BigMike's Forum

Automotive and Theory => Suspension Theory => Topic started by: Sirdeuce on August 18, 2010, 11:43:11 AM

Title: Tyres
Post by: Sirdeuce on August 18, 2010, 11:43:11 AM
This one is basically for Bryan. I haven't looked at tires in about 4 years. Last set I bought for my MR2 was Yokohama AVS ES100. Grip was good, water shed was good. I didn't like the feel, sidewall seed too soft, felt sloppy to me. Wore the tires out in about a week of driving up and down this hill. Wear pattern suggested massive positive camber when I was running with 1.5 degrees of negative camber.  Outside showed belt threads, inside was basically untouched. Haven't had much good to say about Yokohama. Won't say much about what is on the Speed3 as we buy tires based on HER driving style, longevity, comfort, and price. But we have BFG g-Force Super Sport a/s 225/40 ZR18 on it. Not a bad tire, wet or dry.
Title: Re: Tyres
Post by: BryanH on August 18, 2010, 12:26:56 PM
Tyres, eh?  I bet you call them "Kerbs," too.  :P

These days for our little cars, your choices are pretty limited.  At least you run the same size all around - I have to try to find staggered tires for the MK2 MR2s, and last I checked only two companies made tires in both sizes (or even close).  225/50/15s are unobtanium.  But anyway...

I echo your sentiments on the ES100s.  They were great in the wet, and rode really smooth, but the sidewalls were so sloppy they were awful to drive at the limit and wore out in no time.  Here's what mine looked like after a day at Buttonwillow:

(http://www.pbase.com/bryanh/image/24866186/original.jpg)

They turned blue from the heat...

What tire size(s) would work for you?  What are you looking for in a tire?  I usually do all my searching at TireRack and then also Discount Tire Direct online because they carry a few brands TireRack doesn't. 
Title: Re: Tyres
Post by: Sirdeuce on August 18, 2010, 08:16:51 PM
I would like to run 15's, but finding cheap, relatively light rims is pretty hard with the funds we're running on. Trying to go light on the car, so a 205- 215/55 14, or 205/50 15 should suffice. I had pretty decent handling on my 2 with 195/55 14's. But since we are going to push hard all the time, and some of us aren't used to the 2's, I think the added meat would be a good direction to go. We're not too limited on tire type so my first choice would be a Falken Azenis, or the like.  My first set of 15's were the Yokomamas at 205/50 15. Too bad they wore like cheddar cheese. Blew the clutch out and haven't had her on the road since.
Whaaaht, kerb ain't raht? C'mon, y'allr kiddin'.
Title: Re: Tyres
Post by: BryanH on August 18, 2010, 10:54:52 PM
Oh this is for the LeMons car?  I thought it was for your personal car.  Well I would say Azenis or Dunlop Z1 Star Specs off the top of my head.  Will have to find out what else is in 14-15" sizes tomorrow.  Bridgestone's RE-11 should be the longest lasting and most predictable of the super sticky street tires... that's why they cost more.
Title: Re: Tyres
Post by: BigMike on August 18, 2010, 10:56:28 PM
Bryan, do the choices for 13" rims get any better?

If we want a set of cheap tires that are decent, take a look at what I've got on both my MR2 and my Infiniti: General Altimax HP

(http://www.tirerack.com/images/tires/general/ge_altimax_hp_ci2_l.jpg) (http://www.tirerack.com/images/tires/general/ge_altimax_hp_ci1_l.jpg)

I am running 195x60x14. They certainly are no match to my old 225x50x15 (unobtainum you say huh... dang :() Potenza S03 Pole Position tires, but they only cost me $55 each! I was looking at the Potenza RE960AS Pole Position, but they are nearly $100 more for the set and out of stock until December :o

Comparing the Altimax HP's to the cheapest tire in this size, the Bridgestone/Fuzion HRi, it's a no brainer. The HRis sell for $50 each, but look at the comparisons:

Tire Rack Comparison:
Wet   Dry   Treadwear   Price
RE960AS8.99.18.6$75-ish
Altimax HP  8.89.08.3$55-ish
HRi7.98.57.9$50-ish

