R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Electric On-Road

Reply
 
Thread Tools Search this Thread
Old 11-19-2008, 07:26 AM   #1
Tech Master
 
poochy's Avatar
 
Join Date: Apr 2007
Posts: 1,456
Trader Rating: 11 (100%+)
Default tc5 roll center and camber link relation question

im trying to lower my roll center - one of the things im doing to get rid of traction roll. trying to get less traction<---is this correct?

when i read the tc5 manual about camber location and compare the tc5 setup sheets--what the tc5 manual suggest is to raise where the camber link mounts on the shock tower to achieve a lower roll center? the manual also says raising the roll center will decrease grip--thought it was the other way around?

the carpet setup sheets on rc10 suggests a lower camber link location. the info in the manual and setup sheets conflicts?
poochy is offline   Reply With Quote
Old 11-19-2008, 08:33 AM   #2
Tech Elite
 
quietstorm76's Avatar
 
Join Date: Apr 2005
Location: Atlanta
Posts: 2,265
Trader Rating: 10 (100%+)
Default

Raising the Roll center at either end of the car takes away traction from that end.
__________________
Team Shepherd USA:Nugget's Ranch Raceway
Primary Weapon: ?
Secondary Weapon: ?
Tires>>> I don't know yet
quietstorm76 is offline   Reply With Quote
Old 11-19-2008, 09:39 AM   #3
Tech Master
 
PartTime's Avatar
 
Join Date: Mar 2008
Location: Sterling hts MI
Posts: 1,029
Trader Rating: 10 (100%+)
Default

Lowering your roll center will make the car roll more. Hence more traction.

If you are using say, #2 blocks on your a arms then goto #3, that will take traction away. I have been running the b hole on the tc5 for a few now and really like it. No traction rolls and it still hooks up on the light traction tracks.

HTH
DK
PartTime is offline   Reply With Quote
Old 11-19-2008, 09:55 AM   #4
Tech Master
 
poochy's Avatar
 
Join Date: Apr 2007
Posts: 1,456
Trader Rating: 11 (100%+)
Default

.
poochy is offline   Reply With Quote
Old 11-19-2008, 09:56 AM   #5
Tech Master
 
poochy's Avatar
 
Join Date: Apr 2007
Posts: 1,456
Trader Rating: 11 (100%+)
Default

are you guys sure about this? bc it doesnt sound right.
poochy is offline   Reply With Quote
Old 11-19-2008, 10:37 AM   #6
Tech Master
 
TRF415boy's Avatar
 
Join Date: Dec 2004
Posts: 1,857
Default

Yes this is right.

If you're running rubber on carpet and are experiencing traction roll, you can also put a layer of glue on the sidewalls of your front tyres.
TRF415boy is offline   Reply With Quote
Old 11-19-2008, 11:22 AM   #7
Tech Fanatic
 
94eg!'s Avatar
 
Join Date: Jan 2008
Posts: 832
Trader Rating: 17 (100%+)
Default

Moving the inner camber link upwards should bring the upper control arm closer to being parallel to the lower control arm. If that is the case, this should move the roll center (black dot) downward because the instant centers (red & blue dots) have been moved further outwards.



Moving the roll center down should bring it further away from the center of mass of the vehicle. If this is the case, the chassis's tendancy to roll should then be increased...
94eg! is offline   Reply With Quote
Old 11-19-2008, 12:16 PM   #8
Tech Master
 
poochy's Avatar
 
Join Date: Apr 2007
Posts: 1,456
Trader Rating: 11 (100%+)
Default

thank you--ill move my camber links back up a notch
poochy is offline   Reply With Quote
Old 11-19-2008, 12:43 PM   #9
Tech Champion
 
robk's Avatar
 
Join Date: Aug 2001
Location: Macho Business Donkey Wrestler
Posts: 7,586
Trader Rating: 22 (100%+)
Default

Also consider that hinge pin height is a far larger adjustment to roll center than camber links. Some people also consider camber links more important to camber curve than roll center. You do affect roll center with the links, but the hinge pin height will be more noticeable.
__________________
A mutually re-enforcing cascade of failure

