167LikesTamiya XV-01
04-08-2016, 02:17 AM
#706
The plastic spacers allow for a wide range of adjustment in the wheelbase, roll center, anti-squat, etc. etc. etc. Lots of little tweaks you can make after you're "done" building one of these.
You don't have swaybars installed and the spur-gear cover isn't fitting properly. The swaybars are an essential upgrade for this chassis; all four of mine have swaybars installed in various configurations. My FWD XV-01, probably the best dirt-slider of the lot, has the thinnest swaybar installed in the front and the thickest swaybar installed in the rear -- the opposite of the other two that still have the motor mounted up front, but as it happens the thickest swaybar in the rear makes it slide marvelously. Tune the diffs to provide traction, and tune the swaybars to control chassis roll and to make the axles unload when you want them to.
Don't worry about the tie-rod ends hanging up on the chassis, you can bevel the lower edges of the tie-rod ends to make that less of a problem if you want, but it generally doesn't have any effect on the vehicle when it's supporting its own weight anyway.
Here are my two rally builds, for reference:
4WD: http://www.rctech.net/forum/electric...a-xv-01-a.html
FWD: http://www.rctech.net/forum/electric...-xv-01-ff.html
And my two on-road builds:
Rear-motor 4WD: http://www.rctech.net/forum/electric...a-rr-01-a.html
Front-motor part-time 4WD: http://www.rctech.net/forum/electric...01-sh-awd.html
You don't have swaybars installed and the spur-gear cover isn't fitting properly. The swaybars are an essential upgrade for this chassis; all four of mine have swaybars installed in various configurations. My FWD XV-01, probably the best dirt-slider of the lot, has the thinnest swaybar installed in the front and the thickest swaybar installed in the rear -- the opposite of the other two that still have the motor mounted up front, but as it happens the thickest swaybar in the rear makes it slide marvelously. Tune the diffs to provide traction, and tune the swaybars to control chassis roll and to make the axles unload when you want them to.
Don't worry about the tie-rod ends hanging up on the chassis, you can bevel the lower edges of the tie-rod ends to make that less of a problem if you want, but it generally doesn't have any effect on the vehicle when it's supporting its own weight anyway.
Here are my two rally builds, for reference:
4WD: http://www.rctech.net/forum/electric...a-xv-01-a.html
FWD: http://www.rctech.net/forum/electric...-xv-01-ff.html
And my two on-road builds:
Rear-motor 4WD: http://www.rctech.net/forum/electric...a-rr-01-a.html
Front-motor part-time 4WD: http://www.rctech.net/forum/electric...01-sh-awd.html
Last edited by fyrstormer; 04-08-2016 at 02:34 AM.
04-08-2016, 02:43 AM
#707
The plastic spacers allow for a wide range of adjustment in the wheelbase, roll center, anti-squat, etc. etc. etc. Lots of little tweaks you can make after you're "done" building one of these.
You don't have swaybars installed and the spur-gear cover isn't fitting properly. The swaybars are an essential upgrade for this chassis; all four of mine have swaybars installed in various configurations. My FWD XV-01, probably the best dirt-slider of the lot, has the thinnest swaybar installed in the front and the thickest swaybar installed in the rear -- the opposite of the other two that still have the motor mounted up front, but as it happens the thickest swaybar in the rear makes it slide marvelously. Tune the diffs to provide traction, and tune the swaybars to control chassis roll and to make the axles unload when you want them to.
You don't have swaybars installed and the spur-gear cover isn't fitting properly. The swaybars are an essential upgrade for this chassis; all four of mine have swaybars installed in various configurations. My FWD XV-01, probably the best dirt-slider of the lot, has the thinnest swaybar installed in the front and the thickest swaybar installed in the rear -- the opposite of the other two that still have the motor mounted up front, but as it happens the thickest swaybar in the rear makes it slide marvelously. Tune the diffs to provide traction, and tune the swaybars to control chassis roll and to make the axles unload when you want them to.
Yep the spur gear cover won't fit properly. I've been messing with it but for the life of me I could not get it to fit right.
I'll tune the diffs first before fitting swaybars. I want this thing to do large donuts on dirt, and it simply can't with the outside wheels transferring all forward traction to the inner wheels when cornering. It needs a limited slip effect to slide longer.
Here's another shot with my 1:1 GT86
04-08-2016, 02:53 AM
#708
I'm running 30k in the front diff and 10k in the rear diff in my 4WD rally build. I'm running a spool in my FWD rally build, for better traction with only two drive wheels. If you want more oversteer you can use thinner front oil and thicker rear oil than I did, but you really ought to see how the car handles with swaybars before making a final decision about which diff oil to use.
