Custom Crt.5 Project
 

Hey, I bought a crt.5 off ebay last week. I am going to be making a 15" long chassis for it. My setup will be medusa 3300kv 5mm shaft motor, MM esc, 3pm 2.4ghz, hitec 5625mg servo, and a zippy-k 4300mah 3s lipo. One of my question is what pinions should i get i know i need mod1 but am not shure how many teeth i was looking to get 50-65mph out of it. My second question is that am going be using a 1/8" thick 7075-T6 aluminum for the chassis and i would like to know if braces are neccesarry. I will post some pics of the car once i get home and I will update as i go on, I wont be able to finish it so fast because am only 14 years old. So LMK what you guys think and Suggestions.

First off, it's nice to see you have the motivation to take on a project like this.

Second, 50mph might be doable on 3s, but I'd bump up to 4s minimum for that speed. My CRT.5 geared for ~47mph on 3s is pushing the limit of the MM (with a CCBEC).
To determine what gearing to use, you can plug in the values into BrianG's "Parameter Solver":
http://scriptasylum.com/rc_speed/_solver.html
Just remember your tire diameter, and that the spur has 46 teeth.

Third, bracing is a very good idea because you can make the chassis lighter overall. The way you're thinking of it now that chassis would weigh as much as a brick, although would be very rigid.

Here are the pics I promised
http://img219.imageshack.us/img219/6662/img1413vj9.jpg

http://img20.imageshack.us/img20/4607/img1406fu1.jpg

http://img402.imageshack.us/img402/6856/img1407wm2.jpg

http://img510.imageshack.us/img510/4893/img1408at1.jpg

http://img523.imageshack.us/img523/4227/img1409ru0.jpg

http://img88.imageshack.us/img88/986/img1410ve9.jpg

http://img407.imageshack.us/img407/2812/img1411py8.jpg

http://img264.imageshack.us/img264/6481/img1412zb9.jpg

I have more questions, can I gear 46/21 or will i over heat the motor?, i really want to stick to 3s lipo because thats what i have. If I can get 60mph with that motor on 3s what motor will?, I am probably going to race with this car. My last question is how much you huys think i can get for the jammin .12 with the pipe, fuel tank, ofna engine mount, and pull start? (it has less than a quart of nitro threw it according to the previous owner)

60mph is wayy to fast for racing, gear for about 35-40

u dont need that much speed-

Yeah 35-40 MAX. Especially for how small the .5 is.

You probably cant get much for the set up, because it doesnt cost much brand new anyhow. But throw it up on rctech, i sold my crt.5 nitro junk i didnt want there

Will a 15t pinion or a 16t pinion overheat the motor? (i have a fan/heatsink thaa m going to install on the motor)

http://scriptasylum.com/rc_speed/_top_speed.html

Try that out. Comes in big handy... 15 or 16 would be good, but what size tires are u running?

yeah i tried that, but it dosent tell me i fit will over heat or not. am going to be using jato rear rims alll around on pro-line 30 series bow ties

Will these shafts http://www3.towerhobbies.com/cgi-bin...?&I=LXCVX7&P=7 fit in the crt.5 cups?

You gear for 40 or so mph. Your motor, and batt combo sounds fine, I dont know what tires your running, but I assume truck tires with the longer chassis...

anybody know?

They will not fit.

they dont fit in the cup?

(sorry but i need to make shure, because i just placed an order and need to know so i can cancell)

Correct, the diameter of the ball on the ends is too large to fit into the CRT.5's cups.

is there any way i can make them work? because i cant cancel my order because ts already being packed. Like can i use hyper 7 cups? or can i grind down the ball ends ? or can i enlarge the diameter of the crt.5 cups?