Rear wheel allignment help

[ngyoung]

I posted this in another thread but thought it may just be worth asking in a new topic instead of hijacking someone elses.

My son's car (tiger cub) I noticed had a bad rear end drifting/death wobble when running in the pack. His car still smoked everyone in the pack on an aluminum track but the seems were horrible. Our car won every heat and the only time it almost got beat was when it jumped on a bad seem. There really was only one other car that looked like they put in quality time on it so it and they didn't have the starter wired to the finish to get total time. I know from when I was in scouts there there are plenty of serious cars at district. They use the same track for districts but I am hoping the main guy that coordinates that will shim the seems to line up better. When we put it together for the pack most of the seems were clamped using those large black clamps used for office paper instead of good shop clamps.

For his build setup we didn't do any canting but polished the stock BSA axles really good and burnished the wheels with hobb-e-lube. It is a 3 wheeler that naturally turned toward the lifted wheel but I didn't do any tuning for the pack but now that I have learned more and saw it run I wanted to tune it up better. I think it may be too aggressive I just rolled it on a 3.5 ft table leaf and it went at least 5". I will be bending the DFW to start tuning the steer. I am debating whether to cant the back axles and try to tune them so they run true. I think they are fighting each other and the back wheel opposite the DFW pulls into the rail too. I already pulled the wheels off and can tell the back are hitting the body some since there are hub marks around the axle holes. If I don't use an axle bending tool is it dangerous to try to do that for the 2 back wheels, cutting a notch and tapping with a flathead and hammer? Will it just create even more problems since the 2 back axles may not be bent exactly the same? We can't make screw slots in the heads but I was going to drill access holes to avoid turning the axle with nail head

 

[DerbyDad4Hire]

If you are using the slots then just push the axles in at an angle. DO not bend the rears. What axles are you using?

 

[ngyoung]

No I drilled my own holes and used an extended wheel base. Both front and back are about 5/8" from the ends. I didn't have access to a drill press so I bought one of those jigs from the local hobby store to hand drill my holes. I used the original out of box axles, filed off the burs, tapered the head, and polished up to 2000 grit. Would your recommendation be to just leave the rear axles alone regardless? How about just bending the DFW axle to tune the steering?

 

[Dr. T]

ngyoung,

If you had death wobble with a drift of 5 in over 3.5 feet its definitely a rear wheel alignment issue. There is a nice threat here on checking alignment but no need to check yours, its off. I would say you should fill the holes with epoxy and redrill. Would be worth investing in a table top drill press and the Silver Bullet. Without these you might get by with a hand drill and one of those pro body tools but that is a far second to drilling proper canted axle holes with a Silver Bullet or like tool.

Dr. T

 

[ngyoung]

I did use the pro body tool. Wish I would have found you guys 1 month sooner and spent my money on better stuff. It takes a while to dig through all the garbage and pretenders. The book I got handed down to me from another old derby nut that I work with was the Ultimate Speed Secrets, 2005 edition. Seems a lot has changed since that was made.

 

[5KidsRacing]

I did use the pro body tool. Wish I would have found you guys 1 month sooner and spent my money on better stuff. It takes a while to dig through all the garbage and pretenders. The book I got handed down to me from another old derby nut that I work with was the Ultimate Speed Secrets, 2005 edition. Seems a lot has changed since that was made.

And that book is still sold today as the latest and greatest build tip book! Throw it in the recycling bin and read up on the real speed tips here.

 

[ngyoung]

I am hoping next year for us both to build a car each. Being his first time he kind of grumbled through a lot of the tedious stuff but after winning he is all on board. It is something that I wish I did more of when I was a scout and would like to get more into the non-scout events sometime too.

 

[ngyoung]

Would using the same Pro body tool and a small drill bit for a shim be feasible for the rear hole canter if I made new holes? I do have room to make new holes adjacent to the original ones. I am not worried about my CoM, I can adjust if needed.

