Photog's Lifted Suspension 2009 Roadtrek 190V

[booster]

I assume you put GM aluminum wheels on it, and not the Roadtrek factory wheels. Offset should be about +27mm.

What you describe in handling is pretty much the classic symptoms of toed out, instead of in. When toed out, they get "twitchy" with small corrections amplified into big movements. You pretty much weave your way down the road. You had the toe in checked, but I don't understand the numbers. Toe in is plus, toe out is minus, so I think you just have the signs switched. If the front end is worn, the slack from the wear adds to the toe out direction, so it could have toe in when checked, but go to toe out while driving. This is a very common mistake that shops make. They should always push the wheels in and out against the looseness to see how much the toe changes, and make sure it doesn't switch to out. As vehicles age, and the front end parts wear, they generally will need more toe in to keep handling well (this is for rear drive). The spec on our 07 one ton is +.1* +/-.2* total toe in. .1 degree is only about .050" in the old school toe in dimensions, which is pretty small for such a big vehicle 1/16" to 1/8" in was pretty common in the day.

The wheel change changes the load on the spring, bearings, etc, as you mention, but it also changes the scrub radius, making it lower. This makes less effort needed to overcome the roadforce put on the tire, so steering gets a bit lighter. It shouldn't make it twitchy, however. It will reduce the affect how one wheel bumps and puddles throw you around, improving that a bunch.

With the wheels moved in, you may need a different tire pressure. Overinflation in the front can make them twitchy also. On a 170 45/50 psi probably would be plenty.

The negative camber is probably because you are low, and if you are on the bumps while sitting, you are VERY low. The normal ride height for the one ton puts the front wheel wells about 35.5-36" from the ground with 245-16-75 tires. Our factory manual shows the 8600# capacity 2500 at only .3" lower. Negative camber will also make them less directionally stable, as you are running on the inside of tire, which can make the effective scrub radius change to the minus direction. Possibly going to the less offset, which reduced scrub radius, and negative camber reducing scrub radius has put you over the edge. Slight positive camber is usually the best for directional stability. Loose wheel bearings also can move you toward negative camber.

The Bill Erb topic has one positive from the Mexican Doctor, and one negative from someone else who got Erb springs, but his shop was not able to get them into the van. So it's a tie, I guess.

You have a big advantage, as you have a 3/4 ton van. It is very likely that if you put the 1 ton springs in it, you may just come out right. I think all the factory springs are about the same free length, and only change in spring rate. Our Tufftruk 5K springs and factory 4300# springs were essentially the same free length. Both could be put in without a spring compressor. The longer springs folks are talking about are because they want to get lower spring rate (softer ride), but still gain the 2" of lift to get back to factory ride height. You then need a monster spring compressor and can get the bowing and interference issue that have been mentioned. If you put the bigger springs we have been using for the 1 tons in your van, you will be very high and harsh, I think. Most of us have at least 4100# on the front wheels.

The fact that the bottom of the van is all banged up is pretty worrisome. Ours would only hit in the middle, if it was high centered, on uneven terrain. It never hit on highway dips or bumps. A good look over over the frame for damage is probably in order. Negative camber is one of the first things that shows up if a vehicle has bottomed out hard and often.

It certainly wouldn't hurt to go down and see Bill Erb, as he does have an excellent reputation, to see what he recommends, and if it makes sense. One thing all the discussions we have had on here have shown is that there appear to very very different results being achieved from some of the same changes It is very hard to understand why that is happening.

[markopolo]

Re: Bilstein shocks - Mike alerted me of a new part # for the rear shocks so I searched around a bit.

I found this PDF file: New_Products_Datasheet - October 2012.pdf - Bilstein which shows:

Year............Model............. Part #............ Setting........... Position
1996?2013 ... Express 3500 .... 24?221948 ...... 4600 Series ..... Rear
1996?2013 ... Savana 3500 ..... 24?221948 ...... 4600 Series ..... Rear

Some online shops don't show the new part number for my van. It might just be a part # consolidation or an update but I figure I might as well get shocks with the new part number.

