Mazdaspeed Protege D Stock Tire pressures.

[griswold]

Anyone out there running a MSP in D-Stock? Curious to know what tire pressures you're using front / rear.

I was running Hankook Ventus RS-2 212's yesterday at 42 front and rear. Seemed okay, but I'm sure there is a better pressure.

Thoughts?

Thanks.

 

[low_psi]

Do you have any suspension modifications? What's your alginment like? How did the car handle?

There are so many variables that go into tire pressures... Chalk your tires at the next event and find pressures that work with your driving style.

On Potenzas and stock suspension I ran anywhere from 42-45F and 44-45R. I think I run higher pressures than many though, especially in the rear compared to the front.

How did you like the RS2s?

 

[griswold]

Do you have any suspension modifications? What's your alginment like? How did the car handle?

There are so many variables that go into tire pressures... Chalk your tires at the next event and find pressures that work with your driving style.

On Potenzas and stock suspension I ran anywhere from 42-45F and 44-45R. I think I run higher pressures than many though, especially in the rear compared to the front.

How did you like the RS2s?

Bone stock, no mods, factory spec alignment.

Car handled well, though I would have preferred a little more rotation in the rear.

I was running 42 all around... I think some extra pressure in the rear might be good.

I liked the RS2's. Much more of an improvement over the Stock potenza's...at least in the dry.

Thanks for the feedback.

 

[aMaff]

general rule for fwd cars (at least, in my limited experience)
+1 or 2 psi in the rear (compared to the front) = fairly neutral handling
+4 and more = snap oversteer
a few psi lower in the rear will give you a more progressive breakaway. 42 may actually be a little high...do the tire marker trick and see what (if any) rollover you're having. You want it to wear across the whole tread, but not onto the shoulder. If it's not wearing all across all of the tread, you're probably running pressures that are too high.

 

[griswold]

general rule for fwd cars (at least, in my limited experience)
+1 or 2 psi in the rear (compared to the front) = fairly neutral handling
+4 and more = snap oversteer
a few psi lower in the rear will give you a more progressive breakaway. 42 may actually be a little high...do the tire marker trick and see what (if any) rollover you're having. You want it to wear across the whole tread, but not onto the shoulder. If it's not wearing all across all of the tread, you're probably running pressures that are too high.

Hmmm. Thanks. I wasn't rolling over to the shoulder, that I know. I"ll do some more experimenting next time. *(may 14th)

Thanks again.

 

[low_psi]

Thanks for the thoughts on the RS2s, I may pickup a set in the future.

Like amaff said, if you're looking for a little more rotation in the rear, bump it up a few psi.

 

[griswold]

Thanks for the thoughts on the RS2s, I may pickup a set in the future.

Like amaff said, if you're looking for a little more rotation in the rear, bump it up a few psi.

A few psi sounds like it'll help.

Btw, got the RS2's from edgeracing.com for $92 per in 215/45/17. Unbeatable price.

 

[apexlater]

You will notice a HUGE difference if you get a more "performance" alignment done. Start with about 1/16" to 1/8" total toe out in the front and zero toe in the rear. This should help immensely with turn-in and get the back to rotate more.

I was running up to about 1/4" to 3/8" total toe out in the rear when I was running the MP3...that's alot...but that's what it took for the car to rotate the way I wanted to with the r-comps. And you absolutely do NOT want to run on the street with that alignment for very long.

It was sketchy enough just getting to and from the events with that alignment.

 

[Rogue]

how can you adjust the toe at home?

 

[griswold]

You will notice a HUGE difference if you get a more "performance" alignment done. Start with about 1/16" to 1/8" total toe out in the front and zero toe in the rear. This should help immensely with turn-in and get the back to rotate more.

I was running up to about 1/4" to 3/8" total toe out in the rear when I was running the MP3...that's alot...but that's what it took for the car to rotate the way I wanted to with the r-comps. And you absolutely do NOT want to run on the street with that alignment for very long.

It was sketchy enough just getting to and from the events with that alignment.

That's pretty much the reason I'm still on the factory spec alignment. Trying to preserve tire life on the street, etc.

 

[Mallard]

Do you have any suspension modifications? What's your alginment like? How did the car handle?

There are so many variables that go into tire pressures... Chalk your tires at the next event and find pressures that work with your driving style.

On Potenzas and stock suspension I ran anywhere from 42-45F and 44-45R. I think I run higher pressures than many though, especially in the rear compared to the front.

How did you like the RS2s?

I ran almost exactly the same as you when I was stock.

I think the Rs-2's area a really good tire for the price. They're pretty good in the wet too. I used them at Mid-Ohio in the rain and was passing everyone on the track. (they were Shelby Club drivers though...)

You can adjust toe at home with a friend and some measuring tape. There are some threads in the Suspension section on doing your own alignment. Do a search.

 

[dolphin]

I am running Kumho MX tires in our street tire class and my car too is stock with the stock alignment. My pressures depend on the surface that the course is on. For a normal asphalt, I usually end up at at between 38-40 front and 36-44 rear.

