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Old 06-01-2009, 03:35 AM   #7396
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Making the pivots from aluminum or another alloy would not be a good idea as the pivot balls are aluminum and that would increase wear to both items. Delrin is ideal for the part but i will see if there is anything that can be done to increase the strength of them as far as design goes. I am not looking to retire off of these cars. If there is an issue, i will listen and see what i can do to fix it.
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Old 06-01-2009, 05:42 AM   #7397
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I have had the same problem with my DB12RR during a crash. Someone hit me sideways at the rear pod at full speed and all of the three pivots did break.

I have to say I didnīt have any other parts break with my DB12RR also it didnīt tweak. But the pivots are the (only) weak point in my view also.

I know delrin from other cars when this was used for some prototype parts. This material is very smooth for moving parts and but itīs just to brittle. At those cars the delrin parts also did break.
Maybe switching to something like polyamid would help a lot, also using a little more material around the holes.
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Old 06-01-2009, 09:09 AM   #7398
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Hey guys.
Remember if you hit the wall things usually break... If you make these parts stronger to link the front and rear, if you crash the next weak point will break, all carbon fiber parts
Unfortunately sometimes a small bump in the right angle is all it takes to break parts, but I been there back in the day when I started with the L4 T-bar. I had one event where I went through 4 T-bars mostly from small bumps. A friend of mine went through 6 body posts on his touring car and the suggestion was to use aluminum body posts, this would have been bad because the next part down is the shock tower, so if the body post would not break the shock tower would more expensive. Some tracks have sections of curbing or CONCRETE which is never fun for any RC car or our pockets. Try convincing track owners to use different materials so that cars are less likely to break.
I think we all been there where we keep breaking 1 part , but it passes. The famous saying is "...I have never seen that part break before..." until it happens. You will be surprised at some parts that break or bend..

Good luck with all the racing
T Bars cost $5.00 to replace though, and local hobby shops had the parts. These cost nearly $26 with shipping included. thats the harsh part.
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Old 06-01-2009, 09:31 AM   #7399
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What about aluminum sockets and then use delrin pivot balls? It would all cost more (I would imagine), but in the end, the delrin balls would be much cheaper to replace as they wear/break..
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Old 06-01-2009, 02:47 PM   #7400
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It's a nice idea, but it isn't possible to screw them to the bottom plate successfully. In a crash, the balls would strip their threads, and you'd have to buy a new ball. This is very likely to happen with the slightest knock, so it's not a good mechanical solution.

I have broken one of those pivots in 2+ years of racing, and that was with a huge crash into a solid barrier at high speed. I appreciate your concern, but for the vast majority of BMI drivers, this isn't an issue. I hope we can leave the design as it is, since I don't want the extra weight and complication of a different material for this part. Thanks.
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Old 06-01-2009, 04:37 PM   #7401
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I agree that there doesnt seem to be an easy answer to this other than "Dont hit stuff". I guess I just need to plan to stock up on these expensive bits so that when I do break one again I am not left with a busted car.

Really what could help this a bit is a thin alloy band to push around the delrin ball capture plate. Like a belt, just something to give it a bit more strength around the point where the cup and the mounting plate face are.

One common thing is that they always bust out the back of the car... I have not had a ball cub break in any other way other than out the back toward the rear.
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Old 06-01-2009, 04:55 PM   #7402
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One common thing is that they always bust out the back of the car... I have not had a ball cub break in any other way other than out the back toward the rear.
I believe that comes from the rear wheel snagging the board, corner, etc. It would place the shearing force in the proper direction to cause the damage you're experiencing. Have you been trying to tighten up your line? Just a thought.
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Old 06-01-2009, 05:14 PM   #7403
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Just press fit a brass threaded insert into the delrin ball
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Old 06-01-2009, 06:13 PM   #7404
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Really what could help this a bit is a thin alloy band to push around the delrin ball capture plate. Like a belt, just something to give it a bit more strength around the point where the cup and the mounting plate face are.
That should be easy to do...just go to a LHS that carries brass or aluminum tubing and find one that fits tight over the ball cup then just cut bands from that.
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Old 06-01-2009, 06:54 PM   #7405
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Hey Jason.

I do not have the stones to read nearly 500 pages of replies so I will just ask.....

The 1/12RR that is for sale today, is it the latest, bestest, most up to date available? Are there any changes coming down the line any time soon?

Did the piviot ball situation get corrected?

Thank's, Joe.
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Old 06-01-2009, 06:57 PM   #7406
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Quote:
Originally Posted by Serzoni View Post
Just press fit a brass threaded insert into the delrin ball
Excellent...as the kit price soars past $300...

Nothing like a $50 solution to a "problem" with a $8 part that a small minority (one?) seem to have any problem with.
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Old 06-01-2009, 08:18 PM   #7407
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Originally Posted by CrashRipRock View Post
Hey Jason.

I do not have the stones to read nearly 500 pages of replies so I will just ask.....

The 1/12RR that is for sale today, is it the latest, bestest, most up to date available? Are there any changes coming down the line any time soon?

Did the piviot ball situation get corrected?

Thank's, Joe.
There is a version coming out for 1 cell LiPo, other then that the current kit is the latest, and most up to date. The pivot ball issue only seems to occur in rare situations as most people have not had this issue.
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Old 06-01-2009, 08:36 PM   #7408
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hey guys, did you ever see the pivot on a crc car? that thing shatters like a champagne glass when you hit something. what the hell are you guys hitting that you are breaking the pivot? a brick wall. the db12rr is the strongest 1/12th on the market and that pivot is bulletproof under normal racing conditions. i have raced this car for 2 years now and still have my original pivots.
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Old 06-02-2009, 09:45 AM   #7409
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This car is very strong (maybe stronger than other cars) as long as you crash into a wall or trackbarriers or something.
The problem is if someone crashes into your cars rear pod, worst case is a hit from sideways. From what I heard this is the worst case for any 1/12th car. Exactly this happened to my car when someone hit me sideways at full speed. No graphite parts were broken and nothing even was tweaked but all of the three pivots were broken.
Bad thing just is in my country there is no BMI distributor nor any shop carrying BMI. So this wasnīt cheap in the end.

I like the car and I donīt want talk bad regarding BMI but every car (regardless of scale or brand) has itīs weak point and this for sure are the delrin pivots with the DB12RR.

I think one fix for the side pivots could be some sort of aluminium sleeve around that pivots. For the center pivot there should be some more plastic around the pivot ball area, I think there is some room for more. I canīt think someone is using a gearratio forcing the motor until the center pivot.
Beside this Iīm sure there is a stronger plastic possible than delrin.

Jason, donīt take me wrong. As I said before I donīt want bash BMI or something but Iīm about 25 years into this sport and I certainly have some experience with cars. So maybe just take this as an input for development.
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Old 06-02-2009, 02:35 PM   #7410
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Thanks for the info Gadgt..

Ebay auction using your exact verbage, 370199350183, is this you guys? Your not Canadian, your from right here on the West Coast of Fla right?

Can you define the colors listed to the tire performance?

What color = what stickyness?

Thanks Joe
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