39 replies to this topic

[GT40]

When I was racing regularly as a kid from around 1968 to 1971, if we had a car that had front wheels that didn't touch and roll, the term to decribe that car was BROKE.

 

When I got back into racing around 2004, it was all Flexi cars with these little vestigial front wheels that everybody set up so that they were not touching, except maybe in the turns. Seemed goofy to me, but I went along with it.

 

When D3 retro racing came along, I started doing that and it was enjoyable to build and drive cars with working front wheels again - and they worked just fine. Then we started running the JK F1 cars, again with genuine working front wheels, and that worked well too.

 

So, a couple of years ago I started building my Flexi cars with working front wheels. And guess what - that works fine too, if you use the right wheels, and pay attention to set up and maintenance. 

 

I've tried this with a Turboflex, Cheetah 11, Cheetah 21, Mosetti Patriot and Flexi 5, motors including Falcon 7, Hawk 7, SpeedFX 16D and Super 16D, and moderate downforce bodies, such as JK Saleen S7. Most of the testing has been on the Foster's Paperclip and Pacific Coast Hobbies King Cobra.

 

Without getting too detailed, and realizing there are lots of uncontrolled variables, I've been able to turn laps as fast or faster with working front wheels than without, and I have won races in competition with cars that had non-working front wheels.

 

Some observations:

1) Many of the wheels intended for Flexi 1/16 axles are not suitable for this. You need something that rolls true and doesn't wobble on the axle.  

2) I have had better results with foam tires than O-rings. I think the O-rings transmit a lot of vibration to the chassis  and the foam dampens it. Maybe if you have a super smooth track they're alright. 

3) You have to really pay attention to braid recess and guide height. 

4) You have to make sure the axle is straight and aligned.

5) You have to keep those front hubs lubed.

6) You have to round the edges on the front tires.

 

I favor the Pro Track PTC-166 for 1/16 axles. I've also tried putting a 3/32 axle on a Flexi and running D3 fronts.

 

Something else I've noticed, on the Retro cars, the JK F1s and the Flexis: Contrary to what you might expect, a narrower, harder front tire has not necessarily given the best results.

 

I could go on but this post is already way long. Anybody else tried this out?

[Zippity]

A Champion Turbo Flex car with front wheels attached, has NEVER run faster on our track as one without

[CoastalAngler1]

What is a Champion Turbo Flex?

[Samiam]

"Anybody else tried this out?"

 

Only on my track cars. Most all the Flexi racing I've done did not require them. The front wings or ears of the chassis act as front wheels to support the car in the turns. What you have proven is that the front wheels do not hinder the performance any more or less than the chassis  skidding along the track surface.

 

I have used the Parma 5/8" O-ring fronts on most of my non race cars. I do have a set of small foam fronts on a JK Indy car. I'll have to cut down some old dry rears and do some experimenting.

 

The one  Flexi race I ran recently with fronts was at Buzz-A-Rama. Buzzy runs cars with front wheels. He has also been in business for 50 years in the same location. 

 

"Front Wheels Matter"

[Samiam]

What is a Champion Turbo Flex?

The most popular and successful chassis until the present JKs came along. Still a favorite because it is robust.

[GT40]

This.

 

Because the front axle has a long unsupported length, it's easily bent or deflected, and if this happens with front wheels that touch, it ruins the handling. That said,I have one with working Pro-Track fronts that is a rocket. 

[Samiam]

To better support the front axle I solder long spacers to both the upright and axle. I use the collared ones. Simple .062" brass tubing will work also. Better .062" axles  are available like drill blank ones from JK.

[Zippity]

Front wheels achieve nothing.

 

Slot cars are tripods.

[tonyp]

Slot sleds

[Samiam]

Front wheels achieve nothing.

 

Slot cars are tripods.

You are wrong Zippy. Plain and simple.

 

The front wheels support the corners of the car. That is nothing?  REALLY?

 Without the front wheels the chassis fills in for them by scraping along the track. Without this contact the car does not handle. So there goes the "Slot cars are tripods." nonsense. There is actually five points of contact if you add the guide. Try your theory with a Parma Flexi-Kar(Flexi-1). Or ANY slot car with no front wings or ears. Such as Womps,Hard Body or True Scale,ALL Open Wheel,Vintage,Retro,etc. ALL of those are NOT "tri pods". And all of them are "Slot Cars".

 

This thread is about using front wheels on Flexis. You don't run them. Fine. When the rules don't require them I don't run them. Now that Steve has demonstrated that they will perform as good or better than "Slot sleds" that scrape along the track surface,maybe more tracks will require them. If they are damaged during the race......well,that is racing. Build it right. Fix it when it gets damaged. 

[MarkH]

I suppose if the car is setup correctly it might handle as well as running without the front wheels. This has not been my experience most likely because I have not been able to keep them from loosing position in a crash. For me there are just too many things to chase down and ensure everything is correct with the setup: True front wheels, free spinning, height off track surface, alignment and the time to set it up.

I am glad you are having success with running the front wheels. I however must agree with your post #6, it might be just fine until the axle is bent. Then you might as well pull the car and perform repairs. Not much fun.

