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Kyosho Ultima RB6 & RB6.6 Car Thread

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Kyosho Ultima RB6 & RB6.6 Car Thread

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Old 12-21-2016, 08:46 AM   -   Wikipost
R/C Tech ForumsThread Wiki: Kyosho Ultima RB6 & RB6.6 Car Thread
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RB6.6 Kyosho America Product Page: http://www.kyoshoamerica.com/ULTIMA-...T_p_24505.html

RB6.6 Manual http://www.kyosho.com/jpn/support/in...A_RB6_6_IM.pdf

RB6.6 Kyosho Youtube https://www.youtube.com/watch?v=vW_sR667utY

MSRP $639 MAP $399.99

New RB6.6 parts (compared exploded views, prices and links are Kyosho America):

  1. Main chassis - UM731 - $125.99
  2. Side guards - UM732 - $9.99

Battery Holder:
  1. Battery plate - UM733 - $8.99
  2. Battery foam - UM741 - $7.99

Rear Bulkheads:
  1. MM3 and Laydown - UM740 - $9.99
    • MM3 bulkhead
    • Laydown bulkhead
    • Swaybar Holders

3 Gear Transmission (MM and RM):
  1. Transmission - UM734 - $10.99
    • transmission cases
    • spacers
    • caps
    • plastic FR & RR suspension hangers

  2. Gear Cover - UM735 - $6.99

Laydown Transmission (3 and 4 gear possible):
  1. Transmission - UM736 - $10.99
    • transmission cases
    • spacers
    • caps
    • required extra hardware
    • pastic FR suspension hanger

  2. 40T idler - UM737 - $6.99
  3. Motor plate - UM738 - $18.99
  4. Gear cover - UM739 - $6.99

  1. Blade body - UMB05 - $27.99

Optional Parts:
  1. Lightweigt Blade body - UMB05LW - $31.99
  2. Aluminum FR suspension hanger - UMW705B - $28.99 (may be able to file UMW705 to fit)
  3. Brass FR suspension hanger - UMW725B - $30.99 (looks more different than UMW725..someone confirm?)

Typical Upgrades for new RB6.6 Buyers

UMW701 Aluminum Steering Plate (RB6)
UMW702 Aluminum Crank Arm (RB6)
UMW704-0 V2 Aluminum Rear Hub Set(0°/RB6)
UMW705B Aluminum Rear Sus. Holder (RF/RB6.6) or brass UMW725B
UMW707 Aluminum Rear Sus. Holder (RR-Mid)

Nice to have:

UMW723 Aluminum Front Sus Block (Type B/10g/RB6/RT6/SC6).

Aftermarket Parts:

Front Wing: https://www.prolineracing.com/perfor...mount-alum-rb6

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Old 07-31-2012, 08:21 AM
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Default Kyosho Ultima RB6 & RB6.6 Car Thread

Kyosho Ultima RB6 2wd Racing Buggy Basics

Buggy Kit: KYO30068B


Build Manual:

Editable Setup Sheet:

All around starter setup for Rear Motor


Big Bore Spring Chart:

A TON more information on the car:

The new Ultima RB6 is the latest in the Ultima line of vehicles, which is a further development of the breed, and it includes all the enhancements that have been designed by Kyosho engineers and tested over the last year by Kyosho International factory drivers like Jared Tebo and legends of the RC world. This type of development, along with the uncompromising manufacturing standards and the vast experience that can only be gained from decades of high-level competition, makes the Ultima RB6 a strong choice as the car to beat for the 2013 season.

  • 7075 Machined hard anodized aluminum chassis with angled sides.
  • 2 motor layout setups included in kit - Rear 3 gear setup and Mid 4 gear setup.
  • Smart battery tray design Compatible with short, straight and saddle packs with both mid and rear motor setups.
  • Long Wheelbase The chassis is now 13mm longer than the original RB5, giving you amazing stability.
  • Reversable rear gull-wing suspension arms allow for more agile turning and stability in bumpy terrain.
  • Velvet coated big bore shocks with new one piece alloy caps and X-GearŪ springs.
  • X-GearŪ diff lubricants
  • New high down-force "Blade" cab forward body
  • New Step 2.0 M rear wing
  • Super low CG design
  • New steering crank design.
  • All new front end geometry with adjustable caster blocks via inserts.

