[bimmerfan235]

I'm interested in buying a rear spoiler for my M235i.
I searched on ebay and there are all these great looking carbon fiber spoilers coming from china for 100 bucks and free shipping and will be delivered within a few weeks.
Why are these products so cheap? It sounds too good to be true.
How do these compare to the OEM M Performance CF Spoiler in terms of additional downforce, performance, etc...

Thanks.

[Sportstick]

Originally Posted by bimmerfan235

I'm interested in buying a rear spoiler for my M235i.
I searched on ebay and there are all these great looking carbon fiber spoilers coming from china for 100 bucks and free shipping and will be delivered within a few weeks.
Why are these products so cheap? It sounds too good to be true.
How do these compare to the OEM M Performance CF Spoiler in terms of additional downforce, performance, etc...

Thanks.

Read closely and in great detail. Some of those are plastic spoilers with a carbon fiber-appearing covering. In the reality of day to day use, if you are happy with the fit on the decklid, the difference in effect, or any effect whatsoever of any rear spoiler is nil. This is primarily an appearance item.

[Supernaut]

Sportstick is modestly not plugging his own thread with lots of discussion about these spoilers vs the OEM ones: http://www.2addicts.com/forums/showthread.php?t=1067451 The larger spoiler has got to produce a little more effect than the puny OEM one, but I can't imagine it's anything you'd notice at road speeds. As stated, it just looks better.

The RW Carbon spoiler seems to be intermediate in price and be a truer copy of the OEM spoiler than the eBay ones.

BTW, Sportstick, have you heard any more about JB Speed making a truer copy of the OEM shape?

[Sportstick]

Originally Posted by Supernaut

Sportstick is modestly not plugging his own thread with lots of discussion about these spoilers vs the OEM ones: http://www.2addicts.com/forums/showthread.php?t=1067451 The larger spoiler has got to produce a little more effect than the puny OEM one, but I can't imagine it's anything you'd notice at road speeds. As stated, it just looks better.

The RW Carbon spoiler seems to be intermediate in price and be a truer copy of the OEM spoiler than the eBay ones.

BTW, Sportstick, have you heard any more about JB Speed making a truer copy of the OEM shape?

I asked him to send me a note if/when the original shape was revised. As I had not heard anything in the past couple of months, I just picked up the MPerformance one for $405, including shipping, from Sun. It arrived and fits as one would expect on OE part would. My car needs a minor paint repair (small electrical part fell on the roof while parked in the garage) and the spoiler can be shot at the same time and then installed, probably in next week or two.

[Supernaut]

Originally Posted by Sportstick

I asked him to send me a note if/when the original shape was revised. As I had not heard anything in the past couple of months, I just picked up the MPerformance one for $405, including shipping, from Sun. It arrived and fits as one would expect on OE part would. My car needs a minor paint repair (small electrical part fell on the roof while parked in the garage) and the spoiler can be shot at the same time and then installed, probably in next week or two.

Thanks for the update. I want to have a painted one as well.

[Cyberdemon]

There are all different levels of quality when it comes to carbon parts.

In reality, there would not be much of a functional difference if they knocked off the OEM design, simply a matter of cosmetics and longevity. Cheap carbon parts usually have crappy weaving, less than great UV protection (will fade and haze in the long term), etc.

With that said paying hundreds of dollars for OEM prices for a fancy piece strip of plastic is also a bit much.

[midwest 340xi 6sp]

Originally Posted by bimmerfan235

I'm interested in buying a rear spoiler for my M235i.
I searched on ebay and there are all these great looking carbon fiber spoilers coming from china for 100 bucks and free shipping and will be delivered within a few weeks.
Why are these products so cheap? It sounds too good to be true.
How do these compare to the OEM M Performance CF Spoiler in terms of additional downforce, performance, etc...

Thanks.

Then it usually is....

[quiksilver1029]

Haha I have to say, I love the title of this topic...and yes its no secret that Chinese are the world leaders in manufacturing budget friendly replicas.

