40 mph shake
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Joined: Feb 2001
Posts: 80
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From: GULFPORT. MS.
40 mph shake
I know a lot of us have this problem has anyone found a fix I'm taking my truck in soon for this a few other things and was hoping I could give them an idea at 40 mph the truck seems to jump up and down 38mph or 42 mph smooth we have bal. and rotated and bal rotated with out any effect. moter rpm doesn't matter 2nd or 3rd gear does it it also does it when slowing down with no load on the driveline thanks in advance for any ideas or fixes
rick
rick
Senior Member
Joined: Aug 2001
Posts: 1,609
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From: Summerville, SC Near Historic Charleston
Hey TRUSSMAN,
I don't know what to tell you it is for sure but I would be puttin' my money that the wheels must be out of balance. I know you said they've already been balanced twice but are they using weights on both inside and outside of the rims? Are they using a computerized balancer? How accurate are they holding the balance measurements to?
If the truck is hopping up and down then it almost has to be the wheels since there isn't much else that can cause that kind of motion.
Just a thought, try and determine your tire RPM at 40 MPH and make sure the tire balance machine is running at or above that RPM. You might even want to get the technician to check the wheel balance at the exact speed that the wheels are turning when your truck is going 40 MPH and when the shake occurs.
There are several ways to determine your wheel RPM at a specific speed but it can get a little messy if you do it real accurately so I won't even go there. The actual rolling radius is what you need to determine the actual wheel RPM at a specific ground speed and thus this is somewhat difficult to determine. You can estimate the rolling radius fairly accurately with a tape measure and include some sag in the tire during operation but it changes with speed. Well, you get the picutre.
My $0.02
Good luck and keep us posted.
DaveMan
I don't know what to tell you it is for sure but I would be puttin' my money that the wheels must be out of balance. I know you said they've already been balanced twice but are they using weights on both inside and outside of the rims? Are they using a computerized balancer? How accurate are they holding the balance measurements to?
If the truck is hopping up and down then it almost has to be the wheels since there isn't much else that can cause that kind of motion.
Just a thought, try and determine your tire RPM at 40 MPH and make sure the tire balance machine is running at or above that RPM. You might even want to get the technician to check the wheel balance at the exact speed that the wheels are turning when your truck is going 40 MPH and when the shake occurs.
There are several ways to determine your wheel RPM at a specific speed but it can get a little messy if you do it real accurately so I won't even go there. The actual rolling radius is what you need to determine the actual wheel RPM at a specific ground speed and thus this is somewhat difficult to determine. You can estimate the rolling radius fairly accurately with a tape measure and include some sag in the tire during operation but it changes with speed. Well, you get the picutre.
My $0.02
Good luck and keep us posted.
DaveMan
Senior Member
Joined: Aug 2001
Posts: 1,609
Likes: 0
From: Summerville, SC Near Historic Charleston
Hey 2dollar,
I know this if off topic but I just couldn't help noticing a KR in your sig.
Does your KR friend know about the King Ranch trip in November this year. It's listed in the King Ranch forum on this site.
So far we have about 7 trucks going unless some more back out. We could use alot more support so it would be appreciated to ask for me unless you know they don't want to go.
Thanks,
DaveMan
I know this if off topic but I just couldn't help noticing a KR in your sig.
Does your KR friend know about the King Ranch trip in November this year. It's listed in the King Ranch forum on this site.
So far we have about 7 trucks going unless some more back out. We could use alot more support so it would be appreciated to ask for me unless you know they don't want to go.
Thanks,
DaveMan
