R/C Tech Forums

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

Reply
 
Thread Tools Search this Thread
Old 01-10-2003, 02:33 PM   #61
Tech Elite
 
Join Date: Aug 2002
Location: Houston, Texas
Posts: 3,777
Trader Rating: 27 (100%+)
Send a message via AIM to John Stranahan
Default Gear Ratio and Tire Selection

I have come to the conclusion after running stock some mod and 19 turn on the indoor asphalt here at ReflexRC that the majority of tire heating on a touring car comes from accelerating. We need to use softer tires for stock than for 19 turn even though cornering speed is about the same. Last night geared 7.4 my Sorex 32 tires were a little loose and failed to heat up properly. The higher gear had detuned the car just a bit which resulted in less tire heat. Pitz 30's worked alright with this gear. I returned to the 7.5 gear and Sorex 32's for the main. Even though it had cooled off the tires hooked up well.

If you have better corner speed the car needs to accelerate less, you can get by with a little softer tire at the same temperature. Another racer that is not quite as fast may tear up the same set of softer tires if he is not not going as fast around the corners. You can also get by with higher gear ratio (more pinion teeth) if your corner speeds are higher. This also reduces the heating of the tire.

Any thoughts on this subject would be appreciated.
John Stranahan is offline   Reply With Quote
Old 01-11-2003, 12:18 PM   #62
Tech Champion
 
robk's Avatar
 
Join Date: Aug 2001
Location: Macho Business Donkey Wrestler
Posts: 7,586
Trader Rating: 22 (100%+)
Default

Mike D:
What are you changing when you go to the spool?
thanks
__________________
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 01-11-2003, 02:01 PM   #63
Tech Master
 
Mike D's Avatar
 
Join Date: Sep 2001
Location: Maryland
Posts: 1,095
Send a message via Yahoo to Mike D
Default

robk - When running the spool most of your suspension changes are to make the car steer into the turn harder. On power the spool feels exactly like a oneway - very good steering. Off power the spool makes the car understeer. Compared to a front diff setup, the spool setup has softer front end and/or stiffer rear end, batteries back, more front tire compound (for foams), shorter wheelbase, more front droop/less rear droop, etc...
Mike D is offline   Reply With Quote
Old 01-13-2003, 12:40 PM   #64
Tech Elite
 
Join Date: Aug 2002
Location: Houston, Texas
Posts: 3,777
Trader Rating: 27 (100%+)
Send a message via AIM to John Stranahan
Default

I aggree with the changes Mike suggested for the Spool. I made all of those changes on a Losi XXXS when running the spool. Have not run a spool on the TC3 yet.

When running the spool the front tires on the Losi tended to heat faster than the back causing excessive front grip midway in the race. The solution was to move weight back in the car.
John Stranahan is offline   Reply With Quote
Old 01-14-2003, 05:31 PM   #65
Tech Elite
 
Join Date: Aug 2002
Location: Houston, Texas
Posts: 3,777
Trader Rating: 27 (100%+)
Send a message via AIM to John Stranahan
Default Roll Stiffness and Roll Center Changes

I did a couple more experiments today to address a couple of handling problems.

Corner entry push.
I was having a little corner entry push coming off the straight around a hairpin. I reduced the front shock oil from 40 to 35 to address this problem. Seemed to help.

Increased Roll Stiffness
The car was stalling on occasion (slowing severely in the middle of the corner). I thought I needed the top of the shocks moved out one hole to increase the roll stiffness front and back to ease the car around the corners. The front had a blue spring all the way out, so I thought I would try the rear shock tower on the front as I have seen. This provides two holes further outboard than the front tower. It also lowers the shock bodies which might be good or bad. It lowers the center of gravity, but it reduces uptravel when going over the plow disks that mark some of our corners. Iíll see how it works out. I used the middle hole for the upper shock position with the blue spring. Outer hole for the upper rear shock mount with the silver spring.

On Power Push
I was not able to apply as much power in the corners as with my previous car due to a little more push than Iím used to. After adjusting the springs, I tried moving the rear camber links inner pivot to the lower position. This raises the roll center a bit. Anyway this helped the rear rotate a little better on power which reduced the onpower push. The lighter shock oil helped this a bit as well.

Iíll edit the setup I posted previously on page one. The car seemed easier to drive on the indoor asphalt with these settings.
John Stranahan is offline   Reply With Quote
Old 01-15-2003, 11:57 AM   #66
Tech Elite
 
Join Date: Aug 2002
Location: Houston, Texas
Posts: 3,777
Trader Rating: 27 (100%+)
Send a message via AIM to John Stranahan
Default Increasing Front Uptravel

I'm using the rear shock tower on the front now. You can increase the ammount of uptravel of the front wheels by removing about 1/16" of material off of the top of the lower spring mount. Remove material untill it is flush with the top of the plastic shock end. This might prevent bending of the upper shock mount screw in the crashes and will allow smooth driving over plow disk type corner markers without flipping the car over.
John Stranahan is offline   Reply With Quote
Old 01-15-2003, 12:36 PM   #67
51
Tech Regular
 
51's Avatar
 
Join Date: Nov 2001
Location: So Cal
Posts: 360
Default

John: Are you using the new outside hole on the front arms when you went to the rear tower in the front? I've found that when running the rear tower on the front it's almost always better in the outside hole in the arm. I was experiencing the "stall" you were refering to until I made this change. Outside will also result in a bit more uptravel.