 

[OPARENNEN]

ngyoung,

If you had death wobble with a drift of 5 in over 3.5 feet its definitely a rear wheel alignment issue. There is a nice threat here on checking alignment but no need to check yours, its off. I would say you should fill the holes with epoxy and redrill. Would be worth investing in a table top drill press and the Silver Bullet. Without these you might get by with a hand drill and one of those pro body tools but that is a far second to drilling proper canted axle holes with a Silver Bullet or like tool.

Dr. T

Except for GoatBoy's canted drill fixture (or even uncanted). You don't need the "block" for that, just a steady hand on the drill, and a good drill bit.

 

[OPARENNEN]

I did use the pro body tool. Wish I would have found you guys 1 month sooner and spent my money on better stuff. It takes a while to dig through all the garbage and pretenders. The book I got handed down to me from another old derby nut that I work with was the Ultimate Speed Secrets, 2005 edition. Seems a lot has changed since that was made.

And that book is still sold today as the latest and greatest build tip book! Throw it in the recycling bin and read up on the real speed tips here.

Or best of all, get John's DVD.

 

[Kinser Racing]

I did use the pro body tool. Wish I would have found you guys 1 month sooner and spent my money on better stuff. It takes a while to dig through all the garbage and pretenders. The book I got handed down to me from another old derby nut that I work with was the Ultimate Speed Secrets, 2005 edition. Seems a lot has changed since that was made.

And that book is still sold today as the latest and greatest build tip book! Throw it in the recycling bin and read up on the real speed tips here.

Wrong 5Kids!

Tell your biggest competitors that you have this book you wanted their opinion on and then let them use it. /images/boards/smilies/biggrin.gif

 

[bracketracer]

Would using the same Pro body tool and a small drill bit for a shim be feasible for the rear hole canter if I made new holes? I do have room to make new holes adjacent to the original ones. I am not worried about my CoM, I can adjust if needed.

I know a local guy that drills his axle holes that way. His sons have fast scout cars.

 

[B_Regal Racing]

While we are talking about rear wheel alignment, my scout's car has a slight rear wiggle. Nothing particularly bad, and it did not stop us from winning Pack, but we did come in second in Districts, losing by .02 seconds over 4 races (3rd place was .4 seconds behind, almost 1/2 second, way back there). 1st and 2nd were as close as it could be. I knew the rear alignment was a bit off and tried to correct for it by adding more drift. My open class cars run about 4" over 4", but my scout's car is up about 6", much higher than I want. It has a stock WB (rules), 5/8" COM, with the rear axles drilled 5/8" from the back; 3deg cant in the rears.

To correct the rear alignment, can I epoxy a toothpick in the rear giving me the problem and re-drill? What do you do to fill an axle hole? I would have to drill very very very close to original axle hole because of the weight locations. The car would be very competitive in Council, but it could be much better; and there is nothing worse when a 9 year old can identify an alignment problem.

 

[Kinser Racing]

Drift (wiggles) Can be caused by a few different things:

1. Dirty wheels (outside)

2. To little steer

3. To much wheel gap

4. Your axles have been polished to to small of a diameter

5. Alignment

 

[Guest]

While we are talking about rear wheel alignment, my scout's car has a slight rear wiggle. Nothing particularly bad, and it did not stop us from winning Pack, but we did come in second in Districts, losing by .02 seconds over 4 races (3rd place was .4 seconds behind, almost 1/2 second, way back there). 1st and 2nd were as close as it could be. I knew the rear alignment was a bit off and tried to correct for it by adding more drift. My open class cars run about 4" over 4", but my scout's car is up about 6", much higher than I want. It has a stock WB (rules), 5/8" COM, with the rear axles drilled 5/8" from the back; 3deg cant in the rears.

I would have to drill very very very close to original axle hole because of the weight locations. The car would be very competitive in Council, but it could be much better; and there is nothing worse when a 9 year old can identify an alignment problem.

