LNC - More Speed

[Justheman80]

I am needing more wheel speed. I know I am not going to get blistering speed out of this thing and not really wanting to put a lot of money into it either.

*Looking at a putting in a Titan 21T or Homes 21T brushed motor. Opinions? Other cheap options.

*Want change the pinion gear for more wheel speed. I believe 20tooth is stock. What size can I fit to and what would you recommend?

[TheLetterJ]

I stuffed a 17t 550 and 23 tooth pinion in my good friend's Night Crawler. It wouldn't have been my first choice for a motor, but he burned up the 35t 540 and I had the 17t 550 laying around, but it has honestly proven itself to be a good combo on 3s. It has significantly more torque than the 35t 540, and the added wheel speed has really opened up line options and allows a different driving style than the stock snail's pace. It's still slow by most people's definition, but fast enough to reverse out of a would-be rollover, or get a little wheel spin going if an obstacle is loose. The 550 can is a TIGHT fit (less than 1mm of clearance at the upper link) but it does fit. The 23 tooth pinion (which comes in the box with most Traxxas 2wd vehicles to achieve their advertised speed) also puts the motor very close the the chassis, but you might be able to go a tooth or so bigger?

I'd pick the HH 21t 550 Trailmaster Sport over the Titan everytime. I've got 3 of them in various cars (albeit 27t 550) and they've been great. The titans seemed to wear out the shaft bushing and start squeeling and wobbling after a few months of regular use, the Holmes motors use a bearing there instead and have been rock solid for almost a year now.

[Justheman80]

Thanks for your reply. I am super green to the RC world, this is my only RC.

With going to a lower turn motor, what are the negatives? All I know is I will get more top speed. I asu,e I willl lose minor low end, but hoping it will be a wash going to a bigger can. Have been reading a bit.

[TheLetterJ]

You pretty much have the jist of it. The lower turn/higher speed motor will also pull more amps and produce more peak power, all else being equal. Going with the 21t 550 (equivalent in speed to a 27t 540) seems to be the sweet spot for power/speed/efficiency. Much faster and you'll reach a point of diminishing returns where you may make a tiny bit more power/wattage at the pinion, but it will pull noticeably more from your battery to get it, that extra amperage just turns into heat which will shorten the life of... everything. Going much slower/higher turns will give longer run times and less heat, but you'll ultimately have LESS torque than a faster motor that was geared for the same speed.

A 550 motor is 56-57mm long versus a 540 at 50mm long, pretty much all of the extra length is in the armature and magnets. Someone better versed may need to correct my terminology, but that's why the same amount of turns of wire around it results in a longer length of wire, higher resistance, which equals a slower speed i.e.: 21t 550 = 27t 540, 27t 550 = 35t 540, etc. So while the can may only be 10% longer, you may gain 40-50% more torque.

There's obviously going to be much more to it, but that was at least broken down to a point that it made sense to me. In short: my vote is to go with the HH 21t 550, 3s, and try it with the 20t pinion first. If you still want more speed, bump up to a 23 tooth pinion. Remember that taller tires also have the same effect as taller/faster gearing, so don't discount that idea down the road.

[Justheman80]

Thanks for all your help. Do appreciate your detailed explanation. Was not expecting replies so soon, seems a bit quiet here in the Losi section. Will the stock esc and everything else hold up to 3s? Currently running 2s.

Yes, I have been eyeing new tires as well. Stockers are 5.0inches, some of the ones I have seen are 5.5 tall. Seen some 6.0 on a LNC and it looked way out of proportion.

[TheLetterJ]

Yes, the stock Dynamite 60A ESC will happily run 3S, with some caveats. The internal BEC is a bit on the weak side at 5v/2a and being a shunt style regulator it will start running noticeably hotter on 3s because it is essentially just stepping down from 11.1v (3s) to 5v by turning the extra power into heat. If you're running an external BEC (such as the Castle Creations 10a bec) there's nothing to worry about. The stock steering servo doesn't pull too many amps (afterall, it only puts out 9kg of torque) for the built in bec, but its (the servo) life expectancy is very short so it would be a good idea to plan for a more powerful servo in the future, in which case, you'll want a stronger bec anyway, so it wouldn't hurt to add one now.

Tires are an extremely opinionated subject, but I personally like the way the LNC looks on huge/6" Jconcepts Ruptures. It can damn near drive upside down with tires that tall! Hot Bodies/HPI recently announced a new version of the old Rovers which are a more reasonable size at ~5.5" tall. RC4WD Bully pin tires are in the same ballpark for height while being a bit narrower. If you run on varied terrain (not just rock) I'd opt for a lugged tire (such as the Rovers or Ruptures.)

Again, I'm no expert on these cars, but I've spent a good bit of time setting up/ running/ making parts for them.

[goobs]

You can also scour the internet for the 21t worm gears. those help a lot too.

