R/C Tech Forums

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

Reply
 
Thread Tools Search this Thread
Old 09-25-2007, 10:39 AM   #1741
Uga
Tech Regular
 
Uga's Avatar
 
Join Date: Aug 2007
Location: By the Baltic Sea
Posts: 439
Default

Good luck to all out there in Vegas!

jason, how's that tire order from Jaco's coming?
__________________
-=Xray XB4=-
-=Xray T4=-
-=Schumacher Cougar KF2=-
Racing in Latvia
Uga is offline   Reply With Quote
Old 09-25-2007, 01:20 PM   #1742
Tech Fanatic
 
Join Date: Jun 2005
Posts: 900
Default

Quote:
Originally Posted by Scottrik View Post
I ran into the same problem last fall setting up three new cars all with IRS lowered Associated arms. They were all off by about .015. No obvious burrs, etc. I was very surprised by this as I'd been fat dumb and happy (like always) figuring they'd be square since they're milled...I'm sure in a fixture of some sort.

Another thing that's come up...I started getting about a .5mm difference in height side-to-side. Measured springs, etc, re-set spacers, etc. Finally figured out that my pivot balls (always Niftech polished bronze) are floating up and down in the lower arm. No doubt an impact (impacts) have enlarged the socket.

I'm really wanting to try the new IRS lower arms. Also really wanting to try a Laje SpeedEvil front end but they're out of a couple key parts. He'd also not thought of drilling the new IRS arms for his front end when I asked if this was available (and he's a IRS dealer/importer).

Looks like the DB12R will have great success Jason. I was interested to see someone describe it as, basically, the missing link between T-bar and link cars. That was what it looked like to me too. I may have to try one...
I have had similar problems with AE and IRS lower arms, but the 'cure' was different.

On the AE arms, the bottom face is not flat. As you tighten up the screws, the arm deflects until it 'becomes' flat to the chassis. This gives rise to changes in castor and/or ride height. The other thing it does is distort the chassis, giving rise to uneven ride height under the cells from one side to the other.

By sanding the bottom of the arms until they are flat, these problems are avoided. Sometimes, it seems that if you sand one arm, the ride height problem goes away, but my experience is that it is actually clamping the arm flat, and that's why it works.

On the IRS lowered AE arms, and the new IRS arms, the issue arises from the lack of a countersink. Look at an AE standard lower arm, and there is a big countersink in the bottm - none on the IRS arms of either type. The screw's countersink is deeper than the chassis thickness, so to get the screw flush with the underside of the chassis, the countersink sticks through the top.

When the arms are tightened, it is the countersink that contacts first, and this sends the arm any way it can. Put a countersink in the IRS AE lowered arms, or in the washer closest to the chassis on the IRS arms, and this problem goes away. (I wrote to DiffDude on this, and received a very nice reply).

Before you go sanding/filing the arms, put a countersink into the IRS arms/washers (of either make/type) and then fit the arms. Don't overtighten (that chassis distortion thing again!) and then measure. Every time I do this the dimensions come out spot on, and there is almost zero difference in ride height across the chassis. I've fitted three sets like this (including my DB12R!) and I'd say the IRS arms are simply the best!

Sorry this is a bit wordy, no pictures!! HTH
SlowerOne is offline   Reply With Quote
Old 09-25-2007, 02:19 PM   #1743
Tech Elite
 
wallyedmonds's Avatar
 
Join Date: Jul 2006
Location: Brampton ont canada
Posts: 3,662
Default

iv told ppl about this but they did not listen but they may listen to you
wallyedmonds is offline   Reply With Quote
Old 09-25-2007, 02:28 PM   #1744
Tech Elite
 
Grenade10's Avatar
 
Join Date: Nov 2003
Location: Fort Collins, Colorado
Posts: 4,673
Trader Rating: 37 (100%+)
Default

Slowerone - No that really makes sense!!!

I fought an isue last year with a set of arms that the CRC ride height shims kept coming loose. If they were not realy tight, with the taper of the screw head on the block, would explain!!

I'm getting the carpet stuff out, so I'll look at the arms and taper them for the screw head.

