Post by X-Ring Racing on Feb 27, 2011 12:14:47 GMT -7
Hi guys, new to the forum looking for advice. I wanted to share my history with you also. Basically I have built 2 cars for BSA. My goal this year is to break 3.00. I realize this is not easy but at the same time I know we have no chance of winning at 3.00 or above. maybe I'm crazy. Or maybe I'll get lucky. I have been reading and soaking in as much as I can from this forum but now my heads spinning with information overload
This will be my sons 3rd year in cub scouts with next year being his last. The 1st year we did horribly in the pack race, well we did win "Best of Show" which was great and my son was very happy. I was happy because he got to bring home a trophy, it made me feel better since I royally screwed up with speed technique. I actually did a lot of the steps but didn't follow through far enough. After the pack race we went to the districts since we still technically placed in the top 3 of our group. I re-worked the axles and wheels before districts and we ran a 3.14. That left me yearning for the 2010 race the next year.
Last year (2010) I decided things would be different. I already knew tricks from the book (pinewood derby speed secrets) I bought at the scout store and most of my knowledge has come from it. I only had a cheap jigsaw that wouldn’t cut straight so we used a body and weight from the pinecar #360 speed racer kit. www.derbychamp.com/v/vspfiles/360-pinewood-derby-precut.htm . We drilled new axle holes and slightly extended the wheelbase to 4 3/4". It was a 3 wheel car with straight axles (no cant). Used the bsa axles out of the box. metal mold marks removed, underneath of nail head smoothed and very slightly coned the best I could do with a small file in the pro mandrel. And then axles were wet sanded down to 1500. Somewhere along the line I also used pumice on the axles but I cant say if it was the last step or not. COM was 1 1/4 from axle with the lead weight itself being greatly distributed all the way from rear to 3 1/4" towards the front. Wheels were stock bsa out of the box. Nothing done to outside or inside hub (since the 2010 hubs are so much nicer). They were turned on the pro mandrel in a hand drill and wet sanded on the treads to attempt roundness, but it is hard to determine if I succeeded since it's a hand drill. After that the inside hub, outside hub, inside wheel edge and tread area (basically the entire wheel) was polished using derby champ 750 bullet lube graphite. All the paint was ground off on the car around the axle holes and polished with graphite for reduced friction. the inside axle holes on the wheels were polished with pipe cleaners using a gritty tooth paste as polish.
The axle holes were drilled using the pro body tool. I drilled holes in the underside over the axle slots and used crazy glue to lock them in place after tuning was complete. The car was tuned rolling down 4ft pc of plastic sign material until it ran perfectly straight. With the ramp height of about 4".
Graphite was added using a paintbrush. The wheel axles holes were NOT packed tightly using a tooth pick method.
The car ended up weighing in at 4.97 or 4.98 somewhere around there. We ended up averaging a 3.0411 at council. Setting a track record at pack level although I can't tell you what it was (our timer broke on our old wood track on race day and we ended up spotting winners manually with 2 dads on both sides of the track. We went undefeated the entire day. Taking 1st place in the pack, 3rd at districts and 4th in our group at council. We were both extemely happy though just slightly disappointed we didn't place in top 3 (only so my son could bring home another trophy. 3rd was something like a 3.0287 and 2nd - 2.9990, 3rd a 2.9777. Top 5 spots and almost always 1st and 2nd are dominated by the same pack every year. We purchased a new best track this year so we will not be racing on wood anymore.
I took extra care last year scoping out the competitions cars and figured out they were running 3 wheels cars with canted wheels. I wasn't aware of canting wheels last year so this was an eye opener. I do not know if the winners ran oil or graphite. We can use any lube we want "as long as lube is not falling off the car".
All 3 races utilize a best track, I believe they are all 42'. Our derby is coming up in 3 weeks and my goal this year is to have a sub 3.00 car hoping for 1st in pack, and 1st or 2nd in district and 3rd or better in council. Considering all the things I did not do last year I tend to believe my goals are obtainable this year. I will be doing everything I did last year plus the following: Build another 3 wheel car but I want to make it a rail rider with canted rear and dominant front wheel. Using the pro axle press, the pro rider tool, the outer hub shaver, using plastic polish on the wheels including the inside axle holes. Weighing in at exactly 5.00 and shooting for 3/4"- 1" max com using tungsten. I do have use of a reciprocating table saw so we will be cutting our own body this year also. My son has chosen a streamlined style low profile body so I think the body style will be as competitive as last year.
