|
Razon
Date registered: Jul 2008
Location: Vancouver, BC
Vehicle(s): 1986 280ge Cabrio, 617A, 5sp manual
| Re: SACHS HD vs Koni HT SPX on W46
512bbi - 6/8/2011 1:08 AM
With tires that heavy if you have spxs you got the wrong shocks.
Some domestic shocks like Rancho might work for you.
Mario
I'm sorry, not that I disagree with you, but that's a pointless statement.
With probably 300kg of unsprung weight/axle on a relatively light truck, you think some "rancho shocks" (any shocks out of the whole range they make?) will make my truck feel better, while the SPX's are a completely wrong choice? ....Because you say so?
Maybe you should elaborate a little.
I think you guys all say the same thing, but in different words:
If we were to have an ideal setup, with no friction losses, if you drove on a 10cm bump without shocks, the spring will initially compress 10cm, then it would release the storred energy by pushing the truck up exactly 10 cm over the neutral level. Now, if you were to time it right, and you came off the bump exactly when the truck was at max height, it will now drop 20cm (10 for coming off the bump, and 10 from the spring being extended). Without any frictional losses the truck will forever "bounce" 20cm up and down. Now if you hit another bump at the right time yet again, it will further amplify the oscillation.
So yes, without shocks, you can bottom out a suspension if you hit a relatively small bump at the resonance frequency (if you time it right).
The same way you could time it right and completely cancel the initial oscillation. However, most of the times you'll be somewhere in between, and without shocks you will be always bouncing.
The shock's job is to get rid of all the energy storred in the spring when compressed or extended and turn it into heat, bringing the suspension at it's neutral point.
If the shocks are too soft it takes longer to absorb the energy, and the car can bounce up and down multiple times before getting back to the neutral position.
If the shocks are too hard, you will start to 'feel' every bump, as in the process of absorbing the energy too fast, the shock will transfer some of it to the vehicle itself, which can be uncomfortable.
It's all about finding the right spot....even though when the weight of the vehicle can vary so much as in a truck, it's impossible to tune it perfectly.
As much as I understand how the components physically work, I've always had a hard time making suspensions feel right or perform good.
Edited by Razon 7/1/2011 4:41 AM
|
|
| |
|
ewalberg
Expert
Date registered: Apr 2006
Location: Past: San Francisco. Present: Germany
Vehicle(s): 2000 g500
Posts: 1887
| Re: SACHS HD vs Koni HT SPX on W46
the truck feels marginally better in what way? More comfortable than stock shocks? i think if anything ths stock shocks are heavily damped (compared to most vehicles) so to me it's fairly difficult to bottom out the truck. I"m running 40 psi in my bfg's of equivalent overall diamater but they'er on 17's and i think load range D, but i like the ride. It feels more comfortable than stock setup.
Is the ride just too rough over any and all bumps so becuase of that harshness you're describing it as bottoming out or do you think you're actually going all the way through your shock travel and really bottoming on the bumpers? There is a huge difference in what you might need to do to solve this issue.
What was the goal of the shocks? Softer ride? If so you may have a load range problem with the tires... you should be on D range tires perhaps.
If they're softer riding and you think you're actually bottoming the truck, you could probably have the shocks revalved by koni to stiffen compression damping if it's not adjustable. It's gonna make the ride worse, but there's no free lunch. You could put stronger bigger AMG bumps stops but it's a bandaid in my opinion for a different problem. It might work, but it might just feel like you're bottoming even faster. YOu can also try different springs, but that may have little impact if you dont have enough compression damping.
If it's too harsh riding over any and all bumps you don't actaully feel like you're getting too much suspension travel and bottoming out your suspension, then you need softer compression damping. ... okay i just re-read your posts above about harshness over speed bumps... in both scenarios you're referring to increased harshness on bumps at initial impact, and on bumps that are far less than the amount of available suspension travel than you have. My opinion is that your issue is not blowing all the way through your suspension but just general harshness, as in TOO much compression damping. Stiffer springs and stiffer bottom out bumpers will only make the problem incrementally worse. You need to have the shocks re-valved for softer compression damping... if that's possible. How much?... who knows, can you send them you old shocks for evaluation and get them valved similarly or perhaps a little lighter? Running a taller ride height spring would allow you to take advantage of a softer compression damping shock with less chance of physically bottoming out the truck, but you wont get the benefit UNTIL you have a softer valved shock on there.