[2wiresdave]

I have a set of Erb's springs that never got installed. I did have Timbren's put in up front and an extra leaf in the back. Van rides really nice but I am still looking for that 2.5+ inch lift...waiting to hear on the new Tufftrucks and will order them as soon as they get the greenlight. The work done got me around an inch or so - not enough, but the Timbren's really made a ride quality difference in the positive column.

If anybody wants to try my Bill Erb springs I'd sell them...

[booster]

Originally Posted by 2wiresdave

I have a set of Erb's springs that never got installed. I did have Timbren's put in up front and an extra leaf in the back. Van rides really nice but I am still looking for that 2.5+ inch lift...waiting to hear on the new Tufftrucks and will order them as soon as they get the greenlight. The work done got me around an inch or so - not enough, but the Timbren's really made a ride quality difference in the positive column.

If anybody wants to try my Bill Erb springs I'd sell them...

Do you have the capability to measure the Erb springs, so we can compare to the stock and Tufftruck ones?

Tape measure for free height and outside diameter

Caliper or micrometer for the wire size

Count the number of turns, or picture

I think it would be very informative for this discussion.

[2wiresdave]

Sorry for the slow reponse! The springs are 18" long (free height) and about 6" diameter. 8 total coils. Wire size of coils right at 1".

[booster]

Originally Posted by 2wiresdave

Sorry for the slow reponse! The springs are 18" long (free height) and about 6" diameter. 8 total coils. Wire size of coils right at 1".

How did you measure the wire diameter? I have been playing with a spring rate calculator, and even very small changes in wire diameter make a big difference in spring rate. Our 1617s are very similar to what you have 17.7" free length (Photog's measurement), 8-9 coils, 1.050" diameter wire. Using the calculator, if the springs you have are right at 1.000 wire diameter, they would lift the front about 1.2" at the wheelwell. They would require a little under 1000# of compression to get the same length as the 1617 and stock springs, for installation. The Erb springs would be in between the 1617 and the longer ones that Photog had for springrate.

[2wiresdave]

I measured them using a vernier caliper on several of the coils to verify my measurement...boy, I am really scratching my head now since the shop where I brought them acted so shocked at how stiff they were! Are the 1617's (the currently available ones) the same length as stock?

The 1617's I thought were giving somewhere around 2-3" of lift - or did I misunderstand something? I was really hoping you guys would be shocked at the measurements...would have made me feel much better !

Thinking I might try ordering the 1617's and seeing if I can find someone else to install them.

[booster]

Originally Posted by 2wiresdave

I measured them using a vernier caliper on several of the coils to verify my measurement...boy, I am really scratching my head now since the shop where I brought them acted so shocked at how stiff they were! Are the 1617's (the currently available ones) the same length as stock?

The 1617's I thought were giving somewhere around 2-3" of lift - or did I misunderstand something? I was really hoping you guys would be shocked at the measurements...would have made me feel much better !

Thinking I might try ordering the 1617's and seeing if I can find someone else to install them.

Yeah, it is pretty confusing. They are .3" longer than a our 1617s, which isn't much. The wire size is .050" smaller, which softens them a bunch. Photog, IIRC, installed the prototype Tuftruck ones that were 2" longer with the OTC manual spring compressor. When I was playing with the spring calculator is showed a little over 1" of lift with the springs you have. They would have a higher spring rate than the stock springs, it appears.

I don't think the shop should have had any problem putting them in, unless they were using car sized spring compressors.

[2wiresdave]

I have to believe that they knew what they were doing? The shop is a very reputable shop that services everything from cars to class A motor homes. There were several school buses, a dump truck, semi and a fire truck being worked on that I noticed. They put me in heavy truck area...and I was by far the smallest thing there.

[Photog]

Here is a minor update on our front coil springs.

