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Old 09-18-2015, 05:29 AM   #256
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Originally Posted by fyrstormer View Post
Most people don't need to upgrade out of the box. You're an enthusiast, as evidenced by your participation on this forum. Your expectations are higher than the average RCer.

Anyway, it sounds like your steering is binding. Disconnect the steering from the servo and start feeling around for where the binding is happening. It might just need a set of ball-bearings in the steering bellcranks, like my Nitro RS4 did.
For the most part you are correct. This is the first vehicle of the 70+ I've owned that has a "must upgrade". The dog bone issue is unacceptable. Add the heavy body that effects how it drives. With oversized tires that limit replacement options.
The vehicle is flawed. The sealed drivetrain is nice. But doesn't excuse the out the box issues.
I've also got steering issues. Not just the tiny rocks getting under bell crank. Car almost has bump steer. When trying to drive straight it will pull to left or right sometimes. With mine if I push up on ft/rear arms, they flex. Push up on the front of an arm, it bends. Not like any other road car I have.
To me it seems that it was built with form, not function as priority.
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Old 09-18-2015, 06:08 AM   #257
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Hi all, never would I have thought I'd pick upon entry level RTR 1/10 touring after owning 3 brushless sprints setup for different purposes as well as a couple of nitro rs4's.

Saw the new improved Sprint 3 chassis, and compared it against the Tamiya TT-02S, Tamiya XV-01 Pro, TC4 club racer roller, and a few FT TC3 used rollers.

My gf wants to partake in my monthly speed runs and parking lot blasting. Usually I let her drive my basher Slash 4x4 LCG Ultimate Platinum with a bunch of durability mods to handle the MMP/2400kv system on 4s all day. She wants a durable car and me being very familiar on the Sprint 2 and rs4 for so many years I figure why not grab another....especially the flux at $250 off eBay NEW!!

Out of the box I'll definitely upgrade the servo first...then plan on CVD's which I assume are 24mm? Any brands to look into? Usually I go with GPM for on-road CVD's.
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Old 09-18-2015, 07:58 AM   #258
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Default Dog bone update

I called HPI customer service this morning about the dog bone issue I am having with my sport 3 and they have a update with 46.5 millimeter dog bones they are sending me to for FREE will try it out and hope for the best
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Old 09-18-2015, 09:44 AM   #259
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Hello to all!

I was thinking of getting this car as a trainer car.

How is it compared to the TC4 assuming that the RS4 Sport 3 doesn't come with electronics?
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Old 09-18-2015, 01:54 PM   #260
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Originally Posted by DeKuryente View Post
Hello to all!

I was thinking of getting this car as a trainer car.

How is it compared to the TC4 assuming that the RS4 Sport 3 doesn't come with electronics?
Eh? All the RS4 Sport 3's I've seen are all RTR. As just a parking lot runner and possibly rally and drift setups, it seems the stock power plant is okay.

I'd upgrade the servo of course. Radio is completely up to your choice.

Does anyone know if the Flux version and the regular brushed version have any differences in differentials or drivetrain?
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Old 09-18-2015, 01:55 PM   #261
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Originally Posted by Normajean View Post
I called HPI customer service this morning about the dog bone issue I am having with my sport 3 and they have a update with 46.5 millimeter dog bones they are sending me to for FREE will try it out and hope for the best
Old school cheap way was to fit o ring grommets from servos with a dab of grease I to the outputs lol!
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Old 09-18-2015, 02:44 PM   #262
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Originally Posted by DeKuryente View Post
Hello to all!

I was thinking of getting this car as a trainer car.

How is it compared to the TC4 assuming that the RS4 Sport 3 doesn't come with electronics?
Second person to ask with 2 pages. It's not even close to a TC4. And only comes as RTR unless rollers are starting to show up on eBay.
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Old 09-18-2015, 03:21 PM   #263
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Originally Posted by Endaar View Post
There are certainly some good qualities about the car, primarily the sealed drivetrain. But while having the ability to upgrade is great, you shouldn't need to do so out of the box. There are some significant issues with the car, especially the front dog bones, and I'm personally quite disappointed.

As far as easy to fix...I'll throw this out there. I cannot get the steering working well. I have added the Tamiya CVDs, adjustable toe and camber linkages, stronger servo (SF-50WP), and tried both with the stock 31mm (Flux) wheels and standard 26mm TC wheels. I've also tried removing the servo saver.

With all that done, the car will initially track straight, but when I turn even a little, the car continues to head in that direction after I return the wheel to center. It's pretty easy to see this happen even on the bench; the wheels struggle to center, so they always end up continuing to point in the direction of the prior turn.

Other than blaming a sub-optimal steering assembly/layout, I'm not sure what's wrong. And right now this is the biggest thing keeping me from being happy with the car. Any thoughts?

Completely unrelated, if anyone is curious, the 911 body I linked earlier needs 6mm offset rear wheels and 0mm offset fronts to look right.

Endaar

The only issue I've had with binding is that some of the lots I run have quite a bit of grit and gravel and every now and again one will wedge itself in the steering mechanism..but other than that I've not had many issues like you've stated..and I'm still running an entirely stock car, except I swapped the RX/TX from the tf11 to the tf40 since I had one laying around out of my savage(just the radio change made a big difference), put on foam tires,and put adjustable links in the front.
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Old 09-18-2015, 06:01 PM   #264
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Originally Posted by Billy Kelly View Post
For the most part you are correct. This is the first vehicle of the 70+ I've owned that has a "must upgrade". The dog bone issue is unacceptable. Add the heavy body that effects how it drives. With oversized tires that limit replacement options.
The vehicle is flawed. The sealed drivetrain is nice. But doesn't excuse the out the box issues.
I've also got steering issues. Not just the tiny rocks getting under bell crank. Car almost has bump steer. When trying to drive straight it will pull to left or right sometimes. With mine if I push up on ft/rear arms, they flex. Push up on the front of an arm, it bends. Not like any other road car I have.
To me it seems that it was built with form, not function as priority.
I agree completely on all points.

