So we finished up my sons car. The rear axels are bent to 2.5 and DFW to 1.5. When I roll the car forward the wheels migrate properly to the axel head. However when I roll the car backwards, the right rear wheel moves in to the body of the car. I read you want to align so rears migrate to outside rolling in both directions. Can someone advise how to adjust?
Aligning Canted Rears
- Thread starter ChristopherK
- Start date
If it were me, I would polish new axles and not bend them. As it is, scout axles are already bent and really should be tuned when run in the rear. It prevents the car from wiggling and allows you to run less steer. That usually requires a track to do so. Bending the rear axles only compounds the problem. If you are trying to cant the rear wheels, use the silver bullet pro or similar tool to drill the axles holes. If you have to use the slots, there are ways to true up the rear. I would only very slightly bend a rear axle if it was a last resort to save a car.
BUT....
If I had bent rear axles and I wanted to ensure they migrate outward when the car is rolled forward and reward, I would replace the front axle with a straight one (no bend). I would set both rear axles so that the bend is straight up so there is no toe in or toe out; only camber. Rolling the car back and forth should cause the wheels to migrate away from the car. Twist each rear axle independently until it does. When you're finished, the car should role relatively straight. Re-install the front bent axle and set the steer. I would add a little extra steer just to compensate for the rear and ensure the car runs true.
BUT....
If I had bent rear axles and I wanted to ensure they migrate outward when the car is rolled forward and reward, I would replace the front axle with a straight one (no bend). I would set both rear axles so that the bend is straight up so there is no toe in or toe out; only camber. Rolling the car back and forth should cause the wheels to migrate away from the car. Twist each rear axle independently until it does. When you're finished, the car should role relatively straight. Re-install the front bent axle and set the steer. I would add a little extra steer just to compensate for the rear and ensure the car runs true.
I agree with Ed's advice about going with straight axles in the future.
We ran bent axles for about 4 years until I got sick and tired of tuning them(three cars/year).
To tune the rears on this car, these are the steps I used to take.
-measure the height of the nose off of the table.
-remove the front wheel-dfw
-I used to attach a tack to a speed square.....similar to this.
-place car on tac and get the nose at the correct height you measured first.
-tune both rears to migrate the same(I used to tape a popsicle stick to top of car and put some weight on the end of it to make whatever wheel I was adjusting dominate, then switch weight to the other side for that wheel).
-replace dfw and set steer
I don't think you should set the rears using a straight axle because the front will be lower when setting rears and when you reintoduce the dfw it will raise the nose introducing toe-out on the rears.
Ryan
So I got the rears tuned correctly. Also the car veering 4-1-2 over 4 feet in correct direction. Wheels seem to be aligned and functioning correctly. My biggest concern now is that my COM is .875 in front of back axle. In the past is have run at 1 inch. Hope that’s not too aggressive on a brand new Metal track.
Today I glued in the axels with superglue. Now, the car is veering only 3 inches over 4 feet. I have had this happen twice now so despite what the manufacturers say, I believe superglue expands somewhat and moves the axel angle slightly. I’m bout sick of building this little car and learning hard lessons so I’m calling it done, putting it in a box, and waiting for the race. In case this car flies of the track, is there pinewood therapy for disappointed cubs?
You're probably still good. You might slow it down if you start messing with it more. Make sure you clean the wheels. If you want to go crazy like most of the pros do put it in a ziplock bag to keep dust out of the wheels and set it on something that keeps the weight off the wheels as well. Good luck!
Thank your for that tip about dust on the wheels. What should I clean the wheels with before I put it away. I do have a carrier that takes weight off the wheels so good there.
Oh buddy. We've all been there. If you end up taking this hobby to league racing level you'll find that to be a lot less stressful. It's that added pressure of not letting your kid down that'll drive you to the edge.
Don't get me wrong, I REALLY enjoyed the time building and racing with my boy, but I sure don't miss that stress.
That being said failure and disappointment, even after a bunch of hard work, is also a valuable life lesson. Be ready to pass that on should it happen... Been there done that.
Good luck... Try not to stress too much.
I took a pretty big gulp when I just read the 1.5 bend isn't enough. I "thought" the bend in the front DFW axle didn't matter very much, and I read 1.5 was recommended. At this point, I'm pretty much locked in because I superglued the axle. Can someone please advise what type of problem is this going to cause? I sure don't want to start a new car this close to race day...
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Maybe this will help. For me, bend does three things: 1) it allows the FDW to roll over the vertical seams in the rail instead of sliding; 2) it aligns the rear axles; and 3) allows you to add steer
1. Rolling over the seams. Think what happens if the FDW had no camber. The wheel would slide down the rail and snag on the joints. The more bend in the FDW, the easier it is for the FDW to roll over the track imperfections.
2. Alignment. Yes, the bend absolutely effects alignment and can be a cause for the wiggles. When I drill a car, I account for the amount of bend in the FDW. Some raise their NDFW, but I will raise both (the bend itself usually is enough to raise the lifted off the track). The bend in the FDW can make the car ride nose high throwing off the rear alignment. If you do the Lightning Boy checks, all alignment checks are performed with the car level. You do not want to destroy that by making the car un-level due to the bend. Long story short, the bend in the FDW also helps me dial in the rear alignment.
3. Steer. I'll just say duh. No bend, no chance of adding steer.
1. Rolling over the seams. Think what happens if the FDW had no camber. The wheel would slide down the rail and snag on the joints. The more bend in the FDW, the easier it is for the FDW to roll over the track imperfections.
2. Alignment. Yes, the bend absolutely effects alignment and can be a cause for the wiggles. When I drill a car, I account for the amount of bend in the FDW. Some raise their NDFW, but I will raise both (the bend itself usually is enough to raise the lifted off the track). The bend in the FDW can make the car ride nose high throwing off the rear alignment. If you do the Lightning Boy checks, all alignment checks are performed with the car level. You do not want to destroy that by making the car un-level due to the bend. Long story short, the bend in the FDW also helps me dial in the rear alignment.
3. Steer. I'll just say duh. No bend, no chance of adding steer.
Sounds like the moral of this story is my son and I aren’t going to win. After reading all of the replies, it sounds like I’ll be lucky if this car even stays on the track. Gonna lose some sleep ahead of this race but no time for a rebuild now.
I think you'll be fine. Alot of the tips you're getting are for next years car. It's all part of evolving your build style. You're not building a pro car.........yet. If you start implementing some of the build suggestions from here you will be getting closer to one though!
Good luck and let us know how you did.
Thank you for helping me understand that and putting it into perspective. My son and I had a lot of fun building the car and he’s got really high hopes to do well this year. I’m thinking about letting him know I made a mistake or two, just so he can be prepared if the car doesn’t hold to the track.
