Trailing Arm Wheel Hop - The 1947 - Present Chevrolet & GMC Truck Message Board Network

jgreene0717 · 03-02-2009, 10:40 AM

I just got finished installing mini spool and 3.73 gear. Now have bad wheel hop. I have the rear lowered 4.5" with 3" coil and 1.5" drop block. The shocks are still located in original location as well as the track bar. Would relocating the shock mounts with a better shock possibly fix problem?

ripdog28 · 03-02-2009, 10:53 AM

you really do need to get droped shocks and relocate. I would also get an adjustable trac bar. that is your biggest prob. If orig trac bar and not adjustable it is pushing your rear over more then it needs to be. your geometry changed with the drop.

djracer · 03-02-2009, 11:23 AM

He has an adjustable panhard bar but its in the stock location.

jgreene0717 · 03-02-2009, 11:33 AM

As djracer stated I have adjustable track bar in stock location, but shocks are standard length and are in stock location. I was just wondering if getting the shock relocation kit would fix problem or if it could maybe possibly be the pinion angle causing problem?

Wild83C10 · 03-02-2009, 01:08 PM

Have you checked your pinion angle? Perhaps there is some binding that might be causing the wheel hop?

jgreene0717 · 03-02-2009, 01:24 PM

I am not sure on the exact pinion angle. I will have to check to see. The only other thing is that when drive shaft is installed it only has about a 0.25" or so until the yoke bottoms out on output shaft. I would not think that would be a problem with wheel hop though.

Super73 · 03-02-2009, 01:46 PM

I'm running:
Stock Arms
Comp 3-way adjustable in the rear in the factory location (probably going to swap this out very soon)
A early 90's Jeep Cherokee front spring that I had to cut (probably going to swap this out very soon)
2" block

I have not experienced wheel hop. Too heavy of a spring, too loose of a shock, wrong pinion angle, binding sway bar due to the rear being shifted.. All of these could have an effect, so the more info we have, the better help we can be.

I'm with Wild83.. You can get an angle guage at any hardware store.

Here is a write up from CarCraft on the subject of checking it.

http://www.carcraft.com/howto/91758/index.html

Did you lower the vehicle before/after or during the minispool swap?

When lowering, who's spring did you use? Any chance you can get a measurement of the coil diameter (preferably with a caliper).

Are you on stock shocks?

Do you have a rear sway bar?

As far as the Panhard bar being the culprit, I kind of doubt it. Yes there would be rear shift due to the geometry change (unless you fixed that already being you have an adjustable). The only way I could see it being an issue is if it was putting the suspension in to a bind do to the rear being sooo far to one side. The later trucks if I'm right have a shorter PH bar than my truck. So I guess it's possible, but I'm guessing it would have to move it really far to one side.

jgreene0717 · 03-02-2009, 03:07 PM

I will pick up a angle gauge after work to check the exact angle. I have no sway bar front or rear. The springs are classic performance as well as blocks. I installed the drop a couple of years ago and yes it has stock replacement shocks. The only thing I changed at the time was the gears and minispool. It had a open diff and 3.07 gear before. When I intalled the panhard bar I made sure the axle was centered.

Super73 · 03-02-2009, 03:26 PM

Did you change tire too? If so from what to what..

jgreene0717 · 03-02-2009, 03:35 PM

No still on the same tires. 275/60/15 radial on 15x8" aluminum wheel. I will install a drag radial of some sort eventually. I just have to fix this problem first.

jgreene0717 · 03-02-2009, 03:38 PM

Owe yea I went home at lunch and made a visual on the angle of the pinion. It is already rotated up towards the bed so when under power it would rotate even further right?

Super73 · 03-02-2009, 04:02 PM

Depends on if you are squating the rear or not. If the rear squats, then no, pinion would face further down, if it is seperates, pinion would rotate up. By my math it's about 1* per 1" of movement. There is very little pinion wrap due to the suspension design (Being like a ladder bar). Perhaps a little from the factory bushing and the arm might bend a touch.

