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Old 03-11-2009, 03:10 PM   #1
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Default Kyosho st-rr and mp9 research..

Hello guys..

am just doing my own research and am writting down some things about the mp9 and st-rr for my own research.. am trying to see if i made the correct purchases and am trying to find out how to improve...

i dont want people to start taking the piece out of me but i know some will do..

i know it sounds bad to some and who ever feels my question is not worth reading am sorry...

i have already asked some experts these question but the answers are always fifty fifty..

There are a lot of drivers out there from all around the world that race in all kind of classes with big names to amatures..there are a lot of technical minds and a lot of experience from you people..

the two main cars of kyosho now is the mp9 and st-rr...

Question:How do you think these two cars can be compared to all other manufactares....From everyones experience in the tracks, where do you people think the kyosho car lack..and which car you think is better and why?

Thanks!!I wish you all a nice day!!
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Old 03-11-2009, 06:06 PM   #2
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The ST-RR has been great everywhere I have been. The only issue that I have is with bulkhead durability, the seat for the bearing starts to get wobbled out and throws off the gear mesh on the ring/pinion, if cought early, you just replace the bulkhead and you are fine, but if not, you can strip out the ring/pinion. My bulkheads only seems to last 3-6 races
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Old 03-11-2009, 07:43 PM   #3
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Quote:
Originally Posted by BIG RE View Post
The ST-RR has been great everywhere I have been. The only issue that I have is with bulkhead durability, the seat for the bearing starts to get wobbled out and throws off the gear mesh on the ring/pinion, if cought early, you just replace the bulkhead and you are fine, but if not, you can strip out the ring/pinion. My bulkheads only seems to last 3-6 races
Wow never heard of that..gonna have to keep an eye out The only problems i heard from othere about the ST-RR is the rear traction problem, the diffs, and expensive parts! And about it being competative with other manufactures is not a problem, it all driver...
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Old 03-11-2009, 09:23 PM   #4
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There were quite a few people around here who had that issue. Many of them have gone on to different truggies because of it
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Old 03-12-2009, 04:59 AM   #5
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Guys am taking down noetes..

the problem with the rear case is always there what ever shims you put?

i mean if you have the correct mesh again there is that problem?

like the mp9? because the mp9 also has that rear diff case problem...

as for the driving the best i have ever seen i think is the new losi 8t 2.0
but to say the truth i have never seen an st-rr driven by a good driver that spend time with it and had setups...

the 8t i saw was driven by the best driver in that track and it had a lot of practise...but the hadling and speed was very nice...
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Old 03-12-2009, 09:59 AM   #6
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I've ran the same ST-RR bulkheads all season last year. It's all about keeping an eye on the mesh and shimming accordingly. I run 10-15-2 in the diffs, and 45w/45w in the shocks with stock pistons and the truck is dialed everywhere. It's able to hold it's line better when being driven aggressively than any other truggy I've tried, which may or may not fit your driving style. Only issues I've found with the ST-RR is is slightly fragile c hubs, too flexible of a servo saver top, and inconsistent quality of the front arms.

As for the mp9, I dont have enough time on it to tell, but so far so good. Replace the rear pinion bearings with something high quality, and again, keep an eye on the mesh.

RC cars are like shoes....no one buggy/truggy will fit everyone best.
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Old 03-12-2009, 10:32 AM   #7
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+1 on the ST-RR bulkheads...no problems at all so far, but I'll certainly be watching them! I've also experienced some front arm breakage out near the hub carriers, which seems to be the area most vulnerable and less beefy on the arms. Ridley, are you running blue springs all around to go with your 45wt shock oil? My diffs are set at 7-10-2, with medium width hubs (11mm) up front and the wider (14mm) hubs on the rear. The truck is definitely hooked up with great traction, excellent cornering and stable jumping. I just have to learn how to drive it better and be more consistant...general operator error
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Old 03-12-2009, 12:52 PM   #8
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the mp9 if you see down and have a good look at it, it has a lot of good things.. for example the drivetrain is so light, when you turn the wheels keep spin for some time..the brakes are amazing quality, the shocks are also amazing, the towers are top notch.. the knuckles are cnc hard material most expensive in the market, the plastic i dont think is that good, the chassis is milled, the axles and all the drivetrain are smaller than mp777 significantly,

the engine is almost in the middle and everything is well balanced..