THANKS!!
__________________
Darkside, Sweep, BSR, Fantom, IGT Hobbies and IGT8
Byrons Fuel, ProtoForm Bodies & Futaba Radio Gear by Choice
Founding Member of CORRC .... 5280raceway
www.darksidems.com www.igthobbies.com www.IGT8.com
Grenade10 is offline   Reply With Quote
Old 09-25-2007, 02:46 PM   #1745
Tech Lord
 
protc3's Avatar
 
Join Date: Jun 2003
Location: Spring Hill,Florida
Posts: 10,829
Trader Rating: 13 (100%+)
Default

Quote:
Originally Posted by SlowerOne View Post
I have had similar problems with AE and IRS lower arms, but the 'cure' was different.

On the AE arms, the bottom face is not flat. As you tighten up the screws, the arm deflects until it 'becomes' flat to the chassis. This gives rise to changes in castor and/or ride height. The other thing it does is distort the chassis, giving rise to uneven ride height under the cells from one side to the other.

By sanding the bottom of the arms until they are flat, these problems are avoided. Sometimes, it seems that if you sand one arm, the ride height problem goes away, but my experience is that it is actually clamping the arm flat, and that's why it works.

On the IRS lowered AE arms, and the new IRS arms, the issue arises from the lack of a countersink. Look at an AE standard lower arm, and there is a big countersink in the bottm - none on the IRS arms of either type. The screw's countersink is deeper than the chassis thickness, so to get the screw flush with the underside of the chassis, the countersink sticks through the top.

When the arms are tightened, it is the countersink that contacts first, and this sends the arm any way it can. Put a countersink in the IRS AE lowered arms, or in the washer closest to the chassis on the IRS arms, and this problem goes away. (I wrote to DiffDude on this, and received a very nice reply).

Before you go sanding/filing the arms, put a countersink into the IRS arms/washers (of either make/type) and then fit the arms. Don't overtighten (that chassis distortion thing again!) and then measure. Every time I do this the dimensions come out spot on, and there is almost zero difference in ride height across the chassis. I've fitted three sets like this (including my DB12R!) and I'd say the IRS arms are simply the best!

Sorry this is a bit wordy, no pictures!! HTH
This is very true. I never did countersink the new IRS arms but i will take a look at it. My ride height is dead on so it may be fine for now. It doesnt hurt to put a countersink on the washer for the hell of it. Thanks for your input
__________________
Jason Breiner
BMI Racing
Team Associated
J Concepts
protc3 is offline   Reply With Quote
Old 09-25-2007, 03:24 PM   #1746
Tech Elite
 
BlackedOutREVO's Avatar
R/C Tech Elite Subscriber
 
Join Date: Mar 2007
Location: CA
Posts: 3,790
Trader Rating: 67 (100%+)
Default

For carpet, do you guys still use the cheap sunscreen on the tires?

I will be using paragon as thats the only tire sauce allowed, and the best one IMO..... But should I do sunscreen also, or is that only for outdoors?
__________________
R1 Wurks/Awesomatix USA/Roche USA/Protoform/Solaris/Mo Speed/Speedworld Raceway
BlackedOutREVO is offline   Reply With Quote
Old 09-25-2007, 03:34 PM   #1747
Tech Master
 
Kropy's Avatar
 
Join Date: Nov 2003
Location: In a van down by the river
Posts: 1,763
Trader Rating: 12 (100%+)
Send a message via AIM to Kropy
Default

Quote:
Originally Posted by BlackedOutREVO View Post
For carpet, do you guys still use the cheap sunscreen on the tires?
No, Just use the Paragon Ground F/X.
__________________
Dale "Kropy" Kropaczewski
Kolors by Kropy
Postman, Save a spot on the stand for me
Kropy is offline   Reply With Quote
Old 09-25-2007, 03:47 PM   #1748
Tech Lord
 
protc3's Avatar
 
Join Date: Jun 2003
Location: Spring Hill,Florida
Posts: 10,829
Trader Rating: 13 (100%+)
Default

only for outdoors.
__________________
Jason Breiner
BMI Racing
Team Associated
J Concepts
protc3 is offline   Reply With Quote
Old 09-25-2007, 04:12 PM   #1749
Tech Champion
 