[CM9000]

10.5 or 13.5 sensored brushless setups are the best power plants for these rigs. the wheelspeed when you need it and no overheating issues. I know a guy who runs a 13.5 on 6s in his scale rig but that's another topic lol...


so your cheapest bet is some used motor from the racing world and a newer used castle sensored esc. a 17.5 might not be too bad on 3s if you gear it up just a little.

finding the 21:1 gearsets are not as easy. out of my 9 rigs ive only got 1 set of 21:1 axles. < I only use them in the front.

make sure your axles are greased regularly. if you have the comp version of the driveshafts, see if you can get a set of the lnc ones. they are lighter.

check out my time only build in this section. there are some very basic modifications I made using only a dremel and most available parts on the market today. also take some time and read through som popular losi shafty builds on here.


either way, if you want to stay brushed, I think team brood has a cheaper brushed motor you might be able to use. I wouldn't use any cheap off the shelf brushed motor because you might just end up burning up the brushes every 7 runs. maybe the traxxas 12 turn might work? you really need a low turn motor for these rigs. they need rpm's more than they need torque.

[QuesoDelDiablo]

Careful though, if your diffs aren't well greased I've seen the worms gears get hot enough to melt the axle housing when they spin too fast...

[hoghead5150]

I always went brushless. A lot less motor failure going that route. The old Novak crawler 18.5t was good, but the seeet spot is a 13.5t brushless. On 3s it’s almost perfect, and if you need any more wheelspeed you can bump up to 4s. The worm gears are getting easy to find now, the 21t worms come stock in the se. most online places I checked have them in stock. I only run the 21 in the front to help overdrive it and aid in steering.

[Justheman80]

Mine is the 2.0 version which has the 21tooth gears stock front and rear. I have also done the grease port mod, weighted the stock tires & wheels, running softer springs.

Will look for your our build.

[Tib]

LOSA3187 is the part number for the HD 21T gears. You can find them just about everywhere. Since the 2.0 and SE’s came out they have them back in production


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[dentonmac]

Don't know how this is not more out in the LNC Community. I have been having great success with this simple LNC tranny mod.

I am running a 14-15T pinion (I think), 17.5 on 3s, and at the comps it makes people say 'Dang, that is a Losi?'

Runs cool, and I have not found a loss in bottom end. It think I pushed it up to an 18T and still found no depreciable loss. But the top end is MUCH better, and the slow is still great. More compact footprint. I really think it is due to being able to run such a small pinion. Also really brings the brushed motors back into play as a viable option that IMO was not there before.

And, if you don't like it. New LNC tranny gears are ~$6.

I have done it to my sportsman (brushless, 17.5 crawler, 3/4s), Class 2 (brushed, 35T, 3/4s), and Class 1 (brushless, 17.5 crawler, 3s).

Also I was told (have not done it yet) that the HR gears it is a simple press out of the idler gear you don't need. I still run the plastic shaved down idler with nary a problem. I also think that it is good to have a 'weak link'.

Originally Posted by JENS

Have some plans for a new chassis next season .
New chassis means "new" transmission and a more normal driveshaft angle/placement
My current tranny has a 3,67 ratio,-have been tinkering with the LNC tranny and came up with this more compact 3,33 ratio LNC solution :







Motor is only for mock-up

[dentonmac]

Sorry for double posting but this is a quote in my old thread from the person that originally did the mod.

Originally Posted by JENS

Any smaller than 15t would require more extensive work on the motorplate,- I think

18t after the mod equals about 30t with stock LNC......

There is a good example of the the speed gains.

[Justheman80]

You have a links to that page in the thread?

Thanks for the input.

[dentonmac]

Originally Posted by Justheman80

You have a links to that page in the thread?

Thanks for the input.

Just click the blue arrow (>) to the right of JENS name in the quote and you will be taken to that thread. Like the one next to your name just above.

It is a comp based build, but a really good thread.

If you are looking for speed, that will get you more. BUT, in reality the worms were not designed to run for long periods of time at high RPMs.

I have been running the Losi driveline for many, many years, and love it. Dusted the ol' girl off for a few comps this summer. Really put a scare on some of the young bucks that compete on the national level. Had many questions. Funniest was, 'Wait...what...that's a Losi? Wow!'

[Rattzo1]

Originally Posted by dentonmac

Don't know how this is not more out in the LNC Community. I have been having great success with this simple LNC tranny mod.

I am running a 14-15T pinion (I think), 17.5 on 3s, and at the comps it makes people say 'Dang, that is a Losi?'

Runs cool, and I have not found a loss in bottom end. It think I pushed it up to an 18T and still found no depreciable loss. But the top end is MUCH better, and the slow is still great. More compact footprint. I really think it is due to being able to run such a small pinion. Also really brings the brushed motors back into play as a viable option that IMO was not there before.

And, if you don't like it. New LNC tranny gears are ~$6.

I have done it to my sportsman (brushless, 17.5 crawler, 3/4s), Class 2 (brushed, 35T, 3/4s), and Class 1 (brushless, 17.5 crawler, 3s).

Also I was told (have not done it yet) that the HR gears it is a simple press out of the idler gear you don't need. I still run the plastic shaved down idler with nary a problem. I also think that it is good to have a 'weak link'.

.
Yes the HR gears pull right apart if you want more wheel speed this should be your first mod ! You can check out my thread I did a lot of the mods that are from this site with no fancy tools or shop . The hardest part is sourcing the parts . My thread is “where do I go from here”