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Old 09-24-2012, 12:42 AM   #17566
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Originally Posted by Granpa View Post
which has the Tamiya metal bits
The main problem with the steering linkage is the poor fit between the bearings and the steering posts. Since you already have the option parts, it's not going to be an issue.

Standard parts don't return to centre because the bearings find a new centre after every corner. Option parts return to centre, the up/down float that you can shim is on a different axis and has hardly any effect.

And I can measure the amount of side to side movement in a diff with an assembled Mini and a pair of calipers in a few seconds. Just move the from side to side and measure the difference in the amount of outdrive visible. Not that I see any need to shim the diff.
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Old 09-24-2012, 09:26 AM   #17567
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The main problem with the steering linkage is the poor fit between the bearings and the steering posts. Since you already have the option parts, it's not going to be an issue.

Standard parts don't return to centre because the bearings find a new centre after every corner. Option parts return to centre, the up/down float that you can shim is on a different axis and has hardly any effect.

And I can measure the amount of side to side movement in a diff with an assembled Mini and a pair of calipers in a few seconds. Just move the from side to side and measure the difference in the amount of outdrive visible. Not that I see any need to shim the diff.
Thank you for trying to answer my questions and do appreciate the attempt. However, while what you're saying sounds great, on close examination doesn't add up. The bearing fit to the post could not be the major factor cause the misfit is in microns. If you check. there are a number of places between the servo horn and the wheel that have far more play than the bearings to the steering post. There are at least 8-10. There are 4 in just the ball connectors and the adjusters and there is a step screw on each side. There are also several step screws and a couple of hinge pins. All of these points have more play than the bearing and post.

The bearings may indeed find new centers going from corner to corner, but so will everything else from the servo to the wheel. Can't buy the bearing argument at all.

Now as far as your method of measuring the end play of the diff. You left out what to move from side to side, but assumed you meant the outdrives. If you did, I have no idea what you are measuring. You do realize that the shoulder of the outdrive bottoms out on the bearings don't you. There will be very little movement. It could be that I was moving the wrong things cause the outdrives don't move at all.

My fault on the steering question, but the question really is why with all that slop, the steering on a Mini seems to work. I believe that I know the answer, but am interested in other opinions and am curious to see if anyone came to similar conclusions to mine.
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Old 09-24-2012, 09:36 AM   #17568
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Yes, my outdrives also have no discernible movement side to side.
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Old 09-24-2012, 09:59 AM   #17569
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My $.02 on the steering slop issue:

when there is no load (no power being applied and car sitting still on the bench) you see the play in the steering

when under power, the wheels will want to turn in (toe in), so that will take up all the slack in the steering linkages -- the links will be "streched" to their limits

when off power, the wheels will want to turn out (toe out), so that will take up all the slack in the steering linkages -- the links will be "compressed" to their limits

so it's only when nothing is happening and during that small period of time when the links go from "streched" to "compressed" that you can see any impact due to the play in the linkages
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Old 09-24-2012, 10:48 AM   #17570
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Originally Posted by Granpa View Post
Thank you for trying to answer my questions and do appreciate the attempt. However, while what you're saying sounds great, on close examination doesn't add up. The bearing fit to the post could not be the major factor cause the misfit is in microns. If you check. there are a number of places between the servo horn and the wheel that have far more play than the bearings to the steering post. There are at least 8-10. There are 4 in just the ball connectors and the adjusters and there is a step screw on each side. There are also several step screws and a couple of hinge pins. All of these points have more play than the bearing and post.

The bearings may indeed find new centers going from corner to corner, but so will everything else from the servo to the wheel. Can't buy the bearing argument at all.

Now as far as your method of measuring the end play of the diff. You left out what to move from side to side, but assumed you meant the outdrives. If you did, I have no idea what you are measuring. You do realize that the shoulder of the outdrive bottoms out on the bearings don't you. There will be very little movement. It could be that I was moving the wrong things cause the outdrives don't move at all.

My fault on the steering question, but the question really is why with all that slop, the steering on a Mini seems to work. I believe that I know the answer, but am interested in other opinions and am curious to see if anyone came to similar conclusions to mine.
What can I say... my answers are based on experience and observation. I'm sorry that they don't tally with yours.

You seem quick to criticise others' results, yet reticent in sharing your own... what a nice position to be in!
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Old 09-24-2012, 12:14 PM   #17571
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Originally Posted by FauxMako View Post
My $.02 on the steering slop issue:

when there is no load (no power being applied and car sitting still on the bench) you see the play in the steering

when under power, the wheels will want to turn in (toe in), so that will take up all the slack in the steering linkages -- the links will be "streched" to their limits

when off power, the wheels will want to turn out (toe out), so that will take up all the slack in the steering linkages -- the links will be "compressed" to their limits

so it's only when nothing is happening and during that small period of time when the links go from "streched" to "compressed" that you can see any impact due to the play in the linkages
Exactly. Not too sure about the toe in toe out stuff, but the point is that the linkages will be under load.

