Ohio I've been looking a bunch at lifting my Sienna for dirtroad clearance. So far the best and easiest method I've identified is ordering custom springs from coilsprings.com and having a shop install them. The advise I've been given is a 2" spring lift will keep you operating within design specs for the suspension travel. While the lift could cause premature wear of some parts it should not be outside of the limits of anything like hose lengths or wire lengths. Some have expressed to me that this might not be true with a strut extension. For example if you put a 2" strut extension on and normally the suspension travels from 0" to 10" now it will travel from 2" to 12" and this could cause problems.
Coilsprings.com seems to be what people use for custom springs. They gave me a rough quote of $250/pair. They have a quote page on their website. Punch in some numbers if you're serious, they got back pretty quick. Folks seem to be having luck with 2" increase. However, after crawling around under the rig and jacking it up 1.5" seems a little more conservative to me but I'm still debating and probably will not pull the trigger til spring.
A taller spring will help with height but doesn't change the location of the strut to the tire so you'd be very limited to tire size.
Need to have a Strut that is longer from lower spring mount to knuckle mount to allow larger tires, or a knuckle with taller strut mount if you want to put a larger Tire on
Running taller.spring keeps the strut extended and it will top out as the op mentioned in the thread you linked.
I'd prefer strut spacer over taller coils. I have the looked at my van closely yet but based on the photos included within that thread those cvs are no where near being at bad angles. So only concern wpuld be will they rub if suspension drops to frame, or will.you over extend brake lines and abs wires.
ORO you probably want to check out these posts also: NOTE: looks like I can't post links
Google: Introducing the Sienna BE
Google: Update on my Baja edition Sienna LE
LOADS of custom work. I want an easier more straightforward mod.
I'm curious how big of tires you're looking to go with? It has been reported Michelin LTX MS 245/65R17 will fit on an '04 XLE and a 2015. I intend to try them when I buy my summer tires this spring. 29.5" diameter tire. I don't think I need any bigger and they will give a 107 load rating which should hold much better than the typical 103 Sienna rating often of stock size.
Google: will these wheels fit? michelin ltx ms 245 65 r17
Any other item out there is from Tema 4x4. I have yet to hear any report of someone trying them though.
Search eBay for: Front strut spacers for Toyota Camry Avalon Previa HIGHLANDER 30mm
About $100 shipped for a pair. They have front and back.
They are from Tema 4x4 in Russia
The Russia website says those will work with a Sienna. Of course these don't get you the strut clearance. I have considered a combo of a small strut extension and custom spring might be a good mix.
One of those posts using a Strut extension also swapped out the shocks to a shorter throw shock which might be limiting the suspension into the usable range.
I'd want to.go 245 70 17, since that's about the smallest 17 inch mud tires I've found. No point imo to ad a spring or spacer lift if I can't clear an aggressive tire. But that is just my personal preferance.
I was finally able to get my sienna up on a rat and look at the suspension on it.
Lifting the rear will be a piece of cake it has a solid rear axle with coil springs and shocks. Hey longer coil spring or just a simple coil spacer will work fine back there. I don't see any issues with the rear CV shafts. If they did you could build a lowering bracket for the differential, but I seriously doubt that would ever be needed.
Only problem I can foresee with the rear is a lift kit is going to rotate the axle being which will in turn pool the center of the wheel forward. So if you go to big of a lift it could actually pull the fire far enough forward to rub the body.
I did some measuring up front and it looks like there is about an inch and a half of clearance from a stock tire to spring Mount on the strut meaning you could effectively put almost a three inch taller before you ran into any rubbing issues. The amount of lift possible would depend on the size tire you're going to rub it if it will clear the wheel well more so than the strut I think. I do not see anything that the axle shafts could hit.
For some reason I can't post a link but I saw a wheelchair van Sienna yesterday that appeared to have a pretty serious lift, I'd guess 3 inches, maybe 4. It was converted by a company called VMI. Maybe they will sell their suspension lift parts.
They seem to have added skirts that disguised how much it is lift but it was easy to see because of the height of the rear bumper and the gaps at the top of the tire and the wheel wells.
There are a couple of companies that convert minivans over to wheelchair vans I'm going to bet it was not an all wheel drive Sienna though.
Lifting these things is really simple put a coil spacer in the rear and a strut spacer up front and you have a lift, you may have to extend the sway bar links, and you may want to find a longer rear shock, but I would probably keep the stock shock to limit the downward travel so as to not to bind the cv
Since I have a 3rd Gen, I spoke with him about that and he thinks it will work. Since he can't be 100% sure on the 3rd Gens he is looking for a test vehicle so if you have a 3rd Gen in Arizona which is not your daily drive he'd love to talk with you. Details on being a test vehicle are here: http://journeysoffroad.com/contact.html