I'll try an explanation: The strobe balancer has a sensor/pickup that is adjusted up under the jacked up axle and it picks up the vibration caused by the imbalance. That shows up as a strobe flash. The motor driven spinner at the front of the tire allows the tire to be spun up to whatever RPM the vibration occurs. Like a timing light, the strobe visually freezes the spinning tire, and the weight goes on at the 12:00 position. Some strobes have a dial that shows estimated required weight, so you put that on and spin again. If the strobe freezes the weight at 11:00 position, you move the weight around to 12:00 and spin again. When the vibration stops and the weight is frozen at 12:00 the assembly is balanced. You simply rest your hand on some part of the vehicle to feel the vibration and when it stops. You CAN balance an out of round assembly, BUT WHY? You will still feel the physical out of round condition rotating against the pavement. As I posted earlier, FIRST, try to achieve the least amount of TOTAL combined run out possible with wheel, tire and hub, THEN true if needed, THEN balance. I've balanced 100's of truck tires with a strobe and it is very precise, and helpful in finding an out of balance condition at a specific rpm. NV rdr, please feel free to clarify or correct if you see fit. You have a great system.
I didn't read this whole thread, just the oirignal post. I had a similar problem on my couple, the front end would start bouncing all over the place around 50 miles an hour. I balanced the drums, had the tires shaved and rebalanced. . . and it did nothing. I rechecked all of the front end, caster, camber, made sure the rims were still round, made sure the shocks and shackles moved freely, check the tie rod ends, etc. . . everything was fine, but the bouncing issue was still there. Finally, I added five more pounds of pressure to each tire and the problem went away, and only comes back if my tire pressure gets low.
Couldn't have said it better. The tire shaver is made by Amermac. I think one of my strobes is Stewart warner
My machine is an Amermac dating to the late 60s They are well made and durable. Essentially they are tire lathes. The x/y axis can be preset or the operator can manually operate it. Amermac still make the machines. One version does the work on the car the other off the car. I rescued mine from a storage building frozen to the gravel floor.
I used to have a tire guy do mine.He passed away, family sold business. I loved the strobe light. You pretty much quoted him word for word.I hope i can find the tools.
I read many a thread here and was running anywhere from 16 to 20 psi in my fronts and I recently put 26 after reading another thread on this and you are very correct I noticed a lot of the bounce disappeared. One thing I also noticed was my road feel was lighter and the tires seem to wander with imperfection in road surfaces a bit more...controllable of course but different. The thread was on tire pressure to weight ratio. Great addition to this conversation Zombie...
Took the Modified to the tire shaver today, he said the tires were in good shape, rubber still soft, no noticeable flat spotting. Just not round! It didn't take long to shave them and didn't have to remove alot of rubber. I have 3 oz. DynaBeads in the fronts and 5 oz. in the rears. Ran the car up to 80 mph. and was smooth up to 65-70 then a little scary! Sooooo much better than it was and it got rid if the annoying hopping in the rear. I am pleased! Now to play with tire pressures to try to soften the ride some. I don't think a 1600# car needs 30# of air in the tires. Sent from my SM-N900V using The H.A.M.B. mobile app
Cool, think you may be right on the tire pressure. I'd bet that tire truing machine is as old as I am. Now go out and rack up some miles with a big grin.
Being one who like you has put numerous miles with rough tire to road feel...it is a very personal feeling almost surreal to have a smooth drive......have fun let us know what you did out...
I hate to criticize but that's never stopped me in the past. I humbly submit that the cantilever front suspension is not good design even on a light car. Some manufacturers used it into the mid teens and then abandoned it. The leaf springs are strong enough but meant to flex in a plane perpendicular to the road and car frame. Side load would then be eliminated with a stabilizer bar. The side plate links and method of attachment of the springs to the frame are a weak link and never intended to deal with side load in a cantilever system. Any degree of steering wheel input lessons the perpendicular and introduces side load. The further the springs extend from the frame attachment increases the leverage of side load. Essentially there is nothing to prevent the spring pak from twisting instead of flexing.
@modified thanks for the pics with your information too and thanks to the others for explaining these contraptions that improve the experience...
John not sure if this is in reference to my comment on harsh ride. Trust me just because I have smoother ride by no means is saying I now have a luxury automobile I still say it's a little like a horse drawn wagon with an engine......and that's okay with me too.
Stogy, I was referencing the OPs car with cantilever front suspension. I restored the 7th built 1915 Milburn equipped with cantilever front suspension and several cars later the frame was changed to accommodate full parallel leaf springs.
Page Barnes said he has been shaving tires for 30 years and I am sure the machine is older than that! Sent from my SM-N900V using The H.A.M.B. mobile app
Glad to hear you got it sorted out. Just make sure that if you do anything to disrupt the assembly (flat repair) index the tire to the wheel and wheel to drum before removing it, since it's trued as an assembly.
The car drives much better now but seems to go out of balance above 70-75 but that's really too fast to drive in this little car. At lower speeds it still has a little choppy bounce in the rear that the sound of the quickchange gears pronounce, I don't know if anything can be done about that, maybe lower tire pressure? Sent from my SM-N900V using The H.A.M.B. mobile app
I bought my Firestones mounted and balanced on steel wheels from Coker and they also shook the front end at about 65 to 70 mph. A local rebalance solved that problem. The rear tires on my light weight 34 Ford P/U have been an ongoing problem per transmitting bump shocks to the people in the car. I tried different shock absorbers and went to softer parallel springs with no great effect. I have concluded that the ratio between the sprung weight and unsprung weight is such that the inertia of heavy tires and the heavy Ford rear end moving up over a bump cannot be totally absorbed by shocks and springs and the rear of the car jumps. If the car was heavier that would help but I want my car as light as possible. I finally sold my Firestones and another set of wheels and tires and got a set of Excelsior radials (for a few dollars more) which give a softer ride and get around corners better.
I got my bubble balancer. We shall see. I worked with an ol' guy named Walt 30 years ago, he always said he could balance anything...except an egg because he COULD balance the egg....... but he just couldn't make it ROUND!
How do you like the Excelsior's and let's see a photo! Sent from my SM-N900V using The H.A.M.B. mobile app
just bought set of coker l78 www radials for my 55 chrysler and what a mistake that was, i wish i would have researched, both tires shops say they are 3/4 inch out of round, they shake at 65 and violent at 80, drove 40 miles hoping they would straighten out and not a chance. looking at dimondbacks for my 52 studebaker now. ill never buy another coker crapper tire.
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