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Old 06-30-2011, 08:17 PM   #11941
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Originally Posted by Flying Monkey View Post
If im not mistaken, the 2 combinations are the same IF you end up with same FDR. The way it was explained to me is FDR is FDR is FDR lol. Someone please correct me if im wrong.

Not Sure. I know with a Bigger Spur Smaller Pin You Will Have More Tourq of the line thats why i was asking if there was a Diffrance. Guess That would be the only diff.
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Old 06-30-2011, 11:55 PM   #11942
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Not Sure. I know with a Bigger Spur Smaller Pin You Will Have More Tourq of the line thats why i was asking if there was a Diffrance. Guess That would be the only diff.
Bzzzzzzt. No.

If you end up with the same ratio regardless spur size and/or pinion size you have the same torque multiplication.

Spur Pinion Ratio

20 10 2:1

30 15 2:1

40 20 2:1
. . .
. . .
. . .
100 50 2:1

Etc.

Where you get "increased torque off the line" is if you DECREASE pinion size relative to the spur gear OR if you INCREASE the spur gear relative to the pinion. In both cases you alter the gear ratio to a higher numerical ratio. Otherwise, same ratio same torque off the line with (possibly, more theoretical than measureable) efficiency trade offs at some extremes of either.
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Old 07-01-2011, 12:08 AM   #11943
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with the same fdr but with different primary gears i could see a miniscule benefit to using larger gears to get the same ratio only because they would mesh cleaner without an abrupt sliding into mesh. 100/50 would mesh alot cleaner than say a 24/12. there would be almost immeasurable performance gain but the larger gears would last longer due to the smoother introduction to each other.
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Old 07-01-2011, 12:54 AM   #11944
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Originally Posted by Scottrik View Post
Bzzzzzzt. No.

If you end up with the same ratio regardless spur size and/or pinion size you have the same torque multiplication.

Spur Pinion Ratio

20 10 2:1

30 15 2:1

40 20 2:1
. . .
. . .
. . .
100 50 2:1

Etc.

Where you get "increased torque off the line" is if you DECREASE pinion size relative to the spur gear OR if you INCREASE the spur gear relative to the pinion. In both cases you alter the gear ratio to a higher numerical ratio. Otherwise, same ratio same torque off the line with (possibly, more theoretical than measureable) efficiency trade offs at some extremes of either.

Yup. The motor just sees a number. There are differences in F/R weight balance though with different combinations to achieve the same ratio because the motor will move fore/aft. This is a pretty small change in my experience though and not worth me worrying about it.
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Old 07-01-2011, 01:19 AM   #11945
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I remember years ago running a larger spur on my RC10's in the stock classes. I'am no engineer but it had something to do with the larger spur creating more leverage to the top shaft of the tranny.
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Old 07-01-2011, 06:42 AM   #11946
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All good points, but back in the day the numerical difference between spur and pinion is greater with the brushed motors compared to today's brushless motors.

The old TC3 manual recommends a 6.43 FDR with a stock motor. Today we're trying to hit an FDR of 4.0.

100/39 and and 88/34 are pretty close to the 6.43

For today's 25.5 you would need a 100/62 or a 88/55, but good luck fitting a 100/62.

(64 pitch gears)
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Old 07-01-2011, 07:51 AM   #11947
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Here's a video of the 2nd Qualifier from Thursday's VTA Race at Mike's Hobby Shop in Carrollton, TX.
http://www.youtube.com/watch?v=Sj-eg0OWvMs
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Old 07-01-2011, 10:52 AM   #11948
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Here's a video of the 2nd Qualifier from Thursday's VTA Race at Mike's Hobby Shop in Carrollton, TX.
(link deleted because I don't have enough posts)
Wow. As someone thinking about getting back into R/C cars, I gotta say this looks AWESOME. And from everything I've read, it really does appear accessible to novices. Gotta jump in and ask 2 questions:

1. I was recently given an old TL-01 that seems to run pretty well, essentially for free. Does anyone run these in this class? Not looking to challenge the leaders or anything, but I want to at least be able to fulfill my role as lap traffic...

2. Anyone know of any VTA racing going on in southern central PA? Essentially from Harrisburg on south to the MD state line? I'm in Chambersburg, FWIW...

thanks...

--rick
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Old 07-01-2011, 11:32 AM   #11949
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Originally Posted by pejota View Post
All good points, but back in the day the numerical difference between spur and pinion is greater with the brushed motors compared to today's brushless motors.

The old TC3 manual recommends a 6.43 FDR with a stock motor. Today we're trying to hit an FDR of 4.0.

100/39 and and 88/34 are pretty close to the 6.43

For today's 25.5 you would need a 100/62 or a 88/55, but good luck fitting a 100/62.