This brings me to my questions. Should I mess with oil at this point? I was thinking about jewkes krytox mix. But I'm very nervous about trying it, only because I do not have a test track. My plan this year was to build the car and rent a track that was at a local mall, and tune the new car to beat our car from last year. But the place went out of business. If using graphite, should I switch brands since I have plenty of 750 bullet lube left?
I'm also worried about building a rail rider with no test track. I can't afford "the block" so I will be using the bent axle method if attempted, again with no test track. I'd rather build another straight car than risk my sons car crashing and not even placing.
I quickly realized that crazy gluing the axles was a mistake. I was going to work on the axles some more before finals but could not get the axles out of the car. Do you worry about fastening the axles? I saw this site selling set screws and thought it is a great idea. www.fastpinewoodderbytips.com/pinewood-derby-alignment/lock-pinewood-derby-alignment-with-set-screws/
But I do worry about the set screws getting stripped or falling out. Should I just use elmers glue so it can be removed?
And most importantly (i think). What do you guys do to your axles on these sub 2.99 cars where the wheel rides? I have ran smooth axles so far because I didn't think grooves were legal. IMO our rules are not clear on this and I wonder if I can get 2.99 or below with smooth axles? My assumption is the pack that dominates our district has to be grooving the axles but I have no idea. If it's legal I want to do it, but I don't want to do anything that is questionable. I do not want to send the car out to anyone as I want to learn myself. I have gotten bit by this hobby and I think I might try sending in cars and trying out my luck and honing my skills with you guys. So what do you guys think?
Oh yeah, I notice most of your cars run the rear wheels not quite all the way back with plenty of overhang in the front. This goes against what I had thought. I thought an extended wheel base should be as extended as possible in front and back? The winning car we built last year was close to what you guys do, i think? Rear axle was 7/8" from the rear and front was 1 3/8" in from the front. Should I change that?
I also bought 2 sets of wheels and ended up with 2- #15's and 2-#10's as pairs. Does it really matter if have a match set? Should I use 10's or 15's on rear?
Last but not least, anyone in northern ohio willing to let me use a test track?
here are our rules:
1. Dimensions
Height: Maximum of 3.0 in. Width: Maximum of 2 3/4 in.
Length: Maximum of 7 in. Weight: Maximum of 5.0 oz. (141.75 grams)
Center Rail Clearance Height: 3/8 in. Center Rail Clearance Width: Minimum 1 3/4 in. inside wheel to wheel
2. Axles
a. Axles must be official BSA axles as provided in the Grand Prix Kit or Wheel/Axle replacement kit.
b. Axles may not be significantly reduced in size.
3. Wheels
a. Only “Official BSA Wheels” may be used.
b. Wheels may be sanded and polished to remove surface imperfections, to true the roundness of the wheel
and to flatten the tread/contact surface. Coning the inside hub or truing the outside hub face is allowed.
c. Weight reduction or wheel modification is not allowed.
d. Wheel tread must remain flat across the entire width and parallel to wheel bore with a minimum width of
7.5mm.
e. The ribs on sidewall must remain visible around the entire circumference.
4. Lubrication
a. Lubrication cannot be falling off the car at check-in.
5. General
a. The car must be newly built for the current Cub Scouting Year using Official BSA components. The main
part of the body must be made of Pinewood.
b. Car must have at least 4 wheels and 4 axles.
c. Additional materials may be added, as long as they meet the race requirements.
d. All car parts and materials must be firmly attached.
e. Weight shown on the Official Race Scale is final.
f. The car must be free wheeling with no springs, magnets, starting devices, or propellants of any type.
g. Washers, bushings, bearings or inserts are prohibited.
h. Each car must pass inspection by the race day Pinewood Derby Committee before it may compete.
i. It is the responsibility of the Scout to present their car for inspection.
j. A Scout whose car fails inspection will be allowed to make adjustments to the car.
k. After the car has passed inspection, it will be impounded by the Race Officials to await the race. Cars may
not be handled after inspection, except by Race Officials, until all races are completed.
l. Paint and glue must be dry at check-in with no sticky surfaces on the car body.
m. No part of the car can extend beyond the starting peg.
n. In the event of a breakdown during the race, the Scout may make an attempt to repair the car within a
reasonable time. The car must pass inspection again prior to another attempt to race. If, after 3 attempts,
the car cannot complete the heat, it will be given the maximum heat time.
o. A car that jumps off the track or interferes with another car will be allowed to re-run the heat. A car jumping
off the track or interfering with another car 3 times will be given the maximum heat time.