As far as a visual, remember, the trans needs to be pointing down with the same angle the pinion is pointing up to have 0* pinion angle. From that point, if the rear is up say 2* then you have +2* pinion angle. If it's still pointing up, but it is 2* bellow the trans plane, then you have -2* pinion angle.

jgreene0717 · 03-02-2009, 04:16 PM

Thanks alot for the info Super73. I will check out the pinion angle and let you guys no what I find out. In the mean time I will also be relocating the shock mounts,and installing some sort of a different type of shock any recommendations?

shortbed70 · 03-02-2009, 08:10 PM

I have that problem also with 3.73 and mini spool on a 295-50-15 but when I had my 4.56\moroso unit(BOOM) I had no problems. It met it fate coming off the highway when crosspin bolt came out and Kind of locked things up.

whatnow123 · 03-05-2009, 09:15 AM

I'm not sure how a trailing arm rear end could experience wheel hop unless the front bushings are really worn or it has a spool and is making a turn. Are you talking about going around corners ( driving normal) when you have wheel hop?

If yes, there isn't anything you can do unless you install a posi unit.

Is one tire worn much more than the other making it "smaller" than it's mate on the other side? I guess that would do it as well with a spool...

Just a thought...

djracer · 03-05-2009, 10:54 AM

He ordered some rancho 9000 adjustable shocks yersterday as he did have some issues with the rear shocks. We will let you guys know if they solve the problem.

Super73 · 03-05-2009, 01:36 PM

Little soft?

djracer · 03-05-2009, 02:02 PM

A little worn out and 1 bushing was almost gone.

jgreene0717 · 03-05-2009, 02:06 PM

Alot soft. I rechecked my axle to make sure it was centered and the pinion angle is good. So maybe the shocks will help.

jgreene0717 · 03-05-2009, 02:22 PM

Whatnow123 it wheel hops when eccessive wheel spin occurs. I played with air pressure and it was much better but would still do it on occasion. I think it is just the rear shocks being worn out causing problem but we will see.

djracer · 03-05-2009, 05:11 PM

It needs some drag radials so it won't spin then no hop.

jgreene0717 · 03-24-2009, 01:49 PM

Just updating about the wheel hop situation. I replaced the rear shocks, and the trailing arm bushings. It will still hop a little when the radial tires begin to hook up. I put on some M/T ET streets and went to the local drag strip and had no issues with hop with these tires installed. I guess it is something to do with the radial tires.

03-02-2009, 10:40 AM	#1
jgreene0717 Jason Join Date: Sep 2008 Location: Wetumpka, AL Posts: 152	Trailing Arm Wheel Hop I just got finished installing mini spool and 3.73 gear. Now have bad wheel hop. I have the rear lowered 4.5" with 3" coil and 1.5" drop block. The shocks are still located in original location as well as the track bar. Would relocating the shock mounts with a better shock possibly fix problem?

03-02-2009, 10:53 AM	#2
ripdog28 Registered User Join Date: Apr 2008 Location: Imperial Beach, CA Posts: 1,040	Re: Trailing Arm Wheel Hop you really do need to get droped shocks and relocate. I would also get an adjustable trac bar. that is your biggest prob. If orig trac bar and not adjustable it is pushing your rear over more then it needs to be. your geometry changed with the drop. __________________ 69 c-10 BBC 462ci, forged crank, H-beam rods, 10.5-1 KB forged pistons, Dart Iron Eagle 308cc, Straub Cam, Comp Cams chrome moly full rollers, Weiand Team G, Prosystems 950, TH400/3500 Dalenzie stall, Currie 9+ Detroit Locker w/31spline axles.3.5/6in drop. My Build.