It is probably a fools errand.

Just spit balling here.

You might be able to get away by redrilling the hole much larger and inserting a dowel.

Then redrill.

 

[Guest]

Would using the same Pro body tool and a small drill bit for a shim be feasible for the rear hole canter if I made new holes? I do have room to make new holes adjacent to the original ones. I am not worried about my CoM, I can adjust if needed.

I know a local guy that drills his axle holes that way. His sons have fast scout cars.

Dang BR,

You have a very dry wit.

Is this what they mean about a backhanded compliment?

 

[Papa V Racing]

Drift (wiggles) Can be caused by a few different things:

1. Dirty wheels (outside) Pay close attention to this as OPA stated here and Kinser told me last month... Graphite killed us in pack race... Cleaning them took my son to second place in Districts... Clean these wheels good... any amount of graphite can wiggle you we found out the hard way...

2. To little steer- We added a little more steer in his car.. Did the trick

3. To much wheel gap - We open the tight pag on steer and closed the front .. OPA is hitting key areas here guys pay close attention to easy over looked things we do....

4. Your axles have been polished to to small of a diameter

5. Alignment- We have a mirror for tuning right now and it works well make sure to read up on the threads it helped us out a ton!!

I had bold the comments that my son and I did on our car that OPA listed... OPA like others are Great peeps... These are easy to overlook items as us dads tend to rush as our boys minds wonder off or real life things happen... I had Kinser and quaddad, GX, Chief, MOFAST and several others guiding our car build as the pack rules were very tight.. but in the end we followed everything OPA listed and what others told us and guess what... THE WIGGLES were not there for Districts!! We were excited to see our sons car win all his heats... everyone of them.. Try to do your best and follow these gents suggestions they will guide you to the finish line ahead of the others...

By the way a lot of have those other tools.. I like Johns idea and I will use mine as he did to hold the body off the ground to paint it... Don't waste your time and more money... Getting frustrated... DD4H it works!!

 

[ngyoung]

Dirty wheels and track was likely a big factor in our pack race. Our wheels were pretty dirty when done. We didn't clean them after lubing before the race either. No one cleaned the track off after setup. My 3 year old touched the track and got graphite all over herself.

Next year if things work out I may take charge of the derby stuff and do a basic workshop for our den. I felt bad for one kid who never made it to the finish line. I wanted to take a few minutes to figure out what was going on but it was kinda chaotic and my two little ones were being pretty clingy

 

[B_Regal Racing]

Did a little testing and it appears I had two problems, excessive gap (from reading a credit card sized gap is excessive) and a rear wheel alignment. The rear wheel opposite the DFW wheels does not migrate to the axle head as I expected when the car roles backwards on a tuning board. I tried swapping the rear wheels, but still get the same outcome. <cringe> I drill my axle holes with a revel body jig </cringe>. Getting past the "why do I not have a drill press" questions, I have a moral dilemma (maybe). This car is for the Council race, but I lost districts by .02 seconds over 4 races. I have easily made that time up and then some, but I essentially duplicated the car, drilling the axles correctly (well, at least as good as I can do for now). I also cleaned up a few other minor items that inhibited some performance.

My question is: do I enter the new car (it looks almost identical) with same wheels and axles? At council, there are more Dad tuned cars than scout tuned - you tell when you walk in the door and watch who is handling the entrant cars. Or do I put a 1/2 degree bend (or less) in the misaligned axle hole to correct it, if I even can? My kid hates to lose; so do I. Just looking for opinions.

And yes, there is a drill press in my future...

 

[Kinser Racing]

Do you have it steering in reverse? I wouldn't worry to terribly much about what the car does in reverse unless they run it that way. LOL ( Some races I've heard of do). If it's steering in reverse this could cause the wheel to do what it's doing because now the rear wheel is having to take that pressure from the steer. That's just my thoughts. I know it's limited because of the tools.