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Carmine A

DOES a M Chassis Car NEED Tire Foams?

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I SHOULD know this... But my lifetime of experience started with Buggies, including Semi-Pro Racing, then in recent years, RC Scaler/Crawlers - where Foam choice is CRITICAL, due to enormous soft Tires!! 

But these little M Chassis Cars..... They don't weigh much, and I'm not doing any competition beyond a little weekend Club Racing. 

Do People even USE Foams in M Chassis Cars?? 😲  If so, I'd imagine that something very firm would be useless. I've got some fairly soft Tires, and would not want the Tread bowing out, killing traction! 

I've had a M01 two M03s, and a M04. All with bog standard Tires, felt HARD, no Foams. I hope you can help! 😉

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I use foams in mini rally blocks, S-grips and M-grips. Standard 60D radials seem to work fine without them. I sometimes put soft foams in anyway to stop the tyres filling with dirt through the rim vent holes.

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@TurnipJF Somehow I KNEW you were the Man with the answers!! 👍👍🍻  I don't think I would run any Foams in the Rear, because it's so light... But might run a thin strip of Foam around the Wheel, to as you said, keep Dirt out of the Tires. I didn't think of that. Thanks so much!! ✌😉

I still welcome other insights from the Forum.

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When you buy an m chassis kit, it comes with foams. I think this is enough evidence that they are recommended.

I used to race m chassis regularly and always used foam inserts. I always just used the standard kit foams though. 

If you don't use any inserts, I can't help but think you'll wear out the edges of the tires before the main tread is fully utilised. 

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@rich_f First, welcome to the Forum!! I think you'll find this a great source of inspiration, information and friendship! 

Tamiya Kits come with several pieces that end up unused. Sometimes our spare parts Bin is more valuable than our actual Models!! 😜 

Foams have always been the "Tyre Pressure" in a given Tyre. That's why they come in various firmnesses. I've never been Sedan Racing, but I imagine that Foam choice there is vital. I'm heavily into Scaler Trucks. With extra soft Tyres - averaging 115mm, up to 150mm, correct Foam choice has made the difference between 1st and LAST!! 

It's these little 1.45" Wheels and tiny Tyres that perplex me. Like I've mentioned before, the only M Chassis Cars I ran before had bog standard HARD Rubber Tyres. My last M06 Kit came with Foams - but ran better without Foams in the Front. It understeered like mad with Front Foams fitted!! 😲 

You made a valid point. If you're prematurely eating up the edges of your Tyres, that on a real Car, would indicate Underinflation... Requiring fitting Foams - or thicker Foams if the standard ones are fitted. 👍👍

I'm just a bit baffled with tuning this FWD Chassis. I can't run out and buy new Tyres anytime I want to anymore.... I want to get it as close to Right as possible.

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36 minutes ago, Carmine A said:

@rich_f First, welcome to the Forum!! I think you'll find this a great source of inspiration, information and friendship!  

Thanks! I've been a member of this forum for 15 years - does it normally take this long to be welcomed to the group? 😃

When I used to race an m03 I would run the same inserts front and back (standard kit foams) but have slightly softer compound at the back. The tyre choice far outweighs the foam choice in my opinion/experience. 

So for me on carpet would be kit rubber at the front and s-grip at the back. This was before the m chassis craze got to what it is now and now you've got way more tyre options besides tamiya, but still, softer rubber compound at the rear (of an M03 anyway)

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1 hour ago, rich_f said:

Thanks! I've been a member of this forum for 15 years - does it normally take this long to be welcomed to the group? 😃

 

FIFTEEN YEARS!!?? 😲 

My bad, I was going by the number rating of only six... You either must not post much, or hardly anyone ever clicks Like on your Posts! 😜😂

Either way I appreciate the Help.  Tires have always made a big difference in Buggy Racing, and an all important decision in Comp Crawling!! Just in the TYPE and composition of the Foams is Critical - sometimes more critical than the Tires themselves! Some guys are even using Memory Foam, or a combination a Memory Foam Inner Ring, and soft Foam for an Outer Ring. That's for a stiff Sidewall, whilst leaving enough "squish" at the Tread, to Bite into Rocks and other Obstacles....