Last edited by Granpa; 09-24-2012 at 01:12 PM. Reason: addition
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Old 09-24-2012, 01:08 PM   #17572
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What can I say... my answers are based on experience and observation. I'm sorry that they don't tally with yours.

You seem quick to criticise others' results, yet reticent in sharing your own... what a nice position to be in!
I'm sorry that you took it as criticism and so personally. If you will reread my post you will see there was no criticism expressed there, just an additional list of areas that had more play than the one you pointed out. Just my observations. I will have to admit to being wrong more than once and at times have leapt to a faulty conclusion, based on inaccurate data or faulty data collection. Frankly, if someone points that out, I tend to treat it as a learning experience.

Also went back and just reread my post and yes, I can understand why you may have taken it as a personal attack. It was not my intention and apologize that it may have been perceived as such. But I want you to understand, everyone gets the benefit of the doubt with me including you. So I did go to my shop, and carefully check out your observations before posting.

Your method of measuring side play of the diff was a total failure in my hands so decided to post my observations. When you posted, the part that you move from side to side was not there so I could have been using the wrong procedure. Perhaps you could give us a more detailed description of so that the rest of us can understand how it works.

You need to lighten up a little bit. Just because someone does not totally concur with what you are expounding, that doesn't make him some kind of jerk or idiot. No need to get all huffy about it.
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Old 09-24-2012, 01:29 PM   #17573
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Minis get twitchy when they're shimmed out. I think it has something to do with the reduction in slop highlighting all of the chassis other flaws. You can shim and untweak your car, but you're going to need some serious skills as a driver to make it work.

My perspective is that minis are like hammocks: they work best when they're loose enough to sink down into them, but not so loose that you can't get back out gracefully. This kind of jibes with FauxMako's thoughts.
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Old 09-24-2012, 02:56 PM   #17574
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Hi Granpa,

Holding my minis right now. If you press on the diff outdrives with a little pressure (on both ends simultaneously), you then move them side to side to feel the play.

While the outdrive hits the bearing, pressing hard forces the bearing to be tight to the diff, and creates a gap between bearing and the bearing housing. That's the play I feel.

Then I shim accordingly. Or not, as loose is faster. Shimming, while seems perfect under no load, might cause binding under load when the gearbox is under stress and compression.

Just my thoughts.



p.s. on the steering slop, what was said by FauxMako.
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Old 09-24-2012, 05:53 PM   #17575
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Hi Granpa,

Holding my minis right now. If you press on the diff outdrives with a little pressure (on both ends simultaneously), you then move them side to side to feel the play.

While the outdrive hits the bearing, pressing hard forces the bearing to be tight to the diff, and creates a gap between bearing and the bearing housing. That's the play I feel.

Then I shim accordingly. Or not, as loose is faster. Shimming, while seems perfect under no load, might cause binding under load when the gearbox is under stress and compression.

Just my thoughts.



p.s. on the steering slop, what was said by FauxMako.
Hi Joel. How have you been and is your daughter still kicking' butt with her Mini???? It's really funny that what you posted is the same conclusion that I came to. I was driving home from the physical therapist when it hit me. Did try that on two of my Minis and got one to develop some movement, but in the other the bearings were too tight.

Thank goodness the gears were starting to a little "ratty" on that car cause i'll have to split the chassis to reseat the bearings and recreate some clearance.

And that guy FauxMako was dead on about the steering. His post was brilliant. He described it so well and with such clarity that I think he deserves a "well done". My hat's off to you young man. Required reading in my opinion.

Also agree with you on the shimming. Rarely do it now except for the axles.

Joel hasn't posted here for quite awhile, but will attest to the fact that he's worth paying attention to. Really a smart guy. Some of his test equipment like his chassis dyno is absolutely amazing.
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Old 09-24-2012, 07:10 PM   #17576
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Granpa, thanks for kinds words but you're giving me too much credit. I am wrong most of the time. hehehe.

Porsha has not touched mini in a year. But kicking butt in F1...

Shimming axles is good, but be careful as it may bind up during cornering. A little slop might be ok?

How come Swifty did not race mini this year?
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Old 09-24-2012, 07:42 PM   #17577
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Found a better pic of the M-06R on RC Driver. Yup, silver and red plastics and aluminum. But...what's on the rear upright there? A brass weight of some kind?

I saw the same thing. That would be my best guess since they did something similar for the F104.
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Old 09-25-2012, 07:34 AM   #17578
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Shimming minis

I am used to TC and I like play like salt in the eyes, so my natural instinct is to shim all the slop out which is a painful and pointless exercise in the mini. At least those made by Tamiya. Which work because the speeds are low. If you tried running a 17.5 boosted motor in a mini you'd see the difference the slop makes.

I did though the pointless exercise of shimming the M05 (pro) I have just because that is what I do (I gave up on the M02 which is so sloppy you don't know where to begin and all the plastics are so soft the suspension is redundant). Apart from feeling that I control the car now (which may be just the placebo effect) I wouldn't say there is any difference, but I like it that way.

