kawada: there's a thread about Hara 12 you could check it there. here's the link

Hey Andrew,

One thing you will learn about most 1/12 scale racers is that they love to help whenever they can. Feel free to ask your questions here and you will get some answers.

Nick

I have what I was told is a bone stock car. I am obviously starting out with a stock motor ( I am currently running tock and 19t in my rdx). I have a 64 p 100t spur and cant seem to get anything bigger than a 26t pinion on the motor due to not being able to move the motor any more forward. The local fast racer told me I should be running about a 30-32 t pinion for our track and that I would need to cut into the t-bar to get proper gear mesh. It does not appear that the small amo0unt of cutting I could do (the motor is actually hitting the nuts holding the t-bar ontot the rear pod) would make enough of a difference to get much more than a 28 t pinion on the motor. It seems that a better alternative would be to use a smaller spur and then recalculate my fdr to = 100/31 or so. How does this work? Should I secure the battery trays to the chassis in any manner? Any time I do anything with the batteries not in the car they seem to just fall out. I was thinking a bit of shoe goo in a couple spots would keep them in place and still be removeable when needed. Also how do you measure the front toe for a pan car? I am accustomed to using set up blocks for my sedan. Do you twelvies sauce the inside half of the front tires like us sedan guys? What ride height should I shoot for? I will stop asking for now. I need sleep and someone is about to reply usi9ng this emoticon :eek:

I had the same problem, I couldn't get the right gearing for the track I was running, so I switched to a smaller spur gear and I was able to get the rollout I wanted. You could file down the T-Bar and nut, it does make a difference, but switching to a smaller spur gear would be an easier fix. As for you battery trey you could shoe goo it to the chassis or take a piece of battery strapping tape and wrap it around the center bar of the hold down. I measure my toe in just by eye balling it, not the most accurate way of doing it but thats just me. When sausing your tires I usually sause a third to half fronts and full rears depinding on traction. Hope this helps! :nod: :nod:

hey man,

run a 96 spur.
you can chop down the nut and the screw and the tbar. should be ab le to squeeze a 35 into the car.
the fdr of a 1/12 is 1:1 it is direct drive. so we use roll out. tire size is how we control speed.
this weekend J and I ran 31 with 46mm tire and tim ran 34 with 44mm I think
to set toe, Tim tells me to put pressure on the back of the wheel before we check it. just use one of those hudy sheet that most have on the pit board. and set about .5 to 1 degree toe in.
on Mike's track we do not change the battery location much in an L4, just shoe goo the things pointing toward the rear. you can always pull them off if you need to move them up for mod.
you may want to run a 100 spur if you want more top end, but then we usually run 2 screws to get the motor far enough forward.

Niftech makes a NEAT alignment tool that helps you accurately (and repeatably) set toe-in and camber. It also makes an easy-squeezy tool for centering the rear axle, etc. It takes a bit of fiddling the first couple times you use it but once you've got it figured it's a breeze to use. All for a whopping $25 and from some GREAT folks. Been using mine about a year now.

Niftech Ultra-Precision Alignment Tool

The pic below shows the tool as-used on the front of the car and shows how it is used to center the rear axle. Note that one and a half tools are shown--you "only" get two bars and one rod.

Scottrik

Mike McMahon showed me a good idea for a t-bar mounting a few years ago that I have been using ever since...

Use 3mm metric screws and locknuts instead of 4-40 screws on the 2 outer holes of the t-bar to mount the t-bar to the rear pod plate. The 3mm screws are slightly larger than 4-40, and they will thread into the fiberglass t-bar. If you are using a the center screw in the t-bar (as I normally do for extra strength and more steering), use a short 3mm screw and do not use a nut on top of the t-bar. Just thread the screw into the fiberglass t-bar until it is snug. If you can not find a short enough 3mm screw, cut the top of the screw flush with the top of the t-bar with a Dremel tool.

Using the oversized screws helps ensure the pod plate and the t-bar always stay aligned properly, and not having a nut on the center screw allows you to move the motor forward as far as possible.

I'm looking for a starting point for roll out with a 10x2. I have been running my 19T around 6.100 but I know that is way to high for a mod motor. If some one could point me in the direction of a site with suggested roll outs or give the roll out they run that would awesome.

Start with 40mm/rev(1.57") with 10T, every turn goes up or down by 2mm/rev, eg, 9T with 38mm/rev.

First you'd better fill us in on how you've come up with 6:1. You must be hitting peak revs somewhere near the apex of the tightest turn on the track and then getting passed like you're tied to a stake on the straights while your motor tries to throw a wind. ;) BZZZZZZZZZZZZZZZZZ

OR...if you've got 1/10 pan car tires on the rear your gearing is probably spot on.

Somewhere around 4:1 or a little lower (numerically) should be in the ballpark for your 19-turn but it 100% depends on your tire diameter. That's why things like this are quoted as ROLL-OUT, because the gear ratio IS dependant on tire diameter. They can't be separated from each other.

I'm running somewhere in the 38-40mm roll-out range with my Velociti 6.5 which is supposed to be similar to a 9-10 turn motor.

Scottrik

When I said rollout I meant gear ration times tire circumfence. I Come out to about 6.1 inches per revolution with my 19T.

Thanks Caveman! That will save me alot of trial and error I would have never thought of going that low...

are you running 2 minute races?

What is a good setup for a CO27 carpet?


Thanks
Fast Faisal :spidey:

Chassis and tires like 19-turn. Rool-out around 1.85.

Oh Wow BRAIN FART!!!

I was think touring car stuff DOH :D I run around 1.85-1.9 rollout

Anyway thanks again for your help.