2009.12.09, 07:16 PM
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#16
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PN RacingTEAM Driver
Join Date: Jul 2007
Location: southern calfornia
Posts: 1,530
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Quote:
Originally Posted by bermbuster
your camber setting will also have an effect on toe.....
a positive camber uses toe in
a negative camber uses toe out
what camber are you running on your cars???
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on the pn front end i run 1deg camber +1.08 camber gain and .9 caster....unweighted it is toe out,at rest "0"toe, compressed full toe in.....i run the "0" toe bar.... it is a very balanced set up and every time i try the +.5 or+1 my car is hard to drive down the straight....when i ran the std front end i ran 1.5 castor and 2degree camber and a "0"toe bar
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2009.12.09, 07:30 PM
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#17
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Registered User
Join Date: Sep 2007
Posts: 1,840
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Quote:
ok so im not on crack.......so its not driving style.....lol...cause tjay is as smooth as butter.....and i am a lil bit burtal.....lol....may be it in the radio setting.....lol
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Quote:
No, you are both on crack... :P
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hahahha! I've been on a 4 hours meeting that felt like it will never end... This is made my day. lol
For on-road 10th scale sedan and awd miniz, we have to run toe-in rear and toe-out (or zero) front. This set-up makes the car stable. Toe-in will definitely gain more stability vs toe-out or zero toe. In 2wd mini-z, I only have two types of toe bar, 0 and .5. Both felt the same. lol... it must be the +1 wheels that I have.
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2009.12.10, 03:00 PM
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#18
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Registered User
Join Date: Feb 2005
Posts: 1,683
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Quote:
Originally Posted by yasuji
on the pn front end i run 1deg camber +1.08 camber gain and .9 caster....unweighted it is toe out,at rest "0"toe, compressed full toe in.....i run the "0" toe bar.... it is a very balanced set up and every time i try the +.5 or+1 my car is hard to drive down the straight....when i ran the std front end i ran 1.5 castor and 2degree camber and a "0"toe bar
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This my friend, is called bump steer This behavior is actually right in line with what I have discussed before, as the suspension compresses, the car's tires steer inward and create the wandering feeling that I have been telling all of you guys for ever. If you increase the toe-in angle, the bump steer problem is exacerbated even further. The PN Front toes in less at a certain setting, I believe Davey G had posted somewhere on the forums the adjustment that gave the least amount.
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2009.12.10, 05:02 PM
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#19
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Team Reflex
Join Date: May 2007
Location: northern va
Posts: 739
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Put the camber adjustment to 12 o'clock to minimize the bump steer.
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2009.12.10, 08:28 PM
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#20
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PN RacingTEAM Driver
Join Date: Jul 2007
Location: southern calfornia
Posts: 1,530
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Quote:
Originally Posted by CristianTabush
This my friend, is called bump steer This behavior is actually right in line with what I have discussed before, as the suspension compresses, the car's tires steer inward and create the wandering feeling that I have been telling all of you guys for ever. If you increase the toe-in angle, the bump steer problem is exacerbated even further. The PN Front toes in less at a certain setting, I believe Davey G had posted somewhere on the forums the adjustment that gave the least amount.
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so... what u r saying is that in my case ....toe in = instability!lol....
may be that is why i have no clue why bump steer even exists.....i have ZERO INSTABILITY with the zero bar
tried it once again tonight...."0"toe wins out again!
as for dave g's setting.... i tried that as well....good with the 0 bar..... un driveable with any toe in at all!....i read all the lit u guys have posted and i think i have come up with my answer...maybe the car is more stable....and slower to react.....and things just dont happen as quick as i need them to with toe in....
kinda like driving a SLINKY....LOL
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2009.12.11, 03:29 AM
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#21
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Registered User
Join Date: Feb 2005
Posts: 1,683
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Quote:
Originally Posted by yasuji
so... what u r saying is that in my case ....toe in = instability!lol....
