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bork_

Toppest Force

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Hi all! Another long-time lurker, first-time poster here and I'd like to share my 'Toppest Force' project that I've been veeery slowly cobbling together over the last 6 months or so.

I've never actually owned an RC car, and as a kid drove my friends Hornet & Boomer and pored endlessly over Tamiya RC catalogues. So with no prior experience and nothing but faded memories from decades ago I though why not go all in and build a car with enough scope to:

  1. learn how to build & hop-up everything
  2. learn how to set one up
  3. learn how to charge lipos safely
  4. learn how to drive one (!)
  5. join a local RC club and learn how to race (!!)
  6. repeat when it falls to pieces...

Anyways, long story short here's where I am:

- got chassis built with every shiny thing that caught my eye

- bought transmitter, receiver, esc, battery packs, charger etc.

- not gone anywhere near prepping & painting the shell

IMG_5355.thumb.JPG.dcd1399d49872f3ef52be652edca136f.JPGIMG_5354.thumb.JPG.f6d985e3082533ec5deba9fb08536d1b.JPGIMG_5351.thumb.JPG.3439da37ec59d2c0fd77278a5b2a7de7.JPGIMG_5352.thumb.JPG.fbf281b52ee26d356ecd77229a841fc0.JPG

So as I am firmly in the build & setup part of the plan I have the following questions:

  • I blindly built the shocks with no thought on length etc. just to get experience. I'm going to go back and build again, what length should the front & rear shock be?
  • Any suggestion on starting shock positions/hole choices? I'm going to swap the Fibre Lyte custom front tower out for the Top Force Evo styled version as with these shocks none of the tower mounting holes actually make sense and just appear to be for show :(
  • When I have sorted the shocks out what ride height should I be looking for? And that's adjusted by shock spring preload right?
  • When assembled the UJs have about 3-4mm of float between the outside hub bearing and the hex adapter. I've put nylon shims in to remove all slop (look at last 2 photos) and everything seems fine; is that expected?
  • The front hub has 4mm or so float up/down in the carrier; is that expected? I shimmed it out with nylon spacers again and its smooth with no play (you can see the chunk of white under the kingpins on the underside shot) but that seems really excessive to me. The carriers are Tamiya 53226 with Yeah Racing hubs. I tried the same setup with GPM hubs and even the red plastic ones from the kit with the same result.
  • I bought both the Yeah Racing & GPM alloy steering sets but cannot for the life of me get either of them to fit. Has anybody worked it out and have a reference image for me to take reference from?

 

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hello and a warm welcome to tamiya club i see your in brum where about

the shock ride height will depend on where you plan to run it 

as for the mounting position for the shocks just use the kit locations 

and alloy hop up tends not to be a good fit sometimes try and have a look at this video

 

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Welcome.  

As good as Tamiya is, you could find noticeable gaps.  It's better than being too tight.  In fact, DF-01, TA-01 chassis have the problem of prop shaft slightly binding.  I might leave 1-2 mm of play.  When you land hard, the chassis could flex and twist.  The shaft shouldn't turn into a structural beam stopping the flex.  Your chassis being carbon, there is very little flexing.  But it could still flex like 0.2mm overall.  The plastic parts that they are attached to could also give 0.1mm here and 0.1mm there, ending up with 0.5mm total flex at the shaft.  

I like blue parts too (well, I like orange anodizing better). But one thing you should note is that it could be weaker than steel parts.  Because of that, I prefer not to use aluminum on shock tower nuts or drive cups.  If you grind steel pins against aluminum cups, aluminum tends to lose.  

Of course, that depends on the kinds of alloy.  I suspect my old iphone 5 is made out of stronger aluminum alloy.  These "aircraft grade" aluminum are tougher (maintains sharp facets better). But even 6061 aluminum has hardness of 95, where as 361 stainless steel has hardness of 149.  Steel is 50% harder than 6000 grades.  Oddly, one of lower grades has 120 hardness level.  But I doubt that Chinese makers are using that.  The harder the material, the more often they must replace expensive machining parts.  After all, RC parts don't need to be as strong as rock climber's gears.  

Back in early 2000, they used to make bumpers out of the same aluminum too.  If they were 7075 aluminum and as strong as steel, the aluminum bumpers wouldn't have disappeared.  But nobody would buy easily broken bumpers anymore.  

As for shock height and the hole location on the shock towers, that's entirely up to you.  You can adjust depending on the terrain, weight of the oil, etc.  