03-02-2009, 11:23 AM	#3
djracer Registered User Join Date: Feb 2001 Location: Wetumpka, Al, U.S. Posts: 8,891	Re: Trailing Arm Wheel Hop He has an adjustable panhard bar but its in the stock location. __________________ Kevin Special Thanks to All who have helped on the TRUCK! My Pass Time Show http://s129.photobucket.com/albums/p...Chapter1-0.mp4 So Far my best Times are: Motor only: 6.44 1/8 @ 104.13 10.39 1/4 @ 125.83 Nitrous Times: 5.785 1/8 @ 118.65 with a 1.336 60ft 9.168 1/4 @ 142.58 with a 250 shot dead out of the hole!

03-02-2009, 11:33 AM	#4
jgreene0717 Jason Join Date: Sep 2008 Location: Wetumpka, AL Posts: 152	Re: Trailing Arm Wheel Hop As djracer stated I have adjustable track bar in stock location, but shocks are standard length and are in stock location. I was just wondering if getting the shock relocation kit would fix problem or if it could maybe possibly be the pinion angle causing problem?

03-02-2009, 01:08 PM	#5
Wild83C10 Registered User Join Date: May 2002 Location: NJ Posts: 910	Re: Trailing Arm Wheel Hop Have you checked your pinion angle? Perhaps there is some binding that might be causing the wheel hop? __________________ 83 C10 Stepside (SOLD, it was a blast!) 383 MASS-FLO EFI/TKO II 600/3.90 Posi 10 bolt S475 and C4 DM running, fine tuning turbo= Douchebag Racing: Runs Fine all the Time

03-02-2009, 01:24 PM	#6
jgreene0717 Jason Join Date: Sep 2008 Location: Wetumpka, AL Posts: 152	Re: Trailing Arm Wheel Hop I am not sure on the exact pinion angle. I will have to check to see. The only other thing is that when drive shaft is installed it only has about a 0.25" or so until the yoke bottoms out on output shaft. I would not think that would be a problem with wheel hop though.

03-02-2009, 01:46 PM	#7
Super73 Registered User Join Date: Nov 2007 Location: Bay Area, Ca Posts: 2,841	Re: Trailing Arm Wheel Hop I'm running: Stock Arms Comp 3-way adjustable in the rear in the factory location (probably going to swap this out very soon) A early 90's Jeep Cherokee front spring that I had to cut (probably going to swap this out very soon) 2" block I have not experienced wheel hop. Too heavy of a spring, too loose of a shock, wrong pinion angle, binding sway bar due to the rear being shifted.. All of these could have an effect, so the more info we have, the better help we can be. I'm with Wild83.. You can get an angle guage at any hardware store. Here is a write up from CarCraft on the subject of checking it. http://www.carcraft.com/howto/91758/index.html Did you lower the vehicle before/after or during the minispool swap? When lowering, who's spring did you use? Any chance you can get a measurement of the coil diameter (preferably with a caliper). Are you on stock shocks? Do you have a rear sway bar? As far as the Panhard bar being the culprit, I kind of doubt it. Yes there would be rear shift due to the geometry change (unless you fixed that already being you have an adjustable). The only way I could see it being an issue is if it was putting the suspension in to a bind do to the rear being sooo far to one side. The later trucks if I'm right have a shorter PH bar than my truck. So I guess it's possible, but I'm guessing it would have to move it really far to one side. __________________ ------Motor---------------Bottle 60'---1.53---------------1.41 1/8---6.58 @ 105.92----5.87 @ 118.41 1/4---10.38 @ 126.97----9.24 @ 142.49 Last edited by Super73; 03-02-2009 at 01:51 PM.

03-02-2009, 03:07 PM	#8
jgreene0717 Jason Join Date: Sep 2008 Location: Wetumpka, AL Posts: 152	Re: Trailing Arm Wheel Hop I will pick up a angle gauge after work to check the exact angle. I have no sway bar front or rear. The springs are classic performance as well as blocks. I installed the drop a couple of years ago and yes it has stock replacement shocks. The only thing I changed at the time was the gears and minispool. It had a open diff and 3.07 gear before. When I intalled the panhard bar I made sure the axle was centered.