The other variable is how much of the course is short transistions and how much is long turns. If I need the the back end to rotate a little then I run a lower pressure in the rear and trail brake in the tight stuff. If the course is faster and more open then I go higher in the rear, brake in a straight line and use a bit of oposite lock. If the course is very tight, then I raise the rear pressure quite a bit and just try to stay ahead of the oversteer.

One thing that you have to remember, is that there is not a lot you can do in SCCA's Stock catagory. So the driver needs to do a certain amount of adjusting to the car. In the MSP you can't kick the back end around with the throttle like you can in a Miata. But you can try to throw the weight across the rear of the car by steering away from the turn and then into the turn. This is usually not necessary in the MSP because of the stiff suspension.

So one thing that I do is change how I enter a turn. If I have higher pressures in the rear and I am getting oversteer, then I use smooth, slower steering input to enter the turn. If I have understeer, then I use earlier, faster, and more abrupt steering input.

Now you know what I know. I hope it helps.

 

[griswold]

I am running Kumho MX tires in our street tire class and my car too is stock with the stock alignment. My pressures depend on the surface that the course is on. For a normal asphalt, I usually end up at at between 38-40 front and 36-44 rear.

The other variable is how much of the course is short transistions and how much is long turns. If I need the the back end to rotate a little then I run a lower pressure in the rear and trail brake in the tight stuff. If the course is faster and more open then I go higher in the rear, brake in a straight line and use a bit of oposite lock. If the course is very tight, then I raise the rear pressure quite a bit and just try to stay ahead of the oversteer.

One thing that you have to remember, is that there is not a lot you can do in SCCA's Stock catagory. So the driver needs to do a certain amount of adjusting to the car. In the MSP you can't kick the back end around with the throttle like you can in a Miata. But you can try to throw the weight across the rear of the car by steering away from the turn and then into the turn. This is usually not necessary in the MSP because of the stiff suspension.

So one thing that I do is change how I enter a turn. If I have higher pressures in the rear and I am getting oversteer, then I use smooth, slower steering input to enter the turn. If I have understeer, then I use earlier, faster, and more abrupt steering input.

Now you know what I know. I hope it helps.

Thanks. I've always been able to get some trail braking rotation on the longer, more sweeping turns, but it's the tight pivot type ones that get me lately.

I'll give it a shot.

 

[aMaff]

So one thing that I do is change how I enter a turn. If I have higher pressures in the rear and I am getting oversteer, then I use smooth, slower steering input to enter the turn. If I have understeer, then I use earlier, faster, and more abrupt steering input.

wouldn't it be easier to change the tire pressures?

 

[griswold]

wouldn't it be easier to change the tire pressures?

That's a good point, though there was a WRX wagon that was employing the "snap the wheel" oversteer method and he was doing quite well. Well, right up until he spun. He was running crazy rear tire pressure too. He was asking for it.

 

[aMaff]

That's a good point, though there was a WRX wagon that was employing the "snap the wheel" oversteer method and he was doing quite well. Well, right up until he spun. He was running crazy rear tire pressure too. He was asking for it.

yeah, that would do it. In solo, smoother is generally better, so if you have to use abrupt imputs to get the car to do what you want, you may want to make a little adjustment to the car (if you can) to get rid of that. It's almost always that one really smooth run that you get in (unless you're awesome and they're all like that...) that you think, "man, that felt really slow," that ends up being your best time.

 

[dolphin]

Perhaps I did not express myself very well. Let's say that the tire pressures are right for the rest of course but there is one turn that you are understeering in. Now if I change the tire pressure for the one turn, it throws them off elsewhere. So now I use a different corner entry to balance off the initial understeer. Does it make more sense this way?

Yes, in autocross smooth driving is better. But smooth does not always mean slow control movements.

 

[aMaff]

Perhaps I did not express myself very well. Let's say that the tire pressures are right for the rest of course but there is one turn that you are understeering in. Now if I change the tire pressure for the one turn, it throws them off elsewhere. So now I use a different corner entry to balance off the initial understeer. Does it make more sense this way?

yes, very.

 

[griswold]

yeah, that would do it. In solo, smoother is generally better, so if you have to use abrupt imputs to get the car to do what you want, you may want to make a little adjustment to the car (if you can) to get rid of that. It's almost always that one really smooth run that you get in (unless you're awesome and they're all like that...) that you think, "man, that felt really slow," that ends up being your best time.

That's what happened yesterday...fastest felt the slowest...

 

[apexlater]

Having to adjust your driving style to any changes you make to a car are just as important as the changes to the car themselves.

You may think that your car is very loose and oversteers, whereas I may think that the car is too tight.

Being able to adapt and change driving style in different cars is what makes a good/fast driver. But, I will say, that setting up the car so that it is fast for you is more important than what is fast for someone else.

It just takes alot of seat time and tuning, but don't discount what other people think is fast, it can give you a starting point.