Trust me, after building four of these things I've learned that swaybars are a requirement. The shocks are too soft to control body-roll adequately, which is unavoidable because they need to be soft to handle running off-road. Too much body-roll causes the diffs to unload unpredictably.
If you don't have the 42mm double-cardan CVDs in the front, consider getting them; they allow you to achieve more steering angle, which has obvious implications for the car's ability to slide on dirt. With the double-cardan CVDs, you can remove the steering-limiting screws that you had to install in the front caster blocks during the initial build.
Aluminum spacers are nice to have, I agree. It kinda sucks that the XV-01 doesn't come with them, but the carbon-reinforced-plastic spacers work just as well -- the carbon-reinforced plastic really is strong enough to do the job.
It is possible to build TRF-quality shocks for the long-damper setup, you just have to mix-and-match parts to do it. It's detailed in my 4WD rally build.
EDIT: Btw, what's happening isn't that the traction is being shifted to the inside wheels, it's that the *motor's torque* is being dissipated by spinning the inside wheels, which allows the outside wheels to *maintain* traction. The combination of the outside wheels maintaining traction, plus the inside wheels spinning and dissipating the torque that would otherwise keep the car moving, is what causes the powerslide to end sooner than you want. Thicker diff oil will force the outside wheels to receive more of the motor's torque, causing them to break loose, start spinning, and lose traction. You're right about how to tune the diffs to get the effect you want, but I thought a better explanation of what's actually happening might help.
Trust me, after building four of these things I've learned that swaybars are a requirement. The shocks are too soft to control body-roll adequately, which is unavoidable because they need to be soft to handle running off-road. Too much body-roll causes the diffs to unload unpredictably.
If you don't have the 42mm double-cardan CVDs in the front, consider getting them; they allow you to achieve more steering angle, which has obvious implications for the car's ability to slide on dirt. With the double-cardan CVDs, you can remove the steering-limiting screws that you had to install in the front caster blocks during the initial build.
Aluminum spacers are nice to have, I agree. It kinda sucks that the XV-01 doesn't come with them, but the carbon-reinforced-plastic spacers work just as well -- the carbon-reinforced plastic really is strong enough to do the job.
It is possible to build TRF-quality shocks for the long-damper setup, you just have to mix-and-match parts to do it. It's detailed in my 4WD rally build.
EDIT: Btw, what's happening isn't that the traction is being shifted to the inside wheels, it's that the *motor's torque* is being dissipated by spinning the inside wheels, which allows the outside wheels to *maintain* traction. The combination of the outside wheels maintaining traction, plus the inside wheels spinning and dissipating the torque that would otherwise keep the car moving, is what causes the powerslide to end sooner than you want. Thicker diff oil will force the outside wheels to receive more of the motor's torque, causing them to break loose, start spinning, and lose traction. You're right about how to tune the diffs to get the effect you want, but I thought a better explanation of what's actually happening might help.
Last edited by fyrstormer; 04-08-2016 at 03:06 AM.
04-08-2016, 03:21 AM
#709
You're right, it's the torque that's being transferred to the inside wheel. I got my words mixed up Okay I'll get the swaybar set and see how it handles with it.
The Pro comes with CVDs, so the steering angle limiting screw was ommited in the manual.
Okay I'll get the swaybar set and see how it handles with it. The Pro comes with CVDs, so the steering angle limiting screw was ommited in the manual.
04-08-2016, 04:16 AM
#710
Ah, okay. The regular CVDs are better than dogbones, of course, but they still rattle the front suspension in corners, because the "CVD" joints aren't actually constant-velocity. The outboard joints can compensate for the inconsistent rotational speed introduced by the inboard joints as the suspension moves up and down, but they can't do anything to compensate for their own inconsistent rotational speed caused when the steering knuckles turn. The double-cardan CVDs run much smoother because the double-jointed outboard joints compensate for themselves. It's a worthy upgrade if/when you get around to it, and Tamiya's steel is good enough that I haven't noticed any wear on mine despite running on dirt. You'll need to replace the inboard front wheel bearings with 5x10x3 (1mm thinner than stock), which you can get from Team Associated for a few bucks.
My first XV-01 started as an FF-04, so I already had the double-cardan CVDs, I just had to get the shorter 42mm axles to use with them so they would fit on the XV-01. It wasn't until I got my second XV-01 that I found out how much the regular CVDs rattle the front suspension. It doesn't matter nearly as much on vehicles with larger tires, but the small touring-car tires on the XV-01 don't have much inertia to smooth-out their own rotation. I now understand why high-end touring car kits all come with double-cardan CVDs in the front.