In July, Otto-Max sent me another (shorter) set of prototype springs. With these installed, we had a 2" lift, after they settled in. We have had the rig out on several trips. Interstate, curvy roads and dirt roads. There has been a noticable improvement and a reduction of harshness. Much better suspension travel when encountering dips, bumps, etc. We have no front sway bar, but we did add a rear sway bar.

The rear suspension is still too stiff, which makes everything feel a bit harsh on the dirt roads.

We have approximately 4500 pounds on the front suspension of our 2008 Chevy Express 3500. I recommend these springs for anyone with that much weight, looking to get 2" of lift, over the mashed-below-factory ride height. I do not know what they are listed as, but in my e-mail with Otto-Max, we have been describing them as "Set Down TTC-1618". They are 1425 lbs/in spring rate, 18.7" free length, 8 coils of 1" diameter material.

The Bilstein shocks and factory shocks seem to be a little short, and I don't think they have enough rebound control for these heavy rigs and beefy springs. Now we are on the hunt for little longer front shock, with a bit more rebound control. Otto-Max has a 1" longer shock for these vans, but no info on the reboud control to compare with the Bilstein.

[AZ ADVenturist]

Brian; Thanks for your update. Your posts are really the only ones I read anymore. We are still living with half@$$ job we had done in Prescott. Still not happy with the coilbind & wallowing. I've found another shop locally and will take the R/Tvan to them when time & budget allows (before next spring). But I'll be real interested to know what you end with on your coils & shocks. Please post a link for Otto-Max when you can, thnx. good luck with your ongoing project.
Regards, Ric. in Arizona

[booster]

Originally Posted by Photog

Here is a minor update on our front coil springs.

In July, Otto-Max sent me another (shorter) set of prototype springs. With these installed, we had a 2" lift, after they settled in. We have had the rig out on several trips. Interstate, curvy roads and dirt roads. There has been a noticable improvement and a reduction of harshness. Much better suspension travel when encountering dips, bumps, etc. We have no front sway bar, but we did add a rear sway bar.

The rear suspension is still too stiff, which makes everything feel a bit harsh on the dirt roads.

We have approximately 4500 pounds on the front suspension of our 2008 Chevy Express 3500. I recommend these springs for anyone with that much weight, looking to get 2" of lift, over the mashed-below-factory ride height. I do not know what they are listed as, but in my e-mail with Otto-Max, we have been describing them as "Set Down TTC-1618". They are 1425 lbs/in spring rate, 18.7" free length, 8 coils of 1" diameter material.

The Bilstein shocks and factory shocks seem to be a little short, and I don't think they have enough rebound control for these heavy rigs and beefy springs. Now we are on the hunt for little longer front shock, with a bit more rebound control. Otto-Max has a 1" longer shock for these vans, but no info on the reboud control to compare with the Bilstein.

So it looks like they took the 1618 and wound them a bit longer, with the same amount of coils, as I think the 1618 were on 1" wire. Leaving the coil count the same is good as they wind up the same height in the van, and you won't go solid. They sound very similar to the Erb springs that were mentioned recently that were on 1" wire, but were only about 1/2 in longer than stock.

Was the OTC up to the task of compressing them? Did you put them in from the balljoint side, or drop the pivots and go from the inside? When I looked up the OTC compressor, after the posts of the shop breaking their compressor on the Erb springs, I noticed OTC is now saying to put them in from the inside, which is the same as the Chevy service manual says.

[Photog]

The OTC compressor did the job. It was a bit tedious.
I went in from the balljoint side, but, if I were to do it again, I would definitely drop the pivots and come in from that side. Doing that may not require the compressor, but I'm not sure about that.

They have definitely been an improvement for us, providing lift, flex and good ride.

If the lift is too high, I think the upper end of the coil could be "Ground" or "Squared" to reduce free length and effective wire length. Squared and ground would be best, but the spring shop would have to do that during manufacture. This might be something the manufacturers could do, as a way to fine tune the amount of lift. More manufacturing operations means more $$$.


http://www-mdp.eng.cam.ac.uk/web/librar ... intro.html

The lower end of the coil needs to be "Plain" or "Squared", as it fits into an indexing pocket.