1 set of the Altimax HPs was barely over $200. Not bad for only being 1-tenth difference in handling, but of course the treadwear is pretty important to us, but not sure if that justifies 100 more bucks.
Title: Re: Tyres
Post by: BigMike on August 18, 2010, 11:00:56 PM
I am just thinking that we could bring maybe 3 sets of tires (how many sets do we need?): two sets of cheap tires and 1 set of better tires. Run both cheaper tires on Sat and Sun morning (higher treadwear so they can last this long maybe?), and then slap the final better set of tires on to finish strong?
Title: Re: Tyres
Post by: Sirdeuce on August 18, 2010, 11:28:40 PM
I'm thinking we need 4 sets of tires. 1 set for the beginning of the race. Medium treadwear. First set to get through the familiarization period. As we learn the track and push harder, move up to a stickier tire. Oh yeah, when the race(?) starts we'll have a full field, it'll be slower. As cars die, people have accidents etc. the the track should open up a bit. 2 sets of stickier sports/performance tires. 1 set to run if it decides to go south on the weather. Something with a deep, fast shedding tread. Hey Bryan! Do they still make those AVS tires?
Title: Re: Tyres
Post by: BryanH on August 22, 2010, 02:00:21 PM
Bryan, do the choices for 13" rims get any better?
Not for street tires.  In 13-15" sizes, these days it's far easier to find race tires than streets. 

Just did a bit of looking at TireRack and Tires.com

http://www.tirerack.com/tires/tires.jsp?tireMake=Hankook&tireModel=Ventus+R-S3&partnum=245WR5Z222
These are hot stuff.  It's one of the top 2 or 3 street tires for autox and it likes heat, unlike some other top autox tires that need to be cooled after a 60-second run.  So it'd probably make a good track tire.  Autoxers have been known to get hundreds of runs from the RS-3.  It's wide and short.  Might be tough to get them up front on an AW11 without either running low offset wheels and radiusing the fenders, or using coilovers instead of the stock strut bodies.

http://www.tirerack.com/tires/tires.jsp?tireMake=Dunlop&tireModel=Direzza+Sport+Z1+Star+Spec&partnum=05VR5Z1SS
These have been around a couple years and are a proven great versatile tire.  Great in the wet, good on heavy cars too so they can take some abuse.  This one is also available in a 195/60/14.

http://www.tirerack.com/tires/tires.jsp?tireMake=Kumho&tireModel=Ecsta+XS&partnum=05WR5EXS
These are cheaper and not far behind the top street tires.  I don't remember if they like heat or hate it.  It's supposed to be a great tire but not too many autoxers run it for some reason. 

http://www.tirerack.com/tires/tires.jsp?tireMake=Bridgestone&tireModel=Potenza+RE-11&sidewall=Blackwall&partnum=05VR5RE11
The aforementioned Bridgies.  Right up there with the Hankooks and Dunlops.  I know little about these tires specifically - the predecessor, the RE-01R, lasted forever.

Actually I didn't find anything in my searches at Tires.com.  The Azenis is no longer available?

I'm assuming that 140 treadwear is OK... most of the tires above are at the limit for legality in street tire autocross classes.
Title: Re: Tyres
Post by: BigMike on August 25, 2010, 12:33:09 PM
I'm assuming that 140 treadwear is OK... most of the tires above are at the limit for legality in street tire autocross classes.

From http://www.24hoursoflemons.com/pricesandrules.aspx,

2.3: Tire Eligibility: DOT-approved street tires only, minimum treadwear rating 190; no exceptions. Blanco Basura, this means you.
Title: Re: Tyres
Post by: BigMike on August 25, 2010, 12:34:21 PM
Those Direzza Sport Z1 Star Specs look GREAT :D
Title: Re: Tyres
Post by: BryanH on August 25, 2010, 03:01:51 PM
Heh.  Silly treadwear ratings.  Tire manufacturers can put whatever numbers they want on a tire.

With 190 TW minimum, it's gotta be the Z1 Star Specs for maximum grip.
Title: Re: Tyres
Post by: BigMike on September 01, 2010, 02:51:34 PM
Bryan,

It looks like we might get a free set of 15x8" wheels. In this case, we could run 205x50x15. Are our choices better in this size??
Title: Re: Tyres
Post by: Sirdeuce on September 01, 2010, 07:00:56 PM
What did the 15x8s come from? What is the offset? Might have a fitment problem.
Title: Re: Tyres
Post by: BryanH on September 02, 2010, 01:28:15 PM
15x8s will be a big challenge up front.  A 15x7 is a snug fit if you want to keep it within the fenders. 