My first XV-01 started as an FF-04, so I already had the double-cardan CVDs, I just had to get the shorter 42mm axles to use with them so they would fit on the XV-01. It wasn't until I got my second XV-01 that I found out how much the regular CVDs rattle the front suspension. It doesn't matter nearly as much on vehicles with larger tires, but the small touring-car tires on the XV-01 don't have much inertia to smooth-out their own rotation. I now understand why high-end touring car kits all come with double-cardan CVDs in the front.
04-08-2016, 05:36 AM
#711
Tech Regular
Whoa! Thread's alive again! Woot!
I finished installing my stainless screws last night and the aluminum rear suspension mount. Front one is buried under the motor so that'll be a job for this weekend. I've still got a full sealed bearing kit and reinforced belt to install as well.
I finished installing my stainless screws last night and the aluminum rear suspension mount. Front one is buried under the motor so that'll be a job for this weekend. I've still got a full sealed bearing kit and reinforced belt to install as well.
04-08-2016, 01:00 PM
#712
Ah, okay. The regular CVDs are better than dogbones, of course, but they still rattle the front suspension in corners, because the "CVD" joints aren't actually constant-velocity. The outboard joints can compensate for the inconsistent rotational speed introduced by the inboard joints as the suspension moves up and down, but they can't do anything to compensate for their own inconsistent rotational speed caused when the steering knuckles turn. The double-cardan CVDs run much smoother because the double-jointed outboard joints compensate for themselves. It's a worthy upgrade if/when you get around to it, and Tamiya's steel is good enough that I haven't noticed any wear on mine despite running on dirt. You'll need to replace the inboard front wheel bearings with 5x10x3 (1mm thinner than stock), which you can get from Team Associated for a few bucks.
My first XV-01 started as an FF-04, so I already had the double-cardan CVDs, I just had to get the shorter 42mm axles to use with them so they would fit on the XV-01. It wasn't until I got my second XV-01 that I found out how much the regular CVDs rattle the front suspension. It doesn't matter nearly as much on vehicles with larger tires, but the small touring-car tires on the XV-01 don't have much inertia to smooth-out their own rotation. I now understand why high-end touring car kits all come with double-cardan CVDs in the front.
My first XV-01 started as an FF-04, so I already had the double-cardan CVDs, I just had to get the shorter 42mm axles to use with them so they would fit on the XV-01. It wasn't until I got my second XV-01 that I found out how much the regular CVDs rattle the front suspension. It doesn't matter nearly as much on vehicles with larger tires, but the small touring-car tires on the XV-01 don't have much inertia to smooth-out their own rotation. I now understand why high-end touring car kits all come with double-cardan CVDs in the front.
By the way I finally fixed the spur gear cover. Turns out I forgot to cut the excess flashing on the cover lol.
04-08-2016, 06:30 PM
#713
Interesting. I ordered the separate parts to build the double-cardan CVDs because I needed the shorter 42mm axles to use with the XV-01, and I didn't want to spend extra money on the 44mm axles I'd never use. So I had to get the bearings separately too. Whatever, as long as you're happy with it.
04-08-2016, 07:54 PM
#714
Tech Regular
04-09-2016, 04:45 AM
#715
04-10-2016, 08:56 AM
#718
Tech Regular
Well... The 86 anyway. They just won't break down and give us the GT name. Friggin' Toyota, man. I love em but they just... ARGH!!! Anyway... the 2017 86 will be getting a slight bump of 8... yes that's correct lads, 8 more horsepowers and Gazoo Racing has tweaked the suspension a bit. I hope it does well for them.
04-10-2016, 04:53 PM
#719
Ah, so they're not getting rid of the FR-S just because the Scion brand is going away. That's cool.
Honestly I think Scion was doomed the moment they redesigned the xB (which I say means "Xtra Boxy") to be fat and lumpy for the American market. If you're going to resell cars built for the Japanese market to foreign customers who like them, then at least sell *those exact vehicles* instead of screwing them up first. I might've gotten one of the original design if they'd stayed around long enough.
Honestly I think Scion was doomed the moment they redesigned the xB (which I say means "Xtra Boxy") to be fat and lumpy for the American market. If you're going to resell cars built for the Japanese market to foreign customers who like them, then at least sell *those exact vehicles* instead of screwing them up first. I might've gotten one of the original design if they'd stayed around long enough.
04-10-2016, 11:14 PM
#720
Well... The 86 anyway. They just won't break down and give us the GT name. Friggin' Toyota, man. I love em but they just... ARGH!!! Anyway... the 2017 86 will be getting a slight bump of 8... yes that's correct lads, 8 more horsepowers and Gazoo Racing has tweaked the suspension a bit. I hope it does well for them.
