Rear bounce and body wobble

[Differen T]

Be careful cause my big tires have a tube and they also have a washer and nut on the valve stem.

Usually if the tire requires a tube it will be somewhere on the sidewall. Also many tires will state tubeless on the sidewall. This does not eliminate the possibility that someone put a tube in a tubeless tire.

I'm glad you are thinking new tires as once a tire suffers the wear your tires show they usually are out of balance and even air pressure changes will not completely correct the wear pattern. Another caution is DO NOT mix radial and bias ply tires on the same car. Again this information is on the tire sidewall. See www.tirerack.com for good tire information.

Since you are investing in new tires a four wheel alignment is also a good investment and should be done soon after the new tires are installed. You can play with the air pressure on your current tires using the water pattern method and get an idea of where to start with the new tires. You also mentioned new wheels and usually the best wear occurs when the rim width is the same as the tire tread width.

Some tire gauges, usually the pencil type, will not depress the valve inside if the valve stem and you will not get a pressure reading. You need to find a gauge that will give you a reading (usually more expensive than pencil type). If it were my car I would start with 20 pounds of air pressure in the rear tires and 24 pounds in the front and do the water test. You need to get tire pressure close on both ends of the car

You can also use the water test to determine if the car is tracking properly. Move the car in a straight line for several car lengths, wet all four tires and move the car forward several more car lengths without moving the steering wheel. The front tread pattern should be parallel to the rear tire pattern and front tire outer tread edge should about the same distance from the rear tire outer tread edge on both sides.

Al

 

[Tyus]

Usually if the tire requires a tube it will be somewhere on the sidewall. Also many tires will state tubeless on the sidewall. This does not eliminate the possibility that someone put a tube in a tubeless tire.

I'm glad you are thinking new tires as once a tire suffers the wear your tires show they usually are out of balance and even air pressure changes will not completely correct the wear pattern. Another caution is DO NOT mix radial and bias ply tires on the same car. Again this information is on the tire sidewall. See www.tirerack.com for good tire information.

Since you are investing in new tires a four wheel alignment is also a good investment and should be done soon after the new tires are installed. You can play with the air pressure on your current tires using the water pattern method and get an idea of where to start with the new tires. You also mentioned new wheels and usually the best wear occurs when the rim width is the same as the tire tread width.

Some tire gauges, usually the pencil type, will not depress the valve inside if the valve stem and you will not get a pressure reading. You need to find a gauge that will give you a reading (usually more expensive than pencil type). If it were my car I would start with 20 pounds of air pressure in the rear tires and 24 pounds in the front and do the water test. You need to get tire pressure close on both ends of the car

You can also use the water test to determine if the car is tracking properly. Move the car in a straight line for several car lengths, wet all four tires and move the car forward several more car lengths without moving the steering wheel. The front tread pattern should be parallel to the rear tire pattern and front tire outer tread edge should about the same distance from the rear tire outer tread edge on both sides.

Al

Thanks for the info.....Very informative!

 

[Wild Mango]

Wow your ackerman is way out, but I dont think that would account for your problems. I can see from the shinny bits on your shocks that you have less than 1'' of travel on your front end. Shackles look OK but you need some opinions on your front spring from the guys here that know them better than me. I would say it look a little heavy for a T.
C'mon guys you know these things better than I do. (opposed coils are my bag)

Also are you having trouble with bump steer? Your drag link is twice the length of you front R Rods?
Gerry

PS Why a rag over the spring mount? Are you worried about it?

That front end looks kinda ass about face. If the steering arms and the tie rod were behind the axle the ackermann would be close to sweet. IMHO Jerry is correct about having too much spring up front. BUT as someone else said, get one thing sorted at a time to make sure you get 'em all. Get the rears trued for round and balanced and go from there. But the back won't follow the front, and the fronts will scrub because the ackermann is skew whiffed.
Be of good cheer,get her sorted, you got one nice lookin' bucket, so it'll be worth it.

 

[Tyus]

That front end looks kinda ass about face. If the steering arms and the tie rod were behind the axle the ackermann would be close to sweet. IMHO Jerry is correct about having too much spring up front. BUT as someone else said, get one thing sorted at a time to make sure you get 'em all. Get the rears trued for round and balanced and go from there. But the back won't follow the front, and the fronts will scrub because the ackermann is skew whiffed.
Be of good cheer,get her sorted, you got one nice lookin' bucket, so it'll be worth it.

I already removed a front spring to allow more suspension travel, you must have missed that post.

 

[Wild Mango]

I already removed a front spring to allow more suspension travel, you must have missed that post.

OK what you have done by removing a leaf is decrease the spring rate. You will get more deflection because the spring is "softer".This will change things but just what has changed you need to identify. It sounds to us your problem is more one of imbalance or run out. Troubleshooting things like this, it makes it easier to judge changes and effects thereof if you change just one thing at a time. Which is why I suggested truing and balancing the rears first up.

 

[Tyus]

OK what you have done by removing a leaf is decrease the spring rate. You will get more deflection because the spring is "softer".This will change things but just what has changed you need to identify. It sounds to us your problem is more one of imbalance or run out. Troubleshooting things like this, it makes it easier to judge changes and effects thereof if you change just one thing at a time. Which is why I suggested truing and balancing the rears first up.

I actually removed a extra leaf that the previous owner installed to raise the front end a little more for clearance. So it wasn't part of the original set of leafs.

 

[Retroboy]

G'day
I'm newish here and haven't posted much. I'm a Mechanic by training and worked in the field for 15 years, including lots of suspension work. I've also had around 20 years in racing before moving on to Hot Rod pick-up's and now I'm in the early days building my first 23 T inspired vehicle- what I'm saying is I know my way around a car. Your rear tyres are the problem. To get a decent ride on what ever car they were on be it this or some other car, they have been run way under-inflated and have that terrible wear. We can see the whole shape is gone on the right tyre. The tyres have lost there shape and no end of pressure adjustment or balancing is gunna bring it back. Borrow a pair of decent balanced wheels and tyres from a mate and run it (doesn't matter what size provided they are a matching pair) and you find the shake rattle and roll will be gone. Also your rear shocks are up side down.
Cheers
Tony

 

[Gerry]

I think thats sound advice. If you can borrow a pair of 'good wheels and tires' fit em and see what happens.
Gerry

 

[Tyus]

G'day
I'm newish here and haven't posted much. I'm a Mechanic by training and worked in the field for 15 years, including lots of suspension work. I've also had around 20 years in racing before moving on to Hot Rod pick-up's and now I'm in the early days building my first 23 T inspired vehicle- what I'm saying is I know my way around a car. Your rear tyres are the problem. To get a decent ride on what ever car they were on be it this or some other car, they have been run way under-inflated and have that terrible wear. We can see the whole shape is gone on the right tyre. The tyres have lost there shape and no end of pressure adjustment or balancing is gunna bring it back. Borrow a pair of decent balanced wheels and tyres from a mate and run it (doesn't matter what size provided they are a matching pair) and you find the shake rattle and roll will be gone. Also your rear shocks are up side down.
Cheers
Tony

I did some searchin online before installing them and they said they can be installed either way. Maybe this it isn't true. They are not like normal shocks and have tension when opening and closing as opposed to just one way.

 

[Differen T]

I did some searchin online before installing them and they said they can be installed either way. Maybe this it isn't true. They are not like normal shocks and have tension when opening and closing as opposed to just one way.

Some shocks can be installed either way and it seems you have that type of shocks. The "upside down mounting is usually done to reduce sprung weight. No harm, no foul unless after you solve your other problems the shocks are too stiff. But worry about that if it happens.

Al