2015 4x4 Tahoe - purchased lowered and need to raise 2-3" above stock

Discussion in 'Lifted Supension - Z71 & 4x4' started by John Hanses, Feb 13, 2020.

  1. John Hanses

    John Hanses TYF Newbie

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    I have the z85 suspension with the rear air shocks. Previous owner lowered it and I'm trying to get back to stock then raise it ideally 3", keeping the stock rake. Having a hard time identifying how he lowered it - hence what all I'll need replace - control arms, shocks, spindles?? Ideally if I find someone that wants to lower theirs we can swap some or all parts and I'll then lift from stock. Any help would be appreciated! I don't know that attached photos will help.

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  2. iamdub

    iamdub Full Access Member

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    I see Belltech 5305 coils in the rear, so that's about 3"-4" of drop there. I'd assume (hope) that they used shock extenders. If they did it correctly/thoroughly, the ride height sensors links would've been shortened as well. Otherwise, the ALC system ("air shocks") would just lift the rear to make up for the drop, which would result in a firmer ride.

    I'm gonna say that the front has stock spindles since, AFAIK, drop spindles on a 4WD/AWD require trimming the upper ball joint stud to clear the CV axle housing. It looks to have Belltech struts and stock coils, so that's ~1.75 of drop if none of the spacer rings were used.

    If it were me, I'd swap someone that wants to lower for their stock stuff and lift it that 2"-3" with spacers in the front and either lift coils or stock Z71 coils plus spacers in the rear.
     
  3. John Hanses

    John Hanses TYF Newbie

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    Holy cow, I feel like I should pay you! . Great help dub, seriously a relief. I'm chomping to get this set up so I'll order stuff then sell. Thanks again!
     
  4. iamdub

    iamdub Full Access Member

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    Happy to help! Yeah, it's all simple bolt-in/on stuff. Nothing gets cut or permanently altered in lowering or lifting. Does it have shock extenders in the rear? Post up some current side shots to help confirm that it's "only" a 2/3-4 drop.
     
  5. John Hanses

    John Hanses TYF Newbie

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    Aren't shock extenders only used in lifting? Actually I guess they could extend in the opposite direction?
    So getting into the fix: Looks like I should be able to get new shocks up front and use spacers for a 2 to 3" lift there, then in the rear replace those springs, add spacers, and figure how to get the air lift re-calibrated or raised? I'll check and get a pic to confirm no extenders were used.
     
    Last edited: Feb 14, 2020
  6. Akinshake

    Akinshake Member

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    I would like to see side shots to confirm/help also. Depending on if you’re trying to keep the mag ride, I might suggest a different coil to lift it since you might have to buy something anyways. Also, in addition to side shots, a fender to ground measurement of the front and back would be a help.
     
  7. iamdub

    iamdub Full Access Member

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    The shock extenders I'm talking about aren't to make the shock longer, as one would use when lifting (actually more of an old school way). What I'm talking about bolts to the factory shock mount on the axle and extends the mounting point of the shock 2" downward so the shock has an extra 2" of travel. If you were to lower your rig 2", the shock would get compressed 2", putting it 2" closer to bottoming out. To regain the lost travel, you'd either get a 2" shorter shock (AKA "drop shocks") or bolt some shock extenders so the stock shocks would have their full, original range of travel. If you had more drop, such as a 4", you could get 2" shorter shocks and the 2" extenders, etc.


    You have struts up front, not shocks. You could get stock struts and use spacers to lift it. The spacers don't change the travel (stroke) of the strut, they just make its overall size longer, which raises the vehicle. So stock struts are fine. It's the same principle as spacers for the rear coils. That which the vehicle rests on is just 2"-3" longer, but you're not changing the spring rate, so it'll ride the same (not accounting for different shocks). If you were to replace the rear springs with lift coils or even stock Z71 coils, that'd change the ride a little. I think people report that the Z71 coils ride a hair firmer than stock or it might be the Z71 shocks. Technically, you'd need longer shocks for the 2"-3" lift because that's putting the stock shocks 2"-3" closer to being fully extended. I think they only have about 4" to extend and compress, which means you'd only have 1"-2" of droop before the shock bottoms out at full extension. Yes, the shock gets compressed much more than extended during normal driving. But, IMO, that's still too close for comfort if you were hitting some big dips or humps at speed on the highway. There are shock extenders for rear lifts, but I have no experience with them nor do I know of anyone on here that has used them. This is an example: https://www.ebay.com/itm/Rear-Shock...a=0&pg=2047675&_trksid=p2047675.c100005.m1851


    What I don't like about them is that the top shock mount eye will have more radial and tangential loading on it than in a stock setup. This may not be so much of a problem with a standard shock, but the ALC shocks are part of the load-bearing part of the suspension, so it has much more weight and forces acting on it than with a standard suspension. Also, the shock would be rotated 90°. Again, not much of a concern with standard shocks, but the ALC shocks have electrical and air line connections on the side of the shock body and this may position them to interfere with other components.

    If it were me, I'd copy the lowering shock extender idea, but in reverse, and make my own "lifted extenders". I don't know why this hasn't been done already. Maybe it's because the ALC shocks are load-bearing and there are too many liabilities for a company to produce them?


    For the ALC sensor calibration, you just need the sensor to be at the position it would be in if the vehicle were at the height it was when it was stock. If it were me, I'd try one of two things:

    1) Put stock springs in it with no spacers, and accurately mark the sensors after the suspension settles

    or

    2) If the ALC system lifts the rear after startup, mark where this point is since that's where the system is "happy" at.

    Once you have your marks, then you just adjust the sensor link length so these marks align after you lift it. With lowering, you have to shorten the links. With lifting, you lengthen them. I made shorter links for my 4" drop with a piece of 10-24 all thread from Lowe's:

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