•Axle
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Posts posted by •Axle
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29 minutes ago, Matty36 said:
I'm not an engineer, but just looking at your first pictures, I believe that the hubs are machined for the outer bearing, just like most buggys, you should therefore have a crush tube between the bearings then you can tighten the wheel nut fully and there should be no play at all. If i leave the crush tubes out of my race car, it would probably last about a 5 minute race before ruining the inner bearing race. The bearings for reference are 5x10x4 in the team associated front hub. The rear driveshaft is machined to run on the inner race so removes the need for a crush tube, the rear hubs are machined for the outer bearing race, but it also has larger bearings for inner and outer, due to the design of having a captive pin inside the bearing, I will take it apart one day and take pictures of it.
The first time round I attempted this I had a slight amount of understanding of what I was trying to achieve – getting rid of wobble, but did exactly what you said and in the process knackered 8 Fast Eddy bearings within the 5 minutes. I then decided to put everything away not to touch it again as I had no understanding and didn’t want to waste money…
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Yep, I’ve searched for a spacer in the kit I have, the Yeah Racing kit partially uses the original parts to complete it, and there is the clearance on the outer bearing allowing you not to touch the bearings at all, presuming it’s mostly to look pretty with this kit, I just didn’t like the amount of wheel wobble.
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2 minutes ago, Lee76 said:
Yes, metal through metal is fine, but the float would take place between the inner and outer somewhere, so as long as there’s either allowable clearance or a controlled preload at this point you’re good. I imagine most people just have a little float. I have massive float on my monster beetle... I’ve not had a think for a fix on this yet. I’ll let you know.
Apologies, now you’re going understand what you’re dealing with by me asking this question...
What is a float, or do you mean a slight gap / amount of play on the outer part of the bearing?
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3 hours ago, toyolien said:
How odd. I know Martin from rcbitz and hadn't even thought about those. Thank you. I'll get some ordered. How are they in the wet?
I’ve driven back from the park and walks a few times in the wet, it’s hard to tell really because of what the car is. Up hill it’s brilliant, with a 3300kv and short squirts of the throttle I’m getting up quite steep inclines without backwards rolling and grips really well with the big Vs.
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12 hours ago, Lee76 said:
So, a quick look at one type of deep groove ball bearing, the std sizes in my kit are 11 x 5 x 4mm and the static load rating is 0.14kN so half this is 700N which sounds a huge load for a small bearing...But bearing in mind (pun alert) the average load for a decent m4 fastener i think is about 7kN, any form of clamping would be instantly above this limit. If you’re interested for pure academic purposes, let me know the shim stack height you used and I’ll see what spring washer I’d have selected..
I will add a caveat.. I’m an engineer but I am very new to RC I’ve recently built my first cars and as with most things in life the practically experienced people here may well know better.. I’m still on the steep learning curve.
A good read on wave spring pre-load.
https://www.smalley.com/blog/how-and-why-you-should-use-wave-spring-bearing-preload
I’d also add that for this particular application and given the small size I’d also consider an elastomer as a pre-loader.. But then I’ve always been a bit of a cowboy...
So from the blue anodised sheath to the screw thread side goes like this;
0.2
Bearing 5x11x4
x10 0.2 x1 0.1
Bearing 5x11x4
x2 0.2
The thing that I do understand is that it’s a problem to only put pressure on the inner bearing sleeve, it’s only metal on metal contact all the way through.
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32 minutes ago, Matty36 said:
These are team associated b5m crush tubes, I think they measure at 4mm internal diameter and 2mm thick.
Awesome, thanks for that.
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Took my daughter and the GF01 to the park today, it’s hugely satisfying having the play taken out of the steering, feels like a different kit now with it going in a straight line and smaller steering movements being recognised.
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Apologies, when I get my daughter to bed tonight I’ll get one of the wheels off, I’ve used 0.2 shim until the last one where I might of used an 0.1, depending on movement.
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I have used these in both of the GF-01s I’ve put together, they’re definitely not soft and feel quite ‘blown up’ as it were.
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As you guys know I’m a newbie here,
Reading through OP post, he has directly helped me with something, and I’m very grateful for. As someone new to the forum, I can imagine what happens to some here and may happen to me...
You can all see I’ve posted on here a bit, maybe it’s verbal diarrhoea and I post something before thinking about it fully. The more and more I search for help and spend time here the more I’m aware of the ‘old guard’ here and seeing myself look like a total doofus in front of the pros and long time tinkerers, I’m not too worried and how am I going to learn some finer details that translate across all models?
I am conscious that my wafflings might be getting in the way when other people need help with something, so I’ll post less as time goes on not to get in the way.
I would genuinely like to thank the people that have taken their time to help me out, a week before lockdown I went down with something, 2 days later I could hardly breath and get the ambulance out, I made extra A&E visits in the coming months, no one could help me as they were only interested when you had to be admitted.
