wheel configuration
05-24-2004, 03:32 PM
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Hi,
This might be a silly question, but planning on getting 19" rims to fill the wheel gap better.. the question is i dont want to compromise the ride... Is it possible to get a 19" rim with 245/40 in front and 275/35 in the rear? I noticed that that most 19" rims are 245/35 front and 275/30 in the rear. With those configuration kinda afraid that you will bend the rims more easily. thanks
This might be a silly question, but planning on getting 19" rims to fill the wheel gap better.. the question is i dont want to compromise the ride... Is it possible to get a 19" rim with 245/40 in front and 275/35 in the rear? I noticed that that most 19" rims are 245/35 front and 275/30 in the rear. With those configuration kinda afraid that you will bend the rims more easily. thanks
05-24-2004, 04:52 PM
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My Ride: 2008 535i: June 6th start build, complete June 17th, at NY Port July 5th, at dealer July 10th, took delivery Friday July 13- Plantimum Bronze/Natural Brown Leather/Light Poplar, Sport Package, Sport Auto, Active Steering, Premium Package, CWP & PDC. Dinan Performance Software 384hp & 421 ft/lbs.
If you do that your wheel circumference will be greater. For every time your wheel rotates one revolution, you will cover slightly more distance. The biggest side effect will be that your speedometer and odometer will be off as you will be going faster/farther than you are registering. On a 275 mm tire, this number represents the tread width. The 30 number represents the side wall height as 30% of the tread width (275mm). A 19 " wheel = 482.6 mm, a 18 " wheel = 457.2 mm
The side wall are as follows but need to be doubled as you have a two side walls to account for- 275/35=96.25 mm, 275/30= 82.50mm
Circumference is pie (3.14) times the diameter
PLUS One- 275/30 19 tire/wheel = has a total diameter of 647.60 mm, circumference = 2035.31 mm
STOCK Combination- 275/35 18 tire/wheel = has a total diameter of 649.7 mm, circumference = 2041.91 mm or only a 0.3 % difference
YOUR Proposed- 275/35 19 tire/wheel = has a total diameter of 675.1 mm, circumference = 2121.74 mm or a 3.8% difference to stock
The side wall are as follows but need to be doubled as you have a two side walls to account for- 275/35=96.25 mm, 275/30= 82.50mm
Circumference is pie (3.14) times the diameter
PLUS One- 275/30 19 tire/wheel = has a total diameter of 647.60 mm, circumference = 2035.31 mm
STOCK Combination- 275/35 18 tire/wheel = has a total diameter of 649.7 mm, circumference = 2041.91 mm or only a 0.3 % difference
YOUR Proposed- 275/35 19 tire/wheel = has a total diameter of 675.1 mm, circumference = 2121.74 mm or a 3.8% difference to stock
05-24-2004, 05:48 PM
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Stick with the stock 19" offerings and you will always be safe. Also, I have the 19" style 125s, and they still ride smooth. The ride is more a factor of suspension than wheels. It just handles better now. See this....
05-24-2004, 06:13 PM
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Stick with 245/35/19 front and 275/30/19 rear. The run flat tires that are OEM on the sport package have extremely stiff side walls. That equates to a hard ride. Switching to 19" wheels means "normal" - no run flat tires. The ride should be equal to better then the OEM tires.
Be careful of the wheel offsets so the tires do not scuff the wheel wells.
Good luck . . .
(Waiting for my 19" Hartge Classics with Bridgestone SO3 tires to arrive.
)
Be careful of the wheel offsets so the tires do not scuff the wheel wells.
Good luck . . .
(Waiting for my 19" Hartge Classics with Bridgestone SO3 tires to arrive.
)
05-24-2004, 06:19 PM
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My Ride: G30 M550i
Model Year: 2018
One other huge technical thing to consider:
The speedometer is really the least of your worries. These cars rely heavily on a multitude of sensors, etc. that are calibrated with a certain level of precision.
For example, the ABS, DSC, DTC, Active Steering, Active Roll, etc. systems use the wheel speed sensor readings in their computer programs. If you change things like wheels/tires, which almost always causes a different (sometimes slight) outside diameter, you basically feed the sensors and all these systems false data. In addition, the suspension is tuned as a package. Adding wheels from the sport package on a non-sport package car isn't necessarily going to match up with the rest of the components.