may be that is why i have no clue why bump steer even exists.....i have ZERO INSTABILITY with the zero bar
tried it once again tonight...."0"toe wins out again!
as for dave g's setting.... i tried that as well....good with the 0 bar..... un driveable with any toe in at all!....i read all the lit u guys have posted and i think i have come up with my answer...maybe the car is more stable....and slower to react.....and things just dont happen as quick as i need them to with toe in....
kinda like driving a SLINKY....LOL
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Essentially yes, the case is different with the PN double A-Arm due to the "bump steer flaw". By having more toe, the bump steer becomes more drastic. If RCP was perfectly smooth then this problem would not exist, but unfortunately the surface we race on is not very even. By having 0 toe, you are able to mitigate the bump steer to a certain level. I hope PN takes a page out of the Kyosho book and releases knuckles and tie rods that eliminate this issue. If this is done, (and maybe widened by 1mm on each side) the front end would be unbeatable...
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2009.12.11, 08:51 AM
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#22
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PN RacingTEAM Driver
Join Date: Jul 2007
Location: southern calfornia
Posts: 1,530
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Quote:
Originally Posted by CristianTabush
Essentially yes, the case is different with the PN double A-Arm due to the "bump steer flaw". By having more toe, the bump steer becomes more drastic. If RCP was perfectly smooth then this problem would not exist, but unfortunately the surface we race on is not very even. By having 0 toe, you are able to mitigate the bump steer to a certain level. I hope PN takes a page out of the Kyosho book and releases knuckles and tie rods that eliminate this issue. If this is done, (and maybe widened by 1mm on each side) the front end would be unbeatable...
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i would not necessarily call it a "flaw"......imo....bump steer ,as u call it, gives me the best of both worlds.....it does everything i need it to ,when i need it to
think about this....
"unweighted it is toe out,at rest "0"toe, compressed full toe in.....i run the "0" toe bar"
this is something that cannot be achived with fixed toe....there is always a compromise......there is much less with active toe/bump steer
i do not think that this would make any difference on a smooth surface...understand that it doesn't "ping-pong" in all the same spots....
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2009.12.11, 02:45 PM
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#23
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Ain'tSoldEm
Join Date: Jul 2006
Location: Mooresville, NC
Posts: 860
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Take your Ferrari, or rent one, and raise the steering rack in the car 1". Try and drive it, fast.
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2009.12.11, 03:01 PM
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#24
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Registered User
Join Date: Feb 2005
Posts: 1,683
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Quote:
Originally Posted by yasuji
i would not necessarily call it a "flaw"......imo....bump steer ,as u call it, gives me the best of both worlds.....it does everything i need it to ,when i need it to
think about this....
"unweighted it is toe out,at rest "0"toe, compressed full toe in.....i run the "0" toe bar"
this is something that cannot be achived with fixed toe....there is always a compromise......there is much less with active toe/bump steer
i do not think that this would make any difference on a smooth surface...understand that it doesn't "ping-pong" in all the same spots....
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Bump steer is a flaw in this case, there was no way to get around it initially until we saw the simple, but genius solution Kyosho came out with. Sorry, but any engineer with decent automotive design knowledge knows this. In off-road, sometimes it is used since there is not as much traction, so instability is not an issue but in on-road racing scenarios, traction is higher and this creates instability. Remove the bump steer (like on the 03) and see how much more stable the car becomes and how much straighter it tracks.
Active toe making the car better??? The car's tires are constantly pulling in different directions, if you can't see this being a problem, well, I honestly don't know what to say...
As I have said before, this front end is great, and it gives you massive steering traction and corner speed. But it COULD BE better if the bump steer is eliminated.
On a smooth surface, bump steer does not affect the car as much. I hope you can one day make it to MMS in Hong Kong, you will understand what high traction on a super smooth surface is and see how bumpy and inconsistent RCP really is.
