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07-15-2019, 04:01 PM | #1 |
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Location: Warwick , Warwickshire, England
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Need to drop the rear a little more ?
After fitting a 7"/5" drop kit with a notch kit and running 275/60/15 tyres on the rear and 255/60/15 tyres on the front I need to drop the rear 1 1/2" more.
I have looked at drop shackles and thought about fitting 255/60/15 tyres on the rear. What's your thoughts are there other ways ? 1977 GMC C15 short bed by the way |
07-15-2019, 04:55 PM | #2 |
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Location: Alabama
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Re: Need to drop the rear a little more ?
How many springs are in the rear?....could you possibly take a leaf out?
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07-15-2019, 05:30 PM | #3 |
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Re: Need to drop the rear a little more ?
never going to haul heavy loads pull the bottom THICK overload leaf from each pack thats anywere from 3/4" to 7/8" thickness on average for them .
if you do make sure to clamp the leaf pack its under compression with the center pin holding them together . tire swap info 255/60/15 = 27.05" tall 275/60/15 = 27.95" tall half of this is the amount you will gain or loose on the ground . so you would only loose around 1/2" height of tire but might be skinny compared to the older fatter 275 tire .
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77-k30lb BIG truck build . 87-k30lb budget beater build . 85-k30lb the plow machine build . 85-c10sb summer fun toy . ----------------------------- HOLLEY SNIPER efi = worst case of p.i.t.a i ever had . EDELBROCK pro flo 4 = best deal going so far . love my setup works great. |
07-16-2019, 09:37 AM | #4 | |
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Re: Need to drop the rear a little more ?
Quote:
Forgot to mention I've flipped the axle, Will this still work ? |
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07-16-2019, 10:21 AM | #5 |
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Re: Need to drop the rear a little more ?
Shackles are easy enough but dialing in the exact 1.5" might be an issue (I believe they are either 1 or 2"). Word of caution though.... Installing shackles might also require notching the bed floor cross sill in the area directly above the shackle. The later trucks had the more common 52" length leafs which require the clearance. Earlier 56" HD leafs didn't require the clearance on my 74swb.
Once the rear is flipped, removing the HD overload leaf may not work. With the rear relocated on top of the springs, the overload acts as a lowering block of sorts. You could try removing it first & see what happens since you're only losing time vs. time + money.
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67SWB-B.B.RetroRod 64SWB-Recycle 89CCDually-Driver/Tow Truck 99CCSWB Driver All Fleetsides @rattlecankustoms in IG Building a small, high rpm engine with the perfect bore, stroke and rod ratio is very impressive. It's like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar..... Cubic inches is like Indiana Jones with a cheap pistol. |
07-16-2019, 12:38 PM | #6 |
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Re: Need to drop the rear a little more ?
flip kit = no extra drop removing the overload .
as said drop shackles can hit cross member in the box . my 2wd build i worked around it on the 52" springs via cutting / boxing / welding the section in with a chunk of exhaust tube for a super clean look . marked out cut out exhaust pipe cut and halfed and set in welded ends shut drilled drain hole each side and old section on top to show what was removed
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77-k30lb BIG truck build . 87-k30lb budget beater build . 85-k30lb the plow machine build . 85-c10sb summer fun toy . ----------------------------- HOLLEY SNIPER efi = worst case of p.i.t.a i ever had . EDELBROCK pro flo 4 = best deal going so far . love my setup works great. |
07-16-2019, 12:54 PM | #7 |
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Join Date: Sep 2002
Location: Liberty, Mississippi
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Re: Need to drop the rear a little more ?
Are lift blocks available/legal over there? Plenty of companies make a 1.5" block
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07-16-2019, 01:17 PM | #8 | |
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Re: Need to drop the rear a little more ?
Quote:
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07-16-2019, 01:18 PM | #9 |
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Re: Need to drop the rear a little more ?
