DT-03 Slop

[ALEXKYRIAK 1046]

Hi all. I am looking at my DT-03, at the front lower arms specifically, and there is some play or "slop" in the way the lower arm sits on the bracket.

Once installed, the part D1 front arms shift forwards and backwards slightly (1.5mm maybe?)  along the U-shaped BA14 metal shaft part. My question is this: is this slight slop intentional and beneficial (I read from time to time people saying that cars are designed with some slop built in as this is apparently sometimes beneficial), or would this car benefit from having some slim shims added between the arms and the part C2 chassis holes to mitigate the front / back play of the lower arm along the shaft? Page 7, step 9 of the DT-03 manual shows the components in question quite nicely.

In a geeky way, I find this subject quite interesting from an engineering point of view. On my Mad Bull build I went mad trying to remove all the play in the steering mechanism, for example.  

Are there any other DT-03 slop areas that my OCD slop removal syndrome will need to find and get rid of?

Cheers

 

 

 

 

 

[Nobbi1977 1793]

Get a pack of Tamiya shims and add them as needed. I have with mine and it makes no difference to handeing but makes me feel better. I shim wheels as well so there is no slop on the axle,

[Wooders28 4718]

Think they are known as 'engineering tolerances ' 🙄 😀

You'll find as the price of the kits you buy goes up, the tolerances get tighter.

[Saito2 6673]

From my forum travels over the years, here's what I've learned on the subject of "slop". Slop is bad from a competitive standpoint. When you make fine adjustments to camber, etc., they aren't very precise in a sloppy, loose car. It's hard to nail down a car's adjustments when the steering and suspension wobble all over the place. The RC10 taught me this. Grab and RC10 by the front wheel and move it around. No slop. Grab an average Tamiya wheel (non TRF) and the wheel wobbles all around. 

Now the big question, does any of this matter? On average, no. Tightening up that slop isn't a bad idea and certainly helps but for the average customer bashing around with a DT03 or Frog or whatever, it doesn't really matter. At the competitive level, yes, but if you're competing seriously, (unless we're talking DT02 challenge or vintage racing) you're not likely to buy a Tamiya unless its a TRF (which is a total step up in tightness, precision and quality).

Now why are Tamiyas like this and others not? It all comes down to materials and intended use. Tamiyas use a lot of ABS plastics. Tolerancing plastics precisely can be tricky and they sometimes shrink ever so slightly when they cool after injection molding. Tamiyas are meant to go together trouble-free. Everything fits. It might be sloppy, but it fits. For the average Tamiya market, that's fine. If you take an RC10 (vintage), they don't just go together. You would have a bound up mess if you just tossed it together. RC10s often required careful clearancing and filing of parts so things would move smoothly. The end result was after a lot of careful work, you got a nice tight tolerance car. Racers are willing to put in the extra work. Every last bit helps. 

Personally, anything I own more complex than a Hornet or Lunch Box gets shimmed and clearanced just because I like fiddling with stuff like that. Sadly, I'll never get to race (or even bash with anyone else) as I think I'm the only person into RC cars with 100 miles. But, even so, its fun to make these little cars a best as they can be.

[speedy_w_beans 4272]

Alex, once you start building that DB01RR kit, your mind will be blown by how much tighter and slop-free that buggy is.  I guarantee it.

[Jonathon Gillham 4605]

2 minutes ago, speedy_w_beans said:

Alex, once you start building that DB01RR kit, your mind will be blown by how much tighter and slop-free that buggy is.  I guarantee it.

I agree, I cartainly was when I built the TRF102 and even the TA07 as my only experience with new builds had been basic kits. I seem to remember the manual even pointed out you may need shims in some places and I think it is the TA07 that came a sprue half fill of plastic shims.

[Juggular 4961]

14 hours ago, Nobbi1977 said:

it makes no difference to handeing but makes me feel better.

That was funny.... but so true!!

[ALEXKYRIAK 1046]

16 hours ago, Nobbi1977 said:

Get a pack of Tamiya shims and add them as needed. I have with mine and it makes no difference to handeing but makes me feel better. 

Just ordered some 58012055515 Tamiya Placebo Shims. They’re perfect, puts the worrisome slop in my mind to rest... Thanks!

 

4 hours ago, speedy_w_beans said:

Alex, once you start building that DB01RR kit, your mind will be blown by how much tighter and slop-free that buggy is.  I guarantee it.

I was suspecting that and and I’m glad you confirmed it, thanks. Have been reading a lot about the various materials available to different levels of kit; ABS, carbon reinforced, etc. Reading a lot via the 3D printing part of this forum. Can’t wait for DB01RR kit to arrive.

@Saito2 your post is really interesting, thanks. I seem to have a slight compulsive issue to fix slightly sloppy bits.... I guess it’s an extension of my Hop Up Addiction Disorder. It just feels right to fix the slop! But seriously speaking, I can see how a precisely engineered chassis and frame can be a goal to fix up, when it comes to the fine art of decreasing the margins when in a competitive environment. 

 

13 hours ago, Wooders28 said:

Think they are known as 'engineering tolerances ' 🙄 😀

You'll find as the price of the kits you buy goes up, the tolerances get tighter.

Conversely, I like the idea that a sloppy car is actually the most perfect realisation of the engineering within the materials available .... Probably an overly romantic notion ...

 

[4stroker 2]

Sorry for the thread mine, and hopefully you or someone else will answer this 3+ years later (!), but I'm about to build a DT-03 and also want to go to the extra effort of shimming etc.

I notice the part you ordered "58012055515" is the Tamiya 5mm diameter shim set.

My buggy hasn't arrived yet but I have looked at PDF manuals for it, and I would've thought the 3mm shim set is what we need for these cars?

Also, in the interest of tightening things up and offering more refinement, are these hop-up parts beneficial:

https://www.rcjaz.com.au/tamiya-dt03-aluminium-hitorque-servo-saver-25t-with-tie-rod-1set-gpm-dt3025tm-p-90079609.html

Can I adjust toe with these tie-rods?

Thanks, Mark

[ThunderDragonCy 7873]

@4stroker You are correct, you do need the 3mm shims, not 5mm. Most of the shafts and stepscrews are 3mm so that's where you will need shims. 53585 is the set you need. 

That GPM set will allow you to adjust toe, yes. 

[4stroker 2]

Thanks @ThunderDragonCy

Is that GPM set a good thing or is there something else I should be looking at?

[ThunderDragonCy 7873]

1 hour ago, 4stroker said:

Thanks @ThunderDragonCy

Is that GPM set a good thing or is there something else I should be looking at?

GPM set will work fine. Depends on how far you are going with upgrades and how much it costs. I am not a fan of aluminium servo arms because there is no give at all in them, but that's personal preference. The GPM turnbuckles are great, i have some, but i bought them separately. I have a Kimbrough medium setvo saver on my DT03. Worth noting that if you are looking at the tutnbuckle set to get adjustable camber links the Tamiya set includes steering arm turnbuckles too.