2 Inch Lift on H2.

[OrangeCrush]

Originally Posted by tomp

Mark, longer shocks are more of a priority than the UCAs. The shocks are the first limiting factor and then second are the control arms.

I didn't replace shocks but did use the extended shock bracket.

Mark

[Bimmer9938]

Its common with the Truxxx 2.5-3F/ 1.5 R lift at 70-71mph. I have the same lift, and its hardly noticeable and its a good reminder to slow down.

[tomp]

Originally Posted by OrangeCrush

I didn't replace shocks but did use the extended shock bracket.

Mark

Warning: the shock extensions I have seen are too tall for OEM length H2 shocks. To test this, ensure vehicle is on level ground at stock ehight in the front and resting on the bump stops, disconnect the bottom of the shock and see if you can push it up higher then where it would mount to the shock extension bracket. If you can't push it up where the shock's bolt hole goes up higher than the hole in the shock extension, you are either riding on a bottomed out shock if or slamming down on a bottomed out shock when the front end comes down on the bump stops. The latter is the case if you have cranked the TBs. This is true with all H2 shock extensions that I have seen to date. Yes, this is another mark against Truxx.

The reason this is a problem is because these companies assume the H2's shocks are the same as the 2500HD pickup trucks. The shocks are not the same and only have half of the travel that the 2500HDs have.

To correct this problem you must determine the proper amount to shorten the shock extension (to get your shocks into the right range of travel) or use the 2500HD shocks.

The reason the H2's have less travel is because they have extension and compression bump stops in them where the 2500HD shocks only have extension stops. This takes some of the travel away.

Here is the way you need to think about it: Consider the fact that you are pushing up the bottom of the shock much higher than you would be when at factory height and resting on the frame mounted stops.

If anyone doubts what I am saying here, call Rancho and ask them why their online Shock Specifications show H2's shocks with 2.5" of travel and the 2500HD has 4.6". You can also see in this same manual there is a symbol next to the H2's shocks in two places. This "cross" symbol is shown for both compressed length and extended length. This shock symbol is there to inform you of the included bump stops. Notice the 2500HD shocks only show the symbol once?

Also, for those of you thinking it is okay to rest on the stops - think again. Your shocks will start degrading very quicky as you are beating the heck out of them. I went through several sets of shocks and my ride quality went horrible fast - compared to a new vehicle. This was the cause of it!

BTW, my ride quality with torsion bars cranked is much better than stock now

[DuckTruck]

Here are the communications I had with Rick via email:

"give me a shout when you have some free time...I will always make time to talk HUMMERS...now more of a sickness than a hobby, I'm a HUMMER owner for life!!!

Rick

rick,

what size tires are you running...especially in width?

the iroks i am looking at are 13.50 wide.....do you think i will have
any problems with that width on my stock wheels with rubbing?

thanks again,

jdj

Jonathan,

I'm running 39.5 x 13.5 Iroks on stock wheels...as I mentioned, in the front, they rub on the swaybar at full turn...

The rear lower control arm pocket at the frame has about a 1/2" to 3/4" stiffening flange below & in front of the bolt hole...I've ground away the extra material to extend only 1/8" to 1/4" out from the face of the control arm pocket...The extra clearance made me feel more comfortable that I would not rip out the sidewall at low pressure...You don't want to grind it flush, because that may weaken the pocket itself.

The other option that I am toying with is to add 1/4" to 1/2" wheel spacers, giving you a little more room...problem with that, is any more than 1/4" spacers & you'll need longer wheel studs...

One other thing that I failed to mention during our phone conversation...I'm using Fab-Tech tie rods because stock ones are so weak...and x-tra suppout brackets on the Idler & Pitman arms to give them a little more life...

I'll see if I can send you a bunch of pictures in a couple of days or so...

Talk to you soon...I hope that info helps!

Rick
Thanks man.....great info.

JDJ

Rick,

Wanted to follow up and ask you another question......