With regards to the steering...I took the whole front end apart earlier today. Anywhere it was even possible something was binding I used the dremel to grind out some extra clearance. I cleaned the bearings, lubed everything, etc. The steering rack is definitely not binding. It seems to me the steering linkage is just poorly designed. I don't even think it is bump steer as the problem is clearly visible with the car stationary.

Check out this video. (You may need to download and then view; it wouldn't play in the browser for me.)

On the left is the Sport 3, with standard TC tires, an upgraded SF-50 servo, and CVDs. On the right is an RS4 Pro 3 Nitro SS, bone stock, with the same tires, and an SF-1 servo comparable to the standard one in the Sport 3.

Notice how the Sport 3 rarely finds center, while the Pro 3 always does.

https://onedrive.live.com/redir?resi...nt=video%2cmp4

I don't see any way to fix this. Are some of you not experiencing it, or are some of us just more sensitive to it?

Endaar
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Old 09-18-2015, 09:01 PM   #265
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Originally Posted by Endaar View Post
I agree completely on all points.

With regards to the steering...I took the whole front end apart earlier today. Anywhere it was even possible something was binding I used the dremel to grind out some extra clearance. I cleaned the bearings, lubed everything, etc. The steering rack is definitely not binding. It seems to me the steering linkage is just poorly designed. I don't even think it is bump steer as the problem is clearly visible with the car stationary.

Check out this video. (You may need to download and then view; it wouldn't play in the browser for me.)

On the left is the Sport 3, with standard TC tires, an upgraded SF-50 servo, and CVDs. On the right is an RS4 Pro 3 Nitro SS, bone stock, with the same tires, and an SF-1 servo comparable to the standard one in the Sport 3.

Notice how the Sport 3 rarely finds center, while the Pro 3 always does.

https://onedrive.live.com/redir?resi...nt=video%2cmp4

I don't see any way to fix this. Are some of you not experiencing it, or are some of us just more sensitive to it?

Endaar
The video helps a lot. You can see the servo is not returning to center. It's off a couple of degrees each time you turn so I wouldn't necessarily blame the steering parts- servo does sound pretty slow and weak Is it the stock servo and is the battery charged up so that the servo gets enough power and did you tighten down the spring nut on the servo saver?
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Last edited by MikeR; 09-18-2015 at 09:49 PM.
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Old 09-19-2015, 01:45 AM   #266
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Hi guys,

I got mine today (sport 3 flux Porsche) and I immediately changed the dog bones with the spec-r cvds. I also fixed the body because when steering the tires were touching the body.

One problem so far: I wanted to check the motor and pinion gear mesh but I m not able to remove the screw Z353 with the 2mm allen wrench. When I try to spin the screw the allen wrench spins forward and Im not able to open it. Its like if the 2mm allen wrench doesnt fit or the screw is damaged.

Any ideas?

Thanks!
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Old 09-19-2015, 07:08 AM   #267
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Hi guys,

I got mine today (sport 3 flux Porsche) and I immediately changed the dog bones with the spec-r cvds. I also fixed the body because when steering the tires were touching the body.

One problem so far: I wanted to check the motor and pinion gear mesh but I m not able to remove the screw Z353 with the 2mm allen wrench. When I try to spin the screw the allen wrench spins forward and Im not able to open it. Its like if the 2mm allen wrench doesnt fit or the screw is damaged.

Any ideas?

Thanks!
Well HPI thank God finally went hex hardware with their third Sprint chassis!! If you're having problems getting a screw out the try heating the screw head with a heat gun for 2 minutes the use a sharp if possible fresh driver (maybe the L driver that came in the box) and lightly hammer the driver in so that it is completely into the head of the screw the. Gently apply pressure. Don't round out the screw...sometimes those RTR kits get a little too gun ho with loctite!
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Old 09-19-2015, 07:14 AM   #268
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Which cvd's are you guys running on The Sprint 3?

I plan to bash not race and I'd hate to lose dog bones every few runs!

Cheapest I found were Tamiya 46mm....will these work?
http://www.spec-r.com/default/index....roducts_id=357
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Old 09-19-2015, 02:29 PM   #269
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Originally Posted by alexchen86 View Post
Which cvd's are you guys running on The Sprint 3?

I plan to bash not race and I'd hate to lose dog bones every few runs!

Cheapest I found were Tamiya 46mm....will these work?
http://www.spec-r.com/default/index....roducts_id=357
Correct.
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Old 09-19-2015, 05:44 PM   #270
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Originally Posted by MikeR View Post
The video helps a lot. You can see the servo is not returning to center. It's off a couple of degrees each time you turn so I wouldn't necessarily blame the steering parts- servo does sound pretty slow and weak Is it the stock servo and is the battery charged up so that the servo gets enough power and did you tighten down the spring nut on the servo saver?
This is HPI's strongest servo, the SF-50WP. The stock servo did the same thing which is what prompted an upgrade.

I just checked the voltage the receiver is sending to the servo, and it's 6V as expected. What am I missing?
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