BMI's DB12R


Old 01-30-2008, 07:07 AM
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I tried the Lunsford Ti screws to replace the 8/32 screws on the front end. I had a problem with the angle of the flathead screw not matching the countersink in the chassis. It caused some funky toe-in action on the front arms. I guess I'll stick to bending the aluminium ones.
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Old 01-30-2008, 09:14 AM
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Originally Posted by oze View Post

I can imaging that the size of the screws are not selected on the basis of material strength calculation. It is more done on the basis of this screws can still be easily managed by human fingers during maintenance. I can imaging a lot of this screws could be much smaller, specially if it is made of steel.
On the DB12R every screw is as short as it can be for its place in the car. We actually spent quite a bit of time looking at that and home much material there is where all the screws thread into.

Alloy and Ti screws work fine just don't make them shorter than the screw they are replacing.

There are a lot of grades of It screw. Lundsford ones are the best and are as strong as steel. You can use them to replace every screw.

If you are using alloy screws make sure you keep the steel screws for the center pivot ball, center pivot block, rear flex link pivot and front flex plate mount. You can go alloy everywhere else.
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Old 01-30-2008, 03:30 PM
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okay, that sounds great. I might change all the screws other than the ones Adrian mentioned to anodized aluminums, which someone said weigh less than titanium? Lost Aggresiva, you think the stock phillips screws are better fitting than going with the titanium ones? if i can find blue aluminum screws that fit the front, i might pick those up as well, but im having some difficulty finding screws for that size.

Another question- Are some upright blocks (or are they caster blocks in the front? im not sure) interchangeable from other cars? i thinking of changing those to aluminum eventually, as my lhs owner mentioned that some people have been breaking them from the stress the track puts on them.
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Old 01-30-2008, 03:58 PM
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Yes there are interchangeable with several cars. Many of the 1/12th scale cars out there use the Team Associated Dynamic Strut front suspension which is what the BMI uses. The main difference with the BMI is it comes with the aftermarket IRS lower suspension arms which were made to fix the deficiencies of the AE front end which has been out for ages.
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Old 01-30-2008, 04:00 PM
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Originally Posted by Ferrarimk13 View Post
Lost Aggresiva, you think the stock phillips screws are better fitting than going with the titanium ones?
Personally, I think so. Like I said, I had problems with the ones from Lunsford. When I put the kit screws back in, the problem went away. I wish they had fit better. I'm getting tired of replacing the stock ones. Really need to work on that whole 'not hitting boards' thing...
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Old 01-31-2008, 05:51 PM
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haha, okay, i might try to find the aluminum ones. I might change the upper suspension mounts to anodized aluminum, but would the CRC ones work or are they different?
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Old 02-01-2008, 06:27 AM
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Has anyone got any feedback on the car and setups people are using at the Birds?
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Old 02-01-2008, 12:55 PM
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I'm wondering if they are looking at the new AE front end...perhaps we'll see a BMI version with that front end?
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Old 02-01-2008, 02:28 PM
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i doubt they will put a new front end on the BMI. I guess you can try it out if you want to. the speedmerchant Rev5 front end wouldnt work right? what upgrades have people been getting for the front suspension?
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Old 02-01-2008, 02:33 PM
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Originally Posted by Ferrarimk13 View Post
i doubt they will put a new front end on the BMI. I guess you can try it out if you want to. the speedmerchant Rev5 front end wouldnt work right? what upgrades have people been getting for the front suspension?
Actually, the Speedmerchant front end will fit. As long as the car has the holes in the chassis for the AE front end, it will fit fine. As for upgrades, who needs 'em. The car works fine with the included parts. Don't fix what isn't broke...
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Old 02-01-2008, 02:36 PM
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man, you will not believe how much i was hoping for that answer. I dont think i would be able to afford any huge upgrades anyways, lol. If i ever finish buying all the electronics () i might look into trying different front ends, and seeing how each one is.
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Old 02-01-2008, 06:01 PM
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Most of the new 1/12ths come very well fitted these days and don't need much if anything in the way of upgrades. The BMI is very well fitted out with upgrades where needed such as the IRS lower front arms and the IRS rear axle assembly just to name a couple.

The reason I ask about the new AE front end is because most of the smaller 1/12th companies use the existing AE front end and buy the whole front suspension kits for their cars. Cars like the Darkside, Diggity, and others. Even the BMI uses the existing AE front end but they don't get the whole front end kit because they use the IRS lower suspension arms instead of the AE ones. Some companies were running into shortages from AE in trying to get front ends for their cars. When the new front suspension comes out I wonder how available the current front end kits will be. Now BMI shouldn't have a problem since it looks like the upper arm and caster blocks might be the same on the new suspension as they are currently. But it might be prudent to make the change when the front end comes out. Just something to think about.
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Old 02-02-2008, 08:45 AM
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Hey Guy's front tire compound question if I where to run a softer front compund tire like a Double pink or a magenta eventhough i would have more steering, would I carry more speed through the turns with a harder tire compound like a lilac or a black?

At my track any front seems to work i just want to know which compound would carry more speed through the turns?
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Old 02-02-2008, 10:43 AM
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are these the screws you used lost aggressiva? http://www.lunsfordracing.com/mm5/me...y_Code=STDFLAT They are 7/16 instead of 3/8, but all the extra would just continue going up like the 3/8. Was your problem maybe threading it straight? i might buy it to try, because theres no aluminum ones that come in that size that i can find, and the stock ones strip reallly easily.
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Old 02-02-2008, 10:59 AM
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Originally Posted by Ferrarimk13 View Post
are these the screws you used lost aggressiva? http://www.lunsfordracing.com/mm5/me...y_Code=STDFLAT They are 7/16 instead of 3/8, but all the extra would just continue going up like the 3/8. Was your problem maybe threading it straight? i might buy it to try, because theres no aluminum ones that come in that size that i can find, and the stock ones strip reallly easily.
The Lunsford screws are WONDERFUL, except they're too short. The BMI screws are 5/8, not 3/8 (which is actually shorter than 7/16 ) and that 3/16 can often mean the difference between a broken lower arm and not. I've asked Lunsford a couple times now about making a 5/8" 8-32 screw but they don't seem overly interested. Too bad because I REALLY like the added strenght of the Ti over aluminum screws on the front arms, plus I REALLY REALLY like the 3/32 allen head vs the Phillips. I use aluminum throughout the car but would take the couple gram weight hit to the Ti screws in an instant for the added reliability.

Also I'm pretty certain Jason uses a standard countersinking angle so if the screw is off-center in someone's car it's probably due to some other factor.

IF YOU ARE "THREADING" YOUR LOWER ARMS WITH AN 8-32 SCREW, KIT OR OTHERWISE, YOU ARE SETTING YOURSELF UP FOR PAIN. It was always a REALLY good idea to use an 8-32 tap for the lower arm mounting screws on the Associated (and IRS "lowered" Associated) arms. It is pretty much mandatory on the new IRS lower arms. They are SO thin between the screw hole and the cutout for the upper arm mounting block that you can see the plastic stress if a screw is run through to chew threads in them. If you absolutely INSIST on using a screw to force threads into the lower arms at least use a steel one and cut a notch up one side of the threads and make a DIY self-tapping screw. But don't plan on using that screw in the built car...it is now your tool, don't continually run it in and out of the arm.

Last edited by Scottrik; 02-02-2008 at 12:14 PM.
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