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Old 02-26-2021, 03:30 PM   #1
fishmunger
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4" Lift on 72 K10 rubbing with 35s, walk me thru my options for additional lift

Ok, I've searched a lot of threads and have a slew of questions/ideas which I'll get to in a sec.

72 K10 long bed, 350/th350, finally got on the road after a year of working on it. It came from the previous owner with what appears to be a 4" suspension lift. It has 4" blocks in the rear, and I presume 4" springs up front. (Has a raised steering arm which makes the draglink sit close to level - slight slope downward towards the steering box). It has Rancho RS99112 shocks all around. The previous owner removed a 3" body lift before I got it, and I've spent the last year correcting that stuff. I've put extended brake lines on, replaced shroud and trans hard lines, etc. Finally got her 'as she should be' - not realizing the 35s would rub with only 4" lift.

They doesn't rub 'on the street' but it takes very little uneven surface to get some rub when turning on the front of the fenders (I've attached some pics that show clearance on flat ground is down to less than 1" at a certain point when turning). The wheels are 15x10s, which I know is part of the problem, but I want to keep them. The tires are 35x12.5, but actual diameter fully inflated is 33.5", which I think is on the smaller side for 35s?

I want to be able to do moderate off-roading (trail rides - no rock crawling) without rubbing. The truck is also my back-up work truck and I tow with it, so I don't want to lift it more than I have to (I love the stance as-is, just wish it cleared) I've also rebuilt the whole front end and put a new redhead steering box in it, so I don't want to go to crossover steering which sounds like at the 6" level starts to become an issue??

For the rear:

Should I just add an add-a-leaf spring to bring it up ~2"? I wouldn't mind the extra capacity...I imagine it would help some with the bit of rear end squat it has with the trailer hooked up.

Or I've heard talk of a 'shackle flip' - but I don't really understand how to do that, who to purchase it from, how it affects ride, how much lift it would give, or if works with my existing blocks?

Or maybe I just add a 1" zero rate? In fact I am kinda curious if I just put 1" zero rates all the way around the truck - front and rear. Perhaps 5" of lift might be 'just enough' to get the clearance I need with the 'smallish' 35s...?

For the front:

1) Again, If I could get away with just a zero rate up there (for 5" total lift), that might be ideal in terms of not affecting steering too much or risking that the new extended brake lines I've installed might not now be 'long enough'.

- Since the rubbing seems to happen on the front of the fender when turning only, I'm wondering what would happen if used the zero rate to move the front axle 1" back? Maybe that would solve my problem? I have no idea what other problems would arise if I move the front axle back 1" though...?

2) I'm assuming adding a leaf up front is a bad idea and will just make the truck ride terrible?

3) Just buy 6" lift springs. If that's the case, trying to find a brand/distributor that will just sell me piecemeal parts is the next challenge.

Other questions:

Is going up 2" additional inches going to require longer parking brake cables? Transfer case drop? Pinion shims? Driveshaft lengthening? A dropped pitman arm in addition to my raised steering arm? Will I need to replace the Rancho shocks with longer ones if only going up 2" more? Should I plan for this stuff or just install things first and see how it looks? What do I look for/how do I figure this stuff out? I've got more questions than answers...

I'm on a budget. Don't want to go whole hog if I don't have to, but I don't want to do anything sketchy either. I guess I'm hoping someone here will say my odds are good that 1" zero rates and/or add-a-leafs and some axle adjustments forward or back might get it done without other mods but I'm afraid that may not be the case?

Thanks for listening to my long-winded diatribe...! Looking forward to the conjecture!
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Old 02-26-2021, 05:02 PM   #2
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Re: 4" Lift on 72 K10 rubbing with 35s, walk me thru my options for additional lift

Clearance issues at the fender cap are common on these trucks with larger tires. That is why I did this https://67-72chevytrucks.com/vboard/...7&postcount=47
On my old K20 I just trimmed them with a sawzall.

Personally I would not use any type of block on the front. The zero rates are just a block bolted to the pack with the center pin. While they would not dislodge they still exaggerate axle wrap under power and braking. The front end will hop and under hard braking the truck will dart around. Yes, I tried them long ago. If used on the back it would increase your block size to 4.5/5" making wrap even worse there.