It looks like the Z1 is the grippiest tire >190 treadwear so if it's available in a 205/50/15 or so it's still the best bet.  There should be a few more choices in general for 15s though.
Title: Re: Tyres
Post by: Sirdeuce on September 02, 2010, 02:09:21 PM
Put the 8s in the back Get 7s for the front? How do you think the fitmkent will be if we roll the fender beads?
Title: Re: Tyres
Post by: BigMike on September 03, 2010, 07:11:20 AM
Ok, sorry, they must be a 15x7 then. They are the wheels on Chee's car. He is getting new wheels and doesn't need his old ones anymore
Title: Re: Tyres
Post by: Sirdeuce on September 03, 2010, 11:01:49 AM
15x7 work fine!
Title: Re: Tyres
Post by: Sirdeuce on October 08, 2010, 10:05:49 AM
Put a set of Pirelli P-Zero Nero's on the Mazda. The car HATED these tires!! On stretches that we normally travel at 65 to 70 MPH here on the hill, and never invoke the interference of the stability control gods, the DSC was like a Christmas light in the dash! The gods of stability were verry angry! At 35 to 40 MPH on the same section of road the DSC would throw a fit and prevent any speed above 40 MPH. I thought the suspension was falling apart! Felt like the sway bars had magically disappeared! I took the car to Mazda to have it checked out. Yes the front struts are leaking, but that was not the problem. I put the tires we had on before, BFG G Force Super sport,  and the difference was night and day! The struts are on order, so they haven't been replaced. I drove the car home from Lithia and it actually drove right! I was able to drive my normal speed without any complaints from the car. I did push it through an 'S' turn to see if I could get the attention of the stability gods, and they let me know they were still there with a little bit of brake in the beginning of the S. I was traveling at a speed closer to stupid than safe, but it was just a little nudge from the DSC that I was looking for. Now we have 2 tire makes blackballed from the Speed 3 club, Yokohama and Pirelli. They may be good tires, but the little blue Mazda just doesn't like them at all. Two things on this planet you have to keep happy! Your woman and your car! Which one you put first is up to you, but always say the woman is first!
Title: Re: Tyres
Post by: Sirdeuce on December 17, 2010, 09:55:37 PM
I was looking at the Falken Azenis RT-615K tires. The 195 60 14 are 23.2" tall with 900 RPM, The 205 50 15 are 23.2" tall but have an RPM of 895. I don't think it's much of a difference, but................
I'll look around some more.
Title: Re: Tyres
Post by: BryanH on December 18, 2010, 02:03:01 AM
That aren't a significant difference.  We'll want the extra width not only for grip but for heat dissipation as well.
Title: Re: Tyres
Post by: Sirdeuce on December 18, 2010, 09:29:58 AM
I'm not too concerned about speedo accuracy. We don't need to know the actual speed, just need a reference. I'm sure most of us can judge our entry by feel and sight. But when fatigued, you knoow judgement can get skewed. Really would like to get a 205 or 215 45 15 though. One problem we might have is in rim width. I prefer being a little wide over a little narrow. Going narrow allows more 'swing' , feels sloppy. the rims I have are 15X6.5 or 7. 6.5 is perfetct for a 205, ahair wide for 195 and just on the narrow end of what 215 fits.
Title: Re: Tyres
Post by: Sirdeuce on December 18, 2010, 09:30:45 AM
Bryan, how are your feelings on staggered fitment on the AW11?
Title: Re: Tyres
Post by: BigMike on December 18, 2010, 11:40:11 AM
Got a problem with our free 15" rims: They are gone. Chee sold his car and with it the rims we were gonna use (at no cost).

So we need to come up with another set of 15" rims -- and preferably two complete sets so we can have one set fully mounted on stand-by. Bill, we can borrow the 15" rims on my mother's Saturn for the weekend (but if we jack them up I'll have to replace them lol).

Bryan, how are your feelings on staggered fitment on the AW11?
Having a square setup will be good for rotation, but if we had a staggered arrangement, we could still rotate between two sets of tires :idea:

Sears Point is a higher average speed track than Buttonwillow, correct?
Title: Re: Tyres
Post by: Sirdeuce on December 18, 2010, 12:03:02 PM
The size of the rims on your mom's car are 15X6.5 I think. Could you double check  that? We could use mine,  but we need to make sure the sizes are the same. But for this race, at our level, may not be such an issue.
 
Infineon is faster, with a bit of elevation change. I think the biggest problem will be the long sweeping turns, the MR2 needs a constant speed through long sweeps to keep the weight balanced. Too slow it'll be in the way of faster cars, too fast and the weigh in the rear gets the best of it. At speed , letting off the throttle the rear will want to pass the front, getting into the throttle will make it push. Doing the old in and out on the throttle will be a lesson in ballet dancing. Top of the hill is a right hander that gets light. Little car will want to do a little break dancing there. Learn the breaking points well, and corner personalities and you could fly through it! Although the elevation change would be a bit easier to handle with shorter tires, or with more engine torque. Hmmmm, 7AGE?
Title: Re: Tyres
Post by: BryanH on December 18, 2010, 12:15:30 PM
IMO tire/wheel stagger isn't necessary on the AW11 until you start making a lot of power or torque.  A hint of stagger will work fine (10mm) at <150hp but more than that and the car will push too much. 

