I finally managed to pull the trigger on new gears and a Black Bear Performance tune. Like countless threads on here about re-gearing lifted trucks, my only regret was waiting this long to do it. I ended up going with a 4.10 ratio. I love the new setup. I definitely feel like the truck has regained what was lost with the bigger tires. While I was at it with the gears, I also threw a Fabtech add-a-leaf in the rear springs to get a little of the rear height back. The Fabtech lift almost perfectly levels the truck but I prefer the rear a bit higher as it comes from the factory. Here's the new, all-inclusive list of mods: Fabtech 6" Gen II suspension lift Fabtech rear add-a-leaf spring Fuel Krank 20x10 (-24mm offset) wheels Maxxis Bighorn 325/60/R20 tires 4.10 differential gears (AAM rear, Yukon front) Black Bear Performance custom tune McNally 16oz. dual-valve catch can K&N Blackhawk intake New cat-back exhaust with Flowmaster Super 44 muffler Retrofitted GM camper mirrors (swapped door harnesses for light functionality) Replaced mirror lights with smoked lens marker lights and Boost Auto parts relay for turn signals Rockford-Fosgate P3SD4-10 subwoofer in custom enclosure Replaced tail lights with LED bulbs and resisters Replaced headlamp assemblies with LTZ OEM assemblies Replaced door speakers and dash tweeters Painted calipers Frame tube plugs Here's a few recent photos. I apologize for not cleaning the truck beforehand.
There a fairly recent post about this topic somewhere. The inserts are separate but, as I understand it, all of the plastic in the grille is welded together. The grille can only be found as a whole assembly. There are a few guys on eBay selling the parts but that’s all I’m aware of.
I opened up my LT headlights to put Klearz lenses in. It wasn’t bad. I ultimately decided to swap LTZ headlamps in to my LT. That also wasn’t bad and just requires a resistor for the turn signal. The truck-side harness and BCM are already correct to do that swap. I’d love to trade grilles with you if you want the all black version. Do you have a Z71? I like the LTZ chrome inserts.
Thanks! I saw your post earlier but didn’t want to bug you if you hadn’t had a chance to check on it. Thanks again.
Just wanted to give this one bump before I started looking elsewhere. Not too many options in this area. Thanks in advance.
I'm kind of swimming upstream here but I'm trying to get my hands on the exhaust "flapper" valve that everyone is cutting out and throwing away. I'm looking for one from the Silverado 1500 exhaust with a 5.3L motor. I'm hoping one of the members here still has their stock exhaust lying around and wouldn't mind cutting the valve section out and throwing it in a box for me. I'm in Virginia Beach. I'll obviously pay for shipping and am happy to send a little something for the effort. Thanks in advance.
I did the same upgrade on the Silverado. I checked eBay basically every day for months until someone posted a pair of lights. They’re out there but it will take some searching and some patience.
I am interested in making this swap, too. Do you mind sharing the details on the grill insert in that photo? Where you got it? How much? Part number? Thanks.
If anyone wants another data point, I did some digging on this about a year ago and just found my old numbers. I didn't personally weigh any of these but rather used numbers I could find online so consider the source. The aftermarket numbers were easy to find from the manufacturers. The OEM numbers were harder to find and I would consider them less reliable. OEM 2017 Z71 wheel & tire (265/65/R18) combined weight: 65 lbs. 20x10 Fuel Krank & 325/60/R20 tire combined weight: 111 lbs. That's obviously only part of the story since the radius and mass distribution plays a huge role but, as you can see, just switching wheels and tires adds 46 lbs. per wheel.
What state are you in? Every state has different laws regarding tint. I’m not saying you should or should not follow those laws. Lots of people don’t but it would be a good idea to at least know what the limits are for your state. What are you going for? As dark as possible? Match the other windows? I believe 20% (the percentage is how much light is allowed through the tint - lower numbers are darker tint) will most closely match the smoked back windows that came from the factory. I chose 35% for my own truck. I wanted some tint to shield myself and the interior from the sun but not so dark that it was hard to see out at night. I move between states a lot so I honestly don’t know if it’s legal or not.
I appreciate the commentary, fellas. This is all good stuff. Going back to Grumpy’s comments earlier regarding Moment of Inertia, one question I conveyed rather poorly in the original post is this: Why don’t any of the countless online “gear ratio” calculators attempt to capture the requirement to compensate for the heavier/larger wheels and tires? Every calculator I have seen appears to be a fairly simple one that simply tries to give you a gear ratio that will return you to the OEM relationship between driveshaft RPM and wheel RPM. One reason for this might just be that the math is “too hard.” I reject that based on a (possibly erroneous) assumption that people willing to take the time to build something like that online are also going to give it their best effort. Another possibility is that, in the grand scheme of things, the heavier wheel/tire’s net effect on the rear diff isn’t a major contributor when compared to the other forces acting on it. Thoughts?
I mostly agree. Just saying "mechanical advantage" and "working torque" doesn't really say much. My point was choosing your new gear ratio will almost certainly account for those things as best you can. I completely agree that this entire situation begins with a huge sacrifice by departing from the design GM intended by lifting the truck. Without access to a wind tunnel, I can't account for all of those changes but arbitrarily going to lower gears beyond what the math, physics and geometry tell you likely won't help. It won't necessarily hurt but this isn't a case of "if 4.10 is good, 4.56 has to be better." My focus is on trying to restore stock performance. Obviously there are those out there that are looking for something else. Concur. I also don't know what that breaking point is. I hope to never find out. I only brought it up to say higher RPM than designed by any amount generally isn't a good thing. At some point, stuff will start to fail. That breaking point, as you alluded to, is likely well past the life of other critical components but there is still an unknown failure point out there somewhere. I completely agree. I think you would agree there are also a lot of people out there that will just do what the masses do because they aren't willing to take the time to analyze what's actually happening inside the truck. My intent of this thread was less to ask a question and more to start this exact conversation so others can benefit. I have learned immeasurable amounts from a lot of smart, experienced people who have taken their time to post things on forums like this one. I'm trying to do any small thing I can to return the favor.
I think we are both making the same points. I 100% agree that re-gearing is necessary for bigger tires. My main point was that "rolling mass" as it's commonly referred, likely isn't a huge factor and probably shouldn't drive people to a lower-than-necessary gear ratio to meet their other, more important needs. More specifically, my point in writing all of this is to say when someone says "I went with 4.56 gears because I really like the performance." I get frustrated. That statement is fine and certainly honest but it is also an opinion and falls woefully short of being useful feedback for two main reasons: 1. "Performance" can mean any number of things. What performance, exactly, are you getting from 4.56 gears that you like so much? 2. You an I probably don't like the same things. What can you tell me about the truck itself that would help make a decision?
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