Theoretically, if you could grind the spring-end to a point where 1/2 of the diameter was leveled off, this would reduce the free length by 1/2", and this would also reduce the ride height.

[booster]

How did the newest version do in relation to hitting the knuckle? IIRC that the longer ones were hitting for you so they couldn't stay in.

[booster]

Originally Posted by Photog

Here is a minor update on our front coil springs.

In July, Otto-Max sent me another (shorter) set of prototype springs. With these installed, we had a 2" lift, after they settled in. We have had the rig out on several trips. Interstate, curvy roads and dirt roads. There has been a noticable improvement and a reduction of harshness. Much better suspension travel when encountering dips, bumps, etc. We have no front sway bar, but we did add a rear sway bar.

The rear suspension is still too stiff, which makes everything feel a bit harsh on the dirt roads.

We have approximately 4500 pounds on the front suspension of our 2008 Chevy Express 3500. I recommend these springs for anyone with that much weight, looking to get 2" of lift, over the mashed-below-factory ride height. I do not know what they are listed as, but in my e-mail with Otto-Max, we have been describing them as "Set Down TTC-1618". They are 1425 lbs/in spring rate, 18.7" free length, 8 coils of 1" diameter material.

The Bilstein shocks and factory shocks seem to be a little short, and I don't think they have enough rebound control for these heavy rigs and beefy springs. Now we are on the hunt for little longer front shock, with a bit more rebound control. Otto-Max has a 1" longer shock for these vans, but no info on the rebound control to compare with the Bilstein.

Just based on general curiosity, I went back over all the spring information I could find around here, too see if there was now enough to actually make sense and give some predictability.

We now have information on several springs, and the results they give on the vans related to ride height. Most of it makes pretty good sense, and when taken in total, it makes me wonder whey there was so much trouble getting the "right" springs made.

The original Tufftruck 1617's that Photog and I have (may or may not still be available)

17.7" free length-same as the OEM spring
8 coils of 1.050" wire
2026lb/in spring rate per Photog
Spring compression 2.5"
Spring compressed height 15.2"
Height change at wheelwell 2.0"

The first shot, softer/longer version from Tufftruck (1618?) that Photg got

19.7" free length
1427lb/in spring rate per Photog
number of coils unknown, but probably about 9, wire diameter probably 1.000"
Spring compression 3.5"
Spring compressed height 16.2"
Height change at wheelwell 4.33 "

The second shot, softer/longer version from Tufftruck (setdown 1618?)

18.7" free length
1425lb/in spring rate
8 coils of 1.000" wire
Spring compressed 3.5"
Spring compressed height 15.2"
Height change at wheelwell 2.0"


The Bill Erb springs that were made (same as Mexican Doctor's?) but were not able to be installed

18.0" free length
8 coils of 1" wire
Probably 1425lb/in spring rate as the spring is nearly identical to the setdown 1618 above, just slightly shorter
Spring compressed 3.5"
Spring compressed height 14.5"
Height change at wheelwell 0.37"


The OEM spring we all love to hate

17.7" free height
6+ coils of probably 1.000" wire
Spring rate of about 1488lb/in based on ride height differences to known rate springs
Spring compressed 3.36"
Spring compressed height 14.34"
Height change at wheelwell baseline"

Now the assumptions and measurements that can get us all into trouble

Assuming 2150# on each front wheel (rated max load-Photog is heavier)
Stock wheel offset of 28mm positive, with stock suspension
2.33 ratio of wheel to a-arm pivot to spring centerline to a-arm pivot. Measured on on our van.
2" increase in front ride height with the first generation 1617 springs

Calculations

The load on the spring is 5000# (2150# X 2.33 ratio)

How much each spring is compressed is in red above (5000# divided by springrate)

Compressed height of the spring is in green above (free height minus spring compression)

Change in height at wheelwell is shown in blue above ( difference between OEM spring compressed heightand new spring compressed height X 2.33 ratio

What is the end result?