(64 pitch gears)
Quote:
Originally Posted by Lowrance View Post
I remember years ago running a larger spur on my RC10's in the stock classes. I'am no engineer but it had something to do with the larger spur creating more leverage to the top shaft of the tranny.
Quote:
Originally Posted by andrewdoherty View Post
Yup. The motor just sees a number. There are differences in F/R weight balance though with different combinations to achieve the same ratio because the motor will move fore/aft. This is a pretty small change in my experience though and not worth me worrying about it.
Quote:
Originally Posted by looper View Post
with the same fdr but with different primary gears i could see a miniscule benefit to using larger gears to get the same ratio only because they would mesh cleaner without an abrupt sliding into mesh. 100/50 would mesh alot cleaner than say a 24/12. there would be almost immeasurable performance gain but the larger gears would last longer due to the smoother introduction to each other.
Quote:
Originally Posted by Scottrik View Post
Bzzzzzzt. No.

If you end up with the same ratio regardless spur size and/or pinion size you have the same torque multiplication.

Spur Pinion Ratio

20 10 2:1

30 15 2:1

40 20 2:1
. . .
. . .
. . .
100 50 2:1

Etc.

Where you get "increased torque off the line" is if you DECREASE pinion size relative to the spur gear OR if you INCREASE the spur gear relative to the pinion. In both cases you alter the gear ratio to a higher numerical ratio. Otherwise, same ratio same torque off the line with (possibly, more theoretical than measureable) efficiency trade offs at some extremes of either.
Quote:
Originally Posted by tcb22185 View Post
Not Sure. I know with a Bigger Spur Smaller Pin You Will Have More Tourq of the line thats why i was asking if there was a Diffrance. Guess That would be the only diff.
Quote:
Originally Posted by Flying Monkey View Post
If im not mistaken, the 2 combinations are the same IF you end up with same FDR. The way it was explained to me is FDR is FDR is FDR lol. Someone please correct me if im wrong.
Quote:
Originally Posted by tcb22185 View Post
Guys How are you Geting your FDR? Small Spur Big Pin OR Bigger Spur Smaller Pin?
along with all this there is the dynamic of rotating mass smaller pinion spur quicker acceleration larger pinion spur combo more speed through corners with the push effect of the rotation.
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Old 07-01-2011, 01:20 PM   #11950
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My head just exploded. Dang.

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Old 07-01-2011, 06:33 PM   #11951
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Originally Posted by ParkRNDL View Post
Wow. As someone thinking about getting back into R/C cars, I gotta say this looks AWESOME. And from everything I've read, it really does appear accessible to novices. Gotta jump in and ask 2 questions:

1. I was recently given an old TL-01 that seems to run pretty well, essentially for free. Does anyone run these in this class? Not looking to challenge the leaders or anything, but I want to at least be able to fulfill my role as lap traffic...

2. Anyone know of any VTA racing going on in southern central PA? Essentially from Harrisburg on south to the MD state line? I'm in Chambersburg, FWIW...

thanks...

--rick
Glad to see you have an interest in the best class in RC !!
Sadly the TL01 may not be a reasonable choice for racing these days. Parts supply may be a bit difficult, the limited gear ratios available (because of the motor mount) would make it difficult at best, the overall handling of the TL01 has been FAR eclipsed by even very basic chassis these days.
Bottom line....it would be hard to justify sinking money into it in order to make it remotely usable.
There are LOTS of good used chassis out there. As for new...the Schumacher MI1 is one of my favorites.(165 bucks brand new ! ). The new Kyosho TF5S is reasonable also. (200 bucks at my local Hobbytown).
Welcome to our addiction !! Have Fun !!

Last edited by Evoracer; 07-01-2011 at 08:48 PM.
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Old 07-01-2011, 08:04 PM   #11952
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Originally Posted by robk View Post
TC spec has dynamic timing, Comp 07 has dynamic timing. As far as I know the only one that did not have dynamic timing was the original Sphere, but that was never confirmed.
Just ordered a Goose for a USGT car, but I would have used a sphere if I thought it was ok. It's laying around now.
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Old 07-01-2011, 08:23 PM   #11953
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Originally Posted by wwddww34 View Post
Here's a video of the 2nd Qualifier from Thursday's VTA Race at Mike's Hobby Shop in Carrollton, TX.
http://www.youtube.com/watch?v=Sj-eg0OWvMs
I dont think I seen 1 clean pass in the entire race.
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Old 07-01-2011, 09:04 PM   #11954
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Actually there were some pretty "gentlemanly" passes and some good sportsmanship shown. I believe this group is fairly new and I'm not sure of the skill level of all the drivers but I must applaud the effort. You guy's at Mikes are doing well. Keeping the enthusiasm up is hard but you folks seem to have a lot of spirit. Keep it up !!
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Old 07-01-2011, 11:20 PM   #11955
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Originally Posted by Evoracer View Post
Actually there were some pretty "gentlemanly" passes and some good sportsmanship shown. I believe this group is fairly new and I'm not sure of the skill level of all the drivers but I must applaud the effort. You guy's at Mikes are doing well. Keeping the enthusiasm up is hard but you folks seem to have a lot of spirit. Keep it up !!

Thanks dude!

alot of us are new at the 1/10th onroad and there are some much more experienced in the group as well.. me for instance went to vta from nitro 1/8th scale offroad.
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