R/C Tech Forums

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

Reply
 
Thread Tools Search this Thread
Old 01-06-2014, 03:42 AM   #1
Tech Apprentice
 
Join Date: May 2010
Posts: 53
Default Tire Truing

Hi Guys

I am having this problem that is effecting the car handling badly and I cannot solve the problem

I am truing the tires as follows but for some reason the front tires are not keeping the same level at race end but there is a 2mm differnce from the left to the right and we all know that they should be equal

Can you please advise if somebody noticed the problem and what is the solution because if have checked the car like 10 times and everything is perfect with no binding etc etc

This is how a true the tires for our track

Front Left Tire - 64mm
Front Right Tire - 62mm
Rear Left Tire - 66mm
Rear Right Tire - 64 mm

Also - I checked shocks, drop, ride height, ackerman, camber, plastics, aluminium etc etc

I am running 500,000 cst front diff and 80,000cst rear diff

PLEASE HELP ME
Teamcastagna is offline   Reply With Quote
Old 01-06-2014, 06:31 AM   #2
Tech Master
 
Join Date: Nov 2012
Posts: 1,122
Trader Rating: 13 (100%+)
Default

Race end?
If I understood correct, its perfectly normal.
Sometimes I'll be down to plastic in the left side and only 2mm of wear on the right.
Don't know where you race but in the states we run clockwise. This means sweepers and most high speed turns are right turns. When turning right the car leans left and therefore more tire wear.
You'll most likely never have even tire wear from right to left and also front to rear, which is why most go 2mm smaller in front. Thats not the only reason we go smaller, theres also overdrive but I dont really know about that stuff.
JOE SI is offline   Reply With Quote
Old 01-06-2014, 08:08 AM   #3
Tech Master
 
OnRDPassion's Avatar
 
Join Date: Nov 2011
Location: West LA
Posts: 1,185
Trader Rating: 54 (100%+)
Default

This is definitely normal. I would not worry about it. Does the car handle fine and are you fast? That is what really matters. It is also not uncommon at our track for people to run 35 / 40 front to rear left side and 32 / 37 front to rear on the right side to balance tire wear in the mains.

That's why having a tire truer is important so that after the race you can get your car back to balanced.

Good luck and good racing
__________________
Jay Williams
Xray RX8 2014
RC America - Protoform Racing - KO Propo USA - Kevco Racing / Picco EDO Modified - Byrons Fuels
OnRDPassion is offline   Reply With Quote
Old 01-06-2014, 08:08 AM   #4
Tech Master
 
OnRDPassion's Avatar
 
Join Date: Nov 2011
Location: West LA
Posts: 1,185
Trader Rating: 54 (100%+)
Default

Double post
__________________
Jay Williams
Xray RX8 2014
RC America - Protoform Racing - KO Propo USA - Kevco Racing / Picco EDO Modified - Byrons Fuels
OnRDPassion is offline   Reply With Quote
Old 01-06-2014, 09:22 AM   #5
Tech Addict
 
Join Date: Jul 2005
Location: MANILA,PHILIPPINES
Posts: 536
Trader Rating: 1 (100%+)
Default

Check out the Michael salven tutorials in YouTube. And the different diameter AFTER a race is normal.what's impt is the diameter is what u want it to he before the race and both front tires should touch the ground at the same time after u lift the front, they should touch the set up board at the same time. Same for the rear tires. Best to have same diameter for both front tires. Same diameter for both rear too. If tires do not touch the set up board at the same time,check the salven tutorials on how to balance it.
__________________
Serpent 748/Nova Virtus/Sanwa M12/Maxima/Savox Brushless/Xceed
GPXJOE is offline   Reply With Quote
Old 01-06-2014, 09:36 AM   #6
Tech Master
 
azeroth's Avatar
 
Join Date: Aug 2009
Location: Da Burbs
Posts: 1,070
Trader Rating: 20 (100%+)
Default

if you figure your set up is good on a practice day if you get the chance run the track in the other direction to verify most would bet that it will be the other way but you could if this is the only track you run go up a shore on the right or down one on the left
__________________
Nitro is for Racing!!!!!!!!!!!!!!!!!!!!!!!!!
YA SMELL WATTs I BE STEPPIN IN????