Like I've said, I won't be doing any competition Racing with this, beyond the occasional weekend at the local Club's Track. I have been given a set of M-Grip Tires, for all 4.... and no Foams. I'm just trying to figure out how to tune this to be slightly better than just a Basher. 

I've fitted CVDs in front, Aluminium Steering Rack and 60mm Dampers, shimmed to 57mm and increased Suspension travel.

Tamiya lists a part number for its Kit Foam, NO mention of density or firmness...  The only OTHER one is their "M Chassis Foams, HARD", and still no word about HOW firm or dense!! How the #&@% is a Guy supposed to pick from THAT??

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I started mostly as a reader. I have only very recently started posting, and not that often.

 

Yes, tyre deformation sounds like it is quite important for crawling, hence the weight placed on good foam insert choice. 

For m chassis racing a never found it that important. I sometimes even made my own inserts out of old washing-up sponges. 

The biggest problem you'll have in my opinion is the same compound front and rear. Front wheel drive cars do better with softer rears, so if you are stuck with the tyres you've got, then put softer foams in the rear and harder in the front to try to rebalance the handling. 

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3 hours ago, Carmine A said:

It understeered like mad with Front Foams fitted!!

I felt the same way.  That's why I left out the forms in my M06. 

There is no rule written in stone.  Each car is different. 

Tamiya is known to mix and match parts.  Sometimes they don't consider the weight of the new Franken-car, and it would drive wonky.  (like M06 with  heavy Midnight Pumpkin resin shell)  

When it comes to suspension (including tires), you would have to make adjustment for that particular car.  Personally, Tamiya instruction leads to stiffer setting than I would like.  But other people might feel differently.  

 

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A front wheel drive????

Have you tried reversing round the track?

With the driving wheels in the right place?. At the back. Right?. 😆 🤣

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4 hours ago, Juggular said:

I felt the same way.  That's why I left out the foams in my M06. 

There is no rule written in stone.  Each car is different. 

Tamiya is known to mix and match parts.  Sometimes they don't consider the weight of the new Franken-car, and it would drive wonky.  (like M06 with  heavy Midnight Pumpkin resin shell)  

When it comes to suspension (including tires), you would have to make adjustment for that particular car.  Personally, Tamiya instruction leads to stiffer setting than I would like.  But other people might feel differently.  

The highlighted sentence, pretty much sums it up, don't it? 

I know by experience, LOTS of Kits over the past 37 years, that Tamiya LOVES Springs that are WAY TOO stiff!! 😖😲  It's led too many People to believe that the only proper Ride Height - is with the Dampers FULLY extended. 😧👎👎  I've tried debating that point ad nauseam.... Now I'm just OLD and sick of it. If they want to believe that, it's their Life. 

Case in point... My Axial Wraith. 12.3lbs of BEAST, and the Spring Rates are roughly HALF of some of Tamiya's SOFTEST Springs!!!  When you place it on the ground, the Suspension drops about 12mm.... JUST like a Real 1:1 Vehicle would. 😎👍  Those of us heavily into Crawling, understand that.

Tamiya has always been good at Bin swapping with many of their Kits... Remember, THIS is the Model and RC Company that in the late 70's - gave us a nice F-150 Ford Ranger Hardbody on basically a BEETLE Chassis!!!!! 😲😲😲😖 That MAY be the wackiest thing they've ever done.

And of course more recently, AWD Cars on FWD Chassis! RWD Cars on FWD Chassis!!!  OK.... I REALLY like the new VW Type 2 Bus (Van). WHY a FWD Chassis!!?? The M06 is readily available for a budget, and the M08 for an Upper Spec Model.