I am almost 100% confident that I will be installing Cognito Motorsports leveling kit (2 - 3") when purchasing new tires. I also 100% certain that I will be running 39.5 x 13.50 x 17 IROKs on my stock wheels.

The question comes when trying to decide between radial and bias-ply. I do a great bit of highway driving, but have run bias-ply tires before (the 37" boggers I told you about).......it would normally be a hands-down decision, go radial. But I am worried about killing my (already lack of) power. Thus, the weight difference between the bias (84 lbs.) vs. the radial (99lbs.) really concerns me.

What do you think about this? Also, how do your bias-ply 40's do at highway speeds, etc.?

Thanks again buddy,

JDJ

Thank you.

I'm just concerned that when stepping up to 39.5's that my highway cruising will suffer even more than when stepping up to 37"s (ie the constant "transmission kick down" that we all so dread!).

Any input on this issue? How does your truck respond?

JDJ

Jonathan,

I had 37's on the truck from the time it was 2 months old...I didn't notice much difference in vehicle performance from stock, as far as mileage/transmission shift points/power. When I added the 39.5's the road noise increased substantially & the trans stayed in low for slightly longer (slightly slower acceleration)...as far as steep hill climbs, I manually shift the transmission, especially when towing up steep grades, so I wouldn't know about the kick-down pro's & cons...There is a way to re-program your shift points if you need to...

I'm in the process of modifying my 2007 to be just like the 2005...including the 39.5 Iroks!!!

I love the bigger tires...with the snow here in Michigan, the 2" body lift & the bigger tires make for a better drive in the country for me.

I got my 07 buried in a snow drift about two weeks ago...The 05 with the lift & tires had no problem with being stuc...I mean "Temporarily detained".

Best of luck with your modifications...Happy new year, hope to see your rig completed some day!

Rick"

There ya go,

DUCK

[OrangeCrush]

Tomp,

Thanks, I just happened to read your response.

Tomorrow I will unbolt the bottom of the shock. Just to make sure I understand, you want me to compress the shock so the bottom bolt hole in the shock goes higher than the bolt hole in the extension, correct?

I will do that tomorrow but I did notice that the spacing between the bump stop and control arm is about 1/4". Is that correct or no?

If I can not raise it higher than the shock extension bolt hole, can I buy longer H2 shocks?

Thanks for your help,

Mark

Originally Posted by tomp

Warning: the shock extensions I have seen are too tall for OEM length H2 shocks. To test this, ensure vehicle is on level ground at stock ehight in the front and resting on the bump stops, disconnect the bottom of the shock and see if you can push it up higher then where it would mount to the shock extension bracket. If you can't push it up where the shock's bolt hole goes up higher than the hole in the shock extension, you are either riding on a bottomed out shock if or slamming down on a bottomed out shock when the front end comes down on the bump stops. The latter is the case if you have cranked the TBs. This is true with all H2 shock extensions that I have seen to date. Yes, this is another mark against Truxx.

The reason this is a problem is because these companies assume the H2's shocks are the same as the 2500HD pickup trucks. The shocks are not the same and only have half of the travel that the 2500HDs have.

To correct this problem you must determine the proper amount to shorten the shock extension (to get your shocks into the right range of travel) or use the 2500HD shocks.

The reason the H2's have less travel is because they have extension and compression bump stops in them where the 2500HD shocks only have extension stops. This takes some of the travel away.

Here is the way you need to think about it: Consider the fact that you are pushing up the bottom of the shock much higher than you would be when at factory height and resting on the frame mounted stops.

If anyone doubts what I am saying here, call Rancho and ask them why their online Shock Specifications show H2's shocks with 2.5" of travel and the 2500HD has 4.6". You can also see in this same manual there is a symbol next to the H2's shocks in two places. This "cross" symbol is shown for both compressed length and extended length. This shock symbol is there to inform you of the included bump stops. Notice the 2500HD shocks only show the symbol once?