If you don't like the feel of factory shocks (still too harsh), you're shooting in the dark with what you buy if you can't feel before you buy... unless you buy double adjustable (compression/rebound) shocks. Fox now makes piggy back reservoir shocks for our trucks. THey aren't double adjustable, but the single adjustment may be designed to substantially affect both compression and rebound. If so that's be your best bet, but i'd call them to discuss if i were you. OH!... and one of the websites that sells the fox shocks recently noted that the website offers one free re-valving (through fox i would assume) so there's a lot less risk that you'll be stuck with a shock you hate... this is sounding like a best bet to me. Then you could adjust it for street or offroad. Sometimes (many times?) a single adjustable shock only really affects rebound with only a small affect on compression. That, i don't think is not ideal, but since the fox's are re-valveable at least you know for sure you can iterate in with them what you want.
Keep in mind a comfy shock will very likely be more easy to bottom out and damage expensive things like axles, so be careful with that and in if so, stiffer or especially taller springs and bigger AMG bottom out bumpers might be a worthwhile compromise to be safer without fully negating the benefit of softer shocks you want.
Fox may also be willing to make you a set of double adjustable shocks. You're gonna pay for 'em, but it could be worth it depending on your druthers. Ohlins also does all kinds of shocks for everything from stadium trucks to race cars, so they could also possibly put something together for you.
PS. i still think your load range E tires are part of the problem. You're welcome to stop by some time to drive my truck and/or trade wheelset with me for a couple days if you want...
Edited by ewalberg 7/1/2011 5:10 AM
|
|
| |
|
hipine
Date registered: Jul 2006
Location: US, CO, Bailey
Vehicle(s): 460 1980 280GE w. 617A
| RE: SACHS HD vs Koni HT SPX on W46
Redbull Addict - 6/30/2011 11:59 PM
...I'm open to all suggestions. :cheers:
Hey Tom!
Always nice to hear from you. I don't normally get into threads like this, but I couldn't help but notice that in your first post in this thread you mentioned that the factory shocks on your truck had been in place for 94,000 miles and that since you were considering replacing them...
"....I might just do the OEM shocks since I have some faith in MB engineers but if I can find something just as good for less or something noticeably better for just a touch more, I'd go for it...."
Based on that, I might suggest thinking back to whether the ride from factory shocks was problematic at all. I didn't notice you indicate so back then, but maybe you had unstated feelings or I missed something. Maybe think about just replacing the Konis that aren't cutting it for you with a new set of the factory shocks that were designed to work opimally with the spings your truck came with over a wide variety of conditions, and be done with it. In effect going back to a known quantity vs trying to chase more unknowns.
No need to reply or justify anything. Your reasons are your own. But when I saw you open the door to "all" suggestions, I felt obliged to pipe up. The above are ust my thoughts in trying to keep that infectious grin on your face while driving.
All the best,
-Dave G.
PS - would mostly love to hear more about your DV adventure. Maybe a few words in another thread with a few pix! |
|
| |
|
Indiana Drew
Expert
Date registered: Feb 2007
Location: Houston Tx
Vehicle(s): 2002 G500 LWB, 1980 280GE SWB (Sold), S500
Posts: 2223
| RE: SACHS HD vs Koni HT SPX on W46
Redbull Addict - 7/1/2011 12:59 AM OK gents...it's my turn again  15K miles later I can't take it anymore. With my BFG AT's 285/65/18 E-rated at 32lbs cold, the truck feels like its bottoming out when hitting potholes or speed bumps at anything over a slow speed.
When I put the SPX on my truck at 100K+ I also replaced the my tires with Hankook ATM 275/70-18. Running at 32psi I experienced the same jarring feeling. Reducing my pressure to around 28psi for unladen, local driving has mad a huge difference. I still want to do some adjusting of the shocks to see how things are effected. I can say that if I am able to switch things around and run with a 295/75-16 on the '02 the ride will be even better. With shorter sidewalls on vehicles in general these days, I believe the rest of the suspension has to work that much harder to achieve the same "comfort."
Until we acquired our 2000 S500 I thought both the G500 and the 280GE road well - now I feel ignorance was bliss ... |
|
| |
|
512bbi
Expert
Date registered: Jan 2007
Location: North western US and Europe
Vehicle(s): 05G55kge,Range rover classic,clk55amg,ML 430
Posts: 1313
| RE: SACHS HD vs Koni HT SPX on W46
Some great points mentioned here.