Keep up the good work, we appreciate it!
51 is offline   Reply With Quote
Old 01-15-2003, 03:34 PM   #68
Tech Elite
 
Join Date: Aug 2002
Location: Houston, Texas
Posts: 3,777
Trader Rating: 27 (100%+)
Send a message via AIM to John Stranahan
Default

51- Thanks. I am in the outside hole on the A-arm. I'm not in the outside hole on the shock tower yet. I put the two shock towers together and it appeared that the rear tower has two holes further outboard than the front tower. I'm in the middle hole, which makes the shock a little more upright than before. I'll race it tomorrow night and see if I need a little more stiffness.

Last edited by John Stranahan; 01-15-2003 at 03:37 PM.
John Stranahan is offline   Reply With Quote
Old 01-17-2003, 10:48 AM   #69
Tech Adept
 
Join Date: Jun 2002
Location: W. Coast
Posts: 143
Default Smooth Gear

Hi,
I have been building a FT TC3 for few days and notice that
when I spin my drive train with out gear case covers(F/R) spins very nice and free. However once I install a cases, both front and rear, drive trains become very heavy and it seems that gears are binding very tight.
I have build my car according to a instruction and I just wanted to know what is causing it and possible solutions before start to modify a gear cases.
Thanks for your help.
J.
DoCoMo is offline   Reply With Quote
Old 01-17-2003, 11:04 AM   #70
Tech Addict
 
Northerner's Avatar
 
Join Date: Feb 2002
Location: Vermillion, SD
Posts: 535
Trader Rating: 1 (100%+)
Send a message via ICQ to Northerner
Default

more then likely its the gear cases compressing the diff bearings
remove some material a very little at a time on the case opening with a dremel and keep checking untill everything is spinning freely!
Northerner is offline   Reply With Quote
Old 01-17-2003, 11:30 AM   #71
Tech Elite
 
Join Date: Aug 2002
Location: Houston, Texas
Posts: 3,777
Trader Rating: 27 (100%+)
Send a message via AIM to John Stranahan
Default

Jayhaya-To check if the gear cases are compressing the bearings install only the diff without the input shaft and install the cover see if ithe diff spins free. Then do this with the input shaft installed and no diff. Install the cover and see if the input shaft spins free. If both spin free alone then the problem is probably gear mesh and not bearing compression. Remove one or two shims from the input shaft to gain a little bit of play in the gears. On my car the shafts spin free but I had to remove two shims from the input shafts before I had a little play in the gears.

Last edited by John Stranahan; 01-17-2003 at 11:32 AM.
John Stranahan is offline   Reply With Quote
Old 01-17-2003, 04:08 PM   #72
Tech Elite
 
Join Date: Aug 2002
Location: Houston, Texas
Posts: 3,777
Trader Rating: 27 (100%+)
Send a message via AIM to John Stranahan
Default Aluminum Shock Caps

I got the Blue Aluminum Shock caps installed. They are a better fit to the stock plastic nuts and won't bind up. There was some leakage on the first attempt. I lifted the o-rings a little with a pointed tool with the shock cap off so that they would seat better inside the shock cap. This solved the problem. If you are ordering them I would get a new set of o-rings. They really should come with them to avoid this problem. The Blue Aluminum Nylock nuts will also fit with these caps with no problems.

I am told the plastic caps hold more shock oil. Surely can't tell by just looking at them.
John Stranahan is offline   Reply With Quote
Old 01-18-2003, 05:49 AM   #73
dw
Tech Adept
 
Join Date: Nov 2001
Location: Burbage, Leics
Posts: 212
Default

Jayhaya - did you remove the seals on the diff bearings? If you did and reinstalled them then make sure they are seated properly or this will cause the problem you describe.
dw is offline   Reply With Quote
Old 01-18-2003, 06:48 AM   #74
Tech Adept
 
Join Date: Jun 2002
Location: W. Coast
Posts: 143
Default

Thanks for all your help. It seems that removing a shims from input shaft did a trick.
Thanks again.
J.
DoCoMo is offline   Reply With Quote
Old 01-18-2003, 06:02 PM   #75
Tech Elite
 
Join Date: Aug 2002
Location: Houston, Texas
Posts: 3,777
Trader Rating: 27 (100%+)
Send a message via AIM to John Stranahan
Default Gritchy Steering Rack

My steering on the TC3 was funny sometimes. On moving the wheels back and forth by hand it felt like I had trashed the servo gears in a couple of spots. I removed the servo link from the servo and the steering links from the knuckles and the problem was in the rack. The ballbearings tend to roll rubber bits into the rack and it stays there and builds up. It was easy to remove with the rack in the car by scraping the inside of the rack with the backside of an x-acto knife. Then move the rack and scrape the rest. Back to normal.

Put in a KO digital servo which gave me good service in the other car. Had to remove a little bit of the ears near the bottom only, but then it fit OK.
John Stranahan is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
Team Associated 1/8 scale Truggy Info and Tips Kevin Boyle Nitro Off-Road 4505 11-14-2017 12:51 AM
Associated Factory Team TC5, Brushless, LiPo, Li-ion Nanophosphate, Tips and Tricks John Stranahan Electric On-Road 839 11-01-2011 04:31 PM
TEAM DON'T CROWD ME...TIPS FOR PIT SPACING TeamButter Florida Racing 3 10-26-2006 05:51 AM
FS: Factory Team NTC3 with Sirio Evo 2 World Champ Engine, K Factory, MX3-S Radio.. R3VoLuTiOn R/C Items: For Sale/Trade 11 09-23-2006 08:37 AM
factory team rc10t4 and factory team rc18t for sale Zac R R/C Items: For Sale/Trade 28 05-26-2005 05:42 AM



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 02:52 AM.


Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net