Also, for those of you thinking it is okay to rest on the stops - think again. Your shocks will start degrading very quicky as you are beating the heck out of them. I went through several sets of shocks and my ride quality went horrible fast - compared to a new vehicle. This was the cause of it!

BTW, my ride quality with torsion bars cranked is much better than stock now

[tomp]

Hey Mark...you really need to assume that the shock will also need to raise up beyond that 1/4" of space in addition to it raising up above the bolt hole in the shock extension. You also have to consider that bump stops compress when all the weight of your front end comes down hard on the stops. Please take that into consideration.

Yes, the Cognito-Bilstein shocks compress to that of the OEM shocks, plus they are longer for the needed droop required after cranking the TBs.

If the above testing proves that you are bottoming out the shocks, you can still use the shock extensions by switching to the shocks for a 2500HD which are the same extended length as the H2 OEM shock length, plus they compress shorter.

[OrangeCrush]

Man, I appreciate your input. Before I start all this, I'm looking into another lift kit. The reason is because by the time I buy control arms, new shocks, I'll have 1200-1400 bucks in it. If I'm spending that much because of a levelling kit, I'd just as well be better off buying a smaller suspension lift kit. Thoughts/opinions?

Like I said earlier, I didn't want to get a 6" kit simply because that will require taller tires, gears, etc, etc.

....unless of course, I can install a 6" and lower it a bit? Is that possible? I'm assuming that a 6" kit is with the torsion bars cranked up to a certain amount.... what if you didn't crank them that far? Is 6" the minimum you could go?

I talked to a dealer for Cognito and he said they made a 4" kit for the H2.

I looked it up and didn't see anything but did see a 4" kit for an HD2500. Are the front suspensions the same?

Thanks again,

Mark

Originally Posted by tomp

Hey Mark...you really need to assume that the shock will also need to raise up beyond that 1/4" of space in addition to it raising up above the bolt hole in the shock extension. You also have to consider that bump stops compress when all the weight of your front end comes down hard on the stops. Please take that into consideration.

Yes, the Cognito-Bilstein shocks compress to that of the OEM shocks, plus they are longer for the needed droop required after cranking the TBs.

If the above testing proves that you are bottoming out the shocks, you can still use the shock extensions by switching to the shocks for a 2500HD which are the same extended length as the H2 OEM shock length, plus they compress shorter.

[DuckTruck]

I bet the "4 inch kit" he is talking about is the 2-3" kit we are speaking of.

Other option would be to run the Rancho, which is a 4" lift you can crank to 6"......but the difference between these two is about a grand PLUS installation (which will be large for the Rancho).

DUCK

[OrangeCrush]

Just out of curiousity, does anyone know anything about the Rancho suspension? I swear I read that they had a bump steer problem.

Anyone know?

Thanks,

Mark

[tomp]

Mark, all you need to do is take verify the shock extension brackets are not too tall. They most likely are too tall and if they are, they can be easily modified.

Originally Posted by OrangeCrush

Man, I appreciate your input. Before I start all this, I'm looking into another lift kit. The reason is because by the time I buy control arms, new shocks, I'll have 1200-1400 bucks in it. If I'm spending that much because of a levelling kit, I'd just as well be better off buying a smaller suspension lift kit. Thoughts/opinions?

Like I said earlier, I didn't want to get a 6" kit simply because that will require taller tires, gears, etc, etc.

....unless of course, I can install a 6" and lower it a bit? Is that possible? I'm assuming that a 6" kit is with the torsion bars cranked up to a certain amount.... what if you didn't crank them that far? Is 6" the minimum you could go?

I talked to a dealer for Cognito and he said they made a 4" kit for the H2.

I looked it up and didn't see anything but did see a 4" kit for an HD2500. Are the front suspensions the same?

Thanks again,

Mark

[EastTexan]

So if I am going with keys and stock shocks, am I better to use no shock extension at all?