The mechanical engineers at BMW, I think we'll all agree, are pretty darn good at what they do. (Let's not get into the BMW software engineers -- that's a whole other deal!) Hell, it's pretty safe to say that all the German manufacturers excel in the mechanical engineering arena. What's my point? Simple. These guys are way smarter than me (and most likely the rest of us regular folk) and the manufacturers spend tons and tons of money designing and testing everything so the entire package works as well as we've all seen and experienced. For that reason, I wouldn't think of changing anything on my car that would possibly affect the specifications of these well engineered systems. I don't need ABS, DSC, etc. kicking in too late or too early and I certainly don't want any unexpected behavior to occur under extreme conditions.
I'm pretty sure there's no way for someone to recalibrate any of these sensors for variances in wheel sizes, offsets, etc. The only sensor I'm aware of that can be recalibrated is the FTM (flat tire monitor).
Call me conservative or call me an alarmist -- it's just my two cents.
The speedometer is really the least of your worries. These cars rely heavily on a multitude of sensors, etc. that are calibrated with a certain level of precision.
For example, the ABS, DSC, DTC, Active Steering, Active Roll, etc. systems use the wheel speed sensor readings in their computer programs. If you change things like wheels/tires, which almost always causes a different (sometimes slight) outside diameter, you basically feed the sensors and all these systems false data. In addition, the suspension is tuned as a package. Adding wheels from the sport package on a non-sport package car isn't necessarily going to match up with the rest of the components.
The mechanical engineers at BMW, I think we'll all agree, are pretty darn good at what they do. (Let's not get into the BMW software engineers -- that's a whole other deal!) Hell, it's pretty safe to say that all the German manufacturers excel in the mechanical engineering arena. What's my point? Simple. These guys are way smarter than me (and most likely the rest of us regular folk) and the manufacturers spend tons and tons of money designing and testing everything so the entire package works as well as we've all seen and experienced. For that reason, I wouldn't think of changing anything on my car that would possibly affect the specifications of these well engineered systems. I don't need ABS, DSC, etc. kicking in too late or too early and I certainly don't want any unexpected behavior to occur under extreme conditions.
I'm pretty sure there's no way for someone to recalibrate any of these sensors for variances in wheel sizes, offsets, etc. The only sensor I'm aware of that can be recalibrated is the FTM (flat tire monitor).
Call me conservative or call me an alarmist -- it's just my two cents.
05-24-2004, 06:26 PM
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Rudy,
Your advise is well put ... something to think about.. i guess i have to do more homework. BTW. on separate topic..sorry.. thanks alot for last advise on the tracking info. MY car is still waiting at the port of exist .. at least thats what bmwna is telling me. its been there since 21. no info 2wglobal.com either. cant wait any longer. =)
Your advise is well put ... something to think about.. i guess i have to do more homework. BTW. on separate topic..sorry.. thanks alot for last advise on the tracking info. MY car is still waiting at the port of exist .. at least thats what bmwna is telling me. its been there since 21. no info 2wglobal.com either. cant wait any longer. =)
05-25-2004, 03:31 AM
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hi everyone! great analysis pennetta, it couldn't be explained any better than that - via numbers and all, after all says it all. although i must say that i agree with rudy as well as far as manufacturer's specs. it says that on the decal on the upper left hand corner of the windshield - bmw's disclaimer.
capebimmer's comments are exactly what i had decided early on, sport package tires are stiffer which equates to less feel for the road. so i changed mine to hartge's with the Plus One pennetta has discussed. I think that the 0.03% difference from manufacturer's specs as far as wheel size and ratio is almost meets the requirement. i've lined up the 18" sport package wheel with the 19" hartge - i can see no difference in the diameter at all.
i've had my hartge's now for 5 months, logged about 3k miles, very happy i've done it. i'm have the pirelli p-zero's. one other thing i found out, when the car is running, it rides lower therefore the 19's fill up the wheel well. in the garage parked, i can maybe have 2 fingers between the wheel well lip and the top of the tire.
capebimmer's comments are exactly what i had decided early on, sport package tires are stiffer which equates to less feel for the road. so i changed mine to hartge's with the Plus One pennetta has discussed. I think that the 0.03% difference from manufacturer's specs as far as wheel size and ratio is almost meets the requirement. i've lined up the 18" sport package wheel with the 19" hartge - i can see no difference in the diameter at all.
i've had my hartge's now for 5 months, logged about 3k miles, very happy i've done it. i'm have the pirelli p-zero's. one other thing i found out, when the car is running, it rides lower therefore the 19's fill up the wheel well. in the garage parked, i can maybe have 2 fingers between the wheel well lip and the top of the tire.