Mod advice... and info request...

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Jul 15, 2004 | 03:04 PM

#11

Tuga

Senior Members

Joined: Feb 2004

Posts: 523

Likes: 0

From: Portugal

My Ride: 2001 BMW 316ti, 2004 BMW 530d, 2006 BMW 530xd, 2013 BMW 320d touring, 2014 BMW 520d touring, 2016 BMW X5, 2020 BMW 320da touring, 2020 BMW 540i

Model Year: 1974

Engine: Flat six

If you prefer a classic style go for the new ones (18") but if you prefer a more sportive style you can find something diferent in BMW wheels.....

Jul 15, 2004 | 07:32 PM

#12

Ajax545

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Joined: Jul 2004

Posts: 58

Likes: 0

From: USA, Florida

Ski,

When you change the diameter of the wheel, your speedo will change. The speedo is calibrated to the diameter of the stock wheel.

First, measure the diameter of the stock wheel and then the diameter of the new wheel. Even though, the rim is 2" larger in diameter, the critical measurement is the difference in wheel diameter.

So, circum. = pi (diameter). Calculate the circum. of both and then you can determine the % error. For example, if your error is 10%, then with a larger wheel you would be going 66 mph if your speedo showed 60 mph.

I do know that GM (yes, GM - work with me here) allows for some adjustments for wheel diameter in its program. I can only imagine that has the same capability.

However, check the circumferences first and see if the error is even worth the trouble.

Jul 15, 2004 | 08:14 PM

#13

SkiScubaSailDude

Thread Starter

Senior Members

Joined: Jun 2004

Posts: 358

Likes: 0

From: Beautiful North Carolina

My Ride: 2011 F10 528i - Imperial Blue, Oyster/Black, Premium, Premium 2, Cold Weather, Xenons.

Thanks to everyone for your input! If I can just finalize the transaction, I'll soon have some mod'ed pictures.

Juan, I don't think we are going to have much luck getting any additional info on the rack attachments...

I have emailed several online dealers of parts, and have recieved no response. If only I knew who to e-mail at BMWNA for more info...

Jul 16, 2004 | 08:26 AM

#14

juan2mini

Contributors

Joined: Jun 2004

Posts: 434

Likes: 0

From: California

Ski: Thanks for the update, I will keep trying also. Good luck with wheels transaction

Jul 16, 2004 | 06:04 PM

#15

Rudy

Super Moderator

Joined: Mar 2004

Posts: 17,310

Likes: 2

From: Pittsburgh, PA USA

My Ride: G30 M550i

Model Year: 2018

I posted the following in another thread back in June. It will give you an exact calculation of speedometer error and tire size differences:

Quote:

Originally Posted by by Rudy in this thread: [url=http://e60.doit.wisc.edu/forums/index.php?showtopic=1328

http://e60.doit.wisc.edu/forums/inde...showtopic=1328[/url]]You can see all the calculations for yourself using the following calculators:

This one gives a clear explanation of speedometer error:
Speedometer error calculator

This one (using javascript) gives a whole bunch of information:
Javascript tire size calculator

Have fun!

I'm wondering if there needs to be a wheel/tire modification guide added to the soon-to-be-released FAQ?