Stay with MB engineering.
That is what I do,but I also take in consideration my personal experience from having a hobby with setting up my vehicles and make them perform.
Most Gs are built for of road so the factory setting will be good enough if serviced and parts changed when needed.
Amg was made to run a little more spirited both on and off road.
Tom wants comfort and better performance than he has experienced.
The MB way calls for more spring rate and the right shocks for what Tom wants to have...he can copy MB engineering and delete the part that is good for 130mph.
Simple.
Some do not read detail and talk about big springs etc
To elaborate a 50/50 shock works with high unsprung weight unless you know how to custom build something better.
Red springs are soft and about 15 pounds per inch stiffer than yellow orange.
The amg cilastios inside their shocks does not come into play much on pavement but does wonders of road.
Double spring design is for comfort and best handling.
Big bumps require a lot more spring than small bumps at all speeds but crawling.
If you only have higher rate springs you loose comfort and handling on small bumps.
If you only have light springs you loose handling and comfort on big bumps and higher speeds.
Shocks are to control the springs not the rest.
Their function is very complicated and thinking that is simple is silly....there is millions spend in racing by companies like Koni to build winning parts.
The G is not for winning races or a race car.
The Spxs are for light use and the ones that have them and say are great for of road do light use of road if they did not they would be saying something else...
Lets help Tom make a choice that will make him get what he wants,comfort on pavement and ability and comfort to run at an aggressive clip on wash boards at death valley with out beating up his G
The right spring system for his weight is the first and most important part to figure out.
After that he can get the shocks that will work with his springs.....shocks along do not cut it with the wrong springs.
MB usa trucks are heavy at the front and were designed for the US to be driven to the grocery store by most.
Tom if you weight your truck on a truck stop front and rear axle I am confident I can recommend the right set up for what you need with the least expense.
This is not because I know it all but because I have run your exact tires and know what works with them.
Another option you have that I did not mention is to custom order bilsteins for the same money as the ones of the self or less with custom valving and have a lifetime warranty for as long as you own your truck using your old worn out shocks and depending on your weight you might end up keeping your springs and only add the ones inside the shocks....you will not believe what a difference they make..........amg knows best......
Mario |
|
| |
|
512bbi
Expert
Date registered: Jan 2007
Location: North western US and Europe
Vehicle(s): 05G55kge,Range rover classic,clk55amg,ML 430
Posts: 1313
| Re: SACHS HD vs Koni HT SPX on W46
ewalberg - 7/1/2011 3:04 AM
the truck feels marginally better in what way? More comfortable than stock shocks? i think if anything ths stock shocks are heavily damped (compared to most vehicles) so to me it's fairly difficult to bottom out the truck. I"m running 40 psi in my bfg's of equivalent overall diamater but they'er on 17's and i think load range D, but i like the ride. It feels more comfortable than stock setup.
Is the ride just too rough over any and all bumps so becuase of that harshness you're describing it as bottoming out or do you think you're actually going all the way through your shock travel and really bottoming on the bumpers? There is a huge difference in what you might need to do to solve this issue.
What was the goal of the shocks? Softer ride? If so you may have a load range problem with the tires... you should be on D range tires perhaps.
If they're softer riding and you think you're actually bottoming the truck, you could probably have the shocks revalved by koni to stiffen compression damping if it's not adjustable. It's gonna make the ride worse, but there's no free lunch. You could put stronger bigger AMG bumps stops but it's a bandaid in my opinion for a different problem. It might work, but it might just feel like you're bottoming even faster. YOu can also try different springs, but that may have little impact if you dont have enough compression damping.
If it's too harsh riding over any and all bumps you don't actaully feel like you're getting too much suspension travel and bottoming out your suspension, then you need softer compression damping. ... okay i just re-read your posts above about harshness over speed bumps... in both scenarios you're referring to increased harshness on bumps at initial impact, and on bumps that are far less than the amount of available suspension travel than you have. My opinion is that your issue is not blowing all the way through your suspension but just general harshness, as in TOO much compression damping. Stiffer springs and stiffer bottom out bumpers will only make the problem incrementally worse. You need to have the shocks re-valved for softer compression damping... if that's possible. How much?... who knows, can you send them you old shocks for evaluation and get them valved similarly or perhaps a little lighter? Running a taller ride height spring would allow you to take advantage of a softer compression damping shock with less chance of physically bottoming out the truck, but you wont get the benefit UNTIL you have a softer valved shock on there.
