rear wheel alignment?
- Thread starter davet
- Start date
Did you switch axles and wheels around... Just remember these axles are not perfectly straight.. Nor are the wheels but really close.. I've had this happen and by switching wheels it cite the problem.. Otherwise the alignment needs tweeked
Tuning a car at 0100 hrs is not a good idea. Fortunately TRE was up late too and pointed out the obvious alignment issue.
I didn't switch side to side but did twist them a little. I found that with a straight axle in the DFW hole I could get both rears to go the heads in both directions and it ran dead straight forward but about 3" steer in reverse. When I put the bent DFW axle in it seemed the wheels wouldn't go to the heads as quickly though.
When I had less than .60 oz on DFW she had a rear wiggle. Adding more than 4" of steer did not fix it. If I took a little weight off rear by just rolling the rear putty slightly forward the wiggle would lessen. If I moved up to .62 oz on DFW she ran dead straight and pretty silent down my homemade track. Is this indicating still a rear alignment issue since I can't load that rear axle with more weight?
I didn't switch side to side but did twist them a little. I found that with a straight axle in the DFW hole I could get both rears to go the heads in both directions and it ran dead straight forward but about 3" steer in reverse. When I put the bent DFW axle in it seemed the wheels wouldn't go to the heads as quickly though.
When I had less than .60 oz on DFW she had a rear wiggle. Adding more than 4" of steer did not fix it. If I took a little weight off rear by just rolling the rear putty slightly forward the wiggle would lessen. If I moved up to .62 oz on DFW she ran dead straight and pretty silent down my homemade track. Is this indicating still a rear alignment issue since I can't load that rear axle with more weight?
ngyoung said:
I'll redo with a tighter gap. It does look a tad wide now that you mention it.
I'll try moving weight around a bit more. I started with the final 2 cubes and putty to the DFW side then it seemed to get better with weight centered.
If I can twist axles to get wheels to the heads both forwards and reverse and it goes straight forward with a straight DFW axle can I even do better with the rear alignment? Then its all weight shifting correct?
- Nov 24, 2011
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I always have at least 2 cubes to be used as bias weight. If you have a track, you'll know when they are positioned correctly.
Kinser Racing said:
You probably tend to drill em good and keep em good.
I built a BASX car that was a total dog (I mean relative to my other BASX cars which are dogs compared to others). Could not understand why. Ran it forwards down the tuning board ... wheels popped right out to the axle heads just like my post drill test. I ran it backwards down the tuning board totally expecting the same thing but NOPE! ... wheels sucked right into the body. It didn't do that right after I drilled the holes but somehow, during the build process, I induced toed out.
Thing is .. it was really stable on the track so it looked like the alignment was fine.
Moral of the story: run your car backwards down the tuning board. Its the best way to detect toe out.
So, even if my drill is not perfect but I can get the wheels to the heads in both direction AND it goes straight forwards with straight front axle I've got them as good as can be right? Whether I drilled perfectly, drilled poorly or drilled straight with bent axles: if they go to the heads in both directions how can it be wrong?
I can see if maybe they go to the heads sooner in one direction than the other that this would indicate slight toe. I should then be able to fine tune it by twisting axles and then when it goes straight in both directions and wheels to the heads....perfection....right?
I can see if maybe they go to the heads sooner in one direction than the other that this would indicate slight toe. I should then be able to fine tune it by twisting axles and then when it goes straight in both directions and wheels to the heads....perfection....right?
The stock axles have a bend so small I couldn't see it. Twisted them to get wheels to the heads forward and back. Goes dead straight both directions. I closed up the rear wheel gap and I'm now running .57 oz on DFW and 3" of steer. No wobbles and pretty quiet down my homemade track. I increased the steer to 5" and she was much louder, still no wobble. Dropped steer down to 2"and she seemed quiet too.
Thanks for the help all.
Thanks for the help all.
I'm building more and more light-weight ladder type bodies (.3oz or less), using monokote as a covering. When I apply the monokote, I do use a bit of heat to shink it it for a nice tight fit. I'm just wondering if this is warping my bodies just a bit.LightninBoy said:
I need to check......
Davet, when you drill you have to drill the dfw hole higher than the rears when you bend the axle,and install this raises the front of the car causing toe in the rears,with a raised hole this doesnt happen, or shouldent . my 2c
$%&%*^&(*%$&% !!!DerbyDad4Hire said:
I've heard it said a million times. Do a slow roll test throughout the build.
I checked it when it was drilled.
I checkedit when I topped the weight pocket and the supports.
I checked it when 3/4 weighted.
But ...
I'v nevered checked after covering and final weighted, other than track testing. And so, with a slow roll test to a car I did not send because I could not get it up to speed, I found a wheel migrating in towards the body.
Check your build with a slow roll throughout your process and you will know where you went wrong. For me, time to do another build.
B Regal, I hate it when that happens. I used to drill axles first, then weight pockets but DD4H told me to do pocket first and this helped. I now am checking as you are throughout the build and it is amazing what can go wrong. I have had some success switching rear wheels and messing with those but also have had no solution. I know that you never want to take backwards steps. I think this is why I love this so much, it's like golf, some days everything seems easy, and the next the same method blows up. I guess I need to stop using exploding golf balls. Good luck my friend, I'm doing re-prep method testing today, that ought to case some cussing.
DerbyDad4Hire said:
That is true and I learned the hard way on that. I now delay the drill and take steps to "lock it in" once it is drilled.
Yeah, shrinking the monokote can really twist the body. That is how we shaped our wings for model planes.
B_Regal Racing said:
No, it doesn't. I have already checked. But the heat iron I use is the type model airplane hobbyists use. I.e. and adjustable heat range.
Another point about bodies: John's X-type bodies are better than ladder types. Same weight, but the triangulation provides more structural strength against flex at the track's transition point. However, the one thing I do is lengthen the cutout between the front axle holes and the adjacent cutout.
I checked a few of my "slower" cars. A few show the rear wheels do not migrate to the heads like they are suppose to; I had one where the DFW opposite rear wheel was dragging the rail. They did not start out like that. I think I have it licked though; the build takes longer but things just look better.
As a side note, this is the iron I'm using.
I just set the temp to "2", which is a medium temperature setting.
As a side note, this is the iron I'm using.
I just set the temp to "2", which is a medium temperature setting.
B_Regal Racing said:I checked a few of my "slower" cars. A few show the rear wheels do not migrate to the heads like they are suppose to; I had one where the DFW opposite rear wheel was dragging the rail. They did not start out like that. I think I have it licked though; the build takes longer but things just look better.
As a side note, this is the iron I'm using.
I just set the temp to "2", which is a medium temperature setting.
That is the same iron I use. However, I stopped using MonoKote, and use the EconoKote instead. The EK is self sticking, and requires less heat to stretch it out.
