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Old 08-11-2016, 09:42 PM   #886
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So I finally got those $5 tires from China.

Pros:
For a complete set 4 pieces, the rubber, wheels, and foams are good. For bashing, street smashing, this is probably the best value per dollar, so far.

Cons:
Grip. The rubber is fine, but the profile of the tire is somewhat convex; Similar to that of a road bicycle tire. So only 70-80% of the tire is in actual contact with the surface. The foams inside might have an affect on this. If i ever get another set, I'd probably play around with cutting the foams so they aren't so pillow-y. After 2x5000mah packs ~1.5h of driving (hard, with donuts), the psuedo radial v-tread is almost gone, which then in essence make these slicks now There is however still quite of bit of rubber meat left. Who knows, maybe they will wear nice and flat.






Above are the Tires and Wheels I got from ebay for $5. (I know the tread is on backwards) They are almost worn out already so it wont matter

The Ride USGT tires are much more right angled at the edges, which helped with predictable cornering (IE, 4 wheel power slides). Whereas these convex profiled tires, are more likely to spin out in the back. Mind you I am testing them on some different streets. I am in Palm Springs for a couple of days (wife's company conference) drifting out on flat tarmac. Everything here has little pebbles and silty dust.

Today the performance of the car was, pretty good, but not as fun as the last couple runs. Probably because of convex-y tires are not as predictable. And also I am back to a sloppy front end because I replaced my busted carbon reinforced a-arms with the stock plastic and didn't bother to shim. It's so hot here. 105 Degree weather is heat soaking my motor and my face. Everything is slowly melting. I bet my motor was well over 175 Degrees after the all out turbo runs.

I need to find some way to cool down my motor. Would this do anything? Eagle Motor Heat Sink for XV-01


Last edited by 4roller; 08-11-2016 at 10:24 PM.
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Old 08-12-2016, 04:52 PM   #887
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So I figured out a better way to deal with the spin out with those tires. Every set of tires.changes the handling characteristics of the car. Especially if you keep you ESC settings the same. Here, when making a 180 degree turn, with these pillowy tires, the rear end would cut lose and occasionally spin out. My solution was to go into the ESC settings and dial down the punch rates.

My ESC (hobbywing v3.1) has a throttle threshold. Which is set to 50%. So from 0-50% throttle, the ESC delivers 15/30 punch rate (I think of it as torque). From 51-100%, the ESC will deliver 30/30 PR (max torque)

For a while I was driving max torque all the time, and you can easily infer that the tires were breaking lose on low throttle. After the change, the car is much more predictable and easy to drive. Love it.

I also tried setting the car to 30 degrees of timing and 24degrees of turbo. My Max RPM was 49000+ I didn't want to hold the throttle down with the car off the ground because I didn't want to find out if the CA glue would hold the tires on. I think this car can easily hit 45mph with those settings. I am not about to find out since my street is so narrow with a ton of parked cars.

Back to zero timing. Which has plenty of torque. And runs cool as Fk. I might not get the top end but at least I can handle the car.

Back to happy driving again.

Last edited by 4roller; 08-12-2016 at 09:38 PM.
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Old 08-12-2016, 08:46 PM   #888
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I am riding at 5mm ground clearance. I love it when it's slammed so low that it scrapes when the body rolls. #lowlife.

I got some 7mm wide wheel hex's. The stock ones are 5.5mm wide. Now the front wheels are flush, and the rear wheels are just a little inset into the body. Looks better. Handles pretty much the same.

I turned down my Radio TX CH.1 to 85%. This should help reduce spinout.

I also found out an even better way to manage heat and get crazy top end. Set your turbo to start at full throttle and at 15000 RPM+. Turn the turbo delay to 0.5s, instead of instant. This way even if you floor it (finger bang it?) It will still take 1/2 a second to engage, thus keeping you from running too hot.



