Bent Axle Alignment Video(s)

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Stan Pope
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Bent Axle Alignment Video(s)

Post by Stan Pope »

This is the first of the promised Bent Axle Alignment videos.

Bent Axle Alignment Example

The film clip is unedited, presented just as it occurred and lasts 3 minutes 24 seconds. 21 seconds of title added to front and 5 sec added to end.

There are hints of the mnemonic I use to tell which axle to adjust and which direction to adjust it, but I will describe that later.

The primary indicator for rear alignment is the path followed by the wheel behind the DFW. I am aligning it to follow the first line out from the center rail, about 1/16" of separation. Regardless of which side I am aligning, that DFW-side rear wheel is the one I watch.

Cantilevered weight is added to make each rear wheel, in turn, the dominant rear wheel, i.e. the most heavily loaded rear wheel. I stop rear wheel alignment when, with no intervening adjustment, both weights produce the same DFW-side rear wheel path.

The last approximately 30 seconds of the video shows setting the DFW toe-in, so you can see that the alignment of the rears took about 3 minutes.

The video is rather large ... 210MB so it will take a few seconds for it to fully download to your computer. It may not be posted elsewhere. I will move it to a streaming area later.
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Re: Bent Axle Alignment Video(s)

Post by Stan Pope »

Here is same video with annotation to help explain what/why:

Annotated Bent Axle Alignment Example

There is some wasted time in each step ... pointing in the direction I need to move the rear wheel and turning the car over twice when I want to adjust the right rear wheel! So, I could do the alignment more quickly.

Note that I am right handed and start the adjustment with the DFW side downtrack. Then, if the DRW is the left rear, flip the car on its long axis so that the left side is down track. Then adjust the uppermost part of the downtrack rear axle in the direction I need to move the wheel.

If I were left handed, I'd work from the other side of the track (or turn the track around on the table.) Rest of the mnemonic is the same.
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Re: Bent Axle Alignment Video(s)

Post by Stan Pope »

If you ride a Mac "bareback" and can't see those .wmv files, try these mpegs:

Bent Axle Alignment Example

Annotated Bent Axle Alignment Example
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Re: Bent Axle Alignment Video(s)

Post by Stan Pope »

The final note in the video suggests tweaking the non-dominant rear axle based on your test track times to try to improve performance. While it is possible that the times might be improved that way, that has not been my experience. Grandson Andrew's track times suffered with both slight increases and slight decreases in the non-dominant rear wheel toe. So, we put it back on the alignment table and reset it!

We were, of course, able to improve track times by tweaking the DFW toe in!

The alignment in this video follows the plan explained in Aligning Rear Axles that I published in March 2009. The mnemonic mentioned above is new.

The process seems to give good results for any negative camber angles. The forward/reverse roll test loses sensitivity as the magnitude of the camber angle increases.

Alert viewers may question the lack of symmetry shown by the two clip-on weights. They were adjusted to produce comparable rear wheel loads and to make the load on the now dominant rear wheel about 1/2 ounce greater than the other. Since this is a three wheeler and the weight of the car is roughly centered already, the weight is evenly divided side to side. But since the DFW carries about 1/2 ounce, the wheel behind the DFW carries 1/2 ounce less than the wheel on the opposite side already. There is no need to change the weight adjustments so long as they are used on cars on which the right front wheel is dominant.

Without added weights, the rear wheel opposite the DFW is already dominant if the car is balanced left to right. I have been successful using the clip-on weight only to make the wheel behind the DFW dominant, but I can imagine circumstances in which this might fail to produce quality results. So, I recommend using both clip-on's.
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Re: Bent Axle Alignment Video(s)

Post by Stan Pope »

This is a short video showing "rear wheel dominance" ... what happens when the rear wheels don't agree on which direction to go. Which rear wheel decides?

Rear Wheel Dominance.wmv

MPEG for those who can't see Windows media: Rear Wheel Dominance.mpg

Manipulating rear wheel dominance is the key underlying the Bent Axle Alignment videos above.

Note that you can detect rear wheel steering by observing the early movement of the rear of the car ... it moves opposite to the direction it is steering the car! When the car veered left, the rear started by swinging out to the right.
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Re: Bent Axle Alignment Video(s)

Post by Stan Pope »

Streaming Video versions of videos above:
Windows:
[url=mms://205.178.152.128/38788/Rear%20Wheel%20Dominance.wmv]Rear Wheel Dominance[/url]
[url=mms://205.178.152.128/38788/Unedited%20Alignment%20Example.wmv]Unedited Alignment Example[/url]
[url=mms://205.178.152.128/38788/Annotated%20Alignment%20Example.wmv]Annotated Alignment Example[/url]
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Re: Bent Axle Alignment Video(s)

Post by Stan Pope »

Finally, this video shows variations in staging and how they affect the car's path:

[url=mms://205.178.152.128/38788/Staging%20Correction.wmv]Staging Correction[/url]

I don't recommend angling the car! The video shows that the car will self-correct, but there is probably some lost time while it does so. The third staging mode, offsetting the car so that the DFW-side is away from the rail and the opposite side almost touching the rail, may provide some advantage derived from the delay in friction from DFW rubbing the rail.
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Re: Bent Axle Alignment Video(s)

Post by Stan Pope »

I've observed no responses to this series of postings. I would appreciate hearing critiques from those who choose to apply this alignment process.