Yes I race a Snake, VP, Radiopost,Protek,EDS,Matrix
Team Nitro RC Club Lynwood, IL
azeroth is offline   Reply With Quote
Old 01-11-2014, 02:17 PM   #7
Tech Regular
 
intimidator's Avatar
 
Join Date: Oct 2003
Location: Orlando,Florida
Posts: 257
Default

run track backwards to make sure cars good,and maybe run harder compound on one side.i notice u true lefts taller than rights,so that makes me think car might be off.depends on lenght of time your running car for too,that wear in a main seems normal,a heat,not so normal.make sure yiur tires wear flat too,they arent coned real bad.dont be scared to try the diff. compound on one side.a lotta times i will have diff. heights and diff. compounds on just front,or vice with rear.
intimidator is offline   Reply With Quote
Old 01-12-2014, 10:27 AM   #8
Tech Addict
 
JamesHealey's Avatar
 
Join Date: Jul 2011
Location: United Kingdom
Posts: 556
Trader Rating: 1 (100%+)
Default

Uneven diameters can work.

Here's an example using 1/8 scale diameters.

76mm rear left/right
69mm front left/right

This gives a good overdrive ratio of between 1.5% to 0.5% depending on the car, but that's another topic entirely.

So after your first 5 min run you've come back and your car is say:
L R
75/74
68/67

You could expect wear in the region of 1mm/2mm per 5 mins on each side. (Swapping your tires left to right after each run, will ensure more even wear and allow you to get more life out of the tire)

That would then mean by 20mins your car would be unbalanced by approx 4mm at the end, so it maybe worth truing the tyres slightly uneven so the car becomes balanced during the middle of the run, or towards the end or at the start.

There may come a point during a race where the car is simply too unbalanced, and you will require a tyre change, some try calculate the tire wear and only change one side if this is possible, although for the time it takes, I can't see a benefit in this if your calculation happens to be wrong.

You can calculate all of this by writing down your tyre wear after each qualifying heat and keeping track of how the tyres are wearing , I would advise running different diameters over different shore tires to compensate for tyre wear, despite what you might think this generally handles better from what I've been told and have experienced myself than different shore ratings.
__________________
Serpent 977 Evo | Novarossi Engines | Racing Experience Fuel | Xpert-RC Servos | Xtreme Tyres | Bitty Design Body Shells |
http://answer-rc.com/en/ - Answer RC supported driver.

Last edited by JamesHealey; 01-12-2014 at 10:44 AM.
JamesHealey is offline   Reply With Quote
Old 01-12-2014, 10:55 AM   #9
Tech Addict
 
JamesHealey's Avatar
 
Join Date: Jul 2011
Location: United Kingdom
Posts: 556
Trader Rating: 1 (100%+)
Default

Quote:
Originally Posted by GPXJOE View Post
Check out the Michael salven tutorials in YouTube. And the different diameter AFTER a race is normal.what's impt is the diameter is what u want it to he before the race and both front tires should touch the ground at the same time after u lift the front, they should touch the set up board at the same time. Same for the rear tires. Best to have same diameter for both front tires. Same diameter for both rear too. If tires do not touch the set up board at the same time,check the salven tutorials on how to balance it.

Salven's way of setting up the car forces you to work the roll bars and suspension around the weight distribution issues of the chassis to get it balanced, this ends up with a real whack job set up that is really inconsistent and totally different from left to right.

I promise you there are better ways to set up a car than this, check out how Jilles Groskamp sets up his electric touring car in this video below, just make sure the roll bars aren't effecting the droop settings when you do the first part of the setup:

http://www.youtube.com/watch?v=dYLvImYUBt4
__________________
Serpent 977 Evo | Novarossi Engines | Racing Experience Fuel | Xpert-RC Servos | Xtreme Tyres | Bitty Design Body Shells |
http://answer-rc.com/en/ - Answer RC supported driver.
JamesHealey is offline   Reply With Quote
Old 01-12-2014, 11:46 AM   #10
Tech Master
 
Join Date: Nov 2012
Posts: 1,122
Trader Rating: 13 (100%+)
Default

Quote:
Originally Posted by JamesHealey View Post
Salven's way of setting up the car forces you to work the roll bars and suspension around the weight distribution issues of the chassis to get it balanced, this ends up with a real whack job set up that is really inconsistent and totally different from left to right.

