Humor? This is serious stuff, bub! :ha: :lol:

Yeah, I primarily participated in this discussion because I didn't want the newbies thinking that the reason why they might be slow was because they were using a wrong sized spur. ;)

They should be concentrating on suspension setup and carrying corner speed. :)

-Rich

Hello!!!
 

Guys, thanks and I apologize for the fuzz that I created! But seriously, i learned a lot from all of you! And nuff with the spur gears and lets go racing!!

Peace to all men!!

No problem. :) I learned some stuff, too -- like the info OB42TC3 provided. It's all good!

I ran a RC10 then and had the MIP stealth tranny to go with it.
I was thinking it only had 3 gears in it not 6 like stock one.
or maybe it was 1/2 the size, witch ever it was it was less
rotateing mass, thats was big advantage, I think?

I should have wore my boots to work today.

Ok, here goes. On a dirt car, prove to me with actual testing that the car accelerates faster and I'll beleive you. If you guys can feel the differance between the efficiency of 2 gears you should probably all be factory drivers. 6% or so change on a 80% efficient gear is nothing compared to the other things you guys are changing.

There are several things that change when you change the gear ratio and keep the same rollout. Some of these are, axle height, roll stiffness, tire weight, and the location of the motor compared to the suspension pivot point (on a pan car).

One of the biggest changes that I found with 12th and oval pan cars is motor placement. By moving the motor foreward, the pod tends to "wrap up" less and this has a big affect on acceleration off the corners. BTW: Given a fixed rollout, the force at the tire patch is the same at each RPM...The tire is only another gear without the teeth.

As far as the old transmissions are concerned, most of us including the factory guys were using the stealth trans back in the day. It was a godsend after that worthless 6 gear thing. So, when you changed the gearing on the RPM trans, it didn't move the motor? Once again, people were changing something out without knowing the real reason why. BTW: there are 2 main reasons for the new ratio on the B4...Commonized parts and moving the motor.

These discussions always end up in a big I'm right and you're wrong...I only argue the facts to a point then I just give up and chalk it up to close minded people who can't understand the entire picture.

Unregistered
 

Who are you? You seem to have a lot of usefull information. You have answered some questions I have had on the spur gear dilema. After reading your posts and some of the others I have to agree with you. You are moving the motor and thus altering the handling characteristics of the car.

Thanks for the info.

Later:)

But then the hate mail will start :cry:

I'm Fred B from Michigan. Rich was a little off on exactly who I work with but I do work in the auto industry so when I have a question, I just ask around.

????
 

Not that it really matters, but wasn't it a MIP trans.
It was a godsend, lol.


Back in the day we ran a big gear (93T) on the HPI
Pro so we could get the CG lower.

Oh yeah.....well my dad can beat your dad up.......:lol: :p :lol:

I just had one last question on this if you guys dont mind responding to it. If you have two cars with the same Roll-out but one is a shaft drive(tc3) and the other is belt(xxxs) Will the Tc3 not out accelerate the XXXs do to the increased trans ratio of the TC3 giving its drive train a quicker spool up and do to the fact that engery is lost in the belt movement like on the XXXs? But at higher speeds the XXXS will become more effecient do to its belt design and the shaft will become less effecient do to increased friction in the drive line? Is any of this true or am I thinking about this all wrong?

I think one thing that we saw when going to all the early transmissions in offroad was that some of them increased the ratio I know with the RPM trans you could buy a "truck" style gear case for a higer ratio....this will give your drive line a quicker spool up now I would think that it would make the car faster out of the hole if you ran the larger trans with the same FDR as compaired to the lower trans.

I know in a 1/12th scale car that you effect alot of things like axle height and what not when you change your gearing but for the most part on the offroad cars your axle height was the same but the motor might be moved....I know with the XX serries this was not the case when you went to the two Losi transmissions of the time they were different ratios and kept everything in the same static location. I think thats what some people are getting at. Now this would lead me to belive that a larger trans ratio would make your car faster out of the hole do to the increased spool up time.

"Playing Jeopardy Music in the background"
 

Im anxiously awaiting the "Holy One's" answer...
:tire:

Hey Dave how ya doin!? Still coming down in June for the Nats?

Mike D!! What's up!