The original Tufftruck 1617's and the Tufftruck setdown 1618's both wind up 2" above stock ride height based on the calculations and on observations. Makes sense. This puts the van right on factory desired ride height

The Tufftruck first attempt 1618 long springs would give you 4.33" lift at the wheelwell and would put the suspension too high. Photog saw this in his testing.

The Bill Erb spring would only raise the van about 3/8" at the wheelwell. This one didn't make sense until the springrate of the OEM spring was calculated. At 1488, it is stiffer than the Erb spring so the Erb extra length doesn't all go to lifting the van higher. The higher rate of the OEM spring would most likely be because it has less coils (steeper wind angle) which makes springs stiffer. This also makes sense, but the springs were never installed to get actual lift numbers.

The 1617 is 36% stiffer than stock

All the 1618 versions and the Erb springs are about 4% softer than the OEM springs.

From all this, it looks like the setdown 1618 from Tufftruck is the spring to get if you want to keep the ride the same as stock, but get 2" of lift. The hard part to understand is why they had so much trouble getting there. All we can assume is that Tufftruck was tunnel visioned on increased capacity, along with height increase. Their spring calculations may also have shown that the 1" wire springs would have shorter life with the bigger loads on them, so they wanted to keep the life up on them by going to the 1.050 wire. Or maybe they just wanted to keep OEM free height so they could be put in without a spring compressor.

What is of interest to me now is why Photog would be seeing too low damping in the down direction of his shocks. The springs he has are actually a little bit less stiff than stock, the shocks should match the springs well as they are very near OEM rate, so they shouldn't be overpowering the shocks. If they are getting overpowered, it should have been much worse with 1617's he used to have in his van. Perhaps it has to do with the raised spindles, which are designed for the van, but invariably change something in the geometry. It is likely that at the same wheel offset, the scrub radius would change, so the tire contact may be moving on the road differently with suspension compression and decompression than it did stock.

Net conclusion is that it all does make sense, the results match the predicted. The set down 1618 looks like the spring of choice for most folks, unless they are way overweight, looking for the best handling on smooth roads, or reducing sway as much as possible. We will know more about them as Photog gets more miles on them, to make sure no other issues, like interference, show up.

One issue that may, or may not, be of concern is that with the setdown 1618, we have as spring that puts the van at factory ride height, and with slightly reduced spring rate, but it does have a couple of extra coils, also. It would be interesting if Photog could look at how much room is between the tight side of the coils, total, compared to how far it is to bump stop. The factory spring would probably have close to 2" more spring travel available before going "solid", compared to the setdown 1618. Going solid with 5000# base spring load, plus the bump or dip force would almost certainly break something. A simple cure would probably to use one of the Timbrin style, taller, bumpstops if it does turn out to be an issue.

Also shown is that the Erb spring is nearly an OEM, and would not give anwhere near the lift required to get 2". Other than length the Erb spring seems to be nearly identical to the setdown 1618. There should not have been an issue putting the Erb springs in, however, as the setdown 1618 would require considerably more compression and Photog did that when he put his in.

[Photog]

Booster, That is a nice bit of writing.

I will attempt to measure the spring gaps, and remaining up-travel, to see if the springs might go solid.

The times when it feels like the shocks are being overpowered is coming off of a speed bump. The suspension feels like it hits full extension with a loud "thump". This would be a problem on a washboard road, in the boonies. This may have been an issue all along, and I just didn't notice, until I started running some vibration tests for the new springs. I would think the Bilsteins designed for the van would control the suspension. The shocks I had with the TTC-1617 springs were longer, and were designed for the 3500 Silverado. I would think the extra length would allow the control arm to hit the metal stops with a loud "bang", but that never happened. Getting shock specs is like pulling hen's teeth.

If I had numbers to compare, I could make better measurements and come to some useful conclusions.

