I have a 1930 Ford Model A chopped, channeled, and a custom 2"x3" frame. I have a tube straight axle with spring over axle leaf spring. I have SoCal standard front shocks. The wheels are 1935 Kelsey Hayes spoke wheels. Brakes are drums. Bias Ply Tires. When I get to 65 mph the front wheels violently bounce/hop up and down. I have tried a newer style wheel with bias ply and no difference. I have inspected everything numerous times and no issues. It does not do it at all below 65, but at and above 65 it is extremely dangerous.
Have not had good luck with Bias Ply Tires. Welcome to the HAMB from MN, soon to be from WI, nice look'in hot rod!
I did not see mention of balancing the tires. A decent test for "static" unbalance is to back the brakes off and with the wheel jacked in the air rotate it 90 degrees several times and let it seek any heavy spots. You said the wheels bounce up and down. Do they bounce together, or kind of opposite. When driving at contant speed does the bounce " come and go?
You may not have round bias ply tires. Jack up the front, and spin them by hand. Are they round, or do they deflect as much (or more than) .060"? (1/16") If they appear fairly 'true'... Spin them up on a Hunter type motor. (on car) Severe 'bouncing' from approximately 25 MPH indicates static and dynamic unbalance. Bouncing at 65 MPH suggests out of round, dynamic unbalance. May be necessary to have the tires trued, THEN balanced on an electronic machine. Edit: See Post # 2. @lucky ink has hit it on the head!
I had mine balanced on the car and it fixed it 90%. Just mark the rims to be sure they go back on the same if you take them off.
Rotational speed problem. Same same issue with different different wheels and tires. Check Hubs and drums. Balance and bolt pattern. There's a thread around here where the hubs bolt pattern was off a few thousandths. Long term problem and the cause ( bolt circle off) wAS Discovered an unrelated issue. Correcting the bolt circle issue solved the problem that was chased and missed for eons.
Axle castor not being "kicked out" 5-7 degrees can cause that. And borrow a set of radials- you'll be amazed.
Hello, When I changed tires on both 40 Ford Sedan Deliveries, I had them "trued". They put the tires on a machine and it worked like a lathe. The cutting edge tool took off what was not round and left it on the floor. I was amazed that they took off so much rubber from the tread, but in the end, the tire was round. Balancing the tire is also a critical part. Today's balancing machines are so much more accurate than the old style bubble balancers and spinning machines. The front end no longer shook at speed and tracked great. Jnaki
Find a shop that has an on the car spin balancer that can spin the tires while they are on the car. They just jack up the front end and put the drum of the balancer up against the tire tread and spin the whole wheel, tire & drum assembly up to speed. One of the older shops around town probably still has one. I've got one I picked up off a guy who used it in his service station for years a couple of years ago after hunting for one for 20 years.
Had that problem and the bias ply tires I had on the car had a really bad run out, really out of round. Got rid of them and bought some Excelsiors, solved the problem. I was fortunate to have a friend that had an old balancer that balanced the wheels while still on the car.
Around here there are no tire shavers or on car balancer units. Gotta be like that in other places too. How did that feel, seeing all that tread life GONE? Tires ain't cheap- especially for us picky bastards
The local tire shop here(Les Schwab) has an attachment on their spin balancers for road force balancing. Had a tire hopping and they got it back in balance that way. Maybe a shop in your area has something similar? Also, what is your toe in set at? seen that do weird things at higher speeds if it is off....
Nice non-intro first post. Before asking questions, try a search. This has been covered over and over.
Modern production bias plies, especially from that one place, are notoriously not round. You will likely have to have them shaved, and then properly balanced, after. It probably is not your castor, as that is a bean. You could check your caster, though.
Wheels are balanced. They bounce kind of opposite, constant at 65 and above. Below 60, no bounce at all.
Yes,and the HAMB would run much smoother if Intros were required as before...Now it seems as the HAMB is a 'catch-all" for anyone with a car problem. "traditional" has about disappeared from our pages.
I have a 30 Ford Model A chopped,channeled--------------That's enough of an intro for me???? Sent from my iPad using The H.A.M.B. mobile app
Red, black, kidney, baked ?- be specific! (Any good dip recipes?) So.............. about the wheel hop..............
Do you have wheel adapters? We have found these are often not true causing side to side wobble. A tire hanging in the open may look true, put something close to the tire for reference so you can watch the gap and see if the tire moves up and down or side to side.
I had a problem similar to this one and found that the new machines are not perfect. They still require a trained technician to get the balance right. The new machines offer a "range" of imbalance which is reported by the machine as being "in balance" when it actually isn't. Modern cars have so much rubber in the suspension that they will absorb minor imbalance and still ride smoothly. Older cars with little rubber in the suspension are not so forgiving. Find a tire store that has a technician who understands this and is able to fine-tune the balance so that it is perfect, not just close. This solved my tire bounce problem and smoothed the ride greatly.
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