i havent seen and i havednt have any experience with an xray or a mugen but the mp9 seems a high quality car and i dont see the reason why some people say the mugen and the xray is more consistend and better than the mp9..

so there are alot of expensive parts on the mp9 and the problems are the plastic front a-arms and the diff which is now been fixed hopefully..


as for the st-rr i still need to do a lot of setups ..

what clutchbell shall i use for the os 28? i am currantly using the 15t
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Old 03-12-2009, 12:52 PM   #9
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Quote:
Originally Posted by rcgeezer View Post
+1 on the ST-RR bulkheads...no problems at all so far, but I'll certainly be watching them! I've also experienced some front arm breakage out near the hub carriers, which seems to be the area most vulnerable and less beefy on the arms. Ridley, are you running blue springs all around to go with your 45wt shock oil? My diffs are set at 7-10-2, with medium width hubs (11mm) up front and the wider (14mm) hubs on the rear. The truck is definitely hooked up with great traction, excellent cornering and stable jumping. I just have to learn how to drive it better and be more consistant...general operator error
I run a two stage spring I made myself, purple top spring, blue main spring. Before that, I ran yellow springs mostly, occasionally blue on high speed tracks. With my settup now i get the soft spring cornering characteristics at low speed and blue spring characteristics on high speed corners that compress the shocks further. I run 11mm hubs front and rear. I tried your diff settup last season but went back to what I posted, mostly due to my hammer fist style of driving the truggy. 7-10-2 is easier to drive, but i like the on power response of the thicker oils.
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Old 03-12-2009, 01:07 PM   #10
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Both diff case problems (STRR & MP9) are due to heat. The heat is generated because of lack of proper lubrication. (maintenance)

Kyosho ring gear grease is good but doesnt go far enough in heat range especially with the STRR. (Helical cut gears are less efficient and create more friction)

I suggest using Mobil 1 grease (black or red is fine, I happen to use red)

The last ring and pinion/bulkhead units I put in my STRR was 7-4-08 until just recently at the Nitro Challenge. Mobil 1 was used here.

With the MP9 I built the car 10-2-08 and changed diffs/bulkheads also at Nitro Challenge. I tried Eureka lube, but found more wear on the gears.


Don't be shy with the grease on the R&P. Our 1:1 counter parts have them bathed in 80/90wt for a reason.
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Old 03-12-2009, 01:39 PM   #11
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Racecrafter, you've got me a bit confused. Are you using the Mobil 1 grease inside the diff in lieu of diff fluid, or are you talking about applying some of the grease under the diff assembly directly to the ring gear before remounting the whole thing to the chassis?
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Old 03-12-2009, 01:50 PM   #12
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rcgeezer,

yeah thats what he means..

you have to apply some greasy at the ring gear and pinion gear mesh..you know the two are always in contact and movement..as the pinion gear turns the ring gear heat is generated due to friction and everything there starts to get warmer and warmer ..the first thing that will melt is abviously the plastic ..so the diff case starts to melt and all the gear mesh is gone and so the pinion and ring gear worn out.. by putting the mobil 1 grease Racecrafter suggested it will be the best choice for less friction to be generated and so less heat and no warm or melted diff cases..
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Old 03-12-2009, 02:08 PM   #13
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Understood, but given that those gears are spinning pretty quickly doesn't the majority of the grease just get spun off anyways? It's not like they are being bathed continuously in the grease like the diff gears are in their own fluid, right?
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Old 03-12-2009, 02:26 PM   #14
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ofcoarse but i dont think the whole grease will be forced out...some grease is remains in between the teeth..
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Old 03-12-2009, 03:34 PM   #15
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I run the ST-RR and MP9 and am very happy with both... I haven't had any breakages on the MP9 apart from the little lip around the suspension bushings. I've since replaced the and done the washer mod and no problem since.

Broke a couple of front arm and cracked a couple of c-hubs racing over the winter but since boiling them they have been fine since (touch wood).

After a race meeting recently me and another swapped cars to see what each other's setup were like......it was amazing how different 2 cars the same can handle!!!! Mine felt more responsive and buggy like to me and his seemed to lack steering and felt heavy and unresponsive although he goes well with it....and he didn't like how mine drove. It is still a very capable/competitive truggy....I can't wait for the new one!!

How do you like yours to handle? What setup are you running and what do you find it is lacking? Also, what sort of track do you run on?

If you are able to get to Slough Sunday you are welcome to try mine out and see how you find it....
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