If you don't like the feel of factory shocks (still too harsh), you're shooting in the dark with what you buy if you can't feel before you buy... unless you buy double adjustable (compression/rebound) shocks. Fox now makes piggy back reservoir shocks for our trucks. THey aren't double adjustable, but the single adjustment may be designed to substantially affect both compression and rebound. If so that's be your best bet, but i'd call them to discuss if i were you. OH!... and one of the websites that sells the fox shocks recently noted that the website offers one free re-valving (through fox i would assume) so there's a lot less risk that you'll be stuck with a shock you hate... this is sounding like a best bet to me. Then you could adjust it for street or offroad. Sometimes (many times?) a single adjustable shock only really affects rebound with only a small affect on compression. That, i don't think is not ideal, but since the fox's are re-valveable at least you know for sure you can iterate in with them what you want.
Keep in mind a comfy shock will very likely be more easy to bottom out and damage expensive things like axles, so be careful with that and in if so, stiffer or especially taller springs and bigger AMG bottom out bumpers might be a worthwhile compromise to be safer without fully negating the benefit of softer shocks you want.
Fox may also be willing to make you a set of double adjustable shocks. You're gonna pay for 'em, but it could be worth it depending on your druthers. Ohlins also does all kinds of shocks for everything from stadium trucks to race cars, so they could also possibly put something together for you.
PS. i still think your load range E tires are part of the problem. You're welcome to stop by some time to drive my truck and/or trade wheelset with me for a couple days if you want...
Erik
Have you ever driven a G with amg shocks or any set up with their cilastios?
If you do you will have a totally different perceptive of reality instead of estimation.
If pushed hard to bottom out ,not only they feel like they never do but the end travel is soft (no banging from bottoming) and it never comes in too early or cost any limitation in compression travel.
It is all technology invented by koni many decades ago and the smartest cheapest double spring set up out there where is in effect when needed less than all the time but very efficient.
If you try it you will change your mind about lots of things.
Mario |
|
| |
|
Redbull Addict
Veteran
Date registered: May 2006
Location: Morgan Hill, California USA
Vehicle(s): '12 G550
Posts: 171
| RE: SACHS HD vs Koni HT SPX on W46
Hi Guys,
Sorry for the delay in responding. Claudia and I had twin girls two months ago and you can probably imagine where my time goes.
Im typing with one hand so please excuse the grammar and punctuation.
I just had a few minutes to go under the truck because I noticed a fairly strong vibration these last few days after this last trip. Im trying to post some pics using Chrome on my Mac but it doesnt seem to want to work. http://redbulladdict.smugmug.com/Other/misc/2461332_PD8d3#1365180239_ZwvGtrH If you go to this url you will see three pics. T?he front left shock looks like it leaked a while back and is dry while the right is still soaked. I ran my hand on it and I had a nice wet coat of fluid on my hand. I suppose this will answer part of my issue. The ride was never great for me but its noticeably worse now, to the point where I feel a difference. The question now is what to do...Koni's support was non-existant for me before so I almost dont want to bother even trying to deal with them. crap gotta run. |
|
| |
|
dai
Expert
Date registered: Apr 2006
Location: Oregon USA
Vehicle(s): 300GD 300TD BMW R100RS Landini 80F
Posts: 2110
| Re: SACHS HD vs Koni HT SPX on W46
Tom, so sorry you have defective shocks. Mine have been really great and continue to work very well. Get them to refund your $ and get some stock shocks. You have had such a bad run with the Koni's it is unlikely you will be satisfied even if they send you a set of perfect ones in exchange.
-Dai |
|
| |
|
Redbull Addict
Veteran
Date registered: May 2006
Location: Morgan Hill, California USA
Vehicle(s): '12 G550
Posts: 171
| Re: SACHS HD vs Koni HT SPX on W46
dai - 7/3/2011 9:18 AM
Tom, so sorry you have defective shocks. Mine have been really great and continue to work very well. Get them to refund your $ and get some stock shocks. You have had such a bad run with the Koni's it is unlikely you will be satisfied even if they send you a set of perfect ones in exchange.
-Dai
Hi Dai!
Yea, my bad luck I suppose.
Sean at Eurotruck really helped me out already but I think the warranty on these things is up (11 months and 16K miles later).
I'll load up my truck as if heading out for a trip and see what the truck weights. If I'm going to do this again, I want to do it right this time and hopefully last time.