[OrangeCrush]

Originally Posted by EastTexan

So if I am going with keys and stock shocks, am I better to use no shock extension at all?

I'd say yes. The reason I say that is because when I put keys on and used the shock extensions, I literally had no room for the shocks to compress.

They didn't bottom out while driving on the road but I also didn't hit any bumps.

That's the reason I bought the bilstein shocks so I could remove the shock extensions.

Mark

[EastTexan]

What are the Bilstein part numbers for an H2 with 2 - 3 inch lift? What about the Bilstein part numbers for a 2500HD shock to fit the H2 with a 2 - 3 inch lift?

[Egan]

Originally Posted by tomp

Warning: the shock extensions I have seen are too tall for OEM length H2 shocks. To test this, ensure vehicle is on level ground at stock ehight in the front and resting on the bump stops, disconnect the bottom of the shock and see if you can push it up higher then where it would mount to the shock extension bracket. If you can't push it up where the shock's bolt hole goes up higher than the hole in the shock extension, you are either riding on a bottomed out shock if or slamming down on a bottomed out shock when the front end comes down on the bump stops. The latter is the case if you have cranked the TBs. This is true with all H2 shock extensions that I have seen to date. Yes, this is another mark against Truxx.

The reason this is a problem is because these companies assume the H2's shocks are the same as the 2500HD pickup trucks. The shocks are not the same and only have half of the travel that the 2500HDs have.

To correct this problem you must determine the proper amount to shorten the shock extension (to get your shocks into the right range of travel) or use the 2500HD shocks.

The reason the H2's have less travel is because they have extension and compression bump stops in them where the 2500HD shocks only have extension stops. This takes some of the travel away.

Here is the way you need to think about it: Consider the fact that you are pushing up the bottom of the shock much higher than you would be when at factory height and resting on the frame mounted stops.

If anyone doubts what I am saying here, call Rancho and ask them why their online Shock Specifications show H2's shocks with 2.5" of travel and the 2500HD has 4.6". You can also see in this same manual there is a symbol next to the H2's shocks in two places. This "cross" symbol is shown for both compressed length and extended length. This shock symbol is there to inform you of the included bump stops. Notice the 2500HD shocks only show the symbol once?

Also, for those of you thinking it is okay to rest on the stops - think again. Your shocks will start degrading very quicky as you are beating the heck out of them. I went through several sets of shocks and my ride quality went horrible fast - compared to a new vehicle. This was the cause of it!

BTW, my ride quality with torsion bars cranked is much better than stock now

Sorry to bump and old thread, but I found this during an image search on Google and it turns out to be good timing because I am putting together my front suspension right now.

I have Cognito UCA's, Truxx shock extenders and keys, and plan to crank the torsion keys up 2" or so. I bought Bilstein 5100's from http://www.dmaxstore.com and after reading the above bold section I probably ended up with the 2500HD shocks (part# F4-BE5-D146-H1). I have the driver's side done and I had to compress the snot out of the shock to get it to line up with the bracket holes (I haven't cranked the keys yet).

If I ended up with the longer travel shocks from the 2500HD, do I need to go back to the stock lower shock mount or am I okay with the extended ones?

[iwillnc]

I've actually been looking at this thread myself lately, but what made you decide on cognito UCA vs dmax UCA

[EastTexan]

You will definitely need to use the original shorter shock mounts when using longer travel shocks. And you will definitely benefit from the longer travel provided by the longer shocks. Besides looking cool, the whole reason for a lift kit is more suspension travel. Check out the Bilstein shocks specifically for H2's with 0 - 2.5" torsion bar lift.

[Egan]

Originally Posted by iwillnc

I've actually been looking at this thread myself lately, but what made you decide on cognito UCA vs dmax UCA

I didn't see a dmax uca. The Kryptonite ones weren't available when I ordered all of my parts which is why I went Cognito.