I found the Tamiya kits I collected in loft and actually started them. I reverted back to a time before my teens, a safe place where I had some control of what was going on, I could concentrate while tinkering and forget about the pain going on throughout my body. I’m still suffering certain things and this is why I’m up at 3am looking through stuff writing this posts here.
I’m aware of certain posts or polls that are not visible to me concerning new members and can see perhaps the annoyance of having a load of new members turn up and are probably seen as ‘fair weather’ rc enthusiasts, chatting away blocking up the forum with extra posts. I do get it.
As I’m coming close to the end of my test bed GF01, I will have a template to make up a second one with all the extra parts I’ve collected and beginning to refine what I didn't understand first time round, looks like diffs, restricting movement in diffs, clearing the gumph off to let them move freely, shimming – all this stuff.
Anyway, thank you all 👍👍
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12 hours ago, Saito2 said:
After I made my post, I was thinking of suggesting what you did. Sounds like you found a good solution by taking up the slack without imposing any thrust load on the bearings.
Thanks for the help, it was probably a question that never needed to be posted, shimming newbie here.
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8 hours ago, Saito2 said:
A crush sleeve like those used for pinion pre-load on full size differential assemblies? The single row ball bearings typically used in RC cars aren't really meant to accept side or thrust loads from a crush sleeve like a tapered roller bearing. As such, we commonly don't use them as spacers between to bearings in a hub or wheel.
I was trying to find where I saw this and the closest I could find was the way this buggy is setup on the link below, effectively made that spacer up in shims, I can feel a little click in every wheel when pulled, a tiny amount of movement from the free moving bearings, so they haven’t been squashed under load.
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Here’s the Heavy Metal dump truck with the 6900kv castle motor, Rachid’s comments on this is that it was like ‘a spear’ and ‘amazing speeds’ before it flipped until the body broke!
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Probably spent about 50 minutes trying to get a couple of shims behind a steering arm to reduce play, it took a herculean effort to get everything aligned, so glad it’s worked, no more floppy steering!
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1 hour ago, Saito2 said:
A crush sleeve like those used for pinion pre-load on full size differential assemblies? The single row ball bearings typically used in RC cars aren't really meant to accept side or thrust loads from a crush sleeve like a tapered roller bearing. As such, we commonly don't use them as spacers between to bearings in a hub or wheel.
Apologies, I’m unsure...
I knew what I was trying to do and so I did some research on it, I’m trying to reduce wheel slop and have successfully reduced it with x2 0.2 shims on the outside hub bearings, now when I tighten the wheel it can still move freely but the bearings are being pushed one side only which will be an issue over time, I can see how much space there is can perhaps I should just fill them with shims to make up the space...
Update – this works, just filled the space until it reached the same level as where the bearing sits then added an extra shim.
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I have searched and cannot find...
What are you guys using for crush sleeves, the spacer which sits between the two bearings in each wheel hub, are there universal spacers that can accommodate any gap?
I want to clamp down on my wheels when doing them up with shims but realise my bearing won’t last long this way.
Apologies for an extra post from me, I’ll be out of your hair soon!
Cheers,
Al
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I thought it was to prevent the motor melting the chassis if it got too hot, could be wrong and I’ve also wanted to bin mine before.
And just like that I found out the real reason!
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Yes they do, the movement up is restricted by the length of part that controls the camber angle, I’ve bought these Tamiya low friction ball joints to try to make them move as freely as possible, they were closed ball joints a few days ago, might try 70mm springs just to take the edge off.
I really not liking it bottoming out, if the rear bottoms out the tires grind on where the body pegs are mounted.
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Shimming to take the play out of the wheels, feels like 0.4 on the outer bearings all round.
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So could this be the reason why there’s lack of movement in the front suspension? The two pivot points are not parallel... Some sort of dog leg 5mm ball connector joint to compensate??
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Well, they’re a bit of a squeeze but fit perfectly, thanks chaps!
Tamiya 50593 Flanged tube.
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1 hour ago, Bwaaatch said:
Well OK then … Off I go, at my own risk :-)
Really grateful for you checking in with your friend! When i have it running I'll post up a vid.
I’m going to put my money where my mouth is and buy the 4000kv motor for this setup, so there’s a bunch of fast comical cars going to cause a disturbance across the country.
TIRE GLUE & FOAM INSERTS!!
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So, What Have You Done Today?
in General discussions
Posted
I would like to do that, I think this build I’m classing as maybe a reintroducing to the hobby and this next one I have planned will be the one I take some photos of, it’s the silly things that go on them that have had me annoyed at times, after much thought I’m also going to buy a motor over 4000kv for more top end speed, It’s funny how much of a short acceleration range these brushless systems have, the 3300kv seems brilliant at sharp bursts of energy and hill climbing.