Cheers! |
|
| |
|
Redbull Addict
Veteran
Date registered: May 2006
Location: Morgan Hill, California USA
Vehicle(s): '12 G550
Posts: 171
| RE: SACHS HD vs Koni HT SPX on W46
hipine - 7/1/2011 5:02 AM
Redbull Addict - 6/30/2011 11:59 PM
...I'm open to all suggestions. :cheers:
Hey Tom!
Always nice to hear from you. I don't normally get into threads like this, but I couldn't help but notice that in your first post in this thread you mentioned that the factory shocks on your truck had been in place for 94,000 miles and that since you were considering replacing them...
"....I might just do the OEM shocks since I have some faith in MB engineers but if I can find something just as good for less or something noticeably better for just a touch more, I'd go for it...."
Based on that, I might suggest thinking back to whether the ride from factory shocks was problematic at all. I didn't notice you indicate so back then, but maybe you had unstated feelings or I missed something. Maybe think about just replacing the Konis that aren't cutting it for you with a new set of the factory shocks that were designed to work opimally with the spings your truck came with over a wide variety of conditions, and be done with it. In effect going back to a known quantity vs trying to chase more unknowns.
No need to reply or justify anything. Your reasons are your own. But when I saw you open the door to "all" suggestions, I felt obliged to pipe up. The above are ust my thoughts in trying to keep that infectious grin on your face while driving.
All the best,
-Dave G.
PS - would mostly love to hear more about your DV adventure. Maybe a few words in another thread with a few pix!
Hi Dave!
Good to hear from you! I'll work on posting some pics of my trip to DV, Arizona and Utah.
Take care,
Tom |
|
| |
|
hipine
Date registered: Jul 2006
Location: US, CO, Bailey
Vehicle(s): 460 1980 280GE w. 617A
| RE: SACHS HD vs Koni HT SPX on W46
Redbull Addict - 7/2/2011 5:40 PM
....Claudia and I had twin girls two months ago and you can probably imagine where my time goes.
....crap gotta run.
We don't have to imagine a thing Tom. You spelled it out for us!
Thanks for sharing the great news! Best of luck with the shocks. There's a lot of good experience here for you to benefit from. I'm still liking the Doetsch setup I got from Chuque many moons ago, but my case is not the norm, with white springs and going either empty on-road or loaded to the gills + roof top tent when I'm off it.
All the best,
-Dave G.
Edited by hipine 7/3/2011 6:18 PM
|
|
| |
|
512bbi
Expert
Date registered: Jan 2007
Location: North western US and Europe
Vehicle(s): 05G55kge,Range rover classic,clk55amg,ML 430
Posts: 1313
| RE: SACHS HD vs Koni HT SPX on W46
It is so difficult to know when one shock goes bad not both on one axle.
It can feel like nothing is wrong often.
I believe in cases where heavier springs are used the spxs might do better than soft springs because they can have enough extension forces for controlling a heavier spring which helps with lack of compression dampening with normal unsprung weight.
When lighter springs are used(like orange yellow) with spxs is easy to blow a new shock because the soft compression can get them to damage the foot valves at bottoming out(if too long) and mostly at full extension since they do not have limiting travel valves as the 90s have so nothing internally is as strong as it should be to hold all your unsprung weight at full extension and protect the shock.
On the G the shocks limit the full droop at end travel.
Dave
Are the white springs stock equipment on your truck?
The older Gs and everything non MB usa it sounds like it was designed by MB for more of the real purpose of the G in the dirt.
With out cilastios in front shocks I would agree red fronts do not cut it on a heavy front end G like mine since they are about 140 pounds per inch springs and anything up to two hundred pounds per inch can be ok in comfort.
The front white ones are around 190-210 so they should be the right springs for the G for everything with out the modern cilastio approach.
Mario
|
|
| |
|
hipine
Date registered: Jul 2006
Location: US, CO, Bailey
Vehicle(s): 460 1980 280GE w. 617A
| RE: SACHS HD vs Koni HT SPX on W46
512bbi - 7/3/2011 6:56 PM
Dave
Are the white springs stock equipment on your truck?
