[grinchmas]

Originally Posted by bentom2

I’d just suggest that if you’re leaving stability and traction control on for the track, that you put some miles on the square setup before you go out. The DSC/TC will freak out for a bit when you switch and needs to relearn.

Maybe switch your wheels at home before heading to the track. By the time you get to the track, you should be good to go.

I wasted two sessions and a good portion of a set of rear pads by swapping trackside from staggered to square and going straight out.

I haven’t found a need to alter damping or ride height when I switch out between 19" street wheels and tires, and 18" track setup.

Gotcha thanks! Yeah I typically swap at home and drive the hour to the track so that's all taken care of.

[detroitm2]

Originally Posted by tux2005

The diameter of the wheel changes but usually the tire sidewall height is adjusted to compensate and stay fairly close to the same circumference and total wheel + tire diameter. There may still be a slight difference in size but it'll usually be fairly small and wouldn't really require adjusting ride heights. You'd probably want to corner balance etc on the track wheels but shouldn't really run into issues on the street without adjusting heights.

The change from 19" to 18" with the compensating sidewall height adjustment would still change the ride comfort as the taller sidewall would usually provide more softness. But if you're tracking, then your track tires may have a stiffer sidewall anyway and you're also likely to want to adjust damper settings anyway.

Sorry, but this is incorrect. The sidewall height has nothing to do with the size of the wheel.

On a 35 series tire, the sidewall height is equal to 35% of the tire width. For a 265 width tire, that's 265*0.35 = 127.75mm sidewall height. Or just over 5 inches (total). The diameter of the tire on the other hand is directly related to the wheel size. If you take the sidewall height and add the size of the wheel, you get the total diameter of the tire.

An 18 wheel and a 19 inch wheel are exactly 1 inch apart in diameter give the same size tire.

For the ride height, you're effectively a half inch lower with this setup than you would be with the same tire on 19s.

How this affects alignment and suspension geometry I am not sure. I also run a completely different size on the track (265/35r18 square) than I do on the street (oem sizes).

[mr_lab_rat]

Originally Posted by bentom2

I’d just suggest that if you’re leaving stability and traction control on for the track, that you put some miles on the square setup before you go out. The DSC/TC will freak out for a bit when you switch and needs to relearn.

Maybe switch your wheels at home before heading to the track. By the time you get to the track, you should be good to go.

I wasted two sessions and a good portion of a set of rear pads by swapping trackside from staggered to square and going straight out.

I haven’t found a need to alter damping or ride height when I switch out between 19" street wheels and tires, and 18" track setup.

I had this experience with switching to square setup (TCS freaking out). Except it wasn't going away even after weeks of driving. It turned out to be outdated software (my car is MY 2017 and it was running the original version). After updating the problem went away and as a bonus the MDM mode is way more fun, it was too intrusive before.

[MagnusT]

Originally Posted by detroitm2

No, the diameter changes by an inch when you go from 18 to 19.

The width of the tire (265mm) is constant.

Then you are using the wrong tire sizes.

I run both 18 and 19 on my M2


https://www.willtheyfit.com/index.ph...=10&offset2=40


Change in stiffness. Yes. Possible. Change in alignment or height. None whatsoever.

[MagnusT]

If you are using the wrong size of tires within reason (I've run 265/35-18 square too) you still don't need to change anything.

The only real change is that when you run square you change the rake of the car slightly and also give DSC som other input due to change in the front/rear size relationship. But as long within reason the car has no problems with this.

[tux2005]

Originally Posted by detroitm2

Sorry, but this is incorrect. The sidewall height has nothing to do with the size of the wheel.

....

You misunderstood, yes, a 35 ratio tire is set based on the tread with, I was saying you would often compensate by going from a 265/35R19 to a 265/40R18 as MagnusT referenced. You change the ratio of the sidewall to compensate so you end up with a similar diameter, you're absolutely correct that the ratio is only based on the tread width and not the wheel diameter.

But I do also run a 265/35R18 for the track which does result in a smaller tire because of more tires available at that size. In the end while the ride height will vary based on the different wheel & tire combos most of us don't worry about adjusting ride heights to match, you just either compromise both or target a specific setup and miss out on the other.

[detroitm2]

Originally Posted by tux2005

You misunderstood, yes, a 35 ratio tire is set based on the tread with, I was saying you would often compensate by going from a 265/35R19 to a 265/40R18 as MagnusT referenced. You change the ratio of the sidewall to compensate so you end up with a similar diameter, you're absolutely correct that the ratio is only based on the tread width and not the wheel diameter.

But I do also run a 265/35R18 for the track which does result in a smaller tire because of more tires available at that size. In the end while the ride height will vary based on the different wheel & tire combos most of us don't worry about adjusting ride heights to match, you just either compromise both or target a specific setup and miss out on the other.