Ultimately, these vans have such a small amount of suspension travel, with short springs and short shocks. It makes it difficult to control that much weight on a rough road (think heavy washboards).

Originally Posted by booster

How did the newest version do in relation to hitting the knuckle? IIRC that the longer ones were hitting for you so they couldn't stay in.

Close, but no contact.

I would not mind trying a coil-over shock from a company like King, but I don't think the lower shock mount could stand up the the full load of the van, plus the shock damping. Maybe some taller upper spring-buckets and longer shocks (similar to the current Ford truck suspension). Tuff Truck makes springs for those too.

[booster]

I just had another thought on the shock on rebound thing. The OEM and 1617 springs are both shorter than you what you are now running. The 1617 and the 1618's you have both are supporting the same weight at ride height, but they have different rates and free lengths. As the 1617 decompresses on extension, it will lose load capacity faster, per inch of extension. It is very possible that the lower rate 1618's you are now running could actually have higher load capacity, and downforce, at full extension of the shock. The 1617 should also make the wheel drop slower than the 1618 because it is putting less force on the shock at all points except the initial move.

Assuming 1" of shock downtravel, with both starting at 5000# of load, the 1617 at 2026 lb/in of rate is going to be at 2974 pounds of force. The 1618's with 1425 lb/in rate would be at 3575 pounds of force which is 42% higher. I would think that could very easily make more noise as it tops out the shock. Plus the wheel will be moving down faster hit harder

The same thing would happen when the extension is over, and the wheel starts to come back up. The 1618 will be at a higher load capacity, so the initial "hit" of force will actually be higher than with the stiffer 1617. Once the wheel is moving up, the 1618's lower rate should improve it after that.

Maybe a couple of these.

http://www.filthymotorsports.com/Lim...limitstrap.htm

[themexicandoctor]

All I know, not being an Engineer is this;

Bill Erb told me without seeing my truck, but reading these earlier posts, he would make me two sets of springs and the first set will lift the front end 2.75".

He put the first set in and the change in height was 2.74".

We never needed the second set he made.

The truck drives like a Car from the first moment until now and I, like most owners, have a lot of weight in the truck.

I added the new shocks a few weeks later as the others were worn out and it improved the ride but not dramatically.

Plus I haven't bottomed out since.

And the truck looks really good.

[peteco]

I had installed the TufTruck 1617 springs 3 years ago and they have been just fine. 2" lift with a bit firmer ride but I am OK with that. I had advised a fellow RT210 owner and he had a shop order the 1617 but now they are made longer. His shop is unable to install them and said the ride height would be 4 inches higher anyway. Why TufTruck made the 1617 longer I do not know.

He is talking to TufTruck to try to get a spring that will work. Sounds like the one booster called:
"The second shot, softer/longer version from Tufftruck (setdown 1618?)"
is the best spring at this time.

Just wondering if anyone has any recent experience with TufTruck on front springs for their Roadtrek.

Pete
2006 RT210P

[booster]

The amount of space and design of the Express front end must make it a lot tougher than one would expect to get a good solution. Making the spring stiffer, but original length, seems to work well from a geometry standpoint (the original Tufftruk springs we have, also), but stiffen it up a little. We agree with Petco that it is not an issue for us over years of use. The attempts by the spring guys to make springs that are softer, but still raise the van, require them to be longer than the stock ones, and that seems to make for all kinds of issues. I think the getting them into the van issue can be addressed by using very good spring compressors, and doing it by using the factory method of taking the lower a frame loose at the inboard pivots, instead of at the lower ball joint. I say that because some shops have been able to put them in without issue, while others haven't. That said, the longer springs, if they are long enough to do a good job of lifting the front end, seem to all have a bowing problem, even to the point of hitting things. The laws of physics dictate a lot of this, so it may not be able to done just the way that would seem best.

I think it was Photog that said he thought the "new" 1617 was made longer, but still as stiff, because they wanted to address complaints from the folks that were using them in vans with heavy diesels and big snow plows, who were still not getting enough spring with original 1617.