Why can't a crawler also be genuinely fast?

[Greatscott]

RC is an RC is and RC...

The very things we seek out to make the crawler crawl well, or make it look scale, are those very things that make it a bad choice to go fast. One of the main things, tires... Crawler tires are made to be more or less soft and gooy, at higher speeds they become unstable because of balancing issues. At even faster speeds they turn into pancakes.

[kurpis]

Great points!

[$uicide $hift]

Scale driving was mentioned. The fastest I could get my Jeep JL to go on the highway was 110. It just would not go not faster than that. So 11MPH is actually very scale for a crawler even though most say it is too fast.

Currently I have the AXE 550 3300kv on 3S in my SCX10.3 and it does 13MPH in second gear. It is fun to see it whiz across the field but at full speed don't touch the steering wheel! I slow to at least half speed if not more to turn before gunning it in a straight line again.

Now imagine if I am in my 1:1 JL at 110 and decide I want to rip around a corner...... Yea that will not go so well same as in a 1/10 at 11MPH.

So bottom line is you can make it go 10, 20, 30, MPH but it is built for off road and it is not going to turn at all going those speeds same as a 1:1 would not do well at the 1:1 speeds.

I am all for ripping a crawler. It brings a smile to my face. I only have this going this fast as I am waiting on the transmission gears that are 1:7 reduction and then I may need to actually move up in pinion size. For now though I do rip it but only in a straight line as any 1:1 or 1/10 off road vehicle built for rock crawling is not going to turn at speed.

**EDIT**

One last thought. I can take a 1:1 Jeep and build it in a way that makes it have better handling at speed but then it would not be as good at rock crawling. If you want a rock crawler but also speed you may want to look into the Element Enduro as it has an IFS kit you can install. That will give you a bit more stability at speed. You could lower it, push the wheels out wide and install the IFS kit. This would handle speed better than a pure rock crawler and still be able to do some rock crawling albeit not as good as a dedicated rock crawler built for it. You can put a Jeep body on it or whatever body you prefer and have a rock racer, basher, rock crawler all in one. It won't do all of those great but could be what you are looking for. Scale looks and jack of all trades but master of none.

[Voodoobrew]

I have a 2 speed trx4 bronco with a HH puller 2200kv std motor on a mamba x. I changed the pinion to a 9t. I usually run it with a 4s battery but a 3s will work just fine. I also have a wiring harness to run 2 3s batteries in series to get 6s. On 6s it is very fast, it will pop wheelies and do barrel rolls down the street no problem. On 6s it wore off the trailer hitch receiver in about 5 minutes from all the wheelies. It can still do wheelies on 4s but it is much more manageable to control because it has a high center of gravity and loose suspension for crawling. I would recommend this setup for anyone.

Edit: I have no idea what the tip speed is because there is no way i would put my $1000 phone gps in this death trap. Nor can I actualy say that I have ever had it at top speed with out it crashing.

[$uicide $hift]

Originally Posted by Voodoobrew

I have a 2 speed trx4 bronco with a HH puller 2200kv std motor on a mamba x. I changed the pinion to a 9t. I usually run it with a 4s battery but a 3s will work just fine. I also have a wiring harness to run 2 3s batteries in series to get 6s. On 6s it is very fast, it will pop wheelies and do barrel rolls down the street no problem. On 6s it wore off the trailer hitch receiver in about 5 minutes from all the wheelies. It can still do wheelies on 4s but it is much more manageable to control because it has a high center of gravity and loose suspension for crawling. I would recommend this setup for anyone.

Edit: I have no idea what the tip speed is because there is no way i would put my $1000 phone gps in this death trap. Nor can I actualy say that I have ever had it at top speed with out it crashing.

With that 2200kv motor and a 6S battery using 9T pinion you should be at around 15.5 MPH full throttle in 2nd gear and about 9.5 MPH in first gear.

Yea 15MPH sounds slow but when it is a 1/10 vehicle doing that 15MPH it is like a 1:1 doing 150 . So yea that is fast!

[Dangerfirst]

I think a scale-ish jeepspeed build or a U4 chassis would be your best bet for speed and crawling ability. I'm with the consensus here that the crawlers we build are not made for speed. Scale certainly comes into play, because 60mph at full scale is hard to maintain at 1/10 scale in a crawler with locked diffs and soft tires. There has to be a compromise somewhere, because you can only capture so much realism in this hobby. If you want to use a TRX4 as a base, it might be hard to attain but it couldn't hurt to try.

[Voodoobrew]

Originally Posted by $uicide $hift

With that 2200kv motor and a 6S battery using 9T pinion you should be at around 15.5 MPH full throttle in 2nd gear and about 9.5 MPH in first gear.

Yea 15MPH sounds slow but when it is a 1/10 vehicle doing that 15MPH it is like a 1:1 doing 150 . So yea that is fast!

