Rail riding

[g.o.racing]

Can you use rail riding when all four wheels must touch the track? If so, how do you go about doing that?

 

[GravityX]

In my way of thinking, that would cause a lot of drag. The DFW would be fighting the non-DFW for steer, but I've never tried a setup like that.

Not sure if this would work, but if you generated an ever so slight amount of toe-in with both front wheels, the car could track straight and never touch the rail on its way down the track. That would require track testing and a good amount of time. Just a theory.

 

[pony express]

If your rules say all four wheels must touch, then build your usual rail runner with the three wheels. On the fourth wheel you should keep it straight and drill it as close as you can so it will touch. Then slightly bend the fourth axle and test the car until you rotate the axle/wheel where it just barely touches. You will have your rail runner still. It won't be much slower or will be as fast as the three wheeler.

 

[khouse]

You can't have toe in on both front wheels and never touch the rails. All this will do is plow all the way down and esentially put the brakes on the car and bang all the way down. It's best to steer one wheel into the rail and have the other wheel just barely touching the track and polished up with graphite on the tread. Run that wheel strait down the track. Don't put graphite on the steer wheel tread. This is just a theory based on what I ran through my head and from other 4 wheeler posts in the past.

 

[cozybldr]

My District uses the 4 wheel touching and rolling rule. The way I do it that seems to be faster from my timing is what DD4H recommends. Do your build as a 3 wheeler initially and get your steer set. Then install the 4th wheel and make it match the original steer of the 3 wheeler. When you do that, the wheels are not fighting each other. It makes a .03 second faster car on average from my experience.

 

[GravityX]

I guess some of the alignment tricks used with real cars does not work at this scale.

(In reference to my previous toe-in remark.) Full size cars typically see about 1/8" toe-in to account for suspension bushings after thinking about it.

 

[khouse]

When you steer into the rail your car runs strait in the 3 wheel configuration. But running the 4the wheel strait it would seem "to me" to be faster? I'm sure John has tried everything and certainly would take his advice over mine.
GravityX- I know what your talking about on full size cars. It's just that once you steer into the rail all bets are off. There are tricks that race car drivers do to their camber,caster and toe (front and rear) that is used here. Either by accident or other. You may read where someone makes and adjustment and their car is faster and it may seem random. But knowing alignment geometry it's easy to see what's going on.

 

[shovelhead]

Our pack race is like that,(must have 4 wheels touching). As I was tuning I found if I barely had the front NDW touching.... As I checked migration of rear wheels to axle heads, the front NDW would raise just enough not to touch. I don't know if this is normal or I was seeing things or what. But it just seemed the front came up as the rear squatted. Also could have happened because I had too much space between wheel and body. Hope this makes sense.
I'll be the first to admit I found this by accident. But regardless. We were undefeated and heading to districts.

I did have the wheels spaced at about twice the thickness of a credit card.

 

[g.o.racing]

thanx for all the help,you guys are great! I dont have access to a test track but i do have a nice tuning board, think i'll go with steer both fronts. Never built a car with all four down this is for a regional with differant rules.

PS.
Great race yesterday spent most of the day on you tube whatching you guys tear up the track!
I'll send this car in after the regional to see where i stand with the other amateurs.

Thanx again.
gary o. g.o.racing