If you just do 6" front springs and an add-a-leaf in the back. You may need longer shocks so check that out. Could get away without the 2" drop pitman arm. Right turn will be limited at droop. Drivelines should be okay. I know this is not what you want to hear, maybe look into full kits? Have seen some still in the $600 range.
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Old 02-26-2021, 11:11 PM   #3
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Re: 4" Lift on 72 K10 rubbing with 35s, walk me thru my options for additional lift

Thanks Richard. So you think even though I already have a raised steering arm I will need to get the dropped pitman arm as well?

I'm wondering if I will need longer parking brake cables out back. I saw that mentioned in some threads when I was searching...
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Old 02-27-2021, 05:25 AM   #4
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Re: 4" Lift on 72 K10 rubbing with 35s, walk me thru my options for additional lift

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Thanks Richard. So you think even though I already have a raised steering arm I will need to get the dropped pitman arm as well?

I'm wondering if I will need longer parking brake cables out back. I saw that mentioned in some threads when I was searching...
Keeping the drag link level is preferred. The drag link is short on these trucks. Angle will induce more bump steer. So yes, I would recommend adding the pitman arm with a 6 lift. Stay away from the offset drag links as they just relieve ball joint angles, do nothing to actually correct steering geometry. If I recall correctly I just made some drop brackets for the parking cables on my K20.
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Old 02-27-2021, 11:07 AM   #5
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Re: 4" Lift on 72 K10 rubbing with 35s, walk me thru my options for additional lift

When I put 35's on my 76 truck I kinda missed my 33's. I had to do some fender cutting and still rubbing for not a big difference in ground clearance or performance. I think I would buy 33's before cutting classic sheet metal.
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Old 02-27-2021, 01:15 PM   #6
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Re: 4" Lift on 72 K10 rubbing with 35s, walk me thru my options for additional lift

Yeah, I dont want to cut, no way to make it look right while maintaining the orig paint. I really want to rock 35s tho, so Ill do what it takes to get the lift right.

Looking at my rear spring pack, can anyone tell if I already have an add-a-leaf on there?
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Old 02-27-2021, 03:33 PM   #7
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Re: 4" Lift on 72 K10 rubbing with 35s, walk me thru my options for additional lift

I'm hoping special-k weighs in. I think I've read every thread on this forum about lifts and I see he's done quite a few 6" lifts.

Right now, I'm leaning towards buying a set of tuff country 6" ezrides for the front, and adding a leaf in back. Soft in the front stiff in the back...semi-comfortable and good for towing?

Considering skyjackers too, price is about the same, but it seems like reviews lean towards tuff country.

Figure start with that and then figure out what fits and what doesn't?

Hoping I can keep the rancho shocks. They were for a 4" lift, so wondering if they use the same part # for a 6"...? Guess we'll find it out.

If truck doesn't set level after this, I figure I'll add zero rates to whatever end needs it.

I am fairly certain I'll need extended parking brake cables, my stock ones seem to be about 35-36", anyone know how much longer to order them for 6" lift?
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Old 02-27-2021, 07:53 PM   #8
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Re: 4" Lift on 72 K10 rubbing with 35s, walk me thru my options for additional lift

To be honest, I think I would do a 6” spring lift all the way around. Reason I say that is it looks like you’ve got the stock 50 year old springs, it’s probably going to take some fine tuning if you keep the rear springs you’ve got. The 4” blocks as Richard mentioned can cause a lot of axle wrap. with stock springs I would bet the blocks are netting you less than 4”, over stock height currently if that makes sense. I’ve done a few 6” kits on these trucks and square bodies. I know this is more money and you are on a budget but I fear by trying to save money up front you may spend more in the long run. The EZ ride springs are a great choice. Tuff country and skyjacker are both good choices. Richard has done a great job so far on the other questions you’ve asked.

As for brake cables, I can’t speak for the half ton stuff but ive found it a bit difficult to find ready made extended cables for the 3/4 ton stuff. It can be done but it seems like more of a custom one off thing rather than off the shelf.

I meant to reply to this thread last night and got side tracked.
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Old 02-28-2021, 02:33 PM   #9
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Re: 4" Lift on 72 K10 rubbing with 35s, walk me thru my options for additional lift

Thanks 57taskforce!

