need some help with making a brushless LST

[honda237]

so i finally couldn't help myself and i am going to make a brushless lst. Here is the roller i won, pretty nice huh:
http://cgi.ebay.com/ws/eBayISAPI.dll...=STRK:MEWAX:IT

These is what i am going to use:
Motor:
mamba monster 2200Kv system
battery:
zippy 5s 5000mah 30c lipo
other parts
The dudes motor mount & single speed hub
traxxas 2.4ghz radio, and emaxx receiver box
rc-monster pinion and battery box(50X150)
Servos 2 Jr z590

Desired speed 40 mph

My questions:
What size pinion should i run?
What are my runtime looking like? Estimate
Is my desired speed sound realistic, with out over working the motor?
Anything else i am missing?
Any help would be great.

I made a brush-less LST. I used a cheap mystery 100a ESC that I got on ebay for 27.00 shipped. The funds were tight at the time of this build. it was a little over a year ago. It was hard to program. I used a 14.8 cell battery stock transmission a feigao 8xl motor and mechanical brake. The pinion/spur I have are 25/63 I used the fine design kit for my build. I think you will no problem hitting 40 mph. I never tested out doors due to the esc. I have a home made dyno that I can strap it down too and it seems fast. But I really don't know? It has big Joe tires w/ 23mm wheels on it. Its BIG. Will take it out soon. I would post a pic but not sure how too on this forum?

[JAILBIRD]

40 will be easy to hit with that setup. There are quite a few E-LSTs on here lately. Search for the LST threads and start reading. Everything you could ever want to know on an E-LST is in them. The speed calculator at the top of the stickys in this section will help you with the gearing.

-JB

[honda237]

Ya, I know there are, i have been looking. SO what size pinion should i get? 25T?

[suicideneil]

If you know there are lots threads about LST conversions, have you looked through them ( or the gearing calculator ) properly to get ideas for gearing? I'd guess not if you are still guessing..

Differential Ratio: 3.3076923076923075
Transmission Ratio: 2.090909090909091
Other Ratio: 1
Spur Tooth Count: 63
Pinion Tooth Count: 22
Total Voltage: 18.5
Motor KV: 2200
Tire Diameter (inches): 6.75
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor Coil Resistance: 0.006
Spur/Pinion Ratio: 2.86 : 1
Total Ratio: 19.80515 : 1
Tire Circumference (inches): 21.21 inches (538.63 mm)
Rollout: 1.07:1
Total Motor Speed: 40700 RPM
Vehicle Speed: 41.27 mph (66.29 km/h)
Effective KV Value: 2200
KT constant: 0.61 oz-in/A

I dont know what spurs are available off-hand, so here's a rough guess at the gearing required with the XXL tyres and 2nd gear, looks about right.

http://www.scriptasylum.com/rc_speed/_top_speed.html gearing calculator

Definately take the time to look at all the other LST/ LST2 threads though to get some more ideas- there is no magic 'correct sized pinion', it depends very much on the size of tyres you use, and what spurs you have available, and which spurs and pinions will be able to mesh without the motor hitting the tranny for example- cant know that without learning from other people's experience..

[honda237]

Originally Posted by suicideneil

If you know there are lots threads about LST conversions, have you looked through them ( or the gearing calculator ) properly to get ideas for gearing? I'd guess not if you are still guessing..



I dont know what spurs are available off-hand, so here's a rough guess at the gearing required with the XXL tyres and 2nd gear, looks about right.

http://www.scriptasylum.com/rc_speed/_top_speed.html gearing calculator

Definately take the time to look at all the other LST/ LST2 threads though to get some more ideas- there is no magic 'correct sized pinion', it depends very much on the size of tyres you use, and what spurs you have available, and which spurs and pinions will be able to mesh without the motor hitting the tranny for example- cant know that without learning from other people's experience..

Thanks, I have look at all the other threads, spent about 2 hours. Yes there is a lot of different factors i know, but the only guy that was running close to my setup was running a 25T pinion (thats why i asked). I would be running the stock second gear like everyone else. Trust me, i'm not a noob, just like to be particular.
So for general bashing, Should I go with a 22t or a 23T?
Thanks for any help, just want the truck to be perfect.

[JAILBIRD]

For bashing I'd go with the 22t. That will give you a better low end (faster take-off). I'm running 25/63 but I have a lower kv motor (Castle 1717). My top speed is 42-ish and in testing that is plenty for me.

-JB

[honda237]

ok thank you very much, I will get a 22T pinion.
Well i just got a Body, mamba monster 2200kv system, body cutters, and traxxas plugs for $244 shipped, not bad huh? All came from towerhobbies and i got a $60 off coupon for being in their super savers club.

[suicideneil]

Thats not bad at all concidering the MMM combo is about ~$250 on fleebay.
Glad you have a sense of humour too- we do like to tear into eachother quite often around here...

[honda237]

Originally Posted by suicideneil

Thats not bad at all concidering the MMM combo is about ~$250 on fleebay.
Glad you have a sense of humour too- we do like to tear into eachother quite often around here...

I know, I got the email early this morning and just ordered it an hour ago.
Sounds good to me, i like to rip on people for fun.