I've really always loved Tamiya!! But they've made some questionable decisions.....

OK... I'm coming to the conclusion that I need to get creative again. I've got some soft 1.9 Foams. Since most Tamiya Foams are a slash cut strip, to wrap around inside the Tires... I'll simply take those 1.9 ROUND Foams, and simply cut them to fit a 1.4" Tire. 😉 

If I like it, I'll of course leave it. If it feels like it needs a little more firmness, I'll cut up some stiffer Foams. Put those on the Front, and my homemade Front Foams to the Rear! 

Occasionally, I forget that THINKING sux!! Getting outside and experimenting with different tuning options - is FUN!

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9 hours ago, Carmine A said:

..... This should work for starters! 😉

IMG_20200806_161134.jpg

That should work just fine. Probably a dab of CA glue to close the ends wouldn't go amiss.

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I use the standard grey foams supplied with the kit. On my M05ver2 and pit shimizu soft slicks I use the blue tamiya hop up foams

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I certainly believe they need them, the tyre deforms too much under cornering load and with no downward pressure in the centre of the tyre you are losing lateral grip. 

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7 minutes ago, berman said:

I certainly believe they need them, the tyre deforms too much under cornering load and with no downward pressure in the centre of the tyre you are losing lateral grip. 

I agree with you 120%!!  That's exactly why I'm phishing for Info on what type of Foams... It's the WHAT KIND and firmness that has my Head rattling! 😖  Above, I did demonstrate my first Dodgy attempt at making Foams!! Gotta start somewhere - with SOMETHING!!

This Car SHOULD be pretty quick - with a 25T Torque Tuned Motor and a Hobbywing 1060 ESC... On 3S!!! 😧😲😲😁  Indeed, Lateral Grip is another Vital. However, as I mentioned earlier, Foams represent the "Air Pressure" in a given RC Tyre. TOO stiff of a Foam, and it's like running 45-65psi Tyre Pressure! 😲 

The center of the Tread will prematurely wear out. More important than that, a more rigid Tyre, even in RC.....  WILL Slide a lot more uncontrollably, even a soft Compound Tyre!! 😖  That's never been a consideration in my Crawlers, that MIGHT hit 11mph!! 😜  But of course, On-Road Cars go considerably Faster!! Even some of our poor little M Chassis Cars, and especially the FWD ones.

@Fabia130vRS you seem to have taken some time to TUNE your Cars!  But you've just illustrated my conundrum. Gray standard Foams and Blue Hopup Foams.....  Fine and dandy if you've got your Cars Dialed In. 😎  But that doesn't give me any Specs on the Foams themselves. The Listing and Packaging is NO help at all!!! 😖😡

I mean, I'm SURE the TRF Guys are very sure their Cars are Dialed and ready to RACE!! But there's NO Clue as to HOW technically, the Car is Set Up. 

Maybe we're NOT supposed to know!! 😖  EVEN a Soft, Medium, Firm, Extra Firm would be a HUGE Help.

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........ Referring to another Thread, I think I've got the WRONG Pinion Gear in - NOW that I'm nearly done, I plugged in the Electronics, plugged in the Torque Tuned Motor... First trying all the Gears I've gotten over the past week. NONE worked, or even FIT!! 😖😞

Half of them, I'm assuming that they're either Mod 0.5 or 0.3..... NONE of the Mounting Screws lined up! 

There were 3 more. One looked like a 64P Pinion, the other two had NO marks whatsoever. But when I counted the Teeth, one was 18 Tooth. I tried to install it with the Motor...

It finally fit properly, and the the Gearbox had a minimum of Gear Lash!!! 😁  THEN, I powered her up for the first time.

