Hondo's 2006 Roadtrek 210 Popular Build

[Hondo]

Originally Posted by booster

The only true way to tell if the trim height is correct is to measure it, which may not work with the knuckle change, I think, as it is the dimension from the lowest point of the ball joint casting to the center of the control arm pivot, and they may have moved, or not. I can say that everyone who has measured the trim height, and got it correct at 4.3" +/-.5" has the bump stop clearing by about 3/8" like the Photog pic. Were are nearly exactly on 4.3" and that is what ours looks like. I actually just measured it about a week ago when I was doing some more calculations trying to sort out the weird spring results.

The forums are full of stories of low and lopsided GM pickups, too, even when new, so it seems to be a common problem. I think with the vans it may be more likely that the right front would be low in stock form, but with all the rear weight, the Roadtreks and other loaded vans seem to be 3/4" low in the left rear. I have 3/4" of spacer under our RR spring on the axle, and now we sit level with matching airbag pressures.

All good info, thanks!

It would be great if Photog was around to tell us about his final results including the spindles and what springs he used.

I am tempted to buy the 1617s but am waiting to speak with Boulder Off Road about it.

I wish that I REALLY knew what was happening when I am driving it. It feels like the suspension is bottoming on the side that goes over the large whoops, causing a rebound and body kickback or roll.

Is it the lower control arm completely compressing the snubber? That's what it feels like. I guess that I could tape a GoPro in the wheel well and drive it.

I would think that adding the new springs would help with the snubber clearance. Not sure how they would effect the bump steering that I'm also seeing.

[booster]

The pic of your bump stop is interesting. It looks as if the upper control arm is a tubular one from that angle. Is it one of the cast/forged style, sheet metal, or tubular?

[booster]

A pitch that throw the van to the opposite side is the kind of thing you will get when you put a big hit onto the bump stop. It will be worse on one wheel bumps, but uneven full dips can send you one way or the other also.

[Hondo]

Originally Posted by booster

The pic of your bump stop is interesting. It looks as if the upper control arm is a tubular one from that angle. Is it one of the cast/forged style, sheet metal, or tubular?

That is a new upper control arm that is matched to the lift spindle from Boulder Offroad- LINK

"custom Chromoly 4130 upper control arms complete with heavy duty ball joints and polyurethane bushings"

[Hondo]

Originally Posted by booster

A pitch that throw the van to the opposite side is the kind of thing you will get when you put a big hit onto the bump stop. It will be worse on one wheel bumps, but uneven full dips can send you one way or the other also.

I hit a big "bump" or abrupt lane rise on the interstate at 70 mph last week and it was very spooky.

[BBQ]

Originally Posted by Hondo

...

I wish that I REALLY knew what was happening when I am driving it. It feels like the suspension is bottoming on the side that goes over the large whoops, causing a rebound and body kickback or roll.

Is it the lower control arm completely compressing the snubber? That's what it feels like. I guess that I could tape a GoPro in the wheel well and drive it.

I would think that adding the new springs would help with the snubber clearance. Not sure how they would effect the bump steering that I'm also seeing.

You can go to walmart, get a $99 GoPro clone, mount it under the RV and look.

[Hondo]

Originally Posted by BBQ

You can go to walmart, get a $99 GoPro clone, mount it under the RV and look.

Yep, I'm charging up the one I already have, a $30 clone I picked up in Shanghai-

[Hondo]

Talked to Boulder Offroad and we're going to work on a solution next week.

It's leaning towards installing the 1617 springs, we're research stock info now, looking at others as well.

I did measure suspension sag just now.

Measurements were taken between the bottom of the highest point of the wheel well lip and the ground and the top of the tire. This was done while resting and with the tire just barely off the ground, suspension unloaded.

Resting -

Top of tire to lip - 8"
Ground to lip - 38 3/4

Jacked up from center point, tire barely scraping -

Top of tire to lip - 10 1/2"
Ground to lip - 42 1/2"

You would think that they would differ the same amount but tire compression must be a factor.

So there is 3 3/4" difference unloaded.

Using the spring numbers for estimated stock -

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"

and what Tuftruck told me today of the 1617 springs-

18" length
1.062 bar
8 coils
Spring rate 1880
1 1/2 - 2 inches of lift

The difference in spring rate of 392lb in is a 26.3% increase in spring rate or looked at another way a reduction of 23.6% sag.