Technical Data:
  • Scale: 1/10
  • Length: 395mm (15.5in)
  • Width: 249mm (9.8in)
  • Height: 140mm (5.5in)
  • Wheelbase: 285mm (11.2in)
  • Gear Ratio: 2.6:1
  • Weight: 1,620g approx (w/body)

Common Questions about the RB6:
Q: How does the RB6 compare to the RB5? What are the advantages and disadvantages between the two cars?
A: The RB6 is as different from the RB5 as any other two buggies on the market. There really isn't any driving similarity between the two. In my opinion, the RB6 is all the best things about the RB5, but also has everything the RB5 didn't, and with abundance.

The RB5 is a very easy car to drive, and generates a lot of rear traction. Because of the rear traction, the car tends to be very easy to drive. The issue with the buggy, is it becomes a bit difficult to get the buggy to steer aggressively, and therefor tends to be a slightly slower buggy in the right hands, compared to the B4 for example.

The RB6 is a FAR more aggressive car, due to changes in weight shift, chassis material, and geometry. The traction of the car has shifted to the front, making the car a bit more difficult to drive, but making it a much faster feeling car, giving it the ability to turn inside of even the mighty B4.

Here is my take on the differences, and there aren't many: (these are of course my opinions only)

RB6 Pros:
Fantastic Steering
Jumps and Lands better than any other buggy
Down the middle electronics (better balanced)
Better steering rack
More stable due to increased wheel base

RB6 Cons:
Could be a bit hard to drive for newer drivers
early kits had a couple quality control issues (now all resolved)

RB5 Pros:
Very easy to drive
Vast amounts of tried and true setups available
Better on low traction tracks

RB5 Cons:
Doesn't steer as well
Doesn't jump or land nearly as well
Less stable

Q: What parts are shared with the RB5?
A: A lot of the little things are shared, but not much of the big stuff. Here is a list of things that are shared. It may be incomplete. PM me if anything should be added

Q: What are the rear suspension hangers, and do I purchase the wide, or narrow track width hangers?
A: The rear suspension hangers are what mount the rear suspension arms of the car, to the chassis. There is one hanger in front of the rear arms, and one behind. The one in front is marked as a RF (rear front), and the one behind the arm is marked RR (rear rear). There are two different pairs of hangers you can use, and you can either use the plastic versions that come with the car with the metal bushings, or aftermarket aluminum versions with the plastic bushings. On the RB5, they were a weak spot on the car. The plastic ones that come with the RB6 appear to be stronger. So while aluminum versions are not necessary, they are certainly an advisable upgrade if your wallet allows. Always run the plastic or derlin bushings when running the aluminum suspension hangers.

Wide Hangers: The wide hangers provide a wider rear track width. A wider rear track width does two things to the rear of the car: a) Provides a bit more stability over small bumps, and b) raises the roll center in the rear of the car - A higher roll center provides more roll resistance - More roll resistance means the rear of the car will roll less in the corners - Less roll means less traction gain throughout the corner. (i.e. use the wide hangers for more steering)

Narrow Hangers: The narrow hangers provide a more narrow rear track width. A narrow rear track width does two things to the rear of the car: a) Provides a bit less stability over small bumps, and b) lowers the roll center in the rear of the car - A lower roll center provides less roll resistance - Less roll resistance means the rear of the car will roll more in the corners - more roll means more traction gain throughout the corner. (i.e. use the narrow hangers for more rear traction in corners)

Now, you're going to ask, which to run? Well, it is all driver preference. When I ran the RB5, I found the car needed more stability and a LOT more rotation, so I ran the wide hangers. But the RB6 is an entirely different animal. The car is super stable, and is super aggressive right out of the box. I personally run the narrow hangers to help lock the rear end in, in the corners. My RB6 does NOT need more steering. But, your mileage may vary, and most setups are a constant work-in-progress. It might be a good idea to run the plastic hangers first to figure out which you prefer, before you shell out a lot of money for the aluminum version.

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Q: What spare parts should I keep on hand? What commonly breaks on this car?
A: This car is similar to all buggies in what can typically break if the car takes a hit it's not designed to take. Things that can typically break on any buggy are the front and rear arms (arms can be run on either side of the car, there isn't a L, and a R arm), caster blocks, and steering blocks. So far, the car appears to be superbly durable in all regards. I have been running the car since week 1 and have yet to break a single part, except for a ballcup. (the kit comes with extras)

With that being said, there were two parts on the car that seem to break before they probably should, and that is the center steering rack, and the rear upper bulkhead. This was an issue on the first couple rounds of production. Kyosho has since beefed up both the steering rack and the rear upper bulkhead in a running mold change. If you have an earlier car and are going to replace or buy a spare for the steering rack, you might as well grab a nice aluminum rack from Exotek. To help keep your rear upper bulkhead from breaking, (it breaks at the ballstud shelf), it helps to run the middle hole, and make sure to use the extra 3mm set screws supplied in the kit to fill the unused holes. This helps solidify the ballstud shelf. Exotek also makes an aluminum version of the rear upper bulkhead that certainly won't break, that weighs exactly the same as the factory plastic piece does.