About the rear springs - part of why I am reluctant to change is not just money. I'm a bit concerned that these ez-ride or soft ride 'flexy' type of springs will have less weight capacity than a stock spring? And the stock with blocks and add a leaf will have a pretty solid feel, especially when towing/loaded?

I know most are anti-block, but my other truck a 2nd gen dodge cummins 4x4 has 4" blocks from the factory on it and I haul a huge heavy cabover camper offroad with it and tow a boat. Makes me wonder if axle wrap is 'that big a deal' if you drive responsibly/normally?

I've seen people mention getting extended parking brake cables made by inline tube. I'm going to ask them. Not sure how much longer to get them made. The simple answer is 6" longer for 6" lift...?
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Old 02-28-2021, 04:36 PM   #10
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Talking Re: 4" Lift on 72 K10 rubbing with 35s, walk me thru my options for additional lift

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Originally Posted by fishmunger View Post
Thanks 57taskforce!

About the rear springs - part of why I am reluctant to change is not just money. I'm a bit concerned that these ez-ride or soft ride 'flexy' type of springs will have less weight capacity than a stock spring? And the stock with blocks and add a leaf will have a pretty solid feel, especially when towing/loaded?

I know most are anti-block, but my other truck a 2nd gen dodge cummins 4x4 has 4" blocks from the factory on it and I haul a huge heavy cabover camper offroad with it and tow a boat. Makes me wonder if axle wrap is 'that big a deal' if you drive responsibly/normally?

I've seen people mention getting extended parking brake cables made by inline tube. I'm going to ask them. Not sure how much longer to get them made. The simple answer is 6" longer for 6" lift...?
There was a couple posts here a month or so ago saying that in-line wasnt making the extended cables anymore. I tried to get some from them last summer and never got a response to my 3 emails. I understand your sentiments about the load capacity of your Oe springs. My 98 has blocks for that reason as well. You can get Oe weight capacity lift springs from Alcan which are top notch but they are more expensive as they are custom built to order. I get some axle wrap in my 98 K2500, its bearable but I do notice it. With an add a leaf you may be ok in the rear, like I said it will probably take a little fine tuning to get the rear ride height sorted out.
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Old 03-01-2021, 02:01 PM   #11
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Re: 4" Lift on 72 K10 rubbing with 35s, walk me thru my options for additional lift

Inline tube just responded. No longer making custom length parking brake cables. Any body got ideas for another vendor?
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Old 03-01-2021, 02:08 PM   #12
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Re: 4" Lift on 72 K10 rubbing with 35s, walk me thru my options for additional lift

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There was a couple posts here a month or so ago saying that in-line wasn’t making the extended cables anymore. I tried to get some from them last summer and never got a response to my 3 emails. I understand your sentiments about the load capacity of your Oe springs. My 98 has blocks for that reason as well. You can get Oe weight capacity lift springs from Alcan which are top notch but they are more expensive as they are custom built to order. I get some axle wrap in my 98 K2500, it’s bearable but I do notice it. With an add a leaf you may be ok in the rear, like I said it will probably take a little fine tuning to get the rear ride height sorted out.
I don't think I want to spend the money on the alcan springs. So you agree off the shelf rear lift springs might be undersprung? I was thinking keep my blocks, add an add-a-leaf, and if it's 'not high enough' than add a 1" zero rate too. I think it might work out. The truck sits damn near perfect level right now with the 4" blocks and what I presume are 4" rancho springs up front. If anything I'd like to be bow down ever so slightly so she sits near level with the boat trailer hooked up.

Anybody tried both skyjacker and tuff country? I'm thinking I want to go with the 'firmer' of these 'soft' springs as I read a point that special k made that the flexier springs are more likely to lead to rubbing issues with 35s. Trying to find that balance between good ride, but not overly flexy. I saw a chart for the 73-87 trucks that showed tuff country having the lightest spring rate of the bunch, but they are kind of a different animal than skyjacker it looks like as the jackers have more leafs in the pack. I also read someone saying they thought tuff countrys settled fast and they lost some lift relative to other spring brands?
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