No idea where you got your numbers for 15 mph from but they are low. 20mph minimum I'm sure, probably pushing 25mph.

Also the ofset you have between first and second gear is incorrect, first gear is never half as fast as second in the trx4 stock transmission. first gear is 2/5th of second gear. You can check it in my gearing chart or read the manual.

[Voodoobrew]

I probably get 15mph on 4s. Thats plenty fast for me. Since I'm really just a crawler guy and not a speed demon I won't be spending money on a gps to find out the actual speed, but mathematically without considering weight, voltage drop and drag on 6s is 24.24 mph on the stock 1.9 canyons.

9t second gear ratio is 31.60:1 so (2200rpmx25.2v)/31.6 gear reduction =1,754.43rpm at the wheel
1.9 canyon tires are 4.65in tall so 4.65/12 inches to feet x 3.14 pi x 60/5280 feet to mph conversion x 1,754.43rpm = 24.25mph

Basically it's not safe for human use becase going 242mph in a lifted Bronco on 35in tires is not endorsed by highway patrol, not even a little bit.

[vinnieb729]

Originally Posted by Voodoobrew

Basically it's not safe for human use becase going 242mph in a lifted Bronco on 35in tires is not endorsed by highway patrol, not even a little bit.

[kurpis]

Originally Posted by Dangerfirst

I think a scale-ish jeepspeed build or a U4 chassis would be your best bet for speed and crawling ability. I'm with the consensus here that the crawlers we build are not made for speed. Scale certainly comes into play, because 60mph at full scale is hard to maintain at 1/10 scale in a crawler with locked diffs and soft tires. There has to be a compromise somewhere, because you can only capture so much realism in this hobby. If you want to use a TRX4 as a base, it might be hard to attain but it couldn't hurt to try.

Makes sense. I appreciate that you took the time to weigh in. Thanks.

[kurpis]

Originally Posted by Voodoobrew

I probably get 15mph on 4s. Thats plenty fast for me. Since I'm really just a crawler guy and not a speed demon I won't be spending money on a gps to find out the actual speed, but mathematically without considering weight, voltage drop and drag on 6s is 24.24 mph on the stock 1.9 canyons.

9t second gear ratio is 31.60:1 so (2200rpmx25.2v)/31.6 gear reduction =1,754.43rpm at the wheel
1.9 canyon tires are 4.65in tall so 4.65/12 inches to feet x 3.14 pi x 60/5280 feet to mph conversion x 1,754.43rpm = 24.25mph

Basically it's not safe for human use becase going 242mph in a lifted Bronco on 35in tires is not endorsed by highway patrol, not even a little bit.

So a 1/10 RC truck that hits 50mph is in theory going 500mph?

[Voodoobrew]

Originally Posted by kurpis

So a 1/10 RC truck that hits 50mph is in theory going 500mph?

Yes. But mass is different, that's why when you see them in slow motion video they look more realistic.

https://www.youtube.com/watch?time_c...ature=emb_logo

[themountain]

Originally Posted by kurpis

So a 1/10 RC truck that hits 50mph is in theory going 500mph?

well...not really

https://forums.traxxas.com/showthrea...ue-Scale-Speed

[Voodoobrew]

(D/T) * 3600/5280 * S = smph
Where D is the distance measured off (in your example, , in actual feet
T is the time the train takes to cover the distance in seconds
S is the scale factor - for N, 160; for HO 87.1, for O, 48; etc.
http://cs.trains.com/mrr/f/88/p/133525/1499636.aspx

So if you go an actual 10 miles in 1 hour
(52800/3600) * 3600/5280 * 10 = 100

I don't know what math your calculater uses...

__________________________
Handy gearing spreadsheet

[Inspector86]

To the OP, I would recommend you actually buy a truck and drive it before making plans to upgrade something you don't currently have. The TRX4 is probably the best suited for the way you have said you want to drive it.

[kurpis]

Originally Posted by Voodoobrew

Yes. But mass is different, that's why when you see them in slow motion video they look more realistic.

https://www.youtube.com/watch?time_c...ature=emb_logo

Great video.

[kurpis]

Originally Posted by Inspector86

To the OP, I would recommend you actually buy a truck and drive it before making plans to upgrade something you don't currently have. The TRX4 is probably the best suited for the way you have said you want to drive it.

My question was more theoretical than anything else. I'm content with my crappy RGT Rock Cruiser and just on here in the newbie general section to learn the ropes. That said, your advice was on point. Thanks!

[mauric6943]

Great post with lots of useful information as I've had the same question as I try to decide on my first rc.

This thread is pre Axial Ryft. Wonder if that vehicle, stupid fast and has some crawling capabilities, changes anything?

Sent from my SM-G970U using Tapatalk

[lonleycreeper]

Ryft to Crawler Possible ?

the discussion is here. I tried...

[Gula]

Lol, there's always Traxxas's summit, ot the LT conversion with slayer arms