No front wheels on Flexi chassis for me.

[GT40]

Hey guys, I'm not on any sort of crusade. Just sharing my little experiment.

 

If you run more horsepower than a Super 16, and/or you run a lighter chassis than the ones I tried, and/or you have more aero downforce, I don't know what might happen. The obvious extreme is wing cars, which would shred front wheels.

 

And yes, it's more work in set up and maintenance to have functional fronts. I don't mind it; maybe it's not worth it for you.

 

If I have a point, I think it would be that it's interesting to try something that is outside the conventional wisdom and see what happens. 

[Jairus]

I agree with everything Steve said.
While racing flexis, I changed out my front wheels pretty regular.  Then bought a box of "O" rings and just changed the rubber as long as the wheel spun true.
Even had a set of extra axles as they would wear or get bent during warfair.

Found that the side to side axle flop was also a factor. Too loose was bad and too tight the same.  Needed about 1/32" of side to side movement.
Also needed a bunch of those little spring keepers as they tended to get lost.

And, I also regularly tore my car apart every other week (Champion Turbo Zippitydooda!) and hammered the crap out of it just to keep the pans perfectly flat.
Did I win?  Sometimes, and sometimes I didn't.  But I loved the bench time just the same.

[Matt Sheldon]

Front wheels achieve nothing.

 

Slot cars are tripods.

Without front wheels wouldn't they be a reversed tripod?

 

When talking front wheels and slotcars I think one really needs to break down divisions and chassis types as to mechanical advantages and disadvantages. There are many chassis that I would compare many characteristics with gokart technology.

 

I am pro front wheels for form rather than function.

[NY Nick]

Parma pro lites fronts worked great for me.

The car always drove better for me with fronts wheels.

[Zippity]

Sam,

 

If you are so smart, please build me a Flexi chassis with front wheels, (I'll pay costs), that will be faster than one without, to race on my track.

[Pablo]

I'm not a fan of front wheels, either, but it won't change the fact this is a nice thread started by GT40 with testing data and logic.

He's made it very clear he doesn't intend to rub anybody's face in his findings.

 

Administrator

[Samiam]

Sam,

 

If you are so smart, please build me a Flexi chassis with front wheels, (I'll pay costs), that will be faster than one without, to race on my track.

No.

 

[Samiam]

Parma pro lites fronts worked great for me.

The car always drove better for me with fronts wheels.

They worked great at Buzz-A-Rama. But those were the rules. So we built cars as per the rules and raced. Had fun and went home with our four wheelers.

 

Now ,after seeing Steve's results,I'm going to try softer fronts on Buzzy's tracks. Just might be the hot ticket.

[Mark Wampler]

I tend to be a full time front roller, but since the JK's came out,  modern  chassis are designed for the  front pan taking up  tire functions.  Since regular pretzelizing of chassis happens,  straightening out or regularly replacing skinny 1/16 axles and fronts is one more nuisance.  So the reasoning for the presence of fronts are more for aesthetic purposes only.  The idea of slot cars as tripods doesn't fit in my frame of reference.  Since my bent is in Retro,  full time fronts are all VERY important

[Samiam]

.  Since regular pretzelizing of chassis happens,  straightening out or regularly replacing skinny 1/16 axles and fronts is one more nuisance. 

I agree 100%. That is why I don't run them in any of my race cars. Except at Buzzy's. He's funny like that. Like Steve,If he sees a slot car with no front wheels he says "Fix that thing...it's broken". 50 years in the business and 90 years old. I think he knows a thing or two about slot cars.

[Zippity]

No.

 

Why am I not surprised? 

[Pablo]

Front wheels can be a good thing, or a bad thing, on a flexi.

Personally, I've experienced the "bad thing" a lot. Especially on older tracks that aren't perfect.

 

Nirvana would be if the fronts touch and roll a hair before the chassis touches the track surface.

But, it would also depend on what that "touch" does to the car.

 

Flame on, but those of you pushing personal agendas, last warning.

[Samiam]

"fronts touch and roll a hair before the chassis touches the track surface"

 

This used to be the rule for fronts back in the day.

 

I'll be re-introducing one of my customers back to slot cars after a 40+ year sit out. You can rest assured the cars I lend him will have working front wheels. I'll let him settle in a bit before I show him a modern Flexi race car. Hell,he's never even seen a Wing Car!

[GT40]

I've given a lot of thought to this technique of setting the front wheels off the track and having them contact in the turns.

 

I've set up and raced a lot of cars this way. Other things being equal, rolling friction is less than sliding friction. In a high speed turn such as a bank, especially with a glued track, one would expect a significant reduction in friction with the wheel touching rather then metal sliding. Also the reduced tilting of the chassis should add to stability. I can't think of simple method to quantify this. 

 

I wonder about the large change in angular momentum of the outside wheel in a bank that is still, and then suddenly touching, accelerated and rotating at, probably, several hundred RPM. I believe that angular momentum vector would point toward the center of radius of the turn; a sudden change in that would seem to cause some instability. Again, this is just speculation, and I have no simple way to evaluate it. But it is an argument for having the wheels rotate continuously rather than only when the car is in a turn.