03-02-2009, 03:26 PM	#9
Super73 Registered User Join Date: Nov 2007 Location: Bay Area, Ca Posts: 2,841	Re: Trailing Arm Wheel Hop Did you change tire too? If so from what to what.. __________________ ------Motor---------------Bottle 60'---1.53---------------1.41 1/8---6.58 @ 105.92----5.87 @ 118.41 1/4---10.38 @ 126.97----9.24 @ 142.49

03-02-2009, 03:35 PM	#10
jgreene0717 Jason Join Date: Sep 2008 Location: Wetumpka, AL Posts: 152	Re: Trailing Arm Wheel Hop No still on the same tires. 275/60/15 radial on 15x8" aluminum wheel. I will install a drag radial of some sort eventually. I just have to fix this problem first.

03-02-2009, 03:38 PM	#11
jgreene0717 Jason Join Date: Sep 2008 Location: Wetumpka, AL Posts: 152	Re: Trailing Arm Wheel Hop Owe yea I went home at lunch and made a visual on the angle of the pinion. It is already rotated up towards the bed so when under power it would rotate even further right?

03-02-2009, 04:02 PM	#12
Super73 Registered User Join Date: Nov 2007 Location: Bay Area, Ca Posts: 2,841	Re: Trailing Arm Wheel Hop Depends on if you are squating the rear or not. If the rear squats, then no, pinion would face further down, if it is seperates, pinion would rotate up. By my math it's about 1* per 1" of movement. There is very little pinion wrap due to the suspension design (Being like a ladder bar). Perhaps a little from the factory bushing and the arm might bend a touch. As far as a visual, remember, the trans needs to be pointing down with the same angle the pinion is pointing up to have 0* pinion angle. From that point, if the rear is up say 2* then you have +2* pinion angle. If it's still pointing up, but it is 2* bellow the trans plane, then you have -2* pinion angle. __________________ ------Motor---------------Bottle 60'---1.53---------------1.41 1/8---6.58 @ 105.92----5.87 @ 118.41 1/4---10.38 @ 126.97----9.24 @ 142.49

03-02-2009, 04:16 PM	#13
jgreene0717 Jason Join Date: Sep 2008 Location: Wetumpka, AL Posts: 152	Re: Trailing Arm Wheel Hop Thanks alot for the info Super73. I will check out the pinion angle and let you guys no what I find out. In the mean time I will also be relocating the shock mounts,and installing some sort of a different type of shock any recommendations?

03-02-2009, 08:10 PM	#14
shortbed70 Registered User Join Date: Mar 2002 Location: Forney TX Posts: 4,512	Re: Trailing Arm Wheel Hop I have that problem also with 3.73 and mini spool on a 295-50-15 but when I had my 4.56\moroso unit(BOOM) I had no problems. It met it fate coming off the highway when crosspin bolt came out and Kind of locked things up. __________________ Troy 1965 Chevy Bagged,361 sbc,voodoo cam,1.5 full roller rockers,patriot 185cc vortec heads 2.02-1.60,vortec weiand polished intake,demon carb my truckhttp://67-72chevytrucks.com/vboard/s...d.php?t=332884 Big Red Dog build http://67-72chevytrucks.com/vboard/s...d.php?t=572274

03-05-2009, 09:15 AM	#15
whatnow123 Registered User Join Date: Oct 2006 Location: Arizona Posts: 835	Re: Trailing Arm Wheel Hop I'm not sure how a trailing arm rear end could experience wheel hop unless the front bushings are really worn or it has a spool and is making a turn. Are you talking about going around corners ( driving normal) when you have wheel hop? If yes, there isn't anything you can do unless you install a posi unit. Is one tire worn much more than the other making it "smaller" than it's mate on the other side? I guess that would do it as well with a spool... Just a thought... __________________ 67 Short Step, 355, 700R 4.11 posi rear, 4/6 drop Discs on all 4 corners. Build thread: http://67-72chevytrucks.com/vboard/s...d.php?t=219094 Last edited by whatnow123; 03-05-2009 at 09:18 AM.