The right and left should be the same length, obviously.  After that, I just do the drop test.  Lift the front end (with battery in it), and drop it.  If it bottoms out, 3 things to consider: either the spring is too weak, clearance too low, too light an oil.  Do the same for the rear.  If the shocks move too little and the car bounces on the tires, 2 things to consider;  lighter spring and/or lighter oil.  If the shocks oscillate too much, just 1 thing to consider: oil.  

Mounting holes would change the stance: ground clearance.  But it also changes the strength of the springs.  (Strength of the springs don't change, but the force it takes to move the wheels up would change)  I would say just experiment with it and have fun.  Run it, have fun, break it, and also have fun restoring it and upgrading it.  After all, RC is a tool for fun.  

 

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@topforcein I'm living in Shirley, Solihull. That actually leads onto where I plan to run it which is not sure actually! Got a local grass park that has some good open spaces and rolling hills and also has a skate park that I think will get all the bashing (not sure how this thing will survive over the box but I'll soon find out), but looking to find somewhere a bit more dedicated for off-road running, and also wouldn't mind finding an indoor space as the weather is turning a bit... In the longer term I do want to find a club so I can learn from others and get hands on running advice.

Thanks for the video link too; that perfectly answers the aftermarket steering problem as they are made for the plastic tub DF01 (I think?) anyways the issue was the cross-brace was waaay to short in both cases and completely removed all of the lock. I did actually try to build a turnbuckle like the chap in the video but that too offered reduced steering and was a bit close to the gearbox for comfort. Think i'll stick with the plastic parts for now.

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@Juggular thanks for the advice; I'll un-snug the hex adapters a little. Also agree on the aluminium shock tower nuts, the reason they are there is the bolts I used to mount the shocks didn't leave enough thread to get a proper steel nyloc on so used one of the fancy blue ones I have which are much slimmer. It'll be best if I source some longer bolts and get the steel nuts on with a decent washer.

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Have a look at these links.

Basic tuning

More detailed tuning

Will give you a better idea of what everything does.

When tuning I'd suggest making one change at a time and see how it feels on the track.

Make too many changes at once, and you won't know what did what to the handling of your car.

 

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@Falcon#5 Amazing resources thank you! 

First thing for me is to get the base setup correct, and that means building the shocks to the correct length. For my own an any other Top Force owners reference the shock lengths are:

Front: 87mm

Back: 94mm

Well that's what is recommended on the back of the 50520 SHORT CVA SHOCK UNIT II INSTRUCTION CARD..

I'll be rebuilding my shocks this weekend and mounting them as per the Top Force Evo manual; after that i'll do a first set of as-built setup measurements and see where we are.

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So a quick update on the Tamiya 54505 Big Bore Rear Aeration damper rebuild for use as front Top Force dampers; measuring them as built out of the packet they are 92mm eye-to-eye, and as we need 87mm I went on a hunt for a 5mm spacer. Just so happens as I hadn't used my 'D' sprues up building the standard kit shocks, part D2 is the perfect solution! Measuring the Big Bore shocks now they are bang-on 87mm eye-to-eye. Though I'd add this up for other Top Force owners looking to use these dampers.IMG_5363.thumb.JPG.8cd6b3b08273be9da06321dc9ded142e.JPG

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Hi @bork_I came across your TF while browsing the forum, looks very nice!

Interesting comment about the Fibrelyte front tower, you've helped me decide to go with the evo style rather than the Fibrelyte, on my TF racer have to say I thought all those extra mounting holes seem like overkill to me.

What's the battery holder you 're using? I'd like to use shorty lipos eventually and I'm not sure what mounting to use.

Cheers

Mark

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5 minutes ago, kid168 said:

Does the re re TF come with adjustable turnbuckles or just the straight bar?

Straight bar 

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On 2/19/2020 at 8:40 PM, Tamiyold said:

Hi @bork_I came across your TF while browsing the forum, looks very nice!

Interesting comment about the Fibrelyte front tower, you've helped me decide to go with the evo style rather than the Fibrelyte, on my TF racer have to say I thought all those extra mounting holes seem like overkill to me.

What's the battery holder you 're using? I'd like to use shorty lipos eventually and I'm not sure what mounting to use.

Cheers

Mark

Thanks Mark, wish I'd have got a bit further with it but life and bad weather has got in the way since all those months ago I posted this thread..

Anyways, to answer your question the carbon shorty lipo mount was made by a chap on the TopForce Facebook group who does them to order. Unfortunately I don't have his details to hand, and not sure if he's still active either, but I hope that at least helps a little?

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Thanks @bork_ I think that's probably Nick Walker, I've been in touch with him already for prices on shock towers, I'll ask him if he can still do the lipo mount.

Mark

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