BMI's DB12R
01-03-2010, 11:43 AM
#8236
Tech Fanatic
Even with those modifications the BMI springs will not properly fit on the CRC front end. The arm is just too thick to allow you to get any droop out of the front, you get too much pre-load on the spring. I originally had problems with my CRC front end using the long ball conversion as the ball would not thread in straight on one side causing different caster from left to right. So for awhile I went back to the AE front end. Then when I got tired of cracking lower arms I went back to the CRC front end and got the long upper arm which works much better. The front end squares up nicely now and once you glue in the axle and loctite in the king pin there is no need to hybrid the front end with the AE. Also if you want shorter steering arms on the knuckle, CRC is now making them in different sizes.
They don't distort and they don't go soft. The nylon re-enforced plastic simply absorbs the water, and is more resilient. Never broken one I've treated like this, broken several I've fitted straight from the packet. HTH
01-03-2010, 08:09 PM
#8237
I wasn't talking about the regular AE arm but the IRS lower arm which comes with the BMI kit. It cracks right in the bolt hole even when I tap threads into the hole.
01-04-2010, 10:48 AM
#8238
jason can you help, will be running bmi 12th scale at minnregg the 17th, need decent baseline setup for carpet, only run at adrenaline. thanks
01-04-2010, 12:12 PM
#8239
Tech Fanatic
01-04-2010, 02:33 PM
#8240
Tech Regular
Irs used to do lowered ae front arms a few years ago
01-04-2010, 02:48 PM
#8241
i bend the aluminum screw long before the arm cracks. are you using a steel or ti screw?
01-04-2010, 03:07 PM
#8242
New to BMI
Hi Guys,
Got a new BMI for Christmas, put the car together which was no problem, love the quality of the parts. I've installed motor and electronics and did a quick tweak check, lifting the front wheels by the middle of the chassis. The right front lifts first, when I lower it back down the left front is down first. Checked the front end, everything is okay, tried a different front end but still the problem exists. Switched the flex plates from one side to the other, still the same problem. I'm not sure what I've done wrong. Any suggestions?
I currently run an Asscioated 12R5 and chose a BMI because of its reputation for not tweaking. I have the new carbon flex plates coming, maybe that will help.
Thanks Guys.
Got a new BMI for Christmas, put the car together which was no problem, love the quality of the parts. I've installed motor and electronics and did a quick tweak check, lifting the front wheels by the middle of the chassis. The right front lifts first, when I lower it back down the left front is down first. Checked the front end, everything is okay, tried a different front end but still the problem exists. Switched the flex plates from one side to the other, still the same problem. I'm not sure what I've done wrong. Any suggestions?
I currently run an Asscioated 12R5 and chose a BMI because of its reputation for not tweaking. I have the new carbon flex plates coming, maybe that will help.
Thanks Guys.
01-04-2010, 03:45 PM
#8243
Nope...I use the aluminum screw. It's a known issue with the IRS arms...many people have had problems with them cracking. If you've bent the aluminum screw it is likely you cracked the arm and didn't realize it because the crack is under the caster block.
01-04-2010, 04:45 PM
#8244
Tech Elite
iTrader: (64)
Join Date: Jun 2008
Location: Conducting aggressive board meetings at my local track
Posts: 3,301
Trader Rating: 64 (100%+)
Hi Guys,
Got a new BMI for Christmas, put the car together which was no problem, love the quality of the parts. I've installed motor and electronics and did a quick tweak check, lifting the front wheels by the middle of the chassis. The right front lifts first, when I lower it back down the left front is down first. Checked the front end, everything is okay, tried a different front end but still the problem exists. Switched the flex plates from one side to the other, still the same problem. I'm not sure what I've done wrong. Any suggestions?
I currently run an Asscioated 12R5 and chose a BMI because of its reputation for not tweaking. I have the new carbon flex plates coming, maybe that will help.
Thanks Guys.
Got a new BMI for Christmas, put the car together which was no problem, love the quality of the parts. I've installed motor and electronics and did a quick tweak check, lifting the front wheels by the middle of the chassis. The right front lifts first, when I lower it back down the left front is down first. Checked the front end, everything is okay, tried a different front end but still the problem exists. Switched the flex plates from one side to the other, still the same problem. I'm not sure what I've done wrong. Any suggestions?
I currently run an Asscioated 12R5 and chose a BMI because of its reputation for not tweaking. I have the new carbon flex plates coming, maybe that will help.
Thanks Guys.
I've developed the small stress crack in the IRS arm as well, but the arm still holds. As long as the screw will tighten down I'll run it until it completely breaks. Two seasons on my 12RR, and I have only broke one arm completely.
01-04-2010, 05:03 PM
#8245
01-04-2010, 05:13 PM
#8246
BMI sells the lowered associated arms also.
If your car isn't balance side to side it will act that way.
Hi Guys,
Got a new BMI for Christmas, put the car together which was no problem, love the quality of the parts. I've installed motor and electronics and did a quick tweak check, lifting the front wheels by the middle of the chassis. The right front lifts first, when I lower it back down the left front is down first. Checked the front end, everything is okay, tried a different front end but still the problem exists. Switched the flex plates from one side to the other, still the same problem. I'm not sure what I've done wrong. Any suggestions?
I currently run an Asscioated 12R5 and chose a BMI because of its reputation for not tweaking. I have the new carbon flex plates coming, maybe that will help.
Thanks Guys.
Got a new BMI for Christmas, put the car together which was no problem, love the quality of the parts. I've installed motor and electronics and did a quick tweak check, lifting the front wheels by the middle of the chassis. The right front lifts first, when I lower it back down the left front is down first. Checked the front end, everything is okay, tried a different front end but still the problem exists. Switched the flex plates from one side to the other, still the same problem. I'm not sure what I've done wrong. Any suggestions?
I currently run an Asscioated 12R5 and chose a BMI because of its reputation for not tweaking. I have the new carbon flex plates coming, maybe that will help.
Thanks Guys.
01-05-2010, 07:09 PM
#8247
Double check the sockets on the flex links. Make sure the set screws are not too tight on the pivot balls. The flex links should be able to flop under their own weight when detached from the front mounts on the chassis, yet have as little up and down play on the pivot ball as possible. It takes a delicate touch to get them just right.
If your car isn't balance side to side it will act that way.
01-10-2010, 08:41 AM
#8250
Tech Elite
iTrader: (64)
Join Date: Jun 2008
Location: Conducting aggressive board meetings at my local track
Posts: 3,301
Trader Rating: 64 (100%+)
Jason, I'm having a bit of an issue with the 12rr. I sent you a PM and Email. I'm hoping you can help. 