I heard the most ear piercing, HIGH Pitched WHINE I've ever heard!!! 😧😖  I literally have Never experienced anything like that before.  And the Motor got Hot.... VERY HOT!!!!🔥🔥🔥🔥

So I'm currently left CLUELESS. I have nothing to base it on. I did take a blurry Video (just for the Audio).... I'll try to post it later, on my M05 PIECEMEAL build Thread. 😞

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10 hours ago, TurnipJF said:

Sounds like a pitch mismatch. You'll be wanting 0.6 module pinions. 

It sure was, and a new one is on the way. 😉 Thanks!!

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The Video of the BANSHEE SCREAMING Gearbox is around here....

Pulled out the Motor and CAREFULLY inspected the Idler Gear. Well, those FRP Gears are far better than you might think! ZERO Damage!!! 😲💯👍👍

I tried a Stock Aluminium 20T Pinion Gear... SMOOTH and quiet!! That won't last, so a RRP 18T Steel Pinion is coming. 😁

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Thanks to this thread my M05-RA received some foams this afternoon. A real family effort - I removed the tyres and then inserted the foams ready for my son and my wife to put the rubber back on. Thanks guys!

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The only M Chassis I have is a m06 Eunos/ Miata and I don’t race competition, I only challenge myself to autocross in my driveway. The kit came with foams when I built it and I can’t imagine running it without them. 

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2 hours ago, Badcrumble said:

Thanks to this thread my M05-RA received some foams this afternoon. A real family effort - I removed the tyres and then inserted the foams ready for my son and my wife to put the rubber back on. Thanks guys!

Welcome to the Party!!🎉🍻🎉 

The Foam in M Chassis Cars is still a bit in question...  In my case, I'm starting with soft Foams in Front and NO Foams in the Rear. That's subject to change when I get her running. 

I've not seen M Chassis Rally Blocks... But I have 1.9 Rallys on my TT-02. They're semi firm, and stay round with no Foams at all.... However, after doing a Video of it driving around on Tarmac - in slow motion, I saw the sidewalls folding in on sharp turns.  (BTW, slo-mo Video makes an awesome tuning tool !!) 

I then put medium Foams in Front, and soft Foams in Rear. It's not a heavy Car at all - and the M Chassis Cars are even lighter! 😲  The M05 FWD, has MOST of its light weight up Front. So my first test is with nothing in the Rear. 

I GUESS maybe WE should do some theories about Foam densities in M Chassis Cars! 😊  There really seems to be NO significant information on the subject.

Back to @Badcrumble - if you see an improvement, LEAVE that setup. But please let us know the results!  I have no idea if the M Rallys are the same density as the 1.9 Rallys... 

If the back end gets too loose in turns, you may need to remove the Rear Foams.

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1 hour ago, Dakratfink said:

The only M Chassis I have is a m06 Eunos/ Miata and I don’t race competition, I only challenge myself to autocross in my driveway. The kit came with foams when I built it and I can’t imagine running it without them. 

..... Not to seem pushy. It's YOUR Car first!  BUT, try to imagine running it without Rear Foams.  One of the main points made so far is, not everything that comes in a Tamiya Kit is used - JUST because it's there.

Part of the fun of this Hobby is that you're welcome to mess with it! Experiment with it. Unlike Real Cars, the WORST that can happen is that you either get a couple of broken parts, or a bruised ego!! 😜

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1 hour ago, Carmine A said:

..... Not to seem pushy. It's YOUR Car first!  BUT, try to imagine running it without Rear Foams.  One of the main points made so far is, not everything that comes in a Tamiya Kit is used - JUST because it's there.

Part of the fun of this Hobby is that you're welcome to mess with it! Experiment with it. Unlike Real Cars, the WORST that can happen is that you either get a couple of broken parts, or a bruised ego!! 😜

That is actually solid advice, 

for a carpet track I might try no foams ( for a little more grab and sidewalls flex) however, on my driveway, with bumps and cracks between the pavement blocks, the kit foams seem to help the oil shocks I have installed dampen instead of running over cracks on essentially “flat” tires 

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