But I think cyberdemon already gave you a pretty straightforward answer to your question. If you were driving an F1 car and needed to use premium materials then I would buy 'OEM' parts, but any spoiler for our cars is going to add around 1% more downforce, and yes a replica will have the same 'performance' functionality as an OEM part, but with the defects that come with using worse materials...UV haze and imperfect weaves. It all comes down to how much you're willing to spend because you will get the same performance results, which are zero, and basically the same aesthetics but with less durability. Then again you could probably buy 3 reps for the price of 1 OEM so consider that in terms of overall lifespan.

Originally Posted by Cyberdemon

There are all different levels of quality when it comes to carbon parts.

In reality, there would not be much of a functional difference if they knocked off the OEM design, simply a matter of cosmetics and longevity. Cheap carbon parts usually have crappy weaving, less than great UV protection (will fade and haze in the long term), etc.

With that said paying hundreds of dollars for OEM prices for a fancy piece strip of plastic is also a bit much.

[Sportstick]

Originally Posted by quiksilver1029

Haha I have to say, I love the title of this topic...and yes its no secret that Chinese are the world leaders in manufacturing budget friendly replicas.

But I think cyberdemon already gave you a pretty straightforward answer to your question. If you were driving an F1 car and needed to use premium materials then I would buy 'OEM' parts, but any spoiler for our cars is going to add around 1% more downforce, and yes a replica will have the same 'performance' functionality as an OEM part, but with the defects that come with using worse materials...UV haze and imperfect weaves. It all comes down to how much you're willing to spend because you will get the same performance results, which are zero, and basically the same aesthetics but with less durability. Then again you could probably buy 3 reps for the price of 1 OEM so consider that in terms of overall lifespan.

All good points, but the final one raises a related issue. I can share that, having spent two-and-a-half decades in the auto industry, adhesives are not to be taken for granted. I've seen them fail coming out of the plant when a supplier made an unannounced change in their process. Ambient temp, surface temp, degree and duration of pressure are all factors. I strongly suggest using a bead of urethane to seal the spoiler to the decklid surface, instead of just relying on the two-sided tape. Given the risk of a head-height "boomerang" shaped spear aimed at the driver behind you, you don't want one of these things to come loose, and it has happened. When using urethane, you blue-tape the spoiler into position and let it set for a day without any bodyflex action. At that point, it is VERY secure, so be sure you like it and want to keep it, as it is challenging to remove (although a body shop can do that too). BTW, I expect that several anecdotes will follow this post from those who have had success with just tape, but even those people probably buy insurance for their home, although it's never yet burned down!

[Gatte]

Originally Posted by Sportstick

BTW, I expect that several anecdotes will follow this post from those who have had success with just tape, but even those people probably buy insurance for their home, although it's never yet burned down!

.

[quiksilver1029]

Originally Posted by Sportstick

All good points, but the final one raises a related issue. I can share that, having spent two-and-a-half decades in the auto industry, adhesives are not to be taken for granted. I've seen them fail coming out of the plant when a supplier made an unannounced change in their process. Ambient temp, surface temp, degree and duration of pressure are all factors. I strongly suggest using a bead of urethane to seal the spoiler to the decklid surface, instead of just relying on the two-sided tape. Given the risk of a head-height "boomerang" shaped spear aimed at the driver behind you, you don't want one of these things to come loose, and it has happened. When using urethane, you blue-tape the spoiler into position and let it set for a day without any bodyflex action. At that point, it is VERY secure, so be sure you like it and want to keep it, as it is challenging to remove (although a body shop can do that too). BTW, I expect that several anecdotes will follow this post from those who have had success with just tape, but even those people probably buy insurance for their home, although it's never yet burned down!

Yes you are right, adhesives are a game of their own. I used 3M tape on my M3 spoiler for my E92 328i and it held on just fine for 7+ years. But with any part that doesn't require adhesive: mirror covers, interior trim, grilles, emblems, etc...it doesn't really matter if you go for OEM or rep

[horsepower_and_hounds]

Did someone really say.....Down force