smirk-racing

FWIW, the old solution of using aluminum shims for NN4 and removing excess play has been 100% reliable for me over long periods of time with strong brushless systems. I do like this new steel gear but it isn’t strictly necessary and I agree that allowing the pin to stick halfway out of the slot (which is what happens without shimming) is likely to be problematic. In short, shimming is cheap, easy and effective and probably still the right solution. The only hard part about shimming is taking the time to order the right shims (thoroughly detailed many times in TC posts including over the last few years so links to vendors should still be good). Also, I recall having to reassemble the gearbox at least 3-4 times as I tested the right number of shims. I was pretty obsessive about getting it precisely right (down to the level of a .1mm shim). That only took maybe 15-20 min per gearbox though.

This is a small part but a big deal! XV-01 owners have talked about this part for years and years... probably overkill (a little care with shims / spacers can do the trick) but I think this might be popular. I'm grabbing a few.

When you don't need to preserve the connector, you can remove it "destructively". Between an x-acto and a dremel, you should have no trouble, in case getting the wires is proving tricky by other means.

Any idea what it costs to design a new car? Just curious. Even a wild guess?

If you end up buying a set of 4, I'll buy one (or more) of them from you if you like. Based in CA. Shipping one tire won't cost much I would guess.

It will look even better scuffed and loved!

Thanks! This is great info. I am not racing, so no need to be competitive. I am a decent driver (I had better be after all these years) but I am space-constrained.

This is awesome! So glad you are capturing this here. It is so cool to see those old clippings.

Thanks! Sometimes that's the kind of nudge a person needs Thank you! I'm checking out the TC-01 now. Had seen it a long while back but had never given it much thought.

Thank you for this amazing explanation! So much detail. I did a fair bit of web searching before posting, and I don't think the info you shared here was readily available before. Thank you!

Hi All, Merry Christmas! What better thing to do on Christmas than shop for another RC? I've found a listing for a Tamiya F201 which is rather expensive ($500+). I've always had my eye on a Formula 1 RC but have always held off because I've read/heard that they're not very useful away from a prepared track. I do not have access to a prepared on-road track so I'd be driving on the street in front of the house or at various parking lots nearby. All the surfaces are "ok" but we don't have ribbons of fresh smooth asphalt near us. The F201 is obviously long-since discontinued so prices are very high. I'm drawn to it because it is 4wd and I imagine that would be a lot easier to drive (and more suitable to 'street bashing' style driving). The F104 is readily available near me for 60% less than the F201 (barely $200, and I have some discount codes so really we're looking at $175ish all in). However, that's obviously a 2wd so might be even harder to drive. Most of my other RCs are hard-core off-road bashers. The closest thing I have to an on-roader is a Tamiya XV-02. Can I get some of your thoughts and opinions on: -- it is just pointless to get any F1 style RC because they're really just for proper racing (or perhaps display)? I only want runners. -- Is it worth paying 2-2.5x for the 4wd F201 vs the readily-available F104? I would guess the 4wd makes a big difference (despite being not F1-accurate) but maybe both are pretty tricky to drive for my purposes - ie beyond 2wd/4wd they both have low ground clearance etc Any other thoughts on these vehicles? I don't see a lot of videos online that give me insight - most of the vids that are available are building and displaying these vehicles rather than driving them!

Pics please!!

Thanks @Tamiyastef @RichieRich what an awesome memory. Thanks for sharing. Sounds about right!

Hi All, I am building an optima mid (well, 2 actually, one as a runner and one as a fully-functional shelfer) and for the shelfer, I figured I'd configure it to be just like the early Optima Mids in the 80s. Can someone help me out with a few specs? 1. what was the (rough) top speed of an Optima Mid in the 80s? Did speed vary much across different variations of this chassis? 2. what was the rough wattage of the motors used back then (I guess originally the kit came with a LeMans 240)? Thanks!

Did you machine those yourself??!!

Anyone have insight on the last few questions about what a stock / vintage Optima would have drawn back in the day? Probably won't limit myself to that but just curious to get a sense of it.

Agree with @Alex97 XT30s are very small/compact. As it happens, XT30 specs are higher than Tamiya Molex connectors, so you could in theory run them anywhere you'd have a run the old tamiya connector. If you were extremely constrained on space, you could try Deans (not my preferred connector but they work well and are very small, while still being a proper 10th scale connector). XT60 connectors will not fit through the little opening on the XV-01 (I have that chassis too). Two solutions: 1) dremel/cut/trim out 1-2mm of additional space. I've done this and it works fine. You only need to remove a tiny amount of material. 2) use a battery (like many standard 2s batteries) that has bullet connectors on the battery side (https://www.amazon.com/Powerhobby-8000mAh-Battery-Bullet-Connectors/dp/B07GC8Q2NL) and then you can attach/detach the connector easily from the battery. Then the XT60 connector doesn't have to pass through the opening in the chassis.

