So had new tires installed along with UMI upper control arms and Viking coil overs. Had front end alingement using specs supplied by guys on here as well as the spec sheet that came with the UMI and Viking kits. They were all three pretty much same specs. The car now seems to have a shimmy which from my past experience I would say is a tire balance issue steering wheel and seat vibrate at above 45. Tires have been rebalanced 3 time now putting weights on both sides, The shop thinks one of the tires is bad so they have at least one new one coming today one would not balance out properly. My question is a few of you talked about bump steer issues, but everything I read on it does not seem to be what the car is doing so going to see what he finds today, it did not seem to have the issue when i drove it to the shop to get all the work done. Any thoughts are appreciated.
Shimmy
MZBHVIN
1 - 20 of 39 Posts
So had new tires installed along with UMI upper control arms and Viking coil overs. Had front end alingement using specs supplied by guys on here as well as the spec sheet that came with the UMI and Viking kits. They were all three pretty much same specs. The car now seems to have a shimmy which from my past experience I would say is a tire balance issue steering wheel and seat vibrate at above 45. Tires have been rebalanced 3 time now putting weights on both sides, The shop thinks one of the tires is bad so they have at least one new one coming today one would not balance out properly. My question is a few of you talked about bump steer issues, but everything I read on it does not seem to be what the car is doing so going to see what he finds today, it did not seem to have the issue when i drove it to the shop to get all the work done. Any thoughts are appreciated.
My car does the same at 80+. I have new tires but same old bushings, old control arms, sloppy power steering and a cock-eyed steering wheel. After all the work and parts you have done, I would not be happy.
Well I didnt think it was bump steer either from what I had read about it on line it was just a thought. Tires are new rims are old, but it did not have the issue prior to the new tires, and alignment. Hoping he finds out it was the tire he could not get to balance. He tried to keep the weights on the inside the first time, then tried using weights on inside and out I think he said. Originally the weights were stick on near center of rear of hub, I doubt he gets to do any test drives today considering we just got hit with the direcho or what ever the hell all this rain is called and is to rain all the way until tomorrow afternoon. So wait and see.
Joined
·
10,398 Posts
Make sure the tires are balanced with no more than 1 weight on each side.Should be 2oz's or less.It's OK to add a 1/4 or 1/2 ounce weight but anything more than that and they are selling you an out of round tire.
(or your wheels are bent)
Hes a good friend he would not mess with me he is as concerned as I am. They are Cragar SS rims they had a ton of weight (stick on) on the inside with the old tires on them, he was going to try one more time and see what happens. Said most of it is gone until he gets up to 80 then the back end seams to shake until back down to about 50, we have both worked in a shop for many years me prior to what i do now both of us are a bit confused as to why this is happening.
Spoke to him last night, he said that it is pretty smooth now up to about 60, then between 62-70 it gets pretty bad and feel like it is in the rear of the car. He is going to look at the back rims again and
maybe pull tires off rims and spin them on balancer just to see how much they move, says he is not giving up on it yet. I asked if the drive shaft could be out of balance. So we shall see what the day brings.
maybe pull tires off rims and spin them on balancer just to see how much they move, says he is not giving up on it yet. I asked if the drive shaft could be out of balance. So we shall see what the day brings.
So it is up some from previous owner has all tubular components (adjustable) plus air assist bags in spring which I have very little air in. Difference between front fenders and rear is about 1.5 inches.
He just text and said he had it on the lift running and at about 70-75 mph the rear end is moving up and down. Which sounds like something out of balance to me.
He just text and said he had it on the lift running and at about 70-75 mph the rear end is moving up and down. Which sounds like something out of balance to me.
Shocks are just standard shocks in the rear. The car is just a driver show car it will not be raced or ran hard. Anyone know where the settings on the upper and lower bars should be, it has some serious hopping he said at 75
Joined
·
1,669 Posts
If it is raised some from stock, I would DEFINETELY be checking pinion angles. A driveshaft that is binding because of too much angle will cause a movement like that. Its easy to check and fix if the upper trailing arms are adjustable
When he has it on a lift, is the rearend supported with weight of car on it? A suspension in full droop will cause u joint binding and rear end oscillation.
When he has it on a lift, is the rearend supported with weight of car on it? A suspension in full droop will cause u joint binding and rear end oscillation.
Joined
·
1,669 Posts
There are not "settings" for rear arms that are applicable from car to car. It must be measured properly with an angle finder and adjusted within specs.
Ideally, you would want
2 deg down at trans output
.5 down on driveshaft
2 down on pinion. Meaning looking at car from driver side, the pinion would be pointing up and back of housing would be down so it would have same angle as trans
That would give you working angles of 1.5. Easy to measure and adjust and rule that out of the equation
Upper are adjustable for sure and I think the lower arms are as well but not sure I have only had the car for about a month or two. As to how he has it on the lift I am not sure. The guy that had it prior took it on power tours, I havent had it long enough to really drive it other than in town up to getting new tires and alignment.
1 - 20 of 39 Posts
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
