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matty.dc
04-19-2009, 11:40 PM
Sorry for being a pain in the ass about the questions with the spacers, but would a 25mm adapter like this be alright to run ? heres the link as well......http://www.ezaccessory.com/Wheel_Adapter_4_Lug_100_To_4_Lug_100_p/4100-4100.htm

Thanks

Matt

e30_kid89
04-19-2009, 11:50 PM
Looks safe, run it...What wheels are these for?

matty.dc
04-19-2009, 11:51 PM
these are for a set of 16x7 et40 konig freefalls (i know wasn't thinking when i bought them).

e30_kid89
04-19-2009, 11:52 PM
Woah....yeeah you'll need em:)

matty.dc
04-19-2009, 11:54 PM
yea lol i know.......i knew i needed about 15mm to correct the offset issue and then theres 10mm just for the look

echo
04-20-2009, 06:29 AM
If you're going to run a spacer, this is better than the slip-on ones. BUT I'd recommend getting some that have a centre-bore that has a tight fit on the hub, and has a replacement the correct size for the wheel centre bore so the weight is correctly borne by the hub not the studs.

There is some debate as to whether this is important, however I am of the personal opinion that it is.

I wouldn't recommend running more than a 20mm spacer although 25mm would be absolute maximum without other mods to compensate for the load and geometry changes.

I have some engineering documentation I caa dig up for you if you like that covers safe wheels spacer design. Although it is a fairly conservative document - other options are possible.

theox69
04-20-2009, 09:08 AM
You'll be fine.
I'm going to be running 35mm adapters..

matty.dc
04-20-2009, 09:26 AM
i assume your adapters look like this without the centre bore to the correct size?

theox69
04-20-2009, 12:25 PM
actually, my porsche adapters are hubcentric :)

echo
04-20-2009, 05:18 PM
You'll be fine.
I'm going to be running 35mm adapters..

That doesn't make it a good idea. If you drive a slow low and bouncy city cruiser, then all good. If you have a track car, not so good. Some cars (porsche for one) had spacers on some models from factory, and big ones too, but they also have the knowledge to do the calcs and reinforce when necessary.

Be very careful pushing your rims out this much is all I have to say. Just because the wheel doesn't fall of the car the first time you drive it doesn't make it a good idea or mean it handles the same. In fact it would handle like arse in most cases especially if we are talking about the fronts.

matty.dc
04-20-2009, 05:25 PM
hmmm after these thoughts i think ill stick with the 20mm H&R trak hubcentric spacers:)

theox69
04-20-2009, 06:08 PM
That doesn't make it a good idea. If you drive a slow low and bouncy city cruiser, then all good. If you have a track car, not so good. Some cars (porsche for one) had spacers on some models from factory, and big ones too, but they also have the knowledge to do the calcs and reinforce when necessary.

Be very careful pushing your rims out this much is all I have to say. Just because the wheel doesn't fall of the car the first time you drive it doesn't make it a good idea or mean it handles the same. In fact it would handle like arse in most cases especially if we are talking about the fronts.

I will most definitely be careful, I don't drive like an idiot on the street.
But what proof is there that adapters are dangerous?
That's just like saying stretched tires are dangerous...with no proof -- because no one really has any, it's all hearsay and opinions.

echo
04-20-2009, 09:30 PM
Its to do with 1 of 2 things. Spacer design, and suspension geometry change.

I'm sure you can understand spacer design issues - Incorrect centre bores and mounting surfaces can make for improperly centred and balanced wheels = vibration = bad. Slip-on spacers are often the worst in this regard, but poorly designed bolt-ons can be equally bad. The other problem with slip-ons is people not using long enough stud bolts, and then the added danger of using really long stud bolts without proper centre bore mounting on the spacer. This means that the only thing stopping the whole lot shifting is the tightness of the stud bolts, which are now longer, and subject to greater tensile, and shear loads. High tensile bolts are rated on their tension strength, not shear strength.

So basically anything more than 5-10mm should be a bolt-on spacer with proper centre bores to transfer the load correctly to the hub other wise you can get vibration, point loading, stud bolt shear and lose your wheels.

The second factor is suspension geometry which if not properly thought out will negatively affect handling in often surprising ways - especially with a lowered setup where the trailing arm is more likely to traverse past neutral. Especially in an e30 where we have semi-trailing arms and the camber changes toward negative as the suspension compresses. The more negative offset (created by larger spacers) makes this effect more pronounced (in terms of mm toe and camber - the angles of course are the same). Properly thought out, this can be used to your advantage, improperly dealt with this can cause interesting camber and toe changes mid corner and thus loss of traction or unpredictable handling. At the front there is a similar issue with castor and scrub radius - you may experience tramlining or loss of feel and wandering, and heavier steering.

This is not to mention the added load on the wheel bearings, hubs, springs, shocks and shock towers, the rear shock towers on e30s are particularly weak and susceptible to failure with high spring and damping rates and large negative offset.

Of course all this is at the extreme end, and the most likely scenario is simply faster wear, but you wanted to know why. You are wrong to think because you havn't heard any proof, the proof is not there. All you need to do is look and read - plenty of info on how offset affects a semi-trailing arm and McPherson strut suspension setup. All you have to do is look. Here for example (http://www.e30m3project.com/e30m3performance/tech_articles/susp-tech/rear_curves/index.htm)

I'm not an expert, just a passionate enthusiast. I concede that 20-25mm spacers are no problem, and that 35mm spacers, can be used with some thought put into the spacer design, and the intended result. I guess what I'm saying is there is nothing wrong with doing it and there are also some benefits, but use decent spacers, and do the research first.

Why are you running such a large spacer anyway???

Oh and to answer the OP's question more clearly - the spacers pictured would probably be fine if you have stud-centering wheels and stud bolts. Otherwise the spacer must be hubcentric. I'd also want the spacer centre bore to fit over the vehicles hub snugly. (57.1mm for e30)

theox69
04-20-2009, 10:19 PM
Why are you running such a large spacer anyway??

Because I bought Porsche wheels that are 16x8" et49, so I got a 35mm adapter, similar to that of H&R's.
They go from 4x100 to porsche fitment, 5x130, and from the e30's 57.1mm centerbore, to porsche's 72.6mm.
I could take pics if you'd like...

everlast
04-20-2009, 11:21 PM
You guys have to keep in mind that if a 20mm spacer is on a wheel with a ET40 offset it's going to have the exact same bearing load as a 20ET offset wheel with the same dimensions. A 20ET wheel just has more depth of material cast into it.

That said, an ET0 rim would have the same effect of bearing load as a ET35 with 35mm spacers (in the style of the ones in the first pic.) Initally, you'd thing that would be a crazy lateral load on the bearing.. but..

LOTS of guys run ET0 SportMaxx rims all day long and the car doesn't collapse.

Spacers should be used to correctly place the wheel in the fender, and can be used to change the balance of the car. Try adding 8mm spacers on the rear someday and take a familiar corner hard. Be ready for a surprise.

everlast
04-20-2009, 11:24 PM
Oh, and keep in mind that changing the rim width completely changes the offset requirements to get the same 'flush to fender' effect.

The widest factory offset from BMW for E30 was the euro 15" basketweave, at 7" wide and ET25. A super common aftermarket rim for E30 is 8" wide ET20, which places the wheel 18mm closer to the fender than factory. And works perfectly.