Dinan Strut Brace, Camber Plates, etc...
 

I just traded in my 2000 328Ci for a 2005 X5 4.4i Sport... Very happy so far, but I do miss the handling of the 3.

On the X5, I'd like to address understeer and body-roll control (especially when changing directions, e.g. in the middle of an S-turn) I thought I'd first try bumping up the front tire pressure by about 2 psi (I am currently running the stock Sp package 255/55 18" Michelins at 32 psi all around). But I'm also considering a Dinan strut brace, and camber plates...

The front strut brace made a HUGE difference in steering response, turn-in, body-roll control, etc. on my 3 - how effective is it on the X5? Has anyone noticed much of a difference with steering response and mid-S-Turn body control? Also, does it make the ride considerably more choppy over rough, uneven pavement, or is this effect more mild than on the 3-series?

And regarding the camber plates, does anyone have any experience with how well they address X5 understeer... and are there any significant drawbacks, oversteer issues, etc. ?

What other 'favorite' upgrades would you recommend?

Thanks for your help.

- Aaron

Deosn't tire pressure increase upfront reduce the contact patch and thus reduce grip, ineffect increasing front slip or understeer!? It does increase stiffness and make for a firmer ride but I dont know about better grip. I must admit I have limited experience on road-car setup. Just go karts which are a whole different animal.

contact patch size does not change with air pressure. the shape of it changes with air pressure.

more pressure makes the tire stiffer and less compliant to slip forces make it turn in a bit quicker.. its a very fine tuning process. you can get the car more neutral when you adjust more of the suspension (more results from chassis adjustments then from tire pressure)

imo, its a street car and it should have the large amount of factory understeer in it to keep untrained drivers safe (especially since instinct is to lift off the throttle when the rear starts to slide). if other people will be driving your car, i would suggest to still leave in at least some understeer, since you don't know the skill level of the other drivers....

I've always read the oposite... more psi up front is supposed to help a little with understeer.

Agreed. I don't want a drastic change, just more neutral than it is now.
Hayaku, do you have any suggestions for front/rear psi? What do you think of camber plates?

i ran 36 fr/32 rr psi when i had my x5. it was the best compromise i found for turn in and ride comfort on my stock 18"s.

personally, i prefer fix camber plates with fine adjustments by shims over the slotted type or change out the control arms to adjustable ones for camber... i have no idea what dinan offers for their camber plates, but more neg camber up front would help your turn in also (shape of the contact patch is now tear drop instead of rectangular-ovalish)

you can rotate your strut hats or the strut bearings with the stock setup to get more camber now. just disassemble and reassemble the whole thing the way you want it. you can get up to -5 deg camber i believe (way too much).

thats what i said... more psi up front reduces understeer by a tiny amount... :dunno:

I have both (the strutbrace was included in the S2 package) and I think the Dinan camber plates are one of the best mods for the money. They will change the cornering characteristics dramatically and the X5 will go into corners much faster. However the downside of running with camber plates
is that your front tires will start to weave at appr 7000-8000 miles and cause some slight vibration at around 70mph. The solution is to swap either the front tires every 8k or to have them shaved and re-balanced.

- Jan

Dear jmh - was thinking of adding the camber plates with mt Dinan S2 upgrade :cool: - what kind of driving resulted in the weave wear - I have some gorgeous mountain roads with twists'n'turns, but most of my driving is interstate 75+mph - it's going to be real embarrassing having to keep it under 70mph down I15 :loser2: - You do make a good point though, as summer tire set are not rotatable (9.5 n 10.5) - I plan on 18" identical winter set - I will have to look into this further - Any suggestions out there? :dunno:

Sorry - I was respnding to Batman!

I will try bumping up the psi up fron to 36 on your experience...
I just read an article on Motor Trend online (http://motortrend.com/roadtests/suv/112_0406_storm/) where they put the X5 4th behind the Cayenne S, FX45, and SRX (in that order), which is a little disappointing :mad: (The X5 was w/o Sp. package though) Basically, the article complained about understeer when pushed (which I already observed) but also the all-wheel drive system's rear wheel bias as opposed to the Cayenne & FX45's system that utilizes more front tire power to help pull through the turn w/ less understeer... hmm... not sure about that one. (Any thoughts?) They claimed the 5300 lb. Cayenne handled like a sports car!

To those with camber plates: do you think they're worth it overall? I would definately like to take away some understeer, but not with a big sacrifice in stright-line performance and wear.