23.6% less sag would be ..98", let's say an inch. Add that 1.0" to the increased spring length of .3 = and increase of 1.3 inch more lift, wheel lip to the ground. I'd think that the overload bumper would also get that much movement away from the lower control arm. In the jacked up position there was over 1 inch of clearance.

Going with the firmer spring will also make the ride firmer but will not allow it to bottom as quickly. If the new springs provided the 1.5-2.0 inches of lift as advertised the RT would be near the jacked up measurements.

Well, that's how I was looking at it anyway- I'm new at this so see if my logic/math works for you.

All of this is based upon the reported spring rates.

[booster]

The specs you have for the 1617 currently are confusing to me. We have heard that the current production is substantially stiffer and/or taller to give more lift and support for plows on the vans in Canada.

Here is a past Photog post it somehow went dark in the screen print



And here are original 1617 specs for the original 1617. Originally, they said 1.06 wire and several got that, and later folks said the got 1.05 wire



And here are the specs you got for the 1617

18" length
1.062 bar
8 coils
Spring rate 1880
1 1/2 - 2 inches of lift

It is a nearly identical spec except for tiny bit of length, but different spring rate. This spring would not qualify for the description Randy gave to Photog. At 1.06 wire, it will be quite firm, we have had quite few members who didn't like them as they were too harsh, and some others that thought they were firm, but fine.

For the amount of lift you are looking at, I think something in a 1.03 or 1.00 wire would give you plenty of height and better ride. That is basically the same spring that Photog took out of his unit because he thought it was too harsh off of the pavement.

[Hondo]

Well, the specs that I got today from Paul at Tuftruck were just what I posted.

I specifically asked for the spring rate and he said it was 1880. Photog was talking about a spring with a 2026 spring rate and that's 8% stiffer.

If the 1880 is the correct number than it would fit in between nicely. The big problem is what spring am I going to get if I buy from a vendor vs directly from Tuftruck? A current or an old set of springs?

Retail at Tuftruck is much higher than what I can buy them for online - $498 vs $252 at one vendor, not including shipping.

[markopolo]

Originally Posted by Hondo

........................................ I did measure suspension sag just now.

Measurements were taken between the bottom of the highest point of the wheel well lip and the ground and the top of the tire. This was done while resting and with the tire just barely off the ground, suspension unloaded..................................

The coils wouldn't be fully unloaded. They're limited by the maximum extension of the shock absorber. Not sure if or how that factors into your calculations.

It would appear that my older van used coils that are 1" or so shorter than newer vans. I don't know if my data will help at all but here it is:

I measured the 20 year old OEM coils in my older van and they were 0.9375" diameter bar, 15.25" free height. The Moog 81008 coils I installed are 1.031" diameter bar, 16.657" free height.
I ended up with 2.25" height increase measured wheel well to ground. Front of van weighs approx 4000+lbs.

Edit: my assumption has been that Moog 81004 coils in newer vans should give around 2" height increase measured at the wheel well. I don't recall if anyone on the forum has tried them yet.

Do we know the height (for certain) of the OEM coils in the newer vans?

Edit #2: Moog 81004 coils installed here: http://www.classbforum.com/forums/f8...10-a-6322.html

2" height increase. I'm guessing the poster meant 17 3/4 free height.

[markopolo]

Do you think we could summarize the height gain estimates using Moog coils in 2003 and newer GM based 3500 series loaded camper vans as:

81008 - maybe .5" to .75"
81006 - maybe 1.25" to 1.75"
81004 - maybe 1.75" to 2"

Moog 81004 to 81012.JPG

[booster]

Originally Posted by markopolo

Do you think we could summarize the height gain estimates using Moog coils in 2003 and newer GM based 3500 series loaded camper vans as:

81008 - maybe .5" to .75"
81006 - maybe 1.25" to 1.75"
81004 - maybe 1.75" to 2"

Attachment 4559

Assuming the 81004 gives the 1.75 to 2.00" that we have seen as one of the measured gains and using 4600# springload (2.3 ratio times 2000# wheel load) I would get the 81006 at closer to .5" lift and the 81008 no lift.

