I must admit I do not have the experience to answer this. The Pros here will have to chime in. TRE suggested 7+ degrees. Maybe he can comment on the wheel bump influence.
More questions ... how much to bend the DFW axle
- Thread starter Thinkin'Bout Racin
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I must admit I do not have the experience to answer this. The Pros here will have to chime in. TRE suggested 7+ degrees. Maybe he can comment on the wheel bump influence.
I do not know the specific answer to your question. It's likely 7° or so. I know that this time I did achieve the "bend it 'til it buzzes" through my "whack the axle with a hammer and hollowed out broomstick" method.
A couple years ago, all the top cars made that bumps-hitting-the-track whine. I'm happy with it.
Like 5 kids used to say if you are riding on the bumps you are fast
So the track "buzz/whine" is still the accepted amount of axle bend or have things changed
Yes. The whine has disappeared with the allowed disappearance of the nubs on the wheels. (See class rules for specifics)
So for Scouts and Scout dads with the requirement of the "nubs must show", experimenting with the "whine ....not wine" might be worthwhile?
Thanks ....
Hi everyone. New member here. Currently a Webelos 1 dad and racing since first time when a Tiger dad.
I must say that the amount of drift has been something that both surprises and confuses me. Mattering on where I read it seems to range from 1"to 5" on a 4 foot board. Not sure the speed you want when measuring.
I suppose that it might matter on the track? Our pack race is on wood while the districts is on a longer metal. When we build the car they travel very straight down a 20' Masonite strip. About 12" wide and sometimes I make it to the far end. On the wood track we won den each year and were always 1st or second overall. At the metal districts track we podium but are never near best time overall.
I have noticed our car doing some bouncing side to side on the metal. I can't remember the wood.
I understands the theory of the rail rider - but wonder to the degree of drift or how fast rolling while you measure.
I must say that the amount of drift has been something that both surprises and confuses me. Mattering on where I read it seems to range from 1"to 5" on a 4 foot board. Not sure the speed you want when measuring.
I suppose that it might matter on the track? Our pack race is on wood while the districts is on a longer metal. When we build the car they travel very straight down a 20' Masonite strip. About 12" wide and sometimes I make it to the far end. On the wood track we won den each year and were always 1st or second overall. At the metal districts track we podium but are never near best time overall.
I have noticed our car doing some bouncing side to side on the metal. I can't remember the wood.
I understands the theory of the rail rider - but wonder to the degree of drift or how fast rolling while you measure.
This info is mind blowing as I have been doing 1.5 to 2 degrees for my DFW for some weird reason! I have a few questions now that I am wrapping my brain around a large bend.
1st ?- doesn't the large bend make the axle position more likely to rotate out of position run after run?
2nd ?- related to the first ? are you gluing the DFW axle in once you have it where you want it so it doesn't rotate? Seems like you would want the axle to fit very snug otherwise. Could this be why some cars see a slowing after some runs?
3rd?- does the rail running of the wheel against the rail cause your body to wheel gap increase run after run? I know that theoretically the wheel never pushes against the nail head and therefore shouldn't increase the gap but I have a hard time accepting that it never pushes against the nail head.
4th ?- Somewhat unrelated is how do you pros attach your NDFW- do you just glue the wheel to the axle and push it in all the way? Do you use the fender to push up against the wheel to secure it in place?
5th ?- totally unrelated to this topic--- dd4h axle polishing goes up to 5000 grit do most go higher up to 12000 or is this unnecessary or even harmful to the axle speed/ diameter?
Sorry kinda just got a wave of new questions go through my head that ived never thought about before and wanted to get em out there. Thanks for any answers you have!
1st ?- doesn't the large bend make the axle position more likely to rotate out of position run after run?
2nd ?- related to the first ? are you gluing the DFW axle in once you have it where you want it so it doesn't rotate? Seems like you would want the axle to fit very snug otherwise. Could this be why some cars see a slowing after some runs?
3rd?- does the rail running of the wheel against the rail cause your body to wheel gap increase run after run? I know that theoretically the wheel never pushes against the nail head and therefore shouldn't increase the gap but I have a hard time accepting that it never pushes against the nail head.
4th ?- Somewhat unrelated is how do you pros attach your NDFW- do you just glue the wheel to the axle and push it in all the way? Do you use the fender to push up against the wheel to secure it in place?
