bgredjeep is correct about it should only be able to go together in phase. I just checked a spare locker I have. I was sure that was what I had an issue with. It was about 10 years or so ago so my mind be suffering from old timers disease. ;-)
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Steering issue when end points nearing maxed out
- Thread starter high plains drifter
- Start date
Any change you will be able to get video? Just shoot the video with your cellphone and upload it to YouTube, Imgur, etc.
Well I continued replying yesterday because I didn't get the chance to dig into this further. So without being able to actually troubleshoot, I continued in the discussion. It's not a matter of what more suggestions might be offered... I simply wasn't able to get back into this yesterday due to other obligations.
That's okay. I really wasn't sure whether or not axle-shafts could be out of phase... probably b/c I don't remember ever seeing anything about it when working on RC or full size rigs. I'm also aging fast and I'm not in great shape... physically as well as with my mind. Sad thing about aging ( at least in my case) is that it creeps up so slowly but once it starts to take hold, it's hard to get out from under it. When I look at where I was at just 15-20 years ago... pretty sad.
Thank you, nightcrawler48 for your help and patience. I'll get this sorted out with all the assistance offered here. I just need to set aside some time today to go through what was suggested.
I'll look at figuring that out, Jato if I'm unable to troubleshoot this now. I really appreciate your time and input here and although I'm not on the forum much anymore, it's really nice to see you back. Here's hoping that things are going well for you after all that you've been through in recent years. Thanks again.
You’re welcome. You can even send the video to me in email or on Facebook if you do that and I’ll give it a shot to help.
Thank you for the kind words! I’m happy again.
I appreciate that, Jato. I'm going to have to figure that out. Easy for some, lil harder for those old guys that have always been a bit technically challenged. But I know it goes a long way to helping diagnose issues.
So what I've done so far...
Pulled everything out or off of the front end.. complete inspection and thorough cleaning and/ or re-greasing or graphite of king-pins, axle shafts, stub shafts, diffs, c-hubs, portal covers, bearings, hex-hubs, all screws.
Then I double checked to make sure that drive-shafts are in phase. Checked for any binding of rear wheels, axle-shafts, diffs, and ESC settings as well.
There was some dirt, debris around or into the axle shafts, portal covers, and all that.. so meticulously cleaned and re-greased where applicable.
Noticed also several contact areas... the Vitavon portal covers at the c-hubs ( underside) was making a bit of contact so I shaved down the portal covers a bit along those areas. Also some contact at the inside of the portal covers at the inside of pass-side wheel.
Also the nut on the backside of the servo arm was contacting the diff cover when turning towards drive-side.. ever so slightly. I don't think that it was a contributor of the lurching issue but went ahead and filed/ sanded down that too so everything is now free to rotate or spin with no obstructions.
Lastly I noticed that the Axial axle shafts are almost 1 mm smaller than the SSD hubs that I'm using. If I tighten the grub-pins down all the way through, it causes the hub to become off-center a fair bit. But if I back off the grub-pin then the hub wobbles on the shaft. So I dug thru my wheel-parts bin and went with a brass hex that has a smaller ID and a short grub-screw that I just tightened down into the axle-shaft hole. The grub screw is larger than the hole so it tightens down nice and snug into the hole ( but not all the way thru like the grub-pin did) No more wheel wobble now and much more accurately centered.
I think that's about it. I still have a bit more to do before I fire it up but it appears maybe, that at least one or more of these issues might have caused or exacerbated the lurching issue.
I'll report back when I get her back on all fours.
So what I've done so far...
Pulled everything out or off of the front end.. complete inspection and thorough cleaning and/ or re-greasing or graphite of king-pins, axle shafts, stub shafts, diffs, c-hubs, portal covers, bearings, hex-hubs, all screws.
Then I double checked to make sure that drive-shafts are in phase. Checked for any binding of rear wheels, axle-shafts, diffs, and ESC settings as well.
There was some dirt, debris around or into the axle shafts, portal covers, and all that.. so meticulously cleaned and re-greased where applicable.
Noticed also several contact areas... the Vitavon portal covers at the c-hubs ( underside) was making a bit of contact so I shaved down the portal covers a bit along those areas. Also some contact at the inside of the portal covers at the inside of pass-side wheel.
Also the nut on the backside of the servo arm was contacting the diff cover when turning towards drive-side.. ever so slightly. I don't think that it was a contributor of the lurching issue but went ahead and filed/ sanded down that too so everything is now free to rotate or spin with no obstructions.
Lastly I noticed that the Axial axle shafts are almost 1 mm smaller than the SSD hubs that I'm using. If I tighten the grub-pins down all the way through, it causes the hub to become off-center a fair bit. But if I back off the grub-pin then the hub wobbles on the shaft. So I dug thru my wheel-parts bin and went with a brass hex that has a smaller ID and a short grub-screw that I just tightened down into the axle-shaft hole. The grub screw is larger than the hole so it tightens down nice and snug into the hole ( but not all the way thru like the grub-pin did) No more wheel wobble now and much more accurately centered.
I think that's about it. I still have a bit more to do before I fire it up but it appears maybe, that at least one or more of these issues might have caused or exacerbated the lurching issue.
I'll report back when I get her back on all fours.