This will be my sons 3rd year in cub scouts with next year being his last. The 1st year we did horribly in the pack race, well we did win "Best of Show" which was great and my son was very happy. I was happy because he got to bring home a trophy, it made me feel better since I royally screwed up with speed technique. I actually did a lot of the steps but didn't follow through far enough. After the pack race we went to the districts since we still technically placed in the top 3 of our group. I re-worked the axles and wheels before districts and we ran a 3.14. That left me yearning for the 2010 race the next year.
Last year (2010) I decided things would be different. I already knew tricks from the book (pinewood derby speed secrets) I bought at the scout store and most of my knowledge has come from it. I only had a cheap jigsaw that wouldn’t cut straight so we used a body and weight from the pinecar #360 speed racer kit. www.derbychamp.com/v/vspfiles/360-pinewood-derby-precut.htm . We drilled new axle holes and slightly extended the wheelbase to 4 3/4". It was a 3 wheel car with straight axles (no cant). Used the bsa axles out of the box. metal mold marks removed, underneath of nail head smoothed and very slightly coned the best I could do with a small file in the pro mandrel. And then axles were wet sanded down to 1500. Somewhere along the line I also used pumice on the axles but I cant say if it was the last step or not. COM was 1 1/4 from axle with the lead weight itself being greatly distributed all the way from rear to 3 1/4" towards the front. Wheels were stock bsa out of the box. Nothing done to outside or inside hub (since the 2010 hubs are so much nicer). They were turned on the pro mandrel in a hand drill and wet sanded on the treads to attempt roundness, but it is hard to determine if I succeeded since it's a hand drill. After that the inside hub, outside hub, inside wheel edge and tread area (basically the entire wheel) was polished using derby champ 750 bullet lube graphite. All the paint was ground off on the car around the axle holes and polished with graphite for reduced friction. the inside axle holes on the wheels were polished with pipe cleaners using a gritty tooth paste as polish.
The axle holes were drilled using the pro body tool. I drilled holes in the underside over the axle slots and used crazy glue to lock them in place after tuning was complete. The car was tuned rolling down 4ft pc of plastic sign material until it ran perfectly straight. With the ramp height of about 4".
Graphite was added using a paintbrush. The wheel axles holes were NOT packed tightly using a tooth pick method.
The car ended up weighing in at 4.97 or 4.98 somewhere around there. We ended up averaging a 3.0411 at council. Setting a track record at pack level although I can't tell you what it was (our timer broke on our old wood track on race day and we ended up spotting winners manually with 2 dads on both sides of the track. We went undefeated the entire day. Taking 1st place in the pack, 3rd at districts and 4th in our group at council. We were both extemely happy though just slightly disappointed we didn't place in top 3 (only so my son could bring home another trophy. 3rd was something like a 3.0287 and 2nd - 2.9990, 3rd a 2.9777. Top 5 spots and almost always 1st and 2nd are dominated by the same pack every year. We purchased a new best track this year so we will not be racing on wood anymore.
I took extra care last year scoping out the competitions cars and figured out they were running 3 wheels cars with canted wheels. I wasn't aware of canting wheels last year so this was an eye opener. I do not know if the winners ran oil or graphite. We can use any lube we want "as long as lube is not falling off the car".
All 3 races utilize a best track, I believe they are all 42'. Our derby is coming up in 3 weeks and my goal this year is to have a sub 3.00 car hoping for 1st in pack, and 1st or 2nd in district and 3rd or better in council. Considering all the things I did not do last year I tend to believe my goals are obtainable this year. I will be doing everything I did last year plus the following: Build another 3 wheel car but I want to make it a rail rider with canted rear and dominant front wheel. Using the pro axle press, the pro rider tool, the outer hub shaver, using plastic polish on the wheels including the inside axle holes. Weighing in at exactly 5.00 and shooting for 3/4"- 1" max com using tungsten. I do have use of a reciprocating table saw so we will be cutting our own body this year also. My son has chosen a streamlined style low profile body so I think the body style will be as competitive as last year.