Here is the tire wear since yesterday. I went out for maybe 3 more 5000mah runs. So the tires are slick, great traction. But again like the HPI X-partterns I had, the inner rim is where my tires seem to start wearing the quickest. I know not how to fix this. The rest of the tire (tread) is worn evenly. The pillowing is a lot less pronounced now, maybe that's why they hook up better.




I am also trying different springs. Softer than whites all around, seems to make the car handle more to my liking. Yellows up front, reds in the back. I might try reversing them too.
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Old 08-13-2016, 12:04 AM   #889
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I've never used an ESC with turbo. My ESCs are all set to zero timing; I've never noticed a difference advancing the timing on a brushless motor. I notice it plenty when adjusting the endbell timing on a brushed motor, though.

Those tires wore down crazy fast. Camber-out the suspension until the tires stop wearing prematurely on the inner edge. Remember, the built-in caster means, when cornering, the tires camber-in relative to the corner, so cambering-out the suspension won't actually reduce grip.

I like the look of that fan mount. I think I'll get one to have handy in case I ever switch any of my front-motor cars to brushless.
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Old 08-13-2016, 01:52 PM   #890
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Thanks for the suggestion. I cambered out just a hint. Tire wear is actually not as aggressive.

I used those drift wheels I made to guage the camber, it much easier to see when you wheels and tires are hard ABS plastic.

I posted in another thread about uneven tire wear. Basically exactly as you said, the built in caster affects the camber at turn in.

I also finally received my droop screws. I can't say for certain if its the droop screws, the camber out, or the esc reduction, that is keeping this car pretty stable. It is probably a combination of all of them.

Usually when I do slalom down the street, I will end up spinning out after 2 side to sides. Now the car is on point. I can slalom down the while street without washing out.

Magical.



Even though this is a toy car, it's quite interesting to see how these changes actually affects car handling.

Fyrstormer, have you messed around with the caster shims? I noticed that the kit comes with 3-4 different thicknesses. To reduce camber at turn, I would probably use the thinnest shim up front.

Just when you thought your car was dialed, you find another thing to tweak. Endless mucking.
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Old 08-13-2016, 06:47 PM   #891
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I don't worry too much about making sure the camber settings are equal left-and-right; I just dial them so the tires all wear as evenly as possible. I do my best to ensure toe is equal left-and-right, though, because otherwise the steering gets wonky.

I'm not familiar with shims used to adjust the car's caster. There are shims that go under the toe-blocks. You can put the same height of shims under the front and rear toe-blocks to change the axle's roll center, or more shims under the front toe-block to produce an anti-squat effect when accelerating (only really useful on the rear axle), but you can't use those shims to adjust the caster on the front wheels without also changing the anti-squat effect at the same time. Maybe someone has added pro-squat to the front axle to prevent brake-dive with all that weight hanging off the front, but I've never personally tried it. That would also have the secondary effect of reducing the caster.

The only suspensions I've seen that allow adjusting caster using shims are pillow-ball suspensions, where the upper suspension arms can be moved forward or backward on their hinge pins by moving shims on the hinge pins. The Traxxas E-Revo comes to mind. The normal lower-A-arm/upper-camber-link suspension design generally requires replacing the caster block to change the caster setting, and I don't think there are any optional caster blocks for the XV-01 that have different caster settings.

On my rear-motor XV-01, I have the rear axle's toe blocks shimmed to add some anti-squat since there's so much weight sitting on the rear axle. On the rest of my XV-01s I keep the toe blocks level.
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Old 08-13-2016, 07:42 PM   #892
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Caster is preset in these cars by the steering hub. The TC version uses the TC hubs and those are available on 4 and 6. The XV version is set at 6 I believe there are no other options.

The shims you're referring to are probably for altering camber roll centre. They are placed under the turnbuckles to vary the camber roll.
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Old 08-13-2016, 08:24 PM   #893
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Quote:
Originally Posted by Raman View Post
Caster is preset in these cars by the steering hub. The TC version uses the TC hubs and those are available on 4 and 6. The XV version is set at 6 I believe there are no other options.