The reason that I developed the method is that all of the other "bent axle" alternatives seemed to me to be incomplete in that they
(1) ignored an important alignment goal (clearance of rear wheels from the rail),
(2) did not apply to the full range of possibly worthwhile cambers, and/or
(3) did not provide a clear guide as to what to adjust in order to optimize the alignment.

Each of these goals is important, and the alignment process must address them all. This one does!
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Re: Bent Axle Alignment Video(s)

Post by bracketracer »

Sir, I was not able to watch all the video content you have provided. The videos display with quite a bit of chop. I found it hard to see what you are trying to show. The video on rear wheel dominance played better. My take away message from that so far is that toe in on both rears = BAD! That car acted as if you left the parking brake applied! I hope to be able to view the rest of the videos in the future, I'm not sure why they don't play smoothly.
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Re: Bent Axle Alignment Video(s)

Post by FatSebastian »

:offtopic: Eights posts in a row from the same person! That's gotta be the new DT consecutive posting record. :)
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Re: Bent Axle Alignment Video(s)

Post by Stan Pope »

bracketracer wrote:Sir, I was not able to watch all the video content you have provided. The videos display with quite a bit of chop. I found it hard to see what you are trying to show. The video on rear wheel dominance played better. My take away message from that so far is that toe in on both rears = BAD! That car acted as if you left the parking brake applied! I hope to be able to view the rest of the videos in the future, I'm not sure why they don't play smoothly.
I noticed the same thing on the streaming version at times. The links in the first post are not streamed ... they download the whole 200MB before playing the file off your disk! Not a good solution, but better than the "stop and go". I went to another computer on this LAN and it played very nicely. And later it played very nicely on this computer. Dunno if the fact that this computer's 8 cpu's are kept busy doing scientific computing 24 hours a day and interrupt those computations in order to do email and play videos plays a part. Or maybe it is the load on the streaming server at Network Solutions. Just dunno.
If you intend to watch it more than once, save it to your HD and then play and replay it from there.

The key point is that if you get the rear wheel behind the DFW to follow that 1/16" line when the left rear wheel is controlling the rear end location and when the right rear wheel is controlling the rear end location, then you will end up with the rears well aligned!

A secondary point is that it doesn't require hours of "cut and try" effort (as several have reported here on DT) to align with bent axles!
FatSebastian wrote:Eights posts in a row from the same ...
I worried about that a bit, but at each stage I thought I had useful material to add. The whole thing was, after all, an R&D effort. And I don't feel compelled to withhold info until "all the patents are locked down!"
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Re: Bent Axle Alignment Video(s)

Post by whodathunkit »

Stan,
I noted: for the longest time you were the only one posting on your Bent axle alignment topic also.
So congrats on the record..
FatSebastian wrote::offtopic: Eights posts in a row from the same person! That's gotta be the new DT consecutive posting record. :)
But I must say I enjoyed setting in on your how to video classes. :D

So I'll just ask you..
How well do you see this bent axle alignment method working with the 18 wheeler big rigs (?)
What type of automobile can be spelled the same forwards & backwards?
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Re: Bent Axle Alignment Video(s)

Post by chobo »

I haven't had time to watch, but I have plans to. Been busy job hunting and with s couple summer classes lol

Just discovered your website also :mrgreen:
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Re: Bent Axle Alignment Video(s)

Post by Stan Pope »

whodathunkit wrote: How well do you see this bent axle alignment method working with the 18 wheeler big rigs (?)
Is your 18 wheeler articulated?
Which wheels are in contact with the track?
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Re: Bent Axle Alignment Video(s)

Post by whodathunkit »

Stan Pope wrote:Is your 18 wheeler articulated?

Yes haveing two or more sections connected by a flexibe joint.

Which wheels are in contact with the track?
It would be nice if none of them were in contact with the track.. and glide down like cold butter in a hot frypan..
but we know that will never happen ( ha, ha.)

So how about these wheels being in contact with the track.
Tractor: right front & the inner back dules.
Trailor: inner back dules as well. (all the rest of the wheels are shaved or raised.)
What type of automobile can be spelled the same forwards & backwards?
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