Thread: e90 Forged Rims
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      04-05-2009, 02:50 PM   #14
MenTul
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Quote:
Originally Posted by AW325xi View Post
Yes, I know the advantages of forged wheels. I was mearly trying to give you an alternative that you may not have thought of. If you're serious about getting 19" forged wheels then go with Volk. For the money (not as much as HRE), they are a fantastic light weight forged rim.
Also, racing puts more stress on rims than you'll ever see on the street. Higher horsepower, specially tuned suspensions and slick tires will put way more load on the rim than any street car will (well over 1g load in turns). As for being smooth - have you ever watched Sebring? When the Corvette team first went racing in the GT2 (now GT1 category) the BBS wheels they used originally had deflected under load. They switched to OZ and found the chassis was easier to set up due to less deflection. The rims are also reused over and over again. The vast majority of race teams can't afford to purchase new rims after every race. I work on a race team that uses the stock rims (a 335) and they can't afford to purchase new rims over and over again during the season. They've been lucky to not get into trouble and have issues with the rims. So, their cast rims are working fine.
Chances are, if you had a forged rim and hit a missing manhole cover - you would have bent it too. They're very strong, but not indestructible (as you pointed out in your post racing inspection above).

Well thanks for the suggestion of alternatives. I'll stick to forged and check out the Volks.

Yes, I agree that a missing manhole cover would probably ruin a forged wheel, but the lesson I learned is to consider the strength of the wheel when upgrading rather than just going by looks. Remember, the OP was looking for strong, light and easy to clean 19". So far, all the praise for cast has been that cast should be good enough for street, not that its better. Given a choice where price premium of forged is light, I'll pick forged every time.

Again, I'll also stick to my guns that criteria for racing wheels are not universally applicable on the street. As a GT1 expert you will know that 2009 SCCA rules specify the maximum diameter for GT1 racing is 16". And in GT2, you want to run 15x7 to take advantage of th 50lb weight reduction allowance. The OP specified 19" rims. Sidewall profiles in racing are greater than those specified for 19" wheels on an e90.

Tires protect rims from road damage. Shorter sidewalls (low profiles) protect rims less than larger sidewalls. Consequently, I'll maintain that a 19" rim used on the street with 30 profile non-RFT tires will be subject to greater impact stress over the life of the wheel than an 16" wheel running higher profile racing tires.

And to your racing experience, which is more important , that the wheel not fail during the race, or that you are able to get a season out of the wheel?

I will agree with you that racing wheels are subject to greater thermal stresses. But this not a consideration on a street vehicle.

PS. Some of us have racing experience too.
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Last edited by MenTul; 04-05-2009 at 03:14 PM..
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