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2009.12.11, 03:02 PM
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#25
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Registered User
Join Date: Feb 2005
Posts: 1,683
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Quote:
Originally Posted by pedrocamp
Take your Ferrari, or rent one, and raise the steering rack in the car 1". Try and drive it, fast.
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I guess you need to let people know that by doing this you would create massive Bump steer issues... :P
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2009.12.11, 05:41 PM
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#26
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Registered User
Join Date: Sep 2007
Posts: 1,840
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Quote:
As I have said before, this front end is great, and it gives you massive steering traction and corner speed. But it COULD BE better if the bump steer is eliminated
On a smooth surface, bump steer does not affect the car as much. I hope you can one day make it to MMS in Hong Kong, you will understand what high traction on a super smooth surface is and see how bumpy and inconsistent RCP really is.
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Thank you!
This is what I have been trying to tell everyone, both locally and on the web. PN's double A-Arm is a great product and the lap time you'll get with a standard front-end vs A-ARM is not even close to competitive, that is if you can drive the A-Arm around the track consistently for the entire race. With the bumpsteer, it is almost impossible to stay consistent. This is where the kingpin type MR02 frontend favors. Its consistency to go around the track without having to fight it... very forgiving.
RCP is a great versatile track. If you dont have a shop to go to, you can just buy blanks and make your own turns by using ropes or plastic pipes. However, for racing, the track is very inconsistent. Even if they came from the same shipments, few of the tile are about half to a mill taller than the other tile on the track. Half a mill in this scale is like running over a curb on a real car and thats every block at full speed! I have tried carpet (to try only not race) and man let me tell you, it felt like you're in control of the car it's precision is just amazing! As if I was driving a 10th scale sedan onroad.. Very predictable and every little adjustment is very noticeable.
Grant, you should also consider running the MR03. It's an awesome car.
Last edited by Tjay; 2009.12.11 at 05:44 PM.
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2009.12.11, 10:38 PM
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#27
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Ain'tSoldEm
Join Date: Jul 2006
Location: Mooresville, NC
Posts: 860
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Quote:
Originally Posted by CristianTabush
I guess you need to let people know that by doing this you would create massive Bump steer issues... :P
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Poster assumes no liability for wrecked Ferraris! Don't try it on your Civic either.
I run the PN A-Arm on my LM car and like it. I ran it for a while on my 96mm Stk Class car but could not get used to the dartiness on bumps exiting some of the corners at our track. The LM car with it's longer wheelbase doesn't become upset as easily. The PN A-Arm is a beautiful piece of work, it is just hampered by a fixed length tie rod, a design constraint of the chassis. The steering system worked very well with the stock kingpin suspension. The trick, as many have found, is to use the right length tie rod to place the bump steer arc so it goes from slightly toed out to slightly toed in. I run the 0 bar on my LM for this reason.
I have an 03 and love it. The Kyosho designers did a good job giving us an active camber front suspension with minimal bumpsteer by placing the tie rod on the bottom. The lower arm doesn't swing which minimizes the potential problem.
All cars have bumpsteer, even open wheel F1/Indy front suspensions with very long arms, though it is adjusted to minimize it in the expected range of suspension travel.
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2009.12.12, 02:22 PM
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#28
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PN RacingTEAM Driver
Join Date: Jul 2007
Location: southern calfornia
Posts: 1,530
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Quote:
Originally Posted by CristianTabush
Bump steer is a flaw in this case, there was no way to get around it initially until we saw the simple, but genius solution Kyosho came out with. Sorry, but any engineer with decent automotive design knowledge knows this. In off-road, sometimes it is used since there is not as much traction, so instability is not an issue but in on-road racing scenarios, traction is higher and this creates instability. Remove the bump steer (like on the 03) and see how much more stable the car becomes and how much straighter it tracks.
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i have driven the o3 and pushed on the front end.....it toes in just slight ly....minimal compared to the pn front but if these engineers @ kyosho were so great then u would think that they would have been able to not overcorrect the initial toe out effect...