Originally Posted by MagnusT

If you are using the wrong size of tires within reason (I've run 265/35-18 square too) you still don't need to change anything.

The only real change is that when you run square you change the rake of the car slightly and also give DSC som other input due to change in the front/rear size relationship. But as long within reason the car has no problems with this.

I think we're all saying the same thing, I just misunderstood what was being said

[MagnusT]

Originally Posted by detroitm2

I think we're all saying the same thing, I just misunderstood what was being said

[infinitekidM2C]

Anyone have suggestions for front camber on an M2 Comp with the following:
M Performance suspension, lowered all the way in the back and 4-corner balanced.
Occasional track days - 4 a year or so.
Mostly drive for fun, so more of a weekendish car
Only drive about 5k miles at best.
Goals = Very good handling, not too concerned on tire wear

SHould i even get camber plates for the front?

[Bewstd]

are the PFC08's really worth the extra money over some HAWK pads? Daily the car and also starting to track

[bentom2]

Originally Posted by Bewstd

are the PFC08's really worth the extra money over some HAWK pads? Daily the car and also starting to track

The Pagids and PFC08 are popular due to their longevity. I get 10-12 days out of the Pagids, and have only tried the PFC08s once, but got 8-9 days out of them.

I haven’t personally tried any of the Hawk compounds, but friends tell me they have a much shorter life.

So while the PFC and Pagids are more expensive upfront, they’re probably more affordable when you factor in pad life.

[detroitm2]

Originally Posted by bentom2

The Pagids and PFC08 are popular due to their longevity. I get 10-12 days out of the Pagids, and have only tried the PFC08s once, but got 8-9 days out of them.

I haven’t personally tried any of the Hawk compounds, but friends tell me they have a much shorter life.

So while the PFC and Pagids are more expensive upfront, they’re probably more affordable when you factor in pad life.

You also have to take into account that if you switch to a true track pad, it's not very street friendly. Sounds like a bus when you come to a stop.

A lot of us that track and daily our cars swap out pads. It's a quick and easy job.

I personally run Ferodo DS1.11s in the front, and DS2500 in the rear. It gives a good balance of brake responsiveness and they wear at about the same rate on the track. Additionally, if you decide to get new street pads, the DS2500s all around are good. They produce less brake dust than OEM, and are quiet. They also share a similar compound to the DS1.11 so there's no need to rebed the pads after switching from track to street.

[5.M0NSTER]

Originally Posted by Bewstd

are the PFC08's really worth the extra money over some HAWK pads? Daily the car and also starting to track

YES

I have 7 days on my PFC08 and they are at 60% thickness. Never experienced fade with them, and they bleed speed nicely without overpowering 200 thread wear tires.

Also there are stickers which say BRAKES SQUEAL BECAUSE RACECAR if you’re concerned about noise.

[Bewstd]

Ground control or Millway camber plates for my OG M2 on MP coilovers. Car is a DD

[MagnusT]

PFC08 is my favorite. Love the initial bite, good modulation for me on my car, low pad wear (as long as kept at non crazy temps), low disc wear. Do squeal hilariously loud in periods. Thanks to the low wear and totally okay friction at street temps I don't bother swapping, I actually drive them year around even in winter hehehe. Making loud noises. Lazy bastard me haha.

[MagnusT]

Originally Posted by Bewstd

Ground control or Millway camber plates for my OG M2 on MP coilovers. Car is a DD

Millway Street

Nice and silent

[kart driver]

Installed the camber plates + installed the racing brake pads instead of OEM.

They shop could do the following camber:

Front: -2.2 degrees
Rear: -1.8 degrees

I got the following:

1) My lap time became worse, being almost 2 seconds slower (on a 85 minute racetrack) that comparing to OEM set up with no camber plates in place
2) I didn’t like how the tires worked:
- the car was not able to slow down at the same points as I did with OEM setup last week
- the car became extremely tail happy, I had to catch it a lot when it oversteered comparing with last week when I had all OEM set up
3) The bite of the brake pads is better comparing to OEM, you can feel it immediately.
4) With the camber that I have now, the wear of the tires is more in the middle, than it used to be before with OEM set up.


What could be wrong? Any ideas?


I have a feeling that if I just go back to OEM camber angles, the handling will be better and the lap time will also be better.


P.S. I am really pushing the car a lot and use the brakes quite aggressively.


M2C, OEM everything (except for the camber plates, racing brake pads, castrol SRF fluid), michelin cup2 tires 245+265 (this I can’t change due to regulations of the time attack event)

[Megator]

Originally Posted by kart driver

Installed the camber plates + installed the racing brake pads instead of OEM.