Title: Re: Tyres
Post by: BigMike on December 18, 2010, 02:37:44 PM
Could you double check  that?

the MR2 needs a constant speed through long sweeps to keep the weight balanced. Too slow it'll be in the way of faster cars, too fast and the weigh in the rear gets the best of it.
I don't know if Bill & Kevin's old AE86 wasn't tuned properly, but I remember playing in the hills with Kevin and he said he couldn't compete with the high speed constant cornering of my MR2. I could take constant velocity corners at a higher speed than the FR Corolla could. However, when we ran Trimmer Springs from North-to-South, right before we dropped into the Trimmer Springs Forest Station, there are some very tight and slow twisty section that I couldn't keep up with Kevin for the life of me. I had plenty of power, but the faster I tried, the more the car pushed in the slow speed corners.

So my experience with the MR2 has been a very stable at high speed cornering and a big tendency to understeer at low speed corners.

Although the elevation change would be a bit easier to handle with shorter tires, or with more engine torque
Don't forget the 6 speed!!

Infineon is faster

A hint of stagger will work fine (10mm) at <150hp but more than that and the car will push too much.

The reason I asked if the track was fast was regarding understeer. To comment on Bryan, if we lack the torque to induce oversteer, what if we ran 205s in the front and 195s in the rear? I know, opposite for what you'd expect with a rear-heavy car, but I'm just thinking out loud.

I know the slanted radiator with air coming through the hood and over the car (instead of under) will help with down-force and consequently improved front traction at high speeds.

I also really want to make some simple front canards (http://en.wikipedia.org/wiki/Canard_%28aeronautics%29) out of sheet metal. This will help immensely with front down force

Picture 1 & 2: Here is a canard example on an Elise

Picture 3: Here is a double canard example

Picture 4: Look at the canard on this BMW. This is what I had in mind for our car. What do you guys think?

Don't talk to me about how fragile the car will be and it will get damaged. If you saw the amount of plywood aerodynamics that we saw out there this is nothing.

Besides, the whole concept of building them as simple as possible out of sheet metal applies to us bringing a couple back-up sets that can be quickly swapped on.

Picture 5: This is how Lotus positions the radiator on the Elise. Completely flat to my surprise :o Not to say we need to do this, just food for thought
Title: Re: Tyres
Post by: BryanH on December 18, 2010, 07:36:49 PM
The reason I asked if the track was fast was regarding understeer. To comment on Bryan, if we lack the torque to induce oversteer, what if we ran 205s in the front and 195s in the rear? I know, opposite for what you'd expect with a rear-heavy car, but I'm just thinking out loud.
Worked a treat for my stock '87 NA on Konis and race tires at an autox.  With the higher speeds of a track, it's more than likely too much oversteer.  Especially if you guys double up the rear sway bar like we talked about a while back (remember my '87 had no rear bar). 

Speaking of sway bars, I actually liked the softer (stock) set up better on lowering springs and increased negative camber.  I had stiff sway bars on the car for a while and I don't think it was any faster.  The trouble was twofold - one, you had no idea which end of the car would grip and which end would slide when entering a corner.  And two, using the curbs on a track was more difficult because the car was upset more.  The sway bars reduced the independence of the independent suspension in other words.  I had an ST front bar (I forget the size now) and a prototype H&T rear bar (19mm solid -- waaaaay too stiff!).

We'll have to control roll somehow though.  Otherwise we can have tons of static negative camber turn into zero (or positive) camber on the outside wheels when loaded up in a corner.  I know a good budget track solution was ST springs years ago but they probably aren't in a LeMons budget anyhow. 
Title: Re: Tyres
Post by: BryanH on December 18, 2010, 07:42:49 PM
To expand on sway bar experiences a bit, on the MK2 in Stock class autox the car gets faster the more front bar you put on it.  One theory is that the stiff front bar controls roll well enough to reduce the dynamic camber loss of the McPherson struts, and thus gives more front grip while also adding stability by planting the rear tires.  On paper it sounds like a recipe for huge push but it works extremely well.  Of course it helps to run zero rear toe (or even a bit of toe out) to get the car to rotate better off throttle. 

In general sway bars actually reduce grip, and are seen as more of a quick fine tuning device in racing where springs and dampers are very well developed.  This specific case is probably an exception.

Stability is good.  It keeps us consistent on track without having to work as hard in the cockpit.  The trick is to have a stable handling car without it being a push pig. :)
Title: Re: Tyres
Post by: BigMike on December 18, 2010, 10:31:15 PM
Great discussion :thumbs:

We could just run the stock rear bar which is really small. I've got one on my 2 & I have no clue what it does or doesn't do for me :ha_ha: I should remove an end link for a couple of days just to see what the difference is.

Stability is good.  It keeps us consistent on track without having to work as hard in the cockpit.  The trick is to have a stable handling car without it being a push pig. :)
I completely agree with this. If we the drivers are having to concentrate to drive the car quick, and quick we may be, we'll fatigue out and then spin out :driving: :bricks: