General question on adjusting

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Noskills
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General question on adjusting

Post by Noskills »

Hello all,

What do you all do to observe your car while adjusting. (more questions on adjusting to come after I read some more) I have read people running their cars over a 4 foot board lifted a few inches up so it rolls slowly. I assume the car need to roll a full 4 feet so the board needs to be about 5 feet long. Will a piece of 1X8 work with a line down the center? Also I am guessing getting this up to eye level is better than getting on your knees on the floor. I also assume that good lighting is key.

When I made my first car (few weeks ago) I ran it down a while board and I was able to assess drift but I really could not see what the wheels were doing on the axels (ie running to the outside or inside). I assume this just requires good lighting and practice?

Thanks,

Noskills
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sporty
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Re: General question on adjusting

Post by sporty »

It's to check if the rear wheels are aligned well.

yes a 1x8 would would work.


The slow speed. is suppose to allow you to see if the rear wheels are going to the body or the axle head. but most of the time. if the alignment is not right, the car is going to either go to the left or the right and not strait.

Sporty
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Stan Pope
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Re: General question on adjusting

Post by Stan Pope »

A 3' board is long enough. Much longer and you will only be able to see a part of the run up close. So, why make it difficult?

Wiles' procedure works unless you make the rear axle bend too great. Then I think the "sweet spot" become a "semi-sweet zone". Those rolls are made with the front wheel adjusted for "straight ahead". Once you are happy with the rear wheel migration, recheck that the wheel behind the DFW tracks about 1/16" outside. Then insert some toe-in for the DFW, and recheck clearance as the car rolls straddling a yardstick. (My yardstick is tacked to the back of the board.)

Finally go back to the flat side and check drift. Note that drift is difficult to measure accurately regardless of the length of the run because the starting condition plays a large role in the path the car takes. Just like shooting a rifle ... a small change in the direction of the barrel and you are completely "off the paper." So, look at how the wheels are when the car is rolling and start them out that way. Use a reference line down the board and at least two reverence points on the car to align with it. On most of my cars, the side opposite the DFW is parallel to the car's centerline and the planned direction of travel, so I align that side with the reference line on the board.

If you want to convert drift measurements for different board lengths, see my conversion web page: Drift Translator and Toe Angle Calculator ... it is NOT a linear relationship ... doubling the length of the run does much more than double the amount of drift.
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Noskills
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Re: General question on adjusting

Post by Noskills »

Thank you Stan and Sporty,
Let me recap in my novice language. So I get my flat level board, mark the midline and some reference lines (maybe 2 in off center). I raise the board enough so the car goes slowly. I put in my front axels with 0 camber and 0 toe-in. I place my rear axels with the camber I choose. I roll the car slowly and watch the rear wheels. I looks to see that they move to outside and they are not producing any car drift (assuming I want 0 toe-in for the rear). If I dont get the desired lateral movement of the wheels I slowly twist my axels (lets assume I am using bent axels and straight axel holes).

Once this looks good I put the amount of desire toe-in and camber to my DFW. Check to the amount of drift I want and adjust as needed. Also at this point as per Stan I attach a yard stick to the board (which is suppose to mimic the center rail I think) and run it down checking that the wheel behind the DFW clears the yard stick by 1/16 or so?

That sound about right?

Thanks again,
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geauxturbo
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General question on adjusting

Post by geauxturbo »

We're at the aligning stage. We cant seem to get the rear wheels to move to the heads in both fwd and reverse.

So we adjusted until the rear tracked straight going fwd and the wheels went to the nailhead. Axles in rear are canted 2.5*. Using slots. Gap is 1/16". Wondering if the gap is too small and forcing the bend into the slot and pushing down the nail slightly removing some of the cant.

It runs nicely on a 5 ft test board and grabs the rail. Running 2.5" of drift in 4'. More than that seems to "slam" the car into the test rail and makes the non-dominant rear hit the body for a split second until the rear "catches up" to the front.

The rear on dominant side stays off the rail. Should we worry about the fact they dont go to the axle heads in reverse?
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Re: General question on adjusting

Post by sporty »

geauxturbo,

Gets ahrder to address two different people in one topic.

But If I gathered right, you are meanign reverse with the RR wheel and setp up on the car. this will effect things.

Thats why when I tune the rear of the car. no front wheels and axles are on the car. when going down the board.

If you ran the car backwards with no wheels, it should still have the wheels going to the axle head.

A side note:

If you all bent you're axles, for the rears, cant. Tuning is much harder and takes time to perfect. It's likely trying to find youre way down a basement step in pitch black. Until the light comes on, you are just stumbling around.
Well same way for tuning, until it clicks for you and you get it figured out. some never do. It can be a difficult process.

Jusr remember, if this is your 1st or 2nd year, trying alignment and tuning. you have more time next year. Took me 3 years to get good at it, and even now I do not think im that good at it. I have been doing it for 5/6 years. been at this 12 years..

Basically your close, but still need a little more adjustment, if you are not trying to check the rear wheels, with the front/ fronts on.

Because a RR, curves/ drift and going backwards with it, is going to push one the rear wheels into the body.

Sporty
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Noskills
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Re: General question on adjusting

Post by Noskills »

Sporty, when you say that "no front wheels and axles are on the car" do you put a peice of shiny clear tape and some graphite on the front? I think I read that somewhere. Have been reading alot of this site-time to start a notebook :thinking:
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Re: General question on adjusting

Post by FatSebastian »

Noskills wrote:do you put a piece of shiny clear tape and some graphite on the front?
:nod: Yes (see this).
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geauxturbo
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General question on adjusting

Post by geauxturbo »

Ok. We had it right before adding the front rr wheel. Need to go back and reproduce the results then add the rr with drift and make sure the wheels still go to the heads moving forward.

Also, using tape... Wont that skew the angle of toe when you lift the front end to put the wheel on...ie you may go from 0 toe to (-) toe when you lift the front end (as the axles rotate backwards with the rise of the front end).
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Re: General question on adjusting

Post by FatSebastian »

geauxturbo wrote:using tape... Wont that skew the angle of toe...
It could slightly. When that is a concern, one can use a smooth thumbtack to elevate the front end.
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geauxturbo
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General question on adjusting

Post by geauxturbo »

Thumbtack worked like a champ. Running true with only rears, wheels moving to axle heads. We added the front wheel and its steering nicely into the center rail, rears staying out and off the rail, front is going in and riding. 2.25" over four feet and it doesnt "slam".

Thanks!
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Re: General question on adjusting

Post by RRS73 »

geauxturbo wrote:Thumbtack worked like a champ. Running true with only rears, wheels moving to axle heads. We added the front wheel and its steering nicely into the center rail, rears staying out and off the rail, front is going in and riding. 2.25" over four feet and it doesnt "slam".

Thanks!
We used the thumbtack and it worked like a charm. We rolled the car forwards and backwards on rears only, and it took a lot of patience to get it right. This takes time and effort. We spent quite a bit of time off and on in the weeks leading up to the race working on fine tuning. It was worth it.

Most Cubs show up at our race with wheels just slapped onto the car and paint that is still tacky. Had lots of dads ask me about tuning. Most were clueless, but I tried to help on test and tune night. Crash course is tough to absorb.
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geauxturbo
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General question on adjusting

Post by geauxturbo »

I'm hoping we have a test and tune. 5' doesn't inspire a lot of confidence ;)
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Re: General question on adjusting

Post by RRS73 »

geauxturbo wrote:I'm hoping we have a test and tune. 5' doesn't inspire a lot of confidence ;)
Based on my experience in my Pack, most cubs and adult helpers haven't even done half of what you've done. We got a good feel for our car on a 6 foot inclined board with yardsticks for a rail. We knew the car would be fast. Test and tune night was a blast. Cub's car was very fast, and we got to help others with the art of tuning. Most had no idea that you do such a thing! Cub even helped a Webelo II tune his car, and mine is a Wolf. He gained some instant respect as the Webelo had shaved 0.8 sec in 10 minutes of tuning with my boy. It was a 50 foot track. Webelo placed second in his Den, and my son made new friends with the older scouts.
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sporty
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Re: General question on adjusting

Post by sporty »

A real kicker in all of this. Is I have to point out.

That real wheel alignment tuning, is really a result of poor axle whole drilling, Skip axle slots. theres no real solution there but tuning.

So for those who can drill axle wholes. Keep in mind, much of this real wheel tuning can be eliminated by proper axle whole drilling.

Sporty
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