I promise you there are better ways to set up a car than this, check out how Jilles Groskamp sets up his electric touring car in this video below, just make sure the roll bars aren't effecting the droop settings when you do the first part of the setup:

http://www.youtube.com/watch?v=dYLvImYUBt4
When I set the droop on my car, I disconnect the roll bar, which salven does. Also I disconnect the shocks, which salven don't.
He says if your shocks are the same length all around and are long nough not to limit up travel there is no need to disconnect shocks. To me it makes sense, but I disconnect anyway. 99% of the time I setup my car with 58/60mm tires and it's balanced perfect when I lift each end to check tweak. But when it isn't, I start all over. Every time in use the pre load collar to correct tweak it makes it worse, and 1 side of the rear is higher/lower or visa versa.
Is that what you mean by forcing you to work the ARB?
JOE SI is offline   Reply With Quote
Old 01-12-2014, 11:51 PM   #11
Tech Addict
 
JamesHealey's Avatar
 
Join Date: Jul 2011
Location: United Kingdom
Posts: 556
Trader Rating: 1 (100%+)
Default

duplicate
__________________
Serpent 977 Evo | Novarossi Engines | Racing Experience Fuel | Xpert-RC Servos | Xtreme Tyres | Bitty Design Body Shells |
http://answer-rc.com/en/ - Answer RC supported driver.
JamesHealey is offline   Reply With Quote
Old 01-12-2014, 11:58 PM   #12
Tech Addict
 
JamesHealey's Avatar
 
Join Date: Jul 2011
Location: United Kingdom
Posts: 556
Trader Rating: 1 (100%+)
Default

You don't even need to disconnect the roll bars to do the down stops really in all honesty, you can check the roll bar isn't effecting the down stops without disconnecting it.

You don't need to check tweak on an independent suspension car, just set everything even left to right, make sure everything is the same left to right, that the down stops, roll bars, ride height collars, camber & toe are all perfectly even side to side and are responding in exactly the same manor.

The most important part of this is the roll bars, the bars MUST be equal left to right, and you cannot EVER get this right if you start changing collar pre-loads side to side to adjust tweak, they need to be EVEN! Jilles measures his with a digital calliper to make sure they're even, and marks them with a marker pen so he can keep the pre-load identical side to side, you set the roll bars before you even put the shocks on as Jilles does in that video.

If you notice in that video he does say when he measures the ride height at the sides of the chassis "this side is heavier than the other", the car is sat into it's suspension to one side slightly this isn't a problem on an ISTC or 1/8 car!

Watch the back end of part 4 and part 5:

http://www.youtube.com/watch?v=yQImjJ_cYm0

http://www.youtube.com/watch?v=dYLvImYUBt4
__________________
Serpent 977 Evo | Novarossi Engines | Racing Experience Fuel | Xpert-RC Servos | Xtreme Tyres | Bitty Design Body Shells |
http://answer-rc.com/en/ - Answer RC supported driver.
JamesHealey is offline   Reply With Quote
Old 01-13-2014, 12:22 AM   #13
Tech Addict
 
JamesHealey's Avatar
 
Join Date: Jul 2011
Location: United Kingdom
Posts: 556
Trader Rating: 1 (100%+)
Default

Also a point to add it's massively important to make sure shock rebound is even left to right, and that your roll bars are straight true and not tweaked/bent.

Especially on blade types, you can check this by removing the shocks and attaching the roll bar and rotating the blade ball and cup and seeing if at any point during the rotation this engages the roll bar action, if it does.. get a new roll bar blade, some brands are more consistent than others, I've never had a tweaked one from Xray but from other brands I've never had a truly straight one.

Wire roll bars are much easier to get consistent than blade types and getting them to react evenly left to right, is a much simpler process, setting the links same length side to side will get you 99% there, maybe half a turn on either side to get the cars anti roll bar action to response same on both sides.

Much easier than turning an eccentric like you do on a blade type, which like I said if both sides aren't perfectly true, will never really respond properly or give consistent handling, think this is one of the reasons on-road nitro cars are moving away from the blade type bars.
__________________
Serpent 977 Evo | Novarossi Engines | Racing Experience Fuel | Xpert-RC Servos | Xtreme Tyres | Bitty Design Body Shells |
http://answer-rc.com/en/ - Answer RC supported driver.
JamesHealey is offline   Reply With Quote
Old 01-13-2014, 08:06 AM   #14
Tech Master
 
Join Date: Nov 2012
Posts: 1,122
Trader Rating: 13 (100%+)
Default

I always measure my preload collars with a caliper, which is why most of the time my car is balanced 1st time.
JOE SI is offline   Reply With Quote
Old 01-18-2014, 09:12 PM   #15
Suspended
 
Join Date: Feb 2011
Posts: 6,240
Trader Rating: 1 (100%+)
Default

Try running the same size Tires left and right, but different shore ratings: higher shores on the outside Tires....
bertrandsv87 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 03:33 AM.


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