They shop could do the following camber:

Front: -2.2 degrees
Rear: -1.8 degrees

I got the following:

1) My lap time became worse, being almost 2 seconds slower (on a 85 minute racetrack) that comparing to OEM set up with no camber plates in place
2) I didn’t like how the tires worked:
- the car was not able to slow down at the same points as I did with OEM setup last week
- the car became extremely tail happy, I had to catch it a lot when it oversteered comparing with last week when I had all OEM set up
3) The bite of the brake pads is better comparing to OEM, you can feel it immediately.
4) With the camber that I have now, the wear of the tires is more in the middle, than it used to be before with OEM set up.


What could be wrong? Any ideas?


I have a feeling that if I just go back to OEM camber angles, the handling will be better and the lap time will also be better.


P.S. I am really pushing the car a lot and use the brakes quite aggressively.


M2C, OEM everything (except for the camber plates, racing brake pads, castrol SRF fluid), michelin cup2 tires 245+265 (this I can’t change due to regulations of the time attack event)

A vid of your driving will say more than a thousand words and will help analyse whats wrong

Brakes: Did you feel you needed to brake earlier or later (you did not specify this). Sounds like you either did not get them up to temp or didnt apply enough pressure. The OEM pads are quite grabby at the top of the pedal vs. say Pagid RSLs.

Alignment: Your camber is barely different from stock. Cup 2s need much more agressive camber to work well. 3.5 front 2-2.5 rear.

Toe specs?

Remember that more front end grip without corresponding increases in the rear will give oversteer. You may also be feeling more confident and stepping on the gas a little sooner than before or carrying more speed into corners resulting in sliding on the way out.

Oh and how old are the tires? cant compare "fresh" lap times to "part worn". I notice that fuel for example makes a noticable difference in lap times.

[mr_lab_rat]

Originally Posted by kart driver

Installed the camber plates + installed the racing brake pads instead of OEM.

They shop could do the following camber:

Front: -2.2 degrees
Rear: -1.8 degrees

I got the following:

1) My lap time became worse, being almost 2 seconds slower (on a 85 minute racetrack) that comparing to OEM set up with no camber plates in place
2) I didn’t like how the tires worked:
- the car was not able to slow down at the same points as I did with OEM setup last week
- the car became extremely tail happy, I had to catch it a lot when it oversteered comparing with last week when I had all OEM set up
3) The bite of the brake pads is better comparing to OEM, you can feel it immediately.
4) With the camber that I have now, the wear of the tires is more in the middle, than it used to be before with OEM set up.


What could be wrong? Any ideas?


I have a feeling that if I just go back to OEM camber angles, the handling will be better and the lap time will also be better.


P.S. I am really pushing the car a lot and use the brakes quite aggressively.


M2C, OEM everything (except for the camber plates, racing brake pads, castrol SRF fluid), michelin cup2 tires 245+265 (this I can’t change due to regulations of the time attack event)

How did the toe change with the new alignment? In my experience it affects the handling more than the camber.
Do you have the alignment report that would show before and after?

[kart driver]

Originally Posted by mr_lab_rat

How did the toe change with the new alignment? In my experience it affects the handling more than the camber.
Do you have the alignment report that would show before and after?

This is what they did for the first time when the balance became totally ruined.

[kart driver]

Originally Posted by Megator

A vid of your driving will say more than a thousand words and will help analyse whats wrong

Brakes: Did you feel you needed to brake earlier or later (you did not specify this). Sounds like you either did not get them up to temp or didnt apply enough pressure. The OEM pads are quite grabby at the top of the pedal vs. say Pagid RSLs.

Alignment: Your camber is barely different from stock. Cup2s need much more agressive camber to work well. 3.5 front 2-2.5 rear.

Toe specs?

Remember that more front end grip without corresponding increases in the rear will give oversteer. You may also be feeling more confident and stepping on the gas a little sooner than before or carrying more speed into corners resulting in sliding on the way out.

Oh and how old are the tires? cant compare "fresh" lap times to "part worn". I notice that fuel for example makes a noticable difference in lap times.

There is no video unfortunately of those sessions where there was poor balance

Tires were absolutely new.


The shop said they can’t do -3.5 front on the stock suspension of the M2C using just the camber plates. They said they need some aftermarket steering rods to do so.

[Megator]

Originally Posted by kart driver

There is no video unfortunately of those sessions where there was poor balance

Tires were absolutely new.


The shop said they can’t do -3.5 front on the stock suspension of the M2C using just the camber plates. They said they need some aftermarket steering rods to do so.

What camber plates do you have? and the steering rod part is BS never heard of anyone needing or selling special steering rods for our cars running this kind of camber.