Regarding the steering geometry change due to slop on/off power my findings were similar, and I can say that shimming the slop out (as much as you can) allows running less toe out which can help speed. Right now my M05 has slop only in the hingepins which is impossible to take out without major surgery (custom made hingepins to decrease clearance). I have ground my own hingepins out of a bar of titanium I had lying around but that was for a TC car. I wouldn't do or wish that on anyone for a mini.

I shim the diffs as explained above (in fact I found calliper measuring is not exactly effective, so I check the play, estimate how much movement there is, insert some shims, put the chassis together, try movement and adjust from there until there is enough clearance for things to move freely with no noticeable play) because I did find the bearings moving in on the diff. Also, the diff side play allows the driveshaft to move in and out the outdrive and can cause all sorts of ill effects (or at least I imagine so, as I said, I don't race minis). I have noticed this when running my son's first car, a TA02 (has a similar diff/outdrive arrangement) and found that on steering full lock the driveshafts where pushing the outdrive (hence the diff) in eventually dislodging the bearings from the plastic gearbox housing.

Last comment for those who found shimming is a problem, I think you need to realise there needs to be a tiny little clearance. That way, things don't bind. One example is the spacer between wheel bearings after I shim the axle which I found necessary to make sure I don't pinch the bearings when I do up my wheel nuts. I make these spacers from used bearing inner races ground down a bit shorter and then add shims to make sure both bearings are bottomed out in the hub carrier and there is no play.
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Old 09-25-2012, 08:02 AM   #17579
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I eliminated all my m03 slop by shimming and using clear tape. The Car is perfect now and predictable...
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Old 09-25-2012, 09:24 AM   #17580
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Shimming minis

I am used to TC and I like play like salt in the eyes, so my natural instinct is to shim all the slop out which is a painful and pointless exercise in the mini. At least those made by Tamiya. Which work because the speeds are low. If you tried running a 17.5 boosted motor in a mini you'd see the difference the slop makes.

I did though the pointless exercise of shimming the M05 (pro) I have just because that is what I do (I gave up on the M02 which is so sloppy you don't know where to begin and all the plastics are so soft the suspension is redundant). Apart from feeling that I control the car now (which may be just the placebo effect) I wouldn't say there is any difference, but I like it that way.

Regarding the steering geometry change due to slop on/off power my findings were similar, and I can say that shimming the slop out (as much as you can) allows running less toe out which can help speed. Right now my M05 has slop only in the hingepins which is impossible to take out without major surgery (custom made hingepins to decrease clearance). I have ground my own hingepins out of a bar of titanium I had lying around but that was for a TC car. I wouldn't do or wish that on anyone for a mini.

I shim the diffs as explained above (in fact I found calliper measuring is not exactly effective, so I check the play, estimate how much movement there is, insert some shims, put the chassis together, try movement and adjust from there until there is enough clearance for things to move freely with no noticeable play) because I did find the bearings moving in on the diff. Also, the diff side play allows the driveshaft to move in and out the outdrive and can cause all sorts of ill effects (or at least I imagine so, as I said, I don't race minis). I have noticed this when running my son's first car, a TA02 (has a similar diff/outdrive arrangement) and found that on steering full lock the driveshafts where pushing the outdrive (hence the diff) in eventually dislodging the bearings from the plastic gearbox housing.

Last comment for those who found shimming is a problem, I think you need to realise there needs to be a tiny little clearance. That way, things don't bind. One example is the spacer between wheel bearings after I shim the axle which I found necessary to make sure I don't pinch the bearings when I do up my wheel nuts. I make these spacers from used bearing inner races ground down a bit shorter and then add shims to make sure both bearings are bottomed out in the hub carrier and there is no play.
Here's something you might try instead of machining custom hinge pins. Use the option hinge pins and cyano them in the chassis. Then assemble the arms around the hinge pins. This will eliminate a lot of the "slop" and is doable by your average Mini owner, who probably doesn't own a lathe or have access to titanium bar stock.

I have done this to the rear of several Minis when they got a little too loose. It's easy to do and not tricky. The front is more difficult and requires that the rear portion of the arm be on the hinge pin before cyanoing on the right side or maybe both sides. Been so long I don't remember. Besides, I use the screw pin in front cause the large head protects the suspension arm.

I don't think you need a spacer between the bearings on the axles. The drive pin will prevent squeezing the hex down so far that you squeeze the bearings together. As evidence of this, the plastic hex often will crack at the drive pin slot. The hex bottoms out on the drive pin causing this.

Please note that there was no intention to slight, insult, demean etc you in any way. If I caused you any offense, let me apologize and assure you that was the furthest thing from my mind. I was just presenting a procedure on hinge pins that was more in the reach of the average modeler. On the axle bearings an alternative view was offered for your consideration and comment and for anyone else's consideration and comment. Ordinarily, I wouldn't add the disclaimer, but I have apparently caused great injury to some people lately.
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