[Brotherhef]

335i m sport, all stock, daily driver. Mp4s tires. About 3-4 track days/year.

Came factory with 225 front and 255 rear, but previous owner changed to 225 squared.

I'm about to pull trigger on some new apex 9" wheels with 245 squared. My goal is better turn in and most importantly less interference of nanny's in sport plus mode coming out of a corner and therefore a better lap time.

Im leaning towards wider rubber over a LSD because that would be much lower cost and will be very easy to sell them and recoup some cost when I sell this car in a couple years. (Money aside, I'd get both, but I just don't want to drop that type of money because I won't keep long term).

What would you do?

[Logicoeur]

Lsd.

[brigade24]

why limit yourself to 245? you can easily fit 255, even a 265 on a 9"

[Brotherhef]

Originally Posted by brigade24

why limit yourself to 245? you can easily fit 255, even a 265 on a 9"

In the front and without camber plates? Or are you just saying 165+ just on rear? Wasn't really wanting to get into suspension mods because I won't have the car long term. Same reason why I'm just considering some new wider rubber and wheels, which I'll be able to sell eventually and get back some without having to spend much time or money uninstalling parts.

Edit for extra info: Also, to my knowledge, a tire performs better when a tire has a slight stretch so there isn't as much rollover. (I could absolutely be wrong)

[RMachuca3d]

LSD

[zinner]

I would just forget about resale in the equation. I would get a second set of wheels/rubber for the track only. I would also get the front camber sorted to extend tire life.


I think LSD (assuming mperf lsd) vs Wheels tires will work out to about the same price.

I ball park a set of Apex wheels with rubber in the 2k range and theMperf LSD is about the same price as well

[EstorilMSport]

Both I would start with the stickiest and widest tires you can fit (start w/200tw). Tires are our connection to the pavement and how the car communicates with you in hard cornering, always start w/tires and brakes.

[MacklinUSOB]

One doesn't really replace the other. If you are going to invest $3000 in an LSD you should be ready to invest the money in a capable set of shoes to get the most out of it.

If you plan on selling the car just keep in mind that the LSD will not net you nearly the % in resale a set of wheels would. Also note that you can't really buy the MPerf LSD anymore so your only options are WaveTrac or Quaife. Both of these require you to send in your pumpkin for splitting the ring gear and installing the LSD. The turnaround time for this service is 3-4 weeks. I have gotten quotes on both applications through different partner shops, all were $3-3300.

[EstorilMSport]

Post in the F3X Facebook group somebody name Tony Asam is selling one.

[BMWILUVU]

LSD is nice but tires are the more important track factor.

[Brotherhef]

Thank you all for the info!

[jmg]

There is no point in getting the LSD if you aren't going to get the tires. However, you can get the tires and still see significant gains without the LSD, so get the tires first. Then the LSD.

[brigade24]

Originally Posted by Brotherhef

In the front and without camber plates? Or are you just saying 165+ just on rear? Wasn't really wanting to get into suspension mods because I won't have the car long term. Same reason why I'm just considering some new wider rubber and wheels, which I'll be able to sell eventually and get back some without having to spend much time or money uninstalling parts.

Edit for extra info: Also, to my knowledge, a tire performs better when a tire has a slight stretch so there isn't as much rollover. (I could absolutely be wrong)

255s is the max you can fit in the front without suspension mods or plates. keep in mind that i am xdrive so my stock springs are different than yours. your ride hide may be lower since you're rwd which is something to consider. The rear can be significantly wider...you can easily run a 265 in the back if you are limited to 9".

you're partly right about rollover...depends on the sidewall characteristics of the tire. stretch matters alot less with a stiff sidewall (i.e. RE71R) than with a soft sidewall (i.e. Continental DW) so there are few factors to look at.

[Brotherhef]

Originally Posted by jmg

There is no point in getting the LSD if you aren't going to get the tires. However, you can get the tires and still see significant gains without the LSD, so get the tires first. Then the LSD.

That's what I was kinda thinking.

[casualDIYer]

Originally Posted by brigade24

why limit yourself to 245? you can easily fit 255, even a 265 on a 9"

Question on 245s. I have a set of OZ Ultraleggera that are 17x8 I'd like to use for occasional track days. According to the tire maker (I use Bridgestone RE-71Rs), they say a 245 can be mounted on a 17x8 but I'm a little wary of that combo. Anyone have any experience with a 245 on an 8-inch wheel.

[casualDIYer]

Originally Posted by Brotherhef

Im leaning towards wider rubber over a LSD because that would be much lower cost and will be very easy to sell them and recoup some cost when I sell this car in a couple years. (Money aside, I'd get both, but I just don't want to drop that type of money because I won't keep long term).

What would you do?

Get the LSD.

Without an LSD, you head into a turn, slowing at first and then as you close in on the apex you start to apply throttle . . . only to find it's a lot less enthusiastic than it was before you got to the turn. It seems to be doing little.