Q:Where is a good place to buy spare parts for this car?
A:The first place to get parts should always be your local hobby shop. But if that's not possible or practical for you, a lot of the main online retailers sell parts for this car. Below is my personal recommendation on where to go based on price and customer service:

Q:What do you recommend for gearing on this car?
A:This car uses an internal gear ratio of 1:2.6, so this car would be geared basically the same as a RB5 or B4. Gearing also greatly depends on what motor you are running, how much end bell timing you are running, size and nature of the track you are racing on, and how heavy your car is. So your answer will vary greatly based on your unique situation. But in GENERAL, I would recommend the following for blinky mode / zero timing advance racing. Remember, this is just a guideline, it is always best to temp your motor at 2, 4,6, and 8 minutes to make sure you aren't overheating your motor before you toss your car into a race with your new gearing.

17.5 / 20-30 degrees of end bell timing
Spur - 69
Pinion -30-32

17.5 / 0 -20 degrees of end bell timing
Spur - 69
Pinion - 33-34

Q:What are some of the common upgrades/bling for this car? I want it to look cool!
A:The RB6 seems to be getting more love than the RB5 ever did with aftermarket companies making goodies for the car. Here is a list of some of them!
Q: What parts do I need to run the UM521-1 rear arms?
A: If you wanted to go with the 521-1 arm with no modifications you would need to get the following:
UM521-1 Kyosho SP "Type B" Middle Suspension Arm Set, 2 of them
la229 Kyosho Rear Outer Suspension Shaft
KYO1-S12605H Kyosho 2.6x5mm Button Head Screw
OW5015 Kyosho Short Big Bore Shock End Set (4)

If you wanted to use the RB6 rear suspension shaft then you would have to drill out the outer suspension hinge pin hole to allow the hinge pin to pass through it.
Q: What is the difference between the 521-1 rear arms and the 521 rear arms?
A: The 521-1rear arms has one hole in the arm for the lower shock to mount to whereas the 521 arm has two holes in the arm. When compared between the two the 521-1 rear hole is in-between the 521 holes.

Option part available.

UMW720 Lightweight Main Chassis (A7075T6/RB6) Optional lightweight chassis for RB6. Added milling in the rear allows for more flex resulting in added traction on low bite surfaces, and milling in the sides adds torsional flex for a bit more forgiveness on high bite surfaces. 25 grams lighter than stock!

Option part available.

W5303-10 Shock Piston(3x1.4/2pcs/Big Bore Shock)
Optional pistons for RB6/RT6/FS2 SP/SC-R SP big bore shocks.
3 X 1.4mm

Option part available.

W5303-11 Shock Piston(4x1.3/2pcs/Big Bore Shock)
Optional pistons for RB6/RT6/FS2 SP/SC-R SP Big Bore shocks.
4 X 1.3mm.

Option part available.

W5303-09 Shock Piston(2x1.6/2pcs/Big Bore Shock)
Optional pistons for RB6/RT6/FS2 SP/SC-R SP big bore shocks.
2 X 1.6mm

Option part available.

UMB03LW Blade Body (ULTIMA RB6/0.6t)
Lightweight body for RB6. 0.2mm difference in material leads to a 15 gram savings in weight! Used by Tebo to bring home the world championship!


Option part available.

UMW719 Rear Bulk Weight Set(RB6/MID MOTOR)
Rear weight set for RB6 MID, 2 - 5g pieces, and 1 - 15g.
5g-25g can be mounted in 5g increments for improved traction in low grip conditions.

Only fits UM724B rear bulkhead.

