Help Me Spec Wheels and Tires - The Unofficial BMW M5 Messageboard (m5board.com)

Diny · 6th March 2009, 02:08

This isnt normally an issue for me, since tire rack offers the wheels that I could want and offer tires to match. However, a new wheel company is doing wheels to spec and offering a number of sizes that aren't exactly standard, so I'd like to explore my options. By the way, I'm not settled on these wheels yet. But I find them attractive, so I'm exploring my options and setting up possible specs.

The wheels are Forgestar F14s, which can be seen here.

Now, these wheels are made to order and you can specify the offset. These are the specs:

19x8.5 offsets from +26 to +46
19x9.0 offsets from +20 to + 50
19x10 offsets from +20 to +45
19x11 offsets from +33 to +55

And just in case you're wondering about the weight:

19x8.5 Approx weight 22.5 lbs
19x 9 approx weight 24.7 lbs
19x10 approx weight 24.1 lbs

Now, initially, I was thinking of going with the 19x9+20 for the front and 19x10+20 for the rear. Those offsets have been recommended to me. If this was the case, then I'd just go with 255x35x19 tires for the front and 275x30x19 for the rear.

Now, for the cloudy part (while you think of these, keep in mind that I will be getting Bilstein PSS9s in the future, so I want these to go with those)

1) What keeps me from running 19x11s in the rear? I do not want them to stick out beyond the body panels. Would this be the case?
1a) If I went with this size, what offset should I go with, and what tire size?

2) Would it be outlandish to go with 19x10s in the front? Added weight wouldnt be an issue since these seem to be pretty light wheels in comparison to others of similar size. I know that some people run 18x9.5 stock wheels in the front, but would 19x10s be too far and require spacers that make the wheel stick out way too far beyond the body panels?

I know that not every wheel and tire is the same and while some may cause rubbing, others of exactly the same size may not. I don't expect to get definitive answers since there are a number of variables, but I'm looking for a bit of guidance in this department.

BMWMPWR · 6th March 2009, 18:04

What tire would you go with on 19x11? Sounds like it would either be super stretched or possibly too wide (read as "will rub").

I don't know what you have on the M right now but do you realize 275.30 on a x10 wheel will be slightly stretched? The front will have a flat albeit short sidewall but the rear as mentioned will look more barrel shaped.

Going x11 will be even more curved on the sidewall less you go 285, or 295. Maybe the stretched look doesnt matter to you. It did for me as I didn't want the VIP Lexus look on my German car, but to each his own.

Based on my calculations for the x11 a ET33 would be equivilent to x10 with ET20. I am not sure how much inside wheel space there is to play with though. What this means is that the wheel with ET33 will not stick out any farther than a 19x10 wheel with ET20. I just don't know if one would have inner wheel spacing of an entire inch in the back especially if you (will) roll lowered.

Hope this is helpful...

Diny · 6th March 2009, 18:17

I've seen a number of 19x10 wheels with 275/30/19 tires and have noticed that they fit a bit different than on the front where the tire is perfectly flush with the wheel. I can live with this.

It looks like 19x11s would be too wide and cause issues with rubbing, so looks like i'm not gonna go with those. I wasnt planning on doing it anyways but wanted to explore the option further.

As for offset, looks like the one I had in mind is pretty good.

razahyde · 7th March 2009, 19:31

if you go with 8.5x19 and 10x19 id recommend et 10 up front and 15 in back

both the front and rear will be almost lined up with the panels, giving it the aggressive stance.

BMWMPWR · 7th March 2009, 20:17

Just for kicks- two (bad) pics of ET5