Add on the LSD and the moment you touch the throttle in a turn, you immediately understand why anyone with an LSD can't stop praising it. Without a single engine mod, your car all of sudden finds power in a turn.

[alohasurftoad]

Originally Posted by menncars

Question on 245s. I have a set of OZ Ultraleggera that are 17x8 I'd like to use for occasional track days. According to the tire maker (I use Bridgestone RE-71Rs), they say a 245 can be mounted on a 17x8 but I'm a little wary of that combo. Anyone have any experience with a 245 on an 8-inch wheel.

just curious, does the 17x8 work over the M-sport brakes? i believe 18" is the minimum diameter that fit over them.

for a 245/45/17, tirerack has the rim width range at 7.5"9" so a 17x8 will be fine.

[Aldor27]

Originally Posted by alohasurftoad

just curious, does the 17x8 work over the M-sport brakes? i believe 18" is the minimum diameter that fit over them.

for a 245/45/17, tirerack has the rim width range at 7.5"9" so a 17x8 will be fine.

Only the rears can clear 17s with M sport brakes, and that is some wheel manufacturers, not all.

[jbiswurm]

Originally Posted by MacklinUSOB

One doesn't really replace the other. If you are going to invest $3000 in an LSD you should be ready to invest the money in a capable set of shoes to get the most out of it.

If you plan on selling the car just keep in mind that the LSD will not net you nearly the % in resale a set of wheels would. Also note that you can't really buy the MPerf LSD anymore so your only options are WaveTrac or Quaife. Both of these require you to send in your pumpkin for splitting the ring gear and installing the LSD. The turnaround time for this service is 3-4 weeks. I have gotten quotes on both applications through different partner shops, all were $3-3300.

This. They are in a lot of ways unrelated. They best way i can put it is that tires affect grip but the lsd affects power delivery-which is far more than just grip.

For example, the power you get to the outside wheel in a turn makes the car rotate so much more naturally and meaningfully.

That said, if you really have to pick, pick tires because of the enhancement tires provide to both the front and rear of the car.

[brigade24]

Originally Posted by menncars

Question on 245s. I have a set of OZ Ultraleggera that are 17x8 I'd like to use for occasional track days. According to the tire maker (I use Bridgestone RE-71Rs), they say a 245 can be mounted on a 17x8 but I'm a little wary of that combo. Anyone have any experience with a 245 on an 8-inch wheel.

yeppers, i ran a 245/40/18 re71 on an 18x8 setup and it was very good. the tire looked perfect on the wheel, not stretched, not pinched, just right. the sidewall was perpendicular to the ground. the 245s werent enough tire for the weight of the car under load but once i got the pressures right, the grip was good and they lasted a season and a half of autocross (about 25 events iirc)...i beat on those tires man and they took it until they were bald and then i used them on the street until the steel belts appeared. I squeezed every cent out of those tires...

[casualDIYer]

Originally Posted by brigade24

yeppers, i ran a 245/40/18 re71 on an 18x8 setup and it was very good. the tire looked perfect on the wheel, not stretched, not pinched, just right. the sidewall was perpendicular to the ground. the 245s werent enough tire for the weight of the car under load but once i got the pressures right, the grip was good and they lasted a season and a half of autocross (about 25 events iirc)...i beat on those tires man and they took it until they were bald and then i used them on the street until the steel belts appeared. I squeezed every cent out of those tires...

Sure enough, blessed with M Sport brake calipers in a lovely look-plain-grey, but then again, how many $100,000 cars are painted in 'primer grey' these days? A shocking lot of them. So, I must go 18-inch. Perhaps a set of FAST wheels . . .

Wow, 25 events on the RE-71R. You're my hero. I ran the fronts into slicks over 7 days at Mosport. It's like the front tire became one large wearbar.

[brigade24]

Originally Posted by menncars

Sure enough, blessed with M Sport brake calipers in a lovely look-plain-grey, but then again, how many $100,000 cars are painted in 'primer grey' these days? A shocking lot of them. So, I must go 18-inch. Perhaps a set of FAST wheels . . .

Wow, 25 events on the RE-71R. You're my hero. I ran the fronts into slicks over 7 days at Mosport. It's like the front tire became one large wearbar.

lol yeppers, I have more events on my 265s RE71s...I tuned my setup to extract as much as i could out of them because these tires hate being overdriven in heavy cars, gotta be precise and stay patient, unlike the RS4 which you can throw around like a rag doll. RS4 does much better in the heat.

I've got two sets of 18x9.5 RF03RR superspeed wheels, one set is et38 and the other is et35. they are a bit lighter than the FASTs and very robust. FAST is still a very good wheel though and you certainly will not be disappointed. FAST has the 18x10 i like which would allow for rubber so I am trying to see how i can make that work.