The shims you're referring to are probably for altering camber roll centre. They are placed under the turnbuckles to vary the camber roll.

Hrm Raman, roll center is another adjustment I have not delt with. I will have to look into that.

I was talking about the shim under the hinge pin block. There is one in the front-front, and another one in rear-rear. I think they are anti squat shims. The go under the wide hinge pin blocks.

I saw a diagram which showed a kickup angle + steering hub angle, which accumulated to the caster angle. My thoughts were that by replacing that shim it would add or subtract from the kickup angle. But I guess it would affect more than just caster.

I had really thought about trying the parts for the Xv-01 TC. Although I'd need to research all of those part numbers, and see if it's worth the cost. What does this afford? More tuning options? Wider track? I'd probably have to buy DCJ Universal's, bearings and other things. Might not be worth it. Does anyone have the complete list of parts?

Right now the car is set up pretty good.

Aside:
I ran a whole pack drifting. Now I know what I said before. But I think the experience completely changes when you run drift with a body on the chassis. It looks cool. And... You don't wear out your rubber tires. Lol. Still not as fun as ripping with rubber, but a good alternative. And, the runtimes are crazy long. I bet drifting was made by people who were tired of paying for rubber and sick of low run times. Lol
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Old 08-14-2016, 08:57 AM   #894
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Correct, The spacers under the suspension raise and lower the roll centre of arms when is in conjunction / evenly. When used unevenly they act us pro-dive / anti-dive in front and pro squat and anti squat in rear.
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Old 08-14-2016, 12:45 PM   #895
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Quote:
Originally Posted by fyrstormer View Post
I've never used an ESC with turbo. My ESCs are all set to zero timing; I've never noticed a difference advancing the timing on a brushless motor.
Interesting, as the effect of both boost and turbo is quite significant when set correctly on a (sensored) brushless motor. I'm running 17.5t motor, which I would call "lazy" with default timing. However, with boost and turbo, the car is flying.

By boost, I mean function of my ESC which allows me to dynamically adjust timing within some range of RPMs. I start with no adjustments until I reach 4.000 RPMs, and then I'm adding 2 degrees every 250 RPM until +20deg. When I reach full throttle, I add another 20degs after 0.1sec. Only thing one has to watch is motor temperature (therefore I've just added telemetry). But so far, the motor was running pretty cool with these settings (probably because I'm reaching top speed only occasionally).
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Old 08-14-2016, 01:39 PM   #896
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Guys, one more question. I'm looking for 75mm shocks for the long damper stay. I'm thinking about Gmade XD, but I really like my current (slightly extended) 55mm TRFs. Are there any TRFs that would fit the long damper mod? Or can I rebuild some to fit (and give me enough travel)? Or are there some other shocks that would be better than the Gmades? Thanks!
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Old 08-14-2016, 02:24 PM   #897
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The shocks I'm using on my long-damper XV-01s are TRF shocks built with shafts from the long-damper CVA shock kit, and Yeah Racing 60mm bodies. They are the perfect size for the long-damper setup; they allow the A-arms to droop as far as the chassis allows.



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Old 08-16-2016, 01:29 AM   #898
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Nice, thanks. It seems that I need to buy complete YR shocks to get the bodies, as I can't find just the body anywhere, correct?
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Old 08-16-2016, 08:29 PM   #899
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That's correct, but the complete set of Yeah Racing 60mm shocks is less than the cost of TRF shock bodies from Tamiya, so...*shrug*

You can also save some money by building the Yeah Racing shocks using just the Tamiya long-damper CVA shafts, and not getting TRF shocks at all. They probably work just as well, I'm just really picky about using Tamiya parts whenever possible.
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Old 08-16-2016, 09:03 PM   #900
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By the way, the part number for the long-damper shock shafts is 50601.
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