5th ?- totally unrelated to this topic--- dd4h axle polishing goes up to 5000 grit do most go higher up to 12000 or is this unnecessary or even harmful to the axle speed/ diameter?
Sorry kinda just got a wave of new questions go through my head that ived never thought about before and wanted to get em out there. Thanks for any answers you have!
The axle hole is tight enough that it shouldn't be an issue. A #44 bit with a regular BSA axle is plenty tight. If needed, you can add a drop of water to swell the wood in the axle hole, or add white glue which will both swell the wood and glue it in place.
The only time the wheel would be exerting any pressure on the head of the axle is if the car was bouncing down the rail. You'd have to have a pretty loose fit for the axle to hammer its way out of the body.derbydentist said:
I just press fit the wheel against the body by pushing the axle ALL the way in. Since the wheel isn't moving, you can and should fit your fenders right up against it. Pretty much whatever method you want to use is fine.derbydentist said:
I believe a large contingent of the guys here go to 12k. I only have up to 3k + polish & wax. My results may or may not lead you in one direction or another.derbydentist said:
No problem! I know I've learned lots from other people's questions.derbydentist said:
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Wow thanks for the info crash -you da man! Although you are extremely intelligent for a 5 year old!
I came across the idea of putting two cubes of tungsten between the rear axle points and thought what a great idea to get more weight in the back and/or I could use the spot to push my axles out without dinging up my axle heads with pliers but then i read derby dads advice to never cut the space between the rear axles - why do you think he said that? Does it increase the chance of the axles twisting or flexing out of parallel with each other? I did see in his website the underside of a car that had a bulge under the car lower than the rest of the car body in front of the rear axle - I think it was one of the pics showing what the gee fenders look like underneath-- any idea what that might be?
I came across the idea of putting two cubes of tungsten between the rear axle points and thought what a great idea to get more weight in the back and/or I could use the spot to push my axles out without dinging up my axle heads with pliers but then i read derby dads advice to never cut the space between the rear axles - why do you think he said that? Does it increase the chance of the axles twisting or flexing out of parallel with each other? I did see in his website the underside of a car that had a bulge under the car lower than the rest of the car body in front of the rear axle - I think it was one of the pics showing what the gee fenders look like underneath-- any idea what that might be?
Ah that makes sense- you think it's glued on top of the two rows of cubes? Seems like it would have to replace some cubes and not be in addition to it otherwise it would be too much weight- I guess I've never seen that before _ can't believe how many new things I come across in here- new to me anyway haha
My mum lets me play on the 'puter!
It's all about rigidity. We're cutting wood down to rather thin pieces so that the whole body is under 10 grams (~1/3 oz.). When you add in the 4+ oz around the rear axles, you're putting a lot of pressure on that wood. Having the axle beam separated introduces a lot better a chance at flex. <* thinking...*> But if your cubes are glued in and adding structure, you might be okay.
As to any lumps on one of DerbyDad's cars, I'd have to guess that it was part of some quick and dirty testing on his part. General consensus is to have a smooth, flat bottom to your cars.
Then again, I'm not exactly loaded with 'win' badges.
Okay so I thought of another question because I am running the BSA axles out of the box the slop between the wheel and axle is greater. Does this change the amount of bend I need to put in my axle - or do racers generally still do somewhere between 5-9 degrees? I know it means I need to give my wheel some more space between my fender. I guess the guys that race in the class that requires all the box parts may be able to help me the best?.
I appreciate the responses crash -no one else seems to be chiming in on these questions - for fear of seeming like a jerk for my 5 yr old comment I was referring to crash's profile page where he put 5 yrs old for his age! Haha. My wife would probably say I act like a 2 yr old sometimes!
Well crash I did think the glueing of the cubes there between the axles would add back structure but maybe it's to much weight there? I would test this but definitely don't have the time or means-has anyone tested this or tried this?
Well crash I did think the glueing of the cubes there between the axles would add back structure but maybe it's to much weight there? I would test this but definitely don't have the time or means-has anyone tested this or tried this?
How high off the track should the NDFW be? 1/16 or more? What advantage does it give you if said wheel is tight against the body and unable to rotate with and/or without fenders?
I give Crash a ton of credit; he is single handedly answering everyone's questions. And he IS a good racer. Make no mistake - just humble.
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