Option part available.
  • UMW716 Carbon Composite Rear Shock Stay(RB6/MID)
    Optional carbon composite rear tower for MID RB6. Increased stiffness and decreased weight realized.
  • UMW715 Carbon Composite Rear Shock Stay(RB6)
    Optional carbon composite rear shock tower for RB6. Increased stiffness and decreased weight realized.
  • UMW714 Carbon Composite Front Shock Stay(RB6)
    Optional carbon composite front shock tower for RB6. Increased stiffness and decreased weight realized.
  • UMW713 Carbon Composite Front Hub Carrier Set
    Optional carbon composite caster blocks for RB6. Increased stiffness and decreased weight realized.
  • UMW712 Carbon Composite Front Knuckle Arm Set
    Optional carbon composite steering knuckles for RB6. Increased stiffness and decreased weight realized.
  • UMW711 Carbon Composite Rear Sus. Arm Set(RB6)
    Optional carbon composite rear arms for RB6. Increased stiffness and decreased weight realized.
  • UMW710 Carbon Composite Front Sus. Arm Set(RB6)
    Optional carbon composite front arms for RB6. Increased stiffness and decreased weight realized.
  • UMW718 VVC Aluminum Drive Gear (26T/MID Motor)
    Velvet coated aluminum idler gear for RB6/RT6 mid motor. Frees up transmission by using plastic/metal/plastic/metal configuration.


NOTE: The RB6 does NOT come with an aluminum steering rack. This was a pre-production prototype steering rack

Link to the RZ6 thread can be found here.

Last edited by Kraig; 06-17-2016 at 06:42 AM. Reason: Ongoing updates as information on the car develops
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Old 07-31-2012, 08:27 AM
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Looks awesome, and I love the steering rack!
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Old 07-31-2012, 08:28 AM
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that looks sweet i hope those are available soon ,i know 6 to 8 months
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Old 07-31-2012, 08:31 AM
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Rumors were circulating since the beginning of the year the wells associated with the red Japanese company. In RCdevil.gr knew since 2011 that Kyosho will launch this year new models by then the company designer Shin Adachi and now it's time to introduce the first of these, brand new electric buggy pisokinito codenamed Ultima RB6.

This is a brand new 2wd platform designed by Kyosho Racing Team and in accordance with the company represents the next generation of family Ultima able to excel in any terrain.

To achieve this RB6 has some impressive new features:

New chassis made of aluminum 7075
2 mounting options of the transmission - Rear motor (with gears 3) and Mid motor (with 4 gears)
Smart battery connector compatible with all types of batteries in different configurations
New longer wheelbase by 13mm (285mm) for greater stability
New rear gull-wind shears for more direct steering and stability on uneven surfaces
Big bore shocks with springs of X-Gear
Lubricating the X-Gear
New cap brostokampino
Extremely low center of gravity
New design steering


Length 395mm

Width 249mm

Height 140mm

Wheelbase 285mm

Internal Link 2.6:1

Weight 1620gr (with lid)
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Old 07-31-2012, 09:16 AM
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I'm on the RB6 waiting list already! Can't wait!
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Old 07-31-2012, 09:20 AM
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that car looks really good cant wait to see it on the track!
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Old 07-31-2012, 09:21 AM
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Does anyone know the eta or if there is an eta yet?
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Old 07-31-2012, 09:40 AM
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Wish they used captured hinges on the rear instead of the rt5 style nuts.
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Old 07-31-2012, 09:43 AM
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Originally Posted by blingy
Does anyone know the eta or if there is an eta yet?
No idea, but I certainly hope it is soon. This buggy looks badass.

I agree, K_King I prefer captured hinge pins too. Also, did you guys notice the all alum shock cap? Thats a nice little upgrade there and it looks good.
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Old 07-31-2012, 09:44 AM
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From the pics does it look like the whole rear section and be simply swapped around, between mid to rear motor
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Old 07-31-2012, 09:46 AM
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Originally Posted by blingy
Does anyone know the eta or if there is an eta yet?

First production completed to end of july, shipment will be ready from early august.
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Old 07-31-2012, 09:57 AM
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Looks like maybe adj. width caster blocks also
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Old 07-31-2012, 10:05 AM
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I've seen her up close and she is beautiful! Very excited about this new buggy. Looks like we'll be able to get our hands on them soon too!

A few other bits:
- Wing mounts now attach to gearbox in rear motor config.
- Hard to tell in the pics, but there's a channel in the plastic side trays to run your wires through and conceal them.
- Aluminum steering rack! (Edit: this appears to be an option part as the manual shows a plastic part)
- New full aluminum shock caps.
- Tebo had his receiver mounted in the traditional location beside the battery, so that is still an option. He had the R10 capacitor mounted on the opposite side, which comes close to balancing the weight.

Last edited by mdowney; 08-12-2012 at 10:25 PM.
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Old 07-31-2012, 10:05 AM
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Seems really heavy and longer than the 22 by 6mm
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Old 07-31-2012, 10:07 AM
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Looks killer!!! waiting for it to ship... amain has preorders?
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