gridMENSCH

Hi I have a question regarding gearing; i have finished building a totally stock xv-01, but have a circa 4000kv motor on the way for it. I realise that might be a bit extreme, and don't want to go a million miles an hour, but this is my first car so I didn't want it to feel underpowered when i first pull the trigger. So my question is this; with a motor like that can I leave the gearing as it is, or can someone recommend me a different and more appropriate ratio?

thanks for your time.

4roller

I am running a 13.5t HobbyWing motor, which the manufacturer equates to a 3000kv motor. The equivalent 4000kv motor would be a between 8.5 and 10.5t motor. This should be manageable if you don't floor it everywhere. I'd suggest the slipper clutch along with some 48pitch pinions as your next upgrade.

When I first got my car, I too wanted to tone it down until I was used to the car. Your radio should have a setting to limit maximum throttle. I think this setting is sometimes labeled EPA. I'd say, start at 65% and then turn it up when you feel more comfortable.

I have the slipper clutch with my car, as I skipped over the stock mod (metric?) gearing. The slipper clutch has a 77t 48pitch spur and I've started at a 23tooth pinion and have moved up to a 29tooth.

Best of luck. Don't strip your gears if you hear clicking, tension the belt some more.

gridMENSCH

Hi, thanks for your answer. To be perfectly clear, does this mean it'll work from a purely technical point of view and not struggle to take off or whatever, if I just drop it into a stock build?

gigaplex

iTrader: (2)

If you're using the 68T spur and 22T pinion, that's an FDR around 8. If anything you'll have tons of wheelspin, it shouldn't bog down.

fyrstormer

iTrader: (1)

I have a 4000KV motor in my rear-motor XV-01 touring car. With 36/77 gearing it goes 45mph.

4roller

You will have an excess amount of torque and top end rpm with a 4000kv motor. With stock gearing you will have enough power to spin tires (if you want) and go fast (if you want.) No bogging.

If you limit your EPA (transmitter max for throttle, channel 2), it should only limit your maximum speed.

fyrstormer

iTrader: (1)

No touring car will struggle on takeoff with a 4000KV motor. Touring cars don't weigh enough. Remember, the 540 motor size was chosen for touring cars back when RC motors were all silver-can disposable brushed motors, and brushless motors are vastly more powerful at the same size.

gridMENSCH

Thanks for all of your help, I'll look into the slipper gear but at the moment I think I've spent enough on the thing without running it I'll replace and upgrade as things break or need work.

Raman

iTrader: (94)

the slipper is useful when you are taking jumps and powering through the jumps / not releasing the throttle.

If you're running on asphalt / Tarmac / dirt you don't need a slipper, it will only add weight to the drive train.

I've owned my XV since it first come out, motor has ranged from 17.5 to 10.5 boosted. Jumped it on 1:8 scale off road track, raced it on a 1:5 scale on road track (10.5 boosted), driven in ice and snow and have yet to blow a single gear.

fyrstormer

iTrader: (1)

The slipper is also useful for letting you run commonly-available 48-pitch gearing without having to order Kawada spur gears from overseas, and depending on your running conditions it's also useful as a traction control measure. My FWD rally car would be hopeless without a slipper clutch.

Raman

iTrader: (94)

There are plenty of 48p on road style gear options available domestically, such as kimbrough, robinson racing..

http://www3.towerhobbies.com/cgi-bin...?&I=LXCBLP&P=7

http://www3.towerhobbies.com/cgi-bin...?&I=LXEY44&P=7

These all work with the XV01 spur gear hub.

4roller

While we are on the topic of gearing. I have been looking up how to get this cars FDR down to competition spec. I see a lot of posts saying you want you gearing down in the high 3.X to low 4.X (eg, 3.7-4.3)

The only way to achieve such ratios is, a smaller spur and larger pinion.

By my research, fyrstormer has stated in his other xv-01 posts that the maximum pinion size that will fit under the dust cover without modification is a 38T in 48P.

In another forum post, the maximum size for a spur to fit under the dust cover without rub is 79T in 48P.

In yet another post (fyrstormer again) states that the minimum tooth combination (sum of pinion and spur), should be around 100, maximum was I believe 116 (correct me if I am wrong)

In another posts I could only find 2 manufacturers that make spurs compatible for the hexagonal slipper design. Tamiya (77T, 79T) for the off-road buggy trf201. And Jconcepts silent spurs (69T-82T?) Made for the Team Assosiated B4.X cars.

That being said, using this site, which calculates FDR, we can achieve 4.72, which is still a little short of the target FDR.
Xv-01 gearing chart

On top of that, I could only find a 72T in 48P available on the internet. 69T spurs seem to be out of stock.

So if I was going to get my fastest ratio, with the slipper, it would be a 72T/38T FDR of 4.93. which is much taller than my current set up of 77T/29T FDR of 6.9

Go speed!

Any comments or suggestions as to get some different brand hex slipper spurs would be great! I did see fyrstormer's awesome hack to get standard spurs with foam nuggets to fit inside the slipper.

I'd like one day to take this to a track and try to achieve some good zippy speed by utilizing high punch settings without spinning out. In fact, just having these lower ratios will achieve less wheelspin magic.

What ratios were you guys running when racing at the track?

Raman

iTrader: (94)

4Roller, to get down to FDR of 3.7 or so, you would need to switch to 64pitch gears. My last set up sheet for the XV01 I was running a 82T / 48T 64 Pitch gear.

These are 64 pitch I use

Spur

http://www.tqrcracing.com/shop/produ....asp?p_id=9312

Pinion

http://www.tqrcracing.com/shop/produ....asp?p_id=7773

To my knowledge, there are no 64 pitch gears designed for slippers.. so you would need to use the solid hub with these gears.

4roller

Would these fit under the dust cover still?

I am wondering if I can just lock my slipper by sandwiching with a 64P spur. With no need to switch out to the solid gear.

Raman, what class were you running? Motor turn wise?

The closer I get to 3.6FDR, the more I can tune the esc, and motor can timing for optimal insanity.

Raman

iTrader: (94)

They do fit under the dust cover. The 64 pitch are smaller in diameter due to the finer teeth.

I was running my XV01 in RCGT class, which was a 17.5 motor / esc blinky.

As for locking the slipper, the challenge you would have is to perfectly centre the spur. The slipper spur gear have a small hole in the centre for the slipper shaft. The 64 p has a larger diameter to fit the standard spur hub.

Also keep this in mind as a general rule, the lower the fdr the less timing / boost.

You will run the risk of over heating your motor if you run an fdr of 3.5 plus 20% ESC timing and boost.. So be careful

The reason people gear to such low fdr is because those classes do not allow for any timing or boost by the ESC. ESC needs to be in blinky mode. Only motor end bell timing is aloud.