Track to Street Alignment

[gum2012]

Hey everyone! I have an F82 and am getting a new suspension system installed. I run the stock wheels/tires staggered on the street and 18x10 Apex 275s RE-71s on the track. I put in GC plates and ran a 2.75 camber in the front for track and street and had no problem changing tires and running them on both track and street.

I went to a new shop to install my suspension (MCS 1 way ) and the guy installing it said I have to get a new alignment each time to use the different wheels since the stock wheels are 20s and the track wheels are 18s. Has anyone had this problem? Is that normal? I never thought the size of the wheel would make that much of a difference and he said the 20s wheels would last 3,000 miles.

I called another shop I love to use for brakes/wheels/alignments and they said you can do an alignment for both but obviously there is sacrifices both ways...

[dvq]

Trying not to go too far into technical detail, but different sized tire heights, wheel offsets, and tire widths can all have an effect on your dynamic suspension geometry and the way the tire interacts with the road.

However as you stated, there is a middle ground -- and the effects of running a middle ground alignment between your two tire setups are likely just limited to very mild effects such as uneven wear on on the outside shoulder of your track setup or slightly extra wear on your street setup. There are some other issues such as scrub radius that might alter how your car feels like it's handling too.

Don't worry you'll get more than 3,000 mi on your tires unless you're running a huge amount of toe in for the rears or huge amount of toe out for the fronts.

[gum2012]

Originally Posted by dvq

Trying not to go too far into technical detail, but different sized tire heights, wheel offsets, and tire widths can all have an effect on your dynamic suspension geometry and the way the tire interacts with the road.

However as you stated, there is a middle ground -- and the effects of running a middle ground alignment between your two tire setups are likely just limited to very mild effects such as uneven wear on on the outside shoulder of your track setup or slightly extra wear on your street setup. There are some other issues such as scrub radius that might alter how your car feels like it's handling too.

Don't worry you'll get more than 3,000 mi on your tires unless you're running a huge amount of toe in for the rears or huge amount of toe out for the fronts.

Thanks for the information! I tried to get a middle ground and wasn't given one by the shop. They said it's impossible which doesn't seem right.

[dvq]

Originally Posted by gum2012

Thanks for the information! I tried to get a middle ground and wasn't given one by the shop. They said it's impossible which doesn't seem right.

I'm installing camber plates and rear toe arms next week, I use 666m on PS4S for street setup and a set of SM-10 +33 18x10 square wrapped in Nankang AR-1s in 275/35/18. I haven't driven on it all yet, but I'm going to start with -3 degrees of camber and a hint of toe out up front, and -2.5 degrees of camber in the rear with a moderate amount of toe-in.

I'll be measuring tire temps with a pyrometer after each session and determine if any camber settings need to change.

Street-ability should be completely fine, the fronts should barely see any toe wear and the rears might see a little bit.

[irunalot]

How has this alignment worked out for you? I'm having my F80 ZCP corner balanced and aligned in the coming weeks. I'm curious as what these cars like.

[x.shell]

Originally Posted by gum2012

Thanks for the information! I tried to get a middle ground and wasn't given one by the shop. They said it's impossible which doesn't seem right.

Impossible LOL!

Setting up suspension is categorically about trying to find a "middle ground".

[CanAutM3]

Originally Posted by irunalot

How has this alignment worked out for you? I'm having my F80 ZCP corner balanced and aligned in the coming weeks. I'm curious as what these cars like.

Each ideal alignment spec varies with car suspension setup, tires used, tracks driven and driving style. But I can share what works for me on my M4cs with MP-HAS, GC camber plates and 275-305/35R18 NT01. I run -2.5deg camber, 10' toe in and 35psi hot front and -1.6deg camber, 18' toe in and 30psi hot rear.

This gives even temperature across the tread. Rear wear is perfect, I still struggle a bit in front with inner and outer shoulders wearing faster the middle section of the tread.

[jfritz27]

Originally Posted by CanAutM3

Each ideal alignment spec varies with car suspension setup, tires used, tracks driven and driving style. But I can share what works for me on my M4cs with MP-HAS, GC camber plates and 275-305/35R18 NT01. I run -2.5deg camber, 10' toe in and 35psi hot front and -1.6deg camber, 18' toe in and 30psi hot rear.

This gives even temperature across the tread. Rear wear is perfect, I still struggle a bit in front with inner and outer shoulders wearing faster the middle section of the tread.

CanAut, there was some other post by you on this somewhere, but can't find it for the life of me. Your rear toe: that's 18' (= 0.3 deg) total? Meaning 0.15 deg per side (the units my shop uses)? Or, 0.3 deg per side? This always confuses me

THx

[CanAutM3]

Originally Posted by jfritz27

CanAut, there was some other post by you on this somewhere, but can't find it for the life of me. Your rear toe: that's 18' (= 0.3 deg) total? Meaning 0.15 deg per side (the units my shop uses)? Or, 0.3 deg per side? This always confuses me

THx

Yes, correct 60’=1deg, so 18’=0.3deg total toe-in for 0.15deg per side.

Those are the GTS factory toe specs BTW.

[irunalot]

Originally Posted by CanAutM3

Each ideal alignment spec varies with car suspension setup, tires used, tracks driven and driving style. But I can share what works for me on my M4cs with MP-HAS, GC camber plates and 275-305/35R18 NT01. I run -2.5deg camber, 10' toe in and 35psi hot front and -1.6deg camber, 18' toe in and 30psi hot rear.

This gives even temperature across the tread. Rear wear is perfect, I still struggle a bit in front with inner and outer shoulders wearing faster the middle section of the tread.

Thank you for sharing. I'm just starting my research and have a few weeks before my parts come in.

These cars definitely like more negative camber then I expected. Toe is a on par with what I have used in the past.

[jfritz27]

Originally Posted by CanAutM3

Yes, correct 60’=1deg, so 18’=0.3deg total toe-in for 0.15deg per side.

Those are the GTS factory toe specs BTW.

Awesome, thank you.