This brings me to my questions. Should I mess with oil at this point? I was thinking about jewkes krytox mix. But I'm very nervous about trying it, only because I do not have a test track. My plan this year was to build the car and rent a track that was at a local mall, and tune the new car to beat our car from last year. But the place went out of business. If using graphite, should I switch brands since I have plenty of 750 bullet lube left?
I'm also worried about building a rail rider with no test track. I can't afford "the block" so I will be using the bent axle method if attempted, again with no test track. I'd rather build another straight car than risk my sons car crashing and not even placing.
I quickly realized that crazy gluing the axles was a mistake. I was going to work on the axles some more before finals but could not get the axles out of the car. Do you worry about fastening the axles? I saw this site selling set screws and thought it is a great idea. www.fastpinewoodderbytips.com/pinewood-derby-alignment/lock-pinewood-derby-alignment-with-set-screws/
But I do worry about the set screws getting stripped or falling out. Should I just use elmers glue so it can be removed?
And most importantly (i think). What do you guys do to your axles on these sub 2.99 cars where the wheel rides? I have ran smooth axles so far because I didn't think grooves were legal. IMO our rules are not clear on this and I wonder if I can get 2.99 or below with smooth axles? My assumption is the pack that dominates our district has to be grooving the axles but I have no idea. If it's legal I want to do it, but I don't want to do anything that is questionable. I do not want to send the car out to anyone as I want to learn myself. I have gotten bit by this hobby and I think I might try sending in cars and trying out my luck and honing my skills with you guys. So what do you guys think?
Oh yeah, I notice most of your cars run the rear wheels not quite all the way back with plenty of overhang in the front. This goes against what I had thought. I thought an extended wheel base should be as extended as possible in front and back? The winning car we built last year was close to what you guys do, i think? Rear axle was 7/8" from the rear and front was 1 3/8" in from the front. Should I change that?
I also bought 2 sets of wheels and ended up with 2- #15's and 2-#10's as pairs. Does it really matter if have a match set? Should I use 10's or 15's on rear?
Last but not least, anyone in northern ohio willing to let me use a test track?
here are our rules:
1. Dimensions
Height: Maximum of 3.0 in. Width: Maximum of 2 3/4 in.
Length: Maximum of 7 in. Weight: Maximum of 5.0 oz. (141.75 grams)
Center Rail Clearance Height: 3/8 in. Center Rail Clearance Width: Minimum 1 3/4 in. inside wheel to wheel
2. Axles
a. Axles must be official BSA axles as provided in the Grand Prix Kit or Wheel/Axle replacement kit.
b. Axles may not be significantly reduced in size.
3. Wheels
a. Only “Official BSA Wheels” may be used.
b. Wheels may be sanded and polished to remove surface imperfections, to true the roundness of the wheel
and to flatten the tread/contact surface. Coning the inside hub or truing the outside hub face is allowed.
c. Weight reduction or wheel modification is not allowed.
d. Wheel tread must remain flat across the entire width and parallel to wheel bore with a minimum width of
7.5mm.
e. The ribs on sidewall must remain visible around the entire circumference.
4. Lubrication
a. Lubrication cannot be falling off the car at check-in.
5. General
a. The car must be newly built for the current Cub Scouting Year using Official BSA components. The main
part of the body must be made of Pinewood.
b. Car must have at least 4 wheels and 4 axles.
c. Additional materials may be added, as long as they meet the race requirements.
d. All car parts and materials must be firmly attached.
e. Weight shown on the Official Race Scale is final.
f. The car must be free wheeling with no springs, magnets, starting devices, or propellants of any type.
g. Washers, bushings, bearings or inserts are prohibited.
h. Each car must pass inspection by the race day Pinewood Derby Committee before it may compete.
i. It is the responsibility of the Scout to present their car for inspection.
j. A Scout whose car fails inspection will be allowed to make adjustments to the car.
k. After the car has passed inspection, it will be impounded by the Race Officials to await the race. Cars may
not be handled after inspection, except by Race Officials, until all races are completed.
l. Paint and glue must be dry at check-in with no sticky surfaces on the car body.
m. No part of the car can extend beyond the starting peg.
n. In the event of a breakdown during the race, the Scout may make an attempt to repair the car within a
reasonable time. The car must pass inspection again prior to another attempt to race. If, after 3 attempts,
the car cannot complete the heat, it will be given the maximum heat time.
o. A car that jumps off the track or interferes with another car will be allowed to re-run the heat. A car jumping
off the track or interfering with another car 3 times will be given the maximum heat time.