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07-17-2019, 08:28 AM | #10 |
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Re: Need to drop the rear a little more ?
the leaf removal will still work as it will less the load that the springs can handle...the vehicle weight will gain some drop
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07-17-2019, 10:31 AM | #11 | |
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Re: Need to drop the rear a little more ?
Quote:
I was taught the over-load leaf does it's job when the other leafs are compressed enough to make contact @ each end of the over-load. Simply removing it should not impact the other leafs spring rate. Removing other leafs within a spring pack can impact the spring rate & thus yield drop because they are in full contact w/one another regardless of compression amount. Removing one decreases the amount of weight the others can support. What am I missing?
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67SWB-B.B.RetroRod 64SWB-Recycle 89CCDually-Driver/Tow Truck 99CCSWB Driver All Fleetsides @rattlecankustoms in IG Building a small, high rpm engine with the perfect bore, stroke and rod ratio is very impressive. It's like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar..... Cubic inches is like Indiana Jones with a cheap pistol. |
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07-17-2019, 11:30 AM | #12 |
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Re: Need to drop the rear a little more ?
Very nice job! I've been reluctant to simply notch mine, but may do it your way now that one of my buddies has a new shop with 12 ft ceiling.
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Mike 1969 C10 LWB -- owned for 35 years. 350/TH350, 3.08 posi, 1st Gen Vintage Air, recent AAW wiring harness, 5-lug conversion, 1985 spindles and brakes. 1982 C10 SWB -- sold 1981 C10 Silverado LWB -- sold, but wish I still had it! 1969 C10 (not the current one) that I bought in the early 1980s. Paid $1200; sold for $1500 a few years later. Just a hint at the appreciation that was coming. Retired as a factory automation products salesman. Worked part-time over the years for an engine builder and a classic car repair shop. Member here for 24 years! This is the very first car/truck Internet forum I joined. I still used a dial-up modem back then! |
07-17-2019, 01:07 PM | #13 |
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Join Date: May 2012
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Re: Need to drop the rear a little more ?
i got ocd so it would drive me nuts knowing it was not correct under there .
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77-k30lb BIG truck build . 87-k30lb budget beater build . 85-k30lb the plow machine build . 85-c10sb summer fun toy . ----------------------------- HOLLEY SNIPER efi = worst case of p.i.t.a i ever had . EDELBROCK pro flo 4 = best deal going so far . love my setup works great. |
07-17-2019, 01:18 PM | #14 |
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Re: Need to drop the rear a little more ?
I've just notched them in the past w/o boxing. Of course, boxing it in doesn't hurt but my thought is it wasn't beneficial.
The location notched is closer to the bed wall & behind the corner of the tub. That area isn't going to see the weight/forces the center of the floor would. They're not capped @ the ends so capping that local area isn't adding to the weight capacity since the strength is in the height of the channel. The only reinforcement I've done is for the center (when it's notched for differential clearance). I will put in thicker pieces of angle parallel to the notched cross sill above the differential. They get spaced far enough away so they clear while providing support as close as possible to the notched area. Although it's newer so not the exact same issues as a Square, I'll be doing my 99 CC SWB OBS bed in the near future & will get some pics since I know it will need it done.
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67SWB-B.B.RetroRod 64SWB-Recycle 89CCDually-Driver/Tow Truck 99CCSWB Driver All Fleetsides @rattlecankustoms in IG Building a small, high rpm engine with the perfect bore, stroke and rod ratio is very impressive. It's like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar..... Cubic inches is like Indiana Jones with a cheap pistol. |
07-19-2019, 10:12 AM | #15 |
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Join Date: Sep 2018
Location: Moss Bluff, LA
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Re: Need to drop the rear a little more ?
your over load does have some effect all the way through the motion...
old 4wd tricks played here, we used to shorten the length of overload as well as flip them so the have more down ward arch before fully engaging. its a freebie to pull it and see the difference. |
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