Well commenting on the "why soo many spurs" deal. Some cars require 3 different spurs so they can reach a broad range of ratios. Take the 414M2 for example. A 120 spur is good for stock because it can hit all the ratios for a stock motor. The motor only adjusts soo far. So you can only run a select few size pinions. To accommodate this, you add a 128 spur to run the other ratios that the 120 spur cannot attain. And so forth and so forth. Blah blah blah.

Jimmy Mac

Jimmy Mac - couldn't have said it better!

DaveW - how did practice go you lucky guy! :) Who is the 'holy one?'

-Rich

We first changed to the MIP...From the junk 6 gear AE trans (it was inefficient) then, Associated baught the rights to the MIP unit and redesigned the diff...That was the stealth trans. Then RPM made some replacement transmissions (mainly for the Losi's) but installing them moved the motor given the same overall ratio.

Now, I'm done arguing about what we did over 10 years ago...We all knew a lot less back then and in dirt, the tracks and tires were a joke.

Physics are physics, beleive whatever you like but remember that the laws of physics don't change.

JIMMY! Whats up man! Plans are to be there for the Nats... im just waiting back for the word from work. It sure sucks to have to rely on an A-OK from your secular career to go PLAY! :flaming: How are things there going? If all goes well...modified it is!
Rich... practice went well! I smoked a set and a half of tires... 5 pair of brushes and an armature! (Ti 10x1) I wore a set of YOK138G down to the belts! (im gonna take a pic just to give you guys somethin to laugh about) Heck, i even killed the batteries in my M8. I havent had that much practice in a LONG time. But sunburn and all... i managed to whet my appetite for some competetion.
Which brings to mind... anyone have problems twisting IRS pincushions runnin mod? (i was using steel outdrives, i have a complete set of composite and steel diffs to swap out) I didnt get a chance to use a one-way yesterday... but was curious if this was also a problem with a one way and a spool. I went back to the standard driveshaft for some driveline flex, in hopes to take some pressure off of the pincushions ( i was using a titanium driveshaft for a more responsive driveline). I swapped back and forth from foams and rubbers (rubbers usually give some) and still had the same problem. So i just ended up putting the stock composite bones with steel pins in, and no more issues. I also used the front Losi carriers and caster blocks yesterday... i like the ackerman difference with the losi parts. The car had smoother on center steering. My servo is lowered, so it has a tendency to make the steering response a little twitchy in high bite situations. But adding 5-6% negative expo to the steering... and making sure the bumpsteer washer was right... the front end was dead locked on and smooth. No surprises, good and consistent. I ended up running 30wt with silver springs front and rear. Standard swaybar on the front (.055 is standard right? i got a box full of em). 0 degrees of caster...ill have to measure the bumpsteer washer i used... i think it is the grey ones that comes with the TC3 steering rack parts tree for ackerman adjustment. 2 mm of static droop in the rear... 1.5 in the front. I need to do a setup sheet before i forget. Having the NTC3 shock towers made the car feel really smooth when transitioning in the chicane... it took a solid set in the corners and had to be pushed hard to get unruly. Even then... all i had to do was point and shoot... and she went! Ok... enough of my day at the track... my fingers were typing as i was thinking... see what you started Rich?! LOL
Unregistered... no worries man... no need to argue. We all know that physics is a man-made science... and humans are imperfect. I guess it just depends if you are a leader, or a follower, as to who you listen too... "science", or your own gut instinct. ("you" meaning, generally speaking) At any rate...gravity is gravity... and my eyelids are getting heavy... i need to sleep for work tonight. SEE YAS!
:tire: Dave

Hi Dave,

Yeah, I had the same problem with the IRS pin cushions. Someone had asked about them either in this thread a while ago or another thread and I mentioned that problem. Someone else then laughed at me and said they had never heard of that before. :rolleyes:

Anyways, the system I've been using is the Schumacher blades. I had their Axis II so I just popped out the pins from the AE axles and replaced them with the pins from the Schumacher axles. I then put the C-blades on top. I haven't had any problems with them at all.

I have a tool that pops the pins out real easy (especially from the Aluminum axles). Hudy makes a tool to do that, too.

If you want to do the same thing, just buy a set of the Schumacher axles and steal the pins and C-blades. They come with spare C-blades, too (they never seem to wear, but I've lost them before).

-Rich