Congratulations. You're in for a treat. It is a beautiful build. I just completed mine last month. I believe the kit had everything I needed except blue threadlock for a few metal on metal parts. For servo, I opted for a low-profile servo even though it doesn't matter (a full-height servo fits fine, and in fact the face of the servo is in the same position no matter what, so I just picked the low-profile because I like how "tucked" it looks inside the chassis). I used to buy very expensive servos but over the last two years I've switched completely to the amazon specials: https://www.amazon.com/Readytosky-Degree-Standard-Digital-Steering/dp/B088H5369M/ref=sr_1_5?crid=1DOOVM7ZXTMQ4&keywords=low+profile+servo&qid=1701675691&sprefix=low+profile+servo%2Caps%2C137&sr=8-5. They work perfectly and seem to be lasting just fine.

Updates on the hackmotor from yeah racing: 1. To my surprise, it delivers almost precisely the rated RPM (34,000) when measured with a little digital tachometer. It shouldn't be surprising that the product did what the spec sheet said it would do, but deep down I just thought maybe the specs were a lie. I have a digital tach like this one. Bought it during COVID when I had high hopes to measure/optimize various things, it sat unused until now. Got the full purchase price worth of value in a single session. Fwiw, I measured 34,450, give or take. 2. With a 34k RPM motor and the stock 25t pinion from the kit, I was getting 30mph on a 2s lipo. At these low speeds, everything should be pretty linear, so you can estimate your own top speed pretty easily based on motor RPM. 3. Motor temps were too low to be worth measuring while driving (barely warm when touched). Ironically, the motor got much warmer to the touch when it had no load and I was measuring the RPM. When in the actually vehicle, there was no temp worth measuring after half a dozen passes. Ambient temps were 60F/ 15C, roughly. So it was cool but not cold. I was running without a body though so that helped with airflow. 4. The hackmoto has adjustable timing. I'd never adjusted timing on a brushed motor before (went to brushless more than 15 yrs ago, never looked back) so I gave it a try. Only took 30 seconds. Measured new RPM on tach, got about 38,000 rpm. The math would imply top speed should increase by just over 10%, and indeed, the GPS speed went from 30 to 34mph. That's where the buggy stands right now - 34mph on flat smooth streets on foam tires. Can you Optima experts help me with a few questions? What is a right ballpark for the original vintage speed for this vehicle? What amperage did vintage motors draw? I am building another Optima that won't use vintage specs for the motor, and I curious to get a baseline before dropping big brushless power in that one. Thanks!

To keep things interesting: just discovered this motor is rated for 3s. I cannot imagine what that will do for motor longevity (only bad things I am sure) but 3s will resolve the speed problems. Will add that to the testing. https://www.yeahracing.com/hackmoto-v2-13t-540-brushed-motor-mt-0012-00056715

I run this motor: https://www.yeahracing.com/hackmoto-v2-13t-540-brushed-motor-mt-0012-00056715 Supposedly 34k RPM. Need to measure that and see how real that is. Just got my mid up and running for test runs on the street, haven't GPS'd it yet, but it feels slower than I'd like. I don't intend to drive it a lot (let alone bash it hard) but I do want it to show itself well when I drive it once in a while. I am running the stock pinion right now and the next steps for me are: - get out the GPS and temp gun - increase the pinion a few teeth (measure speed & temps) - increase timing (measure speed and temps) I don't need it to be a brushless rocket (I have plenty of those) but the current speed is just too slow (I am guessing 25ish MPH just based on eyeballing it). Thanks @Willy iine for the tips on the brushed motors... I don't intend to drive this even 5 times a year, so I think it will be ok without too much maintenance.

+1 for gf-01 (specially the heavy dump truck). multiple of my neighbors’ children (their equivalent of Timmy let’s say) fell in love with that vehicle and went on to buy their own after seeing mine.

Thanks guys! Lots of great tips here. Two more questions: 1. I thought sharp corners (like, 90 degrees) were a no-no, as they create weak spots which can lead to cracking. There are a number of sharp corners in the Optima body... Including for the body mounts (those are rectangles). I could round all the corners and even use a circular hole for the body mounts. The hole would not be a perfect fit over the mounting point like the rectangular slot is, but the issue of corners would be resolved. 2. To sand or not to sand the inside of the body? I've googled this and there's no clear answer - seems like a roughly even number of people in both camps (not that I can measure scientifically...). For the shelfer body it is probably not an issue, as the body won't see any use/abuse, but for the runner, perhaps it matters. Since the rest of the web seems unable to agree on this point, I'll just take what TC says and call it good. Sand the inside of the body or no (for the supposedly better adhesion of paint)? Thanks for all the rest of the great tips!

Hi all, Any tips/tricks on cutting out an optima mid body? It has so many very sharp angles and tight curves... I used all the tools I could get (new, sharp): body reamer, straight lexan scissors, curved lexan scissors, x-acto knife, utility knife, etc... The only parts that came out cleanly were the long straight bits along the bottom/sides of the body. The complex bits in the front, and the rear over the spur gear look like an angry gopher chewed at them. It is quite unpleasant to look at! I am hoping you all have some tips and tricks that can help me. The only saving grace is that I had already planned for a shelfer body and a runner body, so clearly this first attempt is going to be the runner body... Thanks in advance!

If you want expensive upgrades, here's one option: https://www.ebay.com/itm/314773498590 I bought a similar one from a guy who made them by hand (in the UK actually) but haven't had a chance to install it yet. I am excited about the vastly overbuilt parts I have waiting for the blackfoot