No Mario, I think my truck came from the factory with some combo of yellow/orange springs and Bilstein shocks that were all (springs mostly) totally shot by the time it came into the care of the PO with about 215k on the clock. One of the few things Chuque had time to do with this truck while he had it was slap on the all-white springs. His goal was only height, to fit bigger tires. In hindsight they would have been all wrong for his "extreme rocks only" intentions for the truck. They seem to work pretty well for me. I've been running this combo nearly 200,000 miles now. Yes the same shock bodies, rear shafts replaced once before I added boots (modified by me to prevent internal dirt and ice buildup).
I might be blissfully ignorant of potential for improvement, but in this case, good enough is good enough for me and a lot of my needs outside of top ride qulity are being met too, like $40 rebuilds at my whim (done twice so far), and the abilty of the system to protect the truck from my occaional lapse of concentration. I DO NOT recommend hitting oblique angle ditches hard enough to turn a fully loaded (family of 5 with gear for a week) G into a 3D-gyrating bucking bronco with air under the tires while TOWING A JEEP WRANGLER. But I managed to do it last Christmas along the Wingate Road (beside it really) and the springs, shocks, chassis, AND 617A oil pan, all came through it without any sign of the abuse. I needed to go to 4wd confession for that one.
Bless me Harald, for I have sinned.
I have broken the 3rd, 12th, 19th, and 137th commandments, concurrently.
Peace be with you, child. The father has seen your transgressions and heard your pennance.
Perform five front axle rebuilds and ten full vehicle fluids flushes and your sins will be forgiven.
Go in peace and post no pictures of these transgressions to internet forums.
-Dave G.
PS - honestly I'd probably like a little more front end compliance for daily driving (washboard dirt and rough pavement seen every day), but at the same time, I'd be afraid of what that would do to fully loaded, roof top tent hauling performance in the mountain twisties that I'm lucky enough to see with some regularity. But this is about Tom. I'll shut up. 
Edited by hipine 7/4/2011 10:36 AM
|
|
| |
|
512bbi
Expert
Date registered: Jan 2007
Location: North western US and Europe
Vehicle(s): 05G55kge,Range rover classic,clk55amg,ML 430
Posts: 1313
| RE: SACHS HD vs Koni HT SPX on W46
Dave
That was too funny but it proves a good point.
I run 200 pound springs at front of my Rover and it handles everything just fine.
I wonder what kind of pan hard rod matches the white springs .......on an MB usa G I wonder if they will be sitting taller than reds.
Mario |
|
| |
|
512bbi
Expert
Date registered: Jan 2007
Location: North western US and Europe
Vehicle(s): 05G55kge,Range rover classic,clk55amg,ML 430
Posts: 1313
| RE: SACHS HD vs Koni HT SPX on W46
Dave
Correction here .....I worded this totally wrong .....front whites will be sitting taller than reds ,at least on my truck by 3/4 of an inch at least if one used one stripe at front and another 1/4 inch at least (rough guess ) per additional stripe all for the front.
I run almost at the end of the chart around 6800 N load per spring at the front.
I wonder how much weight Tom has, and any us 500 even empty at front.
That would have the truck totally level with white all around with out load ,so I wonder what happens with load at the rear not to be lower back there.
With winch ,roof top tents and proper weight distribution I would agree whites all around should be ideal springs for one wanting enough spring for lots of over landing with just their matching shocks from MB.
The cilastio spring solution is great for dual pavement and of road combo but would not be the best with full load and priority for of road all the time.
I would love to know if anyone knows which panhard rod( part number) keeps the front axle from sitting left and rear to the right on an average load with all white springs with the 4 door late model G
Mario |
|
| |
|
hipine
Date registered: Jul 2006
Location: US, CO, Bailey
Vehicle(s): 460 1980 280GE w. 617A
| RE: SACHS HD vs Koni HT SPX on W46
512bbi - 7/5/2011 2:10 AM
....I would love to know if anyone knows which panhard rod( part number) keeps the front axle from sitting left and rear to the right on an average load with all white springs with the 4 door late model G...
I had no idea they had different lengths. The G's panhard rods sit so close to level, and near level an inch of vertical offset causes only about 1/8" lateral movement, that I'd find it hard to believe that any difference would be noticeable. I was going to offer to try and measure how far my axles are displaced, but I'd be suspicious of whether I could make measurements accurate enough to tease out that degree of offset.
This brings an interesting thought to mind though. I do my own alignments with the "string and cinder block" method. It never occurred to be in doing that, that my technique should account for axle offset from the taller springs. Now you've got me curious, Mario!