"Failior [sic] crowns enterprise." Robert Goddard

I-Lap Scoring Systems http://www.rclapcounter.com/
robk is offline   Reply With Quote
Old 11-19-2008, 12:47 PM   #10
Tech Master
 
poochy's Avatar
 
Join Date: Apr 2007
Posts: 1,456
Trader Rating: 11 (100%+)
Default

Quote:
Originally Posted by robk View Post
Also consider that hinge pin height is a far larger adjustment to roll center than camber links. Some people also consider camber links more important to camber curve than roll center. You do affect roll center with the links, but the hinge pin height will be more noticeable.
thanks man-i went from 2 dots to the 1 dot arm mount already. i thought i had to move the camber links down from 3 to 5 to get a lower roll center but i was completely backwards with the camber link setup--im going to move the camber link to back 3 all around.
poochy is offline   Reply With Quote
Old 11-19-2008, 01:36 PM   #11
Tech Master
 
PartTime's Avatar
 
Join Date: Mar 2008
Location: Sterling hts MI
Posts: 1,029
Trader Rating: 10 (100%+)
Default

Quote:
Originally Posted by poochy View Post
i went from 2 dots to the 1 dot arm mount already.
That is lowering your roll center and making the car want to roll more. In high traction you want to take tracion away to keep the car flat in the turns.

Couple things you can try to get rid of the traction roll.

Move your hinge pins up, #1 to #2
add more camber (from 1deg to 2deg)
Harder tire up front, if it cant dig in it cant roll the car over.
turn your dual rate down, again if the front tire cant dig in it cant roll the car over.
stiffer oil/spring. transfers less weight
sway bars, again flatens the car in the turns.

Any or all should help with your traction rolling problem.

Let us know what you found out.

DK
PartTime is offline   Reply With Quote
Old 11-19-2008, 01:48 PM   #12
Tech Master
 
poochy's Avatar
 
Join Date: Apr 2007
Posts: 1,456
Trader Rating: 11 (100%+)
Default

Quote:
Originally Posted by PartTime View Post
That is lowering your roll center and making the car want to roll more. In high traction you want to take tracion away to keep the car flat in the turns.

Couple things you can try to get rid of the traction roll.

Move your hinge pins up, #1 to #2
add more camber (from 1deg to 2deg)
Harder tire up front, if it cant dig in it cant roll the car over.
turn your dual rate down, again if the front tire cant dig in it cant roll the car over.
stiffer oil/spring. transfers less weight
sway bars, again flatens the car in the turns.

Any or all should help with your traction rolling problem.

Let us know what you found out.

DK
see-now we are conflicting again
poochy is offline   Reply With Quote
Old 11-19-2008, 02:37 PM   #13
Tech Fanatic
 
94eg!'s Avatar
 
Join Date: Jan 2008
Posts: 832
Trader Rating: 17 (100%+)
Default

Quote:
Originally Posted by robk View Post
Also consider that hinge pin height is a far larger adjustment to roll center than camber links.
I did some Autocad drawings and found this to be very true. For the exact same change in height, the inner hinge-pin produced a 630% larger alteration in roll center over the inner camber link.

An interesting note: I also found that camber makes a difference as well. The following picture illustrates the difference in roll center when going from 0* camber, to -3*. I found that adjusting camber has an effect on every variable of roll center. It moves the tire contact patch, the upper arm angle, and even the lower arm angle (if ride height is maintained). All these alterations add up to a rather minor change in roll center (even less than adjusting inner camber link height), but it is a change none the less:

94eg! is offline   Reply With Quote
Old 11-20-2008, 12:29 PM   #14
Tech Master
 
poochy's Avatar
 
Join Date: Apr 2007
Posts: 1,456
Trader Rating: 11 (100%+)
Default

thanks 94eg! awesome info!
poochy is offline   Reply With Quote
Old 11-20-2008, 01:36 PM   #15
Tech Fanatic
 
94eg!'s Avatar
 
Join Date: Jan 2008
Posts: 832
Trader Rating: 17 (100%+)
Default

Well since I've already done the drawing I figured I'd share this one too:

This illustrates that 630% difference I spoke of. For this same hypothetical suspension, both the inside mounting points for the upper & lower control arms have been moved upwards equal amounts (red=before & green=after). As you can see the subsequent change in RC is very different from one to the other (and in opposite directions)...

94eg! is offline   Reply With Quote
Reply



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -7. It is currently 05:18 PM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net