Wheel flex

[microbrush]

They are slower than when running reversed, correct? They still are faster than the 2g wheels...

I am interested in this. My son's scout car is not faster than my SS car. I was surprised by this. With TRE's answer the scout car with 1.4ish gram wheels should be faster. Maybe my son needs to improve his polishing technique. Are most people finding a Pro SS car is Faster? If you were to take a pro SS car and put MA wheels on it one should see a speed increase? I would think yes. Thoughts?

 

[plhiatt]

I wish I had a 42' track to see, but only a 35'. Set up for hill angle 27.1, and all level.
the times are all around the same, given I pull the lever manually.
I was first thinking the car with trailing fenders/extended wheel base/1.2 gram wheels might
be faster in 42 due to fenders, but now I am thinking the heavier 1.7 wheels on the standard wheel
base car/with front and rear fenders may be faster due to the heavier wheels.
But it has more steer so who knows.

 

[B_Regal Racing]

My son's scout car is not faster than my SS car. I was surprised by this.

I did help the boy build a car to MA rules using dd4h nitros, and FWIW, I did more work to it than the car he ran at districts (districts, he did his own prep). For MA, his car went through the same prep process as my own. To answer your question, his MA car for open scout oil is much faster than my SS cars. I also added full fenders, air deflectors, etc. With a few changes, you might see it in the SP class.

 

[bracketracer]

I wish I had a 42' track to see, but only a 35'. Set up for hill angle 27.1, and all level.
the times are all around the same, given I pull the lever manually.
I was first thinking the car with trailing fenders/extended wheel base/1.2 gram wheels might
be faster in 42 due to fenders, but now I am thinking the heavier 1.7 wheels on the standard wheel
base car/with front and rear fenders may be faster due to the heavier wheels.
But it has more steer so who knows.

Just my 2¢:

Given equal prep, alignment, and aero, there is no way that a heavier wheeled car will beat a lighter wheeled car on a 35' or a 42' track. If your light wheeled car is not faster then something is off in the build. You need to look only as far as comparing race results in the Street Stock class to the Street Pro class. Similar bodies, similar aero, similar axles and wheel diameters. While the SP has no fourth wheel and matching fender, that is worth about .006 or so over the small diameter Pinecar wheel on the SS. A top SP still gaps a top SS by .018 (the gap was actually .024 in the last race minus .006 to account for the raised wheel). If heavier wheels were ever faster we'd ALL be using them! lol

One other thing, whether you pull the lever manually or have an electric release, if you have the start switch set so it trips after the lever releases and as the gate begins to fall then it doesn't matter how consistent the lever is pulled. If you have your switch tripping as the lever is being pulled it's going to be harder to be consistent. If your switch doesn't make an audible click when it trips then hook up an ohmmeter and watch it while you pull the lever slowly. If you see any bounce in the switch before the gate swings free then you need to tighten up the adjustment so it trips later IMHO. Yes, it will change the times on your track so run a known car before and after the adjustment so you know where you're at.

 

[Momentum Racing]

I wish I had a 42' track to see, but only a 35'. Set up for hill angle 27.1, and all level.
the times are all around the same, given I pull the lever manually.
I was first thinking the car with trailing fenders/extended wheel base/1.2 gram wheels might
be faster in 42 due to fenders, but now I am thinking the heavier 1.7 wheels on the standard wheel
base car/with front and rear fenders may be faster due to the heavier wheels.
But it has more steer so who knows.

The track knows. Theory is one thing, real world is another. You can try and determine which car might be faster based on specs, but the track doesn't speculate, it will reveal the true answer.

I have a 42' Best Track set to exact specs. I can tell you I have cars that are very very close at 35', but that are separated at 42'. Anecdotally I can say I have not yet witnessed a car that is behind at around 33', even at 35', and not ahead at 42'.

All else being equal, and equal times at 35', why would you not choose the car that is behind at 33' ish? Unless of course you only have a single lane track and cannot run the cars together, which renders everything I just posted moot./images/boards/smilies/wink.gif

 

[zeebzob]

I have a 42' set-up to exact specs. I can tell you I have cars that are very very close at 35', but that are separated at 42'.

It's been said before, the last 7 feet is the monster.

 

[microbrush]

I am hoping I found my problem. I won't have time to test it, but It looked like the fender/wheel was rubbing on the extra wheel ( We have three on the one side). I corrected it on my 2 foot section of track. That was one great investment!

 

[Momentum Racing]

It's been said before, the last 7 feet is the monster.

Monsters are meant to be slayed./images/boards/smilies/smile.gif

 

[Cramjet]

A little off subject, but I want to add something I learned from a car with Nitro wheels which was underperforming.

One of my scout's cars was hopping up in front when I tested it on Zeebzob's track. Now this was a WEIRD and unexpected problem. I took it home and did a series of slow roll tests. It was the fact the Delryn washer was glued in at a slight angle which made the wheel slide down across it quickly enough to make the front end pop up. Light wheels also slide side to side a little more quickly I suppose. The front end was also VERY light but I might not have learned that had it not been jumping. There wasn't too large of a gap either.

After that, I don't bother to glue the DFW washers in because they will then adjust themselves to the right angle.

 

[HMH Racing]

Wouldn't the difference in wheelbase be an equalizer? The shorter wheelbase car had had the heavier wheels but is on the "hill" longer VS the longer wheelbase and light wheels.

 

[Momentum Racing]

Wouldn't the difference in wheelbase be an equalizer? The shorter wheelbase car had had the heavier wheels but is on the "hill" longer VS the longer wheelbase and light wheels.

But it also has an extra inch of steer, likely due to the shorter wheelbase. An extra inch of steer can really add up at 42'.

 

[Cramjet]

Momentum makes an important point there. Extra steer definitely slows you down.

 

[Momentum Racing]

Since the actual running distance of a 42' Best Track is about 36' feet, the extra 1" of steer adds up to 9" of additional steer over the 3"-4' car.

 

[txchemist]

1" of steer over what you need only drops your speed about 0.002 seconds-(bracketRacer data) , so you have plenty of other things to worry about before you lose sleep over this.

 

[Cramjet]

I'll give you some new data to play with TXChemist. The last race my Street Stock Natalee had 6" of steer and ran 2.971. After the race, Bulldog, at my request dialed it down and found that at 3" it was running 2.959. It must increase the further off you are.

 

[Momentum Racing]

I find it far more critical than .002

 

[HMH Racing]

Also need to remember that all tuning boards are not equal. 3" on one board could be 3 1/4, 3 1/2 on another. The important thing with the board you are using is consistency and repeatability. The car needs to be square and aligned the same way each time. Also the staging of the car at the start will have an impact, each car has a "sweet" spot where it wants to ride on the track.

 

[BulldogRacing]

I'll give you some new data to play with TXChemist. The last race my Street Stock Natalee had 6" of steer and ran 2.971. After the race, Bulldog, at my request dialed it down and found that at 3" it was running 2.959. It must increase the further off you are.

I did a tad more then just adjust steer.

 

[bracketracer]

I did a tad more then just adjust steer.

LOL!
What a friendly 'dog!

 

[Momentum Racing]

I'll give you some new data to play with TXChemist. The last race my Street Stock Natalee had 6" of steer and ran 2.971. After the race, Bulldog, at my request dialed it down and found that at 3" it was running 2.959. It must increase the further off you are.

6" of steer ?.......you should have named that car " U-Turn "./images/boards/smilies/biggrin.gif