tire foams... needed or not?

[jimbo858]

can someone enlighten me on the pro's and con's of using tire

foams?  I got some with a set of wheels and tires. But, to me it

seems to add quite a bit of rotational mass to the wheel.  Which,

IMHO, would cause more wear and tear on the gears and motor. Am I wrong

about this?

[Cul-Tech]

Usually if foams are included with the tires it means the rubber is

made so thin that without the foam they will run FLAT. If you can get

away without them do it, but usually you can't.[:'(]

I'm with you and don't care for them, but usually I have to run them.

[terry.sc]

The rubber used to make tyres these days is usually very soft to give

loads of grip. To help them flex to follow the ground the rubber is

usually thin, so cannot support the weight of the truck by themselves.

The foam inserts are quite a bit lighter than the rubber that would be

needed to thicken up the tyre to support the truck by themselves.

Tamiyas monster truck kit tyres don't have foams as the rubber is

hard/stiff enough to support the truck by themselves. This means they

last forever, but do not give as much grip as better alternatives.

If foams are provided by the tyre manufacturer it is best to use them.

If you don't use them the tyres will flatten, which will put greater

strain on the transmission and steering servo than if you use the

foams. The only exception is on crawlers, where the tyres need to be as

soft as possible to get as much grip as possible, but they are never

run at speed.

[jimbo858]

okay... I just tried running the old TL01B truck today WITH the tire foams. for some reason it seemed like it was causing me to flip endlessly! It could've been the newer tires. I dunno. BUT, on the brightside it almost always landed on it's wheels!  hahahaha... Okay, so tomorrow I'm gonna try bashing around again without the foams and see if there's a difference. thanks for the insight to you both. 

[mud4fun]

I run my crawler 'thunderfoot' without foams and I get a considerable increase in traction on the majority of surfaces this way. I switched back to running with foams for a while but the truck couldn't climb piles of bricks etc anywhere near as good as when running 'aired' down.

There are a couple of downsides to running without the foams though, firstly you need to glue the tyre to the rim or it will simply tear out of the wheel every time you get into a sticky situation, second is that running 'aired' down loses you some ground clearance so where you get better traction you might end up getting hooked up on the chassis due to less clearance - swings and roundabouts really.

Overall I prefer running without the foams although I must point out that my tyres have been custom 'cut' during my many hours of testing and they probably suit being 'aired' down. Stock tread patterns may be better with foams.

As Terry.sc pointed out though, my truck is a crawler and runs a 1/4 scale steering servo and heavy duty transmission, super low gearing etc to compensate. I wouldn't recommend running without foams on a normal monster truck that is driven at speed as you will lose a serious amount of stability, especially under cornering!! (not something you have to worry about with my truck that has a 64:1 gearing.....)

[terry.sc]

The truck will be flipping because the new tyres give much more grip

than the originals, the originals just slid instead. Running with

stiffer springs or thicker damper oil would improve the handling.

[timmo24]

The tyres in my re-re Lunchbox feel ridiculously thin to me!, but I love them, loads of grip. I must get my Mad Bull out of the loft as the tyres I think are identical only I don'r recall them deforming this much?? The tyres "flat spot" very easy while stood for just a night on a table without the battery in.

I think I will make a little stand to go under the chassis when I'm not using it just to keep the weight off the tyres and to stop them flat spotting too much.

[jimbo858]

I had the same flat spotting problem with my tires. So, I went to the local hardware store and bought some 3" to 4" plumbing adapters.  They work great.  They also only cost me $1.98(US).