Join Date: Nov 2001
Location: Hawaii, USA
Posts: 7,176
Default

How often do you bolt the arms directly on the chassis though without some sort of ride height shim? The countersink effect on the arm would only hold true when the arms are directly bolted on. Once you start shimming it the countersink portion comes into contact with the shims not the arm or the spacers in the case of the IRS arms. I'm using the CRC shim set (2 sets actually) on the front of my car to keep a 5mm ride height with 38mm rims on my Mx2. Possibly the holes in the shims are a tad oversized to accomidate the countersink part sticking through.
InspGadgt is offline   Reply With Quote
Old 09-25-2007, 04:58 PM   #1750
Tech Lord
 
protc3's Avatar
 
Join Date: Jun 2003
Location: Spring Hill,Florida
Posts: 10,829
Trader Rating: 13 (100%+)
Default

I think he is talking about the shim that is on the chassis. On the AE arms, I only had to do this on the 2mm chassis that i had. The head didnt come through the chassis on a 2.5mm. It wont hurt it though.
__________________
Jason Breiner
BMI Racing
Team Associated
J Concepts
protc3 is offline   Reply With Quote
Old 09-25-2007, 05:04 PM   #1751
Tech Lord
 
protc3's Avatar
 
Join Date: Jun 2003
Location: Spring Hill,Florida
Posts: 10,829
Trader Rating: 13 (100%+)
Default

Quote:
Originally Posted by Uga View Post
Good luck to all out there in Vegas!

jason, how's that tire order from Jaco's coming?
I spoke to the crew at Jaco today. They said the tires will arrive tommorow. I have placed a very large order and i will be keeping on top of this for now on. Now that i see the demand is large, I have ordered all of the compounds except for black because i havent had a demand. All other compounds will be in stock. I will make sure that there are no more delays. I dont like putting another company under the pressure. I just needed to feel out the demand
__________________
Jason Breiner
BMI Racing
Team Associated
J Concepts
protc3 is offline   Reply With Quote
Old 09-25-2007, 05:12 PM   #1752
Tech Master
 
Kropy's Avatar
 
Join Date: Nov 2003
Location: In a van down by the river
Posts: 1,763
Trader Rating: 12 (100%+)
Send a message via AIM to Kropy
Default

Jason ~ This was by far the easiest 1/12 scale car that I have ever built, Everything just fell together & not to mention the absolute best machining & carbon fiber in the industry......Now I just need a custom car stand for this bad boy
__________________
Dale "Kropy" Kropaczewski
Kolors by Kropy
Postman, Save a spot on the stand for me
Kropy is offline   Reply With Quote
Old 09-25-2007, 05:17 PM   #1753
Tech Lord
 
protc3's Avatar
 
Join Date: Jun 2003
Location: Spring Hill,Florida
Posts: 10,829
Trader Rating: 13 (100%+)
Default

Me too!! Hey PW.....
__________________
Jason Breiner
BMI Racing
Team Associated
J Concepts
protc3 is offline   Reply With Quote
Old 09-25-2007, 05:20 PM   #1754
Tech Lord
 
protc3's Avatar
 
Join Date: Jun 2003
Location: Spring Hill,Florida
Posts: 10,829
Trader Rating: 13 (100%+)
Default

Thanks for the props kropy. I really do spend alot of time on these cars and it is nice when people can see it.
__________________
Jason Breiner
BMI Racing
Team Associated
J Concepts
protc3 is offline   Reply With Quote
Old 09-25-2007, 05:28 PM   #1755
Tech Master
 
Kropy's Avatar
 
Join Date: Nov 2003
Location: In a van down by the river
Posts: 1,763
Trader Rating: 12 (100%+)
Send a message via AIM to Kropy
Default

I took the car to work with me so I could let our machinist of 20+years look at it & He was very impressed.
__________________
Dale "Kropy" Kropaczewski
Kolors by Kropy
Postman, Save a spot on the stand for me
Kropy is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
NEW IN BOX BMI DB12R bigb11 R/C Items: For Sale/Trade 47 10-09-2008 04:36 PM
-BMI DB12R- joey R/C Items: For Sale/Trade 11 05-18-2008 09:25 PM
BMI DB12R wallstreet R/C Items: For Sale/Trade 17 02-15-2008 05:04 PM
BMI DB12R D-Bizzle R/C Items: For Sale/Trade 2 12-21-2007 03:48 PM
WTB BMI DB12R chris moore R/C Items: Wanted to Buy 8 06-29-2007 06:25 PM



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 12:13 PM.


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