not much in-between. It could be almost called twitchy. You also run a greater risk of hitting a cone with the back of the car, or even looping it completely. Yes, it is usually faster than stock, but not necesarily the fastest.

If you look at the BFB approach, the rational is that you are compensating for a lack of suspension stiffness with a swaybar (front is where the weight is) to limit the body roll. If you ever look very closely at a modern VW (in stock form with sticky tires) when it is cornering hard, you will notice that there is so much body roll that the outside front wheel has extreme positive camber relative to the ground. This has caused the contact patch under that tire to become distorted a lot, and as a result grip drops significantly in the front, and the car understeers as a result.

The proper way to fix this would be with stiff springs to limit the roll, but then you are no longer stock (3 pts please vs. 1 for bar), and the stiffness required makes the car harsh (for slaloming) to the point of suspension compliancy becoming a problem (stiff springs require stiff shocks, which require really sticky tires, etc.).

If you can limit the body roll without being too stiff (swaybars), you can achieve a more neutral balance than stock, but not twitchy like with a big rear bar. You can also control rear grip then (if necessary) with just tire pressures, and if you really need to flick the car around, there is also trail braking and LFB.

The camber plates would be awesome, as it is great to have the adjustability. Do they require modifiations to the tower tops (cutting) to install?

-Gord

[Keith-02Accord]

rooo,

You're right about the bar, but I don't think it's a free mod....1 prep point if I'm not mistaken.

Then again, if you're in SS or SP, then I think you're right:rolleyes:

[ctenche]

You're right. Adding a big rear bar will remove grip from the rear tires. You are also right in that body roll will cause positive camber during a turn therefore reducing the amount of grip on the front tires.

Your assumption however that the front grip gained by maintaining proper camber is more important than the grip lost by a big rear bar is incorrect.

Maintaing a wheel's camber curve is important but not as much as you might think. Tires show the difference in wear but lap times simply do not show that much of a difference between a car with a ton of negative camber vs. stock.

Fact is, you want the car to rotate. Removing grip from the rear works. The rear isn't doing anything anyway except for keeping the car off the ground. Who cares is you're loosing grip there? You can't stear with the rear wheels. You can't put power down with the rear wheels. So...might as well remove their drag on turning capability as much as possible.

[Gord]

Originally posted by ctenche

Maintaing a wheel's camber curve is important but not as much as you might think. Tires show the difference in wear but lap times simply do not show that much of a difference between a car with a ton of negative camber vs. stock.

This may be the case for the scenario you are describing, but we are talking about stock(ish) camber vs. extreme positive camber. Believe me, there is a huge difference in lap times.

A personal example of this was when I changed from 6" wide wheels to 6.5". Same tire, car, driver. The wider wheel supported the tire better resulting in a better (not optimum) contact patch which made the car turn much better, and resulted in significantly better lap times. Rear grip improved too, but nothing like the front. And in this case, we weren't even fixing the camber problem, just making the contact patch a little bigger.

Originally posted by ctenche

Fact is, you want the car to rotate. Removing grip from the rear works. The rear isn't doing anything anyway except for keeping the car off the ground. Who cares is you're loosing grip there? You can't stear with the rear wheels. You can't put power down with the rear wheels. So...might as well remove their drag on turning capability as much as possible.

You want the car to turn, not be hanging the back end out. Now mind you, a lot of this depends on personal driving style.

However, from my personal experience, most cars that are setup loose in the rear tend to spin a lot, and never seem to be as quick down a slalom as the ones that have the front end that just goes where pointed. Plus, the only time I can see wanting to have the backend sliding is on enter tight turns. This is easily done with a bit of trail braking, or LFB.

Again, a lot of it is personal style, but I know what the quick guys have.

-Gord

[ctenche]

Agreed. A lot of it has to do with personal style. I personally like a loose rear (shut it...no wise ass comments please) :D

[andrew1984]

gord,

if i did say that my car turns by the back braking loose,then i said it incorrectly.

my car will go anywhere i tell it to. i have the neuspeed front and rear sways.

there is only oversteer if you take your foot off the gas in higher speeds in the corner.

sorry for confusion. my car -IS- neutral.

i am not sure if the camber plates require any additional work.

i am still waiting for my shipment to come in, but i could ask a friend who already has them setup. ( at -2.75*)

what size tires are you running?

my car came stock with 225/45/17, and i will be switching to 235/40/17 yoks a032-r's for every day & auto-x.

sure they will run down faster then my azenis, but at least they have more tread to start with , stick way better & are cheaper.

[roooo]

Front bars are free.
Rear bars count for points.

At least it's that way in SCCA ...

[Gord]

Andrew,

Yes, having both bar helps to keep things balanced. Your car is the silver turbo with the Caracature rear wing right? You ran at the regional event MCO held last summer right? What all was done to you car at the time? It sure looked fast! I was running the black Paseo in B1.

I'm running the stock 205/55-16's (crappy goodyears) on the stock wheels right now (for the street). I want to use 225/45-15's, or 50 series if I can't get that.