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westerlycarrot9
Pebble Pounder
Greetings,
I know this is an old post but i got kind of the same problem after yesterday's run (second ever run of the truck). For some reason that I still don't know about, i get this rubbing problem whenever i steer fully left or right. If i set the steering at 80% everything's fine. Also when i remove both wheels everything is also fine so my thought was that the rims suddenly started rubbing. After inspection I've found no marks or scratches on the plastic that indicate any contact.
I got busy with other projects and failing to be able to upload any video, put this one on the back-burner. I also checked wheel contact and even changed wheels/ tires and hex widths to see if I could track down the issue. Only thing that was different when I experienced this and subsequently made this thread, was that I had just changed out my ESC. Other than that I hadn't made any major changes to the rig. But yeah... it's like a hopping or lurching when my steering is maxing out left/ right. For me to eliminate it I had to really dial back on the endpoints... much less than 80%. I don't remember if I tried things with the wheels removed or not. I'll be looking back into this before too long but I'm buried under other hobby/ home projects for now.
westerlycarrot9
Pebble Pounder
I see. If it is the nature of the steering axle/rod (ujoint) it really sucks
I mean you should be able to steer fully without any issues whatsoever. The truck crawls beautifully but this kind of breaks the immersion.
Do you have a video showing what you mean by "rubbing"? It just may be a limiting in the universals that are only rated for 45°.I see. If it is the nature of the steering axle/rod (ujoint) it really sucks
Sounds like you are describing the normal behavior of ujoints. The video below shows some examples of the behavior for a driveshaft. In the case of the front axle the same concepts from the video apply, but the center shaft in the video would be driven at constant rpm instead of the ends. The higher the angle, the more the shaft beyond the ujoint will pulse.
1 solution is a cvd style shaft, but that will also limit the total steering angle to about 45°. Another other is a double cardan shaft like meus released for the 10 pro. 3rd option is to steer less, or understand that it's normal and fine.
The only thing is though, that I don't recall that it did this prior to me installing the new ESC. I had the rig pulled apart though and am still not sure if something went wrong or ( as it was already suggested) if it was like this all along and I'm just now noticing it. Being somewhat familiar with full-size rigs ( mine's nothing like your bad boy but I am on a 4.5" LA lift, 37's, 5:13s, etc) I understand driveshafts being out of phase, ackerman/ camber/ toe, suspension geometry regarding drag-link/ track bar... all the basics. I just can't seem to figure it out on this Capra.
I know the only thing that's going to help is to try to post a video so I'll try to do that when I get back into this project. I do appreciate the help and at least I'm not the only one it seems, experiencing this. I just don't recall that my Capra was always doing this.
I know the only thing that's going to help is to try to post a video so I'll try to do that when I get back into this project. I do appreciate the help and at least I'm not the only one it seems, experiencing this. I just don't recall that my Capra was always doing this.
One thing that people don't understand with Why this happens on our scale vehicles. Take a look at the actual u-joints. Measure them. Then convert them to full scale 1:1. The u-joint in RC are always over sized, for strength, and non of the actual pin to pin distances of the joint are in the correct math for a 1:1 relationship. Thus, since they're over sized, we end up with problems like this. It's a trade off reliability vs physical scale and machining capabilities.
The other side of the issue is people are looking at servo steering percentage, not actual steering angle. The generally accepted steering angle (be it CVD or U-Joint) is 30* with a maximum of 36*. So if you're exceeding 30*, expect this behavior.
I don't think the size really plays into it, other than the larger joint providing the clearance needed to actually work at the higher angles. Ex. My current 1:1 axle runs 1480 u-joints and can turn around 38° before the ears on the axles start hitting and binding. I'm getting ready to build a new axle for a buggy that will use 1550 joints and can be setup to steer 50°.
HPD, here's a video I just took showing the pulsing that it's completely normal. As the steering angle increases the pulse is more apparent.
HPD, here's a video I just took showing the pulsing that it's completely normal. As the steering angle increases the pulse is more apparent.
lonleycreeper
I wanna be Dave
My Trail king does this, as does my Wraith... Both have in common Uni's up front and sharp steering angles.
@bgredjeep - That seems to be pretty much what I'm experiencing. I dunno why I never noticed it before and I guess that after I do work on something RC or full-size, I'm honed in on any little thing that might seem new or out of the ordinary. Maybe the case with my Capra. I may also go back in and make sure since it's a new ESC, that I don't have some setting out of whack... like drag-brake or something.
Thank you for posting that. Very much appreciated.
Thank you for posting that. Very much appreciated.
westerlycarrot9
Pebble Pounder
That is exactly what happens and now that i think about it also used to happen with my TRX4 sport and maybe scx10ii rtr that i owned years ago. The more i steer the more pulsy and bumpy it gets.
try lubing the u joint if those pins are sticky it would cause some jumpyness before the ujoint binds up
ive had several shafts were the pins rusted together also junk in the joints but they would start jumping around at around 15° of steering were nice and free for the first few degrees of steering but about half way through the steering through it would start to bind cleaning and lubing them fix the problem
also my subaru one of the cv axles locked up and acted the same way
ive had several shafts were the pins rusted together also junk in the joints but they would start jumping around at around 15° of steering were nice and free for the first few degrees of steering but about half way through the steering through it would start to bind cleaning and lubing them fix the problem
also my subaru one of the cv axles locked up and acted the same way
This can also occur if a pin is bent.