-Dave G. |
|
| |
|
512bbi
Expert
Date registered: Jan 2007
Location: North western US and Europe
Vehicle(s): 05G55kge,Range rover classic,clk55amg,ML 430
Posts: 1313
| RE: SACHS HD vs Koni HT SPX on W46
Dave
I have seen different part numbers on EPC so I am thinking they have to be different lengths since there is so many different riding heights as there is MB springs
It can get even more interesting.
The panhard rod is more sensitive in axle position than I thought also initially(just by looking ) when I first installed the red springs and then after they settled gained some more ride height with the amg little cilastios.
It gets even more complicated if one considers the fact that the front trailling arms are further from each other at front end at the axle than the chassis and the rears are parallel.
Even more interesting is if you string measure diagonally your thrust angles you will discover a front axle facing left(as of left hand turn on the direction of travel forward) and the rear facing right!
Now is the best part ....it all shifts the opposite way as the axles get further from the chassis on extension,in other words the front axle will start moving facing more the right and the opposite with the rear ......getting straighter as you lift.
If all this was not enough when you shift the front axle left by taller springs and the rear to the right from the panhard rods action, your trailing arms operate different with braking forces when the axles pull against them(at the front) or away (the rear) because by shifting sideways one of them will effect the bushing flex different than the other.
Also your ride height changes from side to side because the length of trailling arm to axle gets shorter on the front left when you lift and the right one gets longer .
Longer and shorter meaning the distance of point of attachment on chassis and to axle.
Now that also effects your handling since your corner heights operate different on left turns versus right turns.
When you turn left your front right will lean more than your front left does when you go right(more body lean to the right than left cornering) created by the tralling arm positions and both front and rear making the front right lower.
Also the rear left will compress easier than the rear right for the same reason on cornering which makes the the truck corner better going right than left.
If I remember right you are the only one with out the G wobble with out a heavy duty steering shock.
I would love to find out if maybe the specific height of your well settled white springs might be the perfect geometry for when the G was designed or if maybe the front spring rate might be doing wonders on the same issue not allowing excessive compression on small bumps as with softer springs.
If we knew your specific axle weights front and rear we could determine your spring loaded height easily and have a good source of comparison for reference together with your findings measuring.
One of the reasons for the mushy trailing arm bushings I believe is to make up for thrust angle changes as they constantly happen in operation of the old beast.....
I do not believe thrust angle makes much of a difference unless excessive but the way left and right corners operate with trailing arms out of place because of wrong panhard rod length should unless you drive on big open smooth dirt roads like Harald does on rocks............
Mario |
|
| |
|
AlanMcR
Expert
Date registered: Apr 2006
Location: US, CA, Los Altos
Vehicle(s): G300DT E300DT 230SL
Posts: 3500
| RE: SACHS HD vs Koni HT SPX on W46
I know there are two different front panhard rods, however these differ in strength not length. Apparently people were bending the front by wedging the tire against a rock/curb and then turning the steering wheel. Since they strengthened the panhard, I wonder what bends now?
|
|
| |
|
Redbull Addict
Veteran
Date registered: May 2006
Location: Morgan Hill, California USA
Vehicle(s): '12 G550
Posts: 171
| Re: SACHS HD vs Koni HT SPX on W46
I spent this morning running around trying to find a place that would let me weight my truck or weight it for me but no luck. The best I could do is get an appointment for tomorrow morning to get the whole truck corner weighted.
Should I weight it with my gear and without? Any other measurements worth capturing? |
|
| |
|
hipine
Date registered: Jul 2006
Location: US, CO, Bailey
Vehicle(s): 460 1980 280GE w. 617A
| RE: SACHS HD vs Koni HT SPX on W46
512bbi - 7/5/2011 2:18 PM
Dave
I have seen different part numbers on EPC so I am thinking they have to be different lengths since there is so many different riding heights as there is MB springs
Oh. Well, my only experience with different panhard bars is in relation to what Alan mentions below, strength, not length. That doesn't mean they didn't make different lengths, just that if they did, we I haven't heard of it before. If they did as you say, I'd expect the packages to be lumped into an "SA" number applied together. Maybe you can find evidence of this on a data card, or in the EPC.
I do know that the military Gs that have significantly more axle-to-chassis distance than our civy ones, use a lowered panhard bar (and radius arm for that matter) mounting point on the chassis to maintain optimal near horizontal panhard bar geometry, and not merely increase panhard length to get the axle in the right place. Just more food for thought.
-Dave G. |
|
| |