I don't like having to shift to first on course (I'm not good at it, and the transmission doesn't like it), so with the lower gearing that I can get with the smaller combo, and the torque of the diesel, I should be able to get away with 2nd (and 3rd if needed). It's also lighter.

If I might suggest, the Toyo's would make a better tire (IMHO) than the Yok's for street/course use. Wear is similar, but the Toyo's are stickier, quieter, and better in the rain. It's the one R I could see using on the street and have had numerous friends already do so. Can't comment on the price, but there is the Toyo R group racing discount.

Cheers,

-Gord

[andrew1984]

toyo's dont come in the size i need.

plus, these are the new "soft compound" yoks.

i was in super stock that part of the year.

all i had were shine springs.

that was my worst event EVER.

i had a wedding before, i was in the wedding party - and i left at 3am to come to ottawa. what a big mistake that was. needless to say, i was pretty ruined from 1 hr of sleep :eek:

that pretty much shattered my chance for rookie of the year, but you definitely cant win them all.. :o

[andrew1984]

i always thought that the yoks were best in the rain?

maybe its just personal preference?

[Gord]

I used to think the yoks were the choice in rain tires (for R's), but a lot of the racers in the club use the Toyo's at full tread depth. Looking at them, I guess it kind of makes sense since the toyo has a lot smaller tread blocks and circumfurential grooving. I never had any complaints about my toyos in the wet (when newer).

My big beef with the yoks has always been that they aren't as grippy as the others. If this new tire can soften things up to the point of a toyo or kumho, then I think it will be a real winner. Big sticky tread blocks are nice. :)

Mmmm, big meaty tread blocks :p (hmmm, we need a Homer drooling style emoticon...)

-Gord

P.S. What have you done to the bug to put you into SP if you took out the springs?

[ice/solo racer]

Rooo,your right that front bars are allowed in the scca stock classes but ANY sway bar modification including end links and bushings are 1 point each in the casc rules.
Andrew I doubt it'll make you feel any better but ottawa sucked for lisa and I as well.A bunch of wins and then an 8th there,just when I needed a win and 100 points for overall.Our you staying in BSS this year?with springs and bars I guess you're all maxed out for prep points in SS.
If so i look forward to resuming battle this summer,looks like the competition will be even faster and more furious(nice pun eh!)the neat part of solo 2 is seeing fwd turbo cars running against cars like my underpowered 1600cc car against WRX's,cooper s etc etc.
Since I've played with(and researched alot)VW race cars,the front bar vs rear bar debate is a good one.Since stock VW's have one of the largest cambers gain due to excessive body roll and strut front suspension there is good reason to consider a bigger front bar.I've tended to set up fwd with stiff front springs and no front bar with a bigger rear bar.The no front/bigger rear bar allows better corner exit throttle application-very important for fwd.However VW's(and only VW's IMO,I mean the outside front allready carries most of the entire car weight anyway)do resond well to only adding a front bar to limit body roll and the considerable camber change,you can always use other means to limit rear grip to fine tune the balance-after optimizing front grip adjust rear pressure to suit or even try a smaller tire in the rear(or mount the same size tire on a narrower rim for the rear).

[andrew1984]

i replaced my shine springs with a full neuspeed suspension.

neuspeed race springs, front and rear sway & and a BOV is enough to get my ass into S/P.

hell, last year i was in S/S because of my damned blow off valve!

shoulda just kept the stocker in!

oh well, i was lazy- and didnt figure that id get sucked into the soloII frenzy :p


ill let you know how my yoks do... wheel & tire zone (plug) is tossing them on .. monday i believe.

[ice/solo racer]

Are the yoks the sc's or normal comound Andrew?the wheel tire zone told me 2-3 weeks ago that the sc's would be at least 6-8 weeks away at that time.
So I went with victoracers-hope the sc's don't turn out to be the tire to have:( (next to hoosiers of course)

[andrew1984]

they are SC's.

they did have to pick them up from some other location though - and thats why i get them on monday.

[roooo]

I would guess ... from Fourstar Motorsports?

The seemed to think the new 032R-SC would be a great improvement for dry track tires but not necessarily be a lot better for autocross.

[andrew1984]

i dont know. but im willing to try them out, since they have the most tread and treadwear rating and i will be using them on the street & track.

[ice/solo racer]

Hey Andrew don't feel bad,I just made a deal on a supercharger from a 1st gen MR2 to bolt onto my corolla for next year.So I'll be playing with you again next year-I should go and study the cnac rules if thats what may be adopted for 2004.(who knows where I might end up?)
I know solo 1 won't chance much for next year and the supercharger will take me the top of the next class above me now.(which is ok)

[andrew1984]

Originally posted by ice/solo racer
Hey Andrew don't feel bad,I just made a deal on a supercharger from a 1st gen MR2 to bolt onto my corolla for next year.So I'll be playing with you again next year-I should go and study the cnac rules if thats what may be adopted for 2004.(who knows where I might end up?)
I know solo 1 won't chance much for next year and the supercharger will take me the top of the next class above me now.(which is ok)


feel bad? sure, i feel sorry for having to hand your tin can its ass :p

bring it old man :D