Quote:
Originally Posted by CristianTabush
Active toe making the car better??? The car's tires are constantly pulling in different directions, if you can't see this being a problem, well, I honestly don't know what to say...
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i do not see it as a problem.....and understand it is due to the fact that my car is faster and more consistent than it has ever been.....i even us less brake i can be on throttle earlier an and hold it on longer than i could with a kingpin front.....(if it was a bad thing...wouldnt my car be worse!)
Quote:
Originally Posted by CristianTabush
As I have said before, this front end is great, and it gives you massive steering traction and corner speed. But it COULD BE better if the bump steer is eliminated.
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i feel if the active toe is reduced it will also reduce the steering traction and corner speed.....it is simple....for me, king pin front end everything fixed position....slower and less consistent lap times!....AAarm....active everything
faster and more consistant lap times!
Quote:
Originally Posted by CristianTabush
On a smooth surface, bump steer does not affect the car as much. I hope you can one day make it to MMS in Hong Kong, you will understand what high traction on a super smooth surface is and see how bumpy and inconsistent RCP really is.
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i think we have the bumpiest tracks here in so cal.....and the grippiest....without a doubt!....all of the guys here in socal use the AAarm front end and are faster and more consistent that they have ever been
i have done numerous tests going from a std front end to the AAarm front end...when ever i go to another track where the people complain that the rcp is bumpy and inconsistent ....i feel that its alot smoother than my track....lol
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2009.12.12, 03:07 PM
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#29
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Registered User
Join Date: Feb 2005
Posts: 1,683
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Grant, you don't get the point... I am not saying that it is not faster or better than a king-pin set-up, but what I am saying is that the front end would be better without bump steer... If you still believe that it isn't, you probably never will, after all you are a PN guy, all the way...
I try to be objective as I can with my evaluations, be it a Reflex, PN, Atomic or 3 Racing part. I look for the best parts, regardless of brand. This is delicate topic for me because we do make a front end, and I try not to bring comparisons for this reason, because I respect Philip very much and his product line. The truth is, when I find a product that can be improved, I try to manufacture it, if it can't be improved, I simply run it, regardless of brand. If the 03 had not been released, you would have definitely seen a geometry correction kit for the PN front. I was already working on a different steering rack with adjustable tie rods to adjust toe and ackerman.
Fact is, my findings are consistent with everyone's on the PN front end. Be it Reflex drivers (who I tried to get to run the front for touring cars), forum members, or drivers from all over the US and Europe, the consensus is they feel the PN front makes their car wander more than the king-pin type front, not that it makes them slower lap per lap.
I am not debating the capability of an advanced driver to control this car quicker around the track with a PN double A-Arm system than with a king-pin type. Especially when you run as much scrub as you do with +3 front wheels. While you have an unorthodox driving style, car dynamics, are car dynamicss and what I am trying to get to is that for all practical applications, bump steer is not a desirable characteristic when engineering a front end. You eliminate it and you have a TRULY superior product that is both more consistent and faster around the track.
Basically, in a perfect world, a PN front with bumpsteer vs a PN front without bumpsteer the one without bumpsteer would be king.
About the 03; yes the 03's still bump in slightly, but it is a MASSIVE improvement over the PN front and the cars run much better and tracks straighter than a PN front ever has. I think I speak for the majority of drivers out there that this yields a more consistent car that is easier to drive lap in- lap out, all while still gaining the advantages of increasing camber.
I am not even going to touch on the active toe. You truly believe this is beneficial, and I will have to respectfully disagree with this as this is at odds with all theory and implementation of car design as well as with my 20+ years of experience racing RC cars.
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2009.12.12, 03:36 PM
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#30
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Curmudgeon & Moderator
Join Date: Jan 2008
Location: Kannapolis, NC
Posts: 2,549
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Grant is a motorcycle guy. It is hard to work with bump steer with only one front wheel. That is why he likes so much caster. Right Grant?
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