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03-05-2009, 10:54 AM	#16
djracer Registered User Join Date: Feb 2001 Location: Wetumpka, Al, U.S. Posts: 8,891	Re: Trailing Arm Wheel Hop He ordered some rancho 9000 adjustable shocks yersterday as he did have some issues with the rear shocks. We will let you guys know if they solve the problem. __________________ Kevin Special Thanks to All who have helped on the TRUCK! My Pass Time Show http://s129.photobucket.com/albums/p...Chapter1-0.mp4 So Far my best Times are: Motor only: 6.44 1/8 @ 104.13 10.39 1/4 @ 125.83 Nitrous Times: 5.785 1/8 @ 118.65 with a 1.336 60ft 9.168 1/4 @ 142.58 with a 250 shot dead out of the hole!

03-05-2009, 01:36 PM	#17
Super73 Registered User Join Date: Nov 2007 Location: Bay Area, Ca Posts: 2,841	Re: Trailing Arm Wheel Hop Little soft? __________________ ------Motor---------------Bottle 60'---1.53---------------1.41 1/8---6.58 @ 105.92----5.87 @ 118.41 1/4---10.38 @ 126.97----9.24 @ 142.49

03-05-2009, 02:02 PM	#18
djracer Registered User Join Date: Feb 2001 Location: Wetumpka, Al, U.S. Posts: 8,891	Re: Trailing Arm Wheel Hop A little worn out and 1 bushing was almost gone. __________________ Kevin Special Thanks to All who have helped on the TRUCK! My Pass Time Show http://s129.photobucket.com/albums/p...Chapter1-0.mp4 So Far my best Times are: Motor only: 6.44 1/8 @ 104.13 10.39 1/4 @ 125.83 Nitrous Times: 5.785 1/8 @ 118.65 with a 1.336 60ft 9.168 1/4 @ 142.58 with a 250 shot dead out of the hole!

03-05-2009, 02:06 PM	#19
jgreene0717 Jason Join Date: Sep 2008 Location: Wetumpka, AL Posts: 152	Re: Trailing Arm Wheel Hop Alot soft. I rechecked my axle to make sure it was centered and the pinion angle is good. So maybe the shocks will help.

03-05-2009, 02:22 PM	#20
jgreene0717 Jason Join Date: Sep 2008 Location: Wetumpka, AL Posts: 152	Re: Trailing Arm Wheel Hop Whatnow123 it wheel hops when eccessive wheel spin occurs. I played with air pressure and it was much better but would still do it on occasion. I think it is just the rear shocks being worn out causing problem but we will see.

03-05-2009, 05:11 PM	#21
djracer Registered User Join Date: Feb 2001 Location: Wetumpka, Al, U.S. Posts: 8,891	Re: Trailing Arm Wheel Hop It needs some drag radials so it won't spin then no hop. __________________ Kevin Special Thanks to All who have helped on the TRUCK! My Pass Time Show http://s129.photobucket.com/albums/p...Chapter1-0.mp4 So Far my best Times are: Motor only: 6.44 1/8 @ 104.13 10.39 1/4 @ 125.83 Nitrous Times: 5.785 1/8 @ 118.65 with a 1.336 60ft 9.168 1/4 @ 142.58 with a 250 shot dead out of the hole!

03-24-2009, 01:49 PM	#22
jgreene0717 Jason Join Date: Sep 2008 Location: Wetumpka, AL Posts: 152	Re: Trailing Arm Wheel Hop Just updating about the wheel hop situation. I replaced the rear shocks, and the trailing arm bushings. It will still hop a little when the radial tires begin to hook up. I put on some M/T ET streets and went to the local drag strip and had no issues with hop with these tires installed. I guess it is something to do with the radial tires.

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