I used the calculation of springload(4600) divided by springrate(1570) times the spring to wheel ratio(2.3) to get the amount of compression at load, which should be the same for each of the springs. I got 2.96"

I then figured baseline compressed spring height by using the free spring length of the know lift 81004(17.7 minus the 2.96 compression and got 14.82"

The other compressed spring heights were then calculated the same way and then subtracted from the 14.82", giving the amount less height the spring had compressed. Multiply that by the 2.3 ratio to get the amount of wheel change.

81004 2.96compression 14.82 high 2"lift

81006 2.96compression 14.2high .6"lift

81004 2.96compression 13.7 high lose height

I do think that the 81004 would likely be a good spring for those that want 2" or a bit less lift. By the time they sag out over time probably at 1.5" lift.

As we can see, if the springs are at or under the pocket height, the lose effectiveness to lift very quickly with length charge.

[Hondo]

I emailed my contact at Tuftruck and asked him to verify and then send me the specifications of the 1617 springs now being made/sold.

When I was looking at those springs at a vendors website they had a 5,000 lb load specified.

[Hondo]

Here's a list at Tuftruck- TTC-1617

TUFTRUCK TTC-1617A Available Now – McAllister Industries Blog

[markopolo]

We do have a third party report on the 81006 coils here: http://www.classbforum.com/forums/f8...html#post19226

Interchange part numbers for the Husky SC20470 springs:
Husky SC20470
Moog 81006
ACDelco 45H0341
Napa 277-3436
Raybestos 585-1341

Interchange part numbers for Moog 81004:
Moog 81004
ACDelco 45H0340
Napa 277-3435
Husky SC20468
Raybestos 585-1340

[booster]

The "new" specs that Hondo got from Tufftruck really are confusing to everything.

All of the old predicted lifts were made because people got about 2" of lift from the springs that were 17.7" high and stated by Tufftruck to be at 2026# rate. Now Tufftruck is saying that a spring that looks to be identical except for being .3" longer is at 1880# rate and will give 1.5-2.0 lift. Based on what we have seen, I would expect that spring to lift about 2.7".

If the 81004 also gives 2" of lift that means we have same height springs rated at 1570, 1880, and 2026 all giving the same amount of lift.

This makes me suspect of my original calcs of the compressed height of the original 1617 that were based on observed lifts of 2" and Tufftrucks rate of 2026. If that compressed height is off because of a rate error, all of the other predicted heights are also off regardless if their rates given are accurate or not, because they are being adjusted to the wrong baseline.

I tried to call Erb yesterday afternoon, but he was out for the day. I will try again Monday. I am hoping he will be able to provide good specs for his springs, especially the spring rate. It is easy to measure the the other stuff, except the compressed height which is calculated from the rate.

[markopolo]

Originally Posted by Hondo

Here's a list at Tuftruck- TTC-1617

TUFTRUCK TTC-1617A Available Now – McAllister Industries Blog

Note that list dates back to 2013.

[Hondo]

Originally Posted by booster

The "new" specs that Hondo got from Tufftruck really are confusing to everything.

All of the old predicted lifts were made because people got about 2" of lift from the springs that were 17.7" high and stated by Tufftruck to be at 2026# rate. Now Tufftruck is saying that a spring that looks to be identical except for being .3" longer is at 1880# rate and will give 1.5-2.0 lift. Based on what we have seen, I would expect that spring to lift about 2.7".

This makes me suspect of my original calcs of the compressed height of the original 1617 that were based on observed lifts of 2" and Tufftrucks rate of 2026. If that compressed height is off because of a rate error, all of the other predicted heights are also off regardless if their rates given are accurate or not, because they are being adjusted to the wrong baseline.

I tried to call Erb yesterday afternoon, but he was out for the day. I will try again Monday. I am hoping he will be able to provide good specs for his springs, especially the spring rate. It is easy to measure the the other stuff, except the compressed height which is calculated from the rate.

Hopefully Boulder Offroad can come up with the real specs for stock springs as well as some options. He's researching it this weekend and hopefully he will come up with some valid data.

Very cool that you are calling Erb Booster!. It would be great if he could produce hard specs for what he has or what he can make. When I asked Tuftruck about making custom springs they told me $1,500 each unless I ordered a lot of springs....

I think it would be great if we at a minimum had the specs of the stock springs so that we have a standard to start from.

[Hondo]

Originally Posted by markopolo

Note that list dates back to 2013.

Yeah, I saw that, makes what Paul at Tuftruck told me yesterday even more intriguing- maybe they changed the springs...