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Post by scoutsdad on Feb 8, 2011 17:19:40 GMT -7
A relative newbie here with a question for all the seasoned vets...
How much is too much bend on the DFW?
The car is for our local pack race, built as a 3-wheel rail-rider with axle holes drilled using The Block. Rear axle holes slightly higher than DFW with negative cant using the pin included with The Block. The DFW axle hole is drilled straight.
After prep'ing the axles we bent the DFW axle for the positive cant and rail-riding.
My son and I put together a little tuning board with glass over a piece of wood - 4 feet long. We got it tuned to turn about 2.5" over 4 feet or so, with just a slight turn of the axle from 6 o'clock - so the bend is now pointing to around 5 o'clock, I'm guessing.
Here's the question / concern: When I run the car down the tuning board I hear a little whining sound - which is (I think) the DFW riding on the little ridges along the outside edge of the wheel.
If the DFW is riding so far out on the edge that I can hear those ridges did we bend that axle too much? or is that normal? will riding on those ridges slow us down?
Any help would be appreciated!
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Ca$h
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Posts: 65
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Post by Ca$h on Feb 8, 2011 17:51:48 GMT -7
Yes what you are hearing is the wheel running on the decorative edge, this shouldn't' t hurt your speed. The way I tell if I have the axle bent enough I use derby worx axle bender/straighter drop axle into axle hole and if the hub and outside of the wheel (the part that runs against the rail) touch the flat part of the bender/straighter you have about 3 degrees of bend.
Terry
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Post by W Racing on Feb 8, 2011 22:54:18 GMT -7
Sounds like you have a nice car there. ;D ;D ;D
How long is the track? What kind of track? And what COM?
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Post by scoutsdad on Feb 9, 2011 7:39:36 GMT -7
It's a 42' BestTrack in pretty good shape. COM is a little less aggressive than I was shooting for - it's at about 7/8". I guess wheel-base is also relevant - it's an extended wheel-base (5/8" from the rear) but not fully extended on the front... we left a little room in front of the front wheels for small fenders.
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Post by W Racing on Feb 9, 2011 9:40:51 GMT -7
Sounds really nice.
5 oclock is where lot of my DFW axles wind up.
What steer are you hoping for? Are you looking for a certain steer in 8 feet?
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Post by scoutsdad on Feb 9, 2011 20:17:02 GMT -7
Thanks for the thoughts, Ca$h!
W - Not sure what the right steer is as we won't have time on the pack track until race-day, when we will be able to make a few test runs before the event starts. Hopefully we'll be able to get enough runs in to tune it up!
So, based on all the great information you folks on PDDR have shared on the forum we figured 2.5" over 4' was a good place to start.
I was just nervous 'cause I've seen a couple comments along the lines of "a quiet car is a fast car". So when our car runs down the glass and kinda "buzzes" along those decorative ridges I was worried we bent that axle a bit too much.
My little 8-year-old partner will be very disappointed in his Dad's advice if we turn out to be slow - so I figured I'd put the question to the Pro's and see if I should be worried about letting the little guy down by overlooking something so obvious!
So running along those ridges is pretty typical for a well-built rail-rider or should I prep a new axle with a little less bend to be safe?
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Post by W Racing on Feb 9, 2011 23:34:54 GMT -7
Thanks for the thoughts, Ca$h! W - Not sure what the right steer is as we won't have time on the pack track until race-day, when we will be able to make a few test runs before the event starts. Hopefully we'll be able to get enough runs in to tune it up! So, based on all the great information you folks on PDDR have shared on the forum we figured 2.5" over 4' was a good place to start. I was just nervous 'cause I've seen a couple comments along the lines of "a quiet car is a fast car". So when our car runs down the glass and kinda "buzzes" along those decorative ridges I was worried we bent that axle a bit too much. My little 8-year-old partner will be very disappointed in his Dad's advice if we turn out to be slow - so I figured I'd put the question to the Pro's and see if I should be worried about letting the little guy down by overlooking something so obvious! So running along those ridges is pretty typical for a well-built rail-rider or should I prep a new axle with a little less bend to be safe? I dont think you are going to be slow... Any pics of the car? Some of my axles are bent more than 3 degrees.
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Post by scoutsdad on Feb 11, 2011 10:36:47 GMT -7
Thanks again, W. I will have to try and take a couple shots of our little project and share!
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