2003.01.20, 03:27 AM
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#1
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Mini-Zedologist - Fear me
Join Date: Dec 2001
Location: Bristol, England
Posts: 3,610
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GPM Overland parts arrived
On Friday I collected my order of GPM Overland hop-ups and bearing kit up from the local postal depot.
I ordered 1 set of GPM oil shocks, 1 GPM ball-diff, bearing kit and 2 sets of replacement drivetrain gears.
When I opened the parcels I was quite shocked as I got the bearings, ball-diff, ONE set of gears and TWO sets of GPM oil shocks.
Hell, I'm not complaining. I checked my PayPal account and was charged for two gear kits and one set of oil shocks
The bearing kit really takes the chatter out of the drivetrain, this is the biggest improvement I've seen on any Mini-Z from a bearing kit.
With the standard bushes, I noticed the Overland was especially noisy in reverse, the bearings are a 100% improvement. They are RCRM bearings.
The GPM ball-diff was the next item to be fitted. It's not a badly made unit with an anodised blue finish.
It is ajdustable, but forget about loosening it at all. It's a lot more effective in it's tightest position.
It uses an O-ring to pressure the rear friction plate. The GPM does not offer a diff lock and there is no way to adapt the standard diff-lock plate to it. It also does not ship with a hex-key, grease or any spare parts. The main gear is delrin and it contains 6 thrust balls.
Functionally it's better than the standard diff, the power delivery is much smoother and quieter too. Remember, no diff-lock with the GPM, so if you want to clamber up steep ascents, it means an outright diff-swapping session.
On the upside, the rubber O-ring that is used between the adjustment collar and pressure plate is the same size as those shipped with the HPI Micro RS4 wing mount kits, so sourcing a spare shouldn't be an issue.
Unfortunately the GPM ball-diff is a dust-buster, it collects carpet fibres and hair on both the spur gear and hub side and cleaning means removing the rear-right hub. As I suspected that the sealed drivetrain is not as sealed-off as it should be when using the GPM ball-diff. I took it for a little drive outside and got a piece of grit in the drivetrain.
The GPM oil shocks were a nice surprise, one set only costing me $9.99.
I fitted them without putting any oil in them.
They ship with their own pillar balls, bushes and screws.
GPM provide metric threaded screws, don't use them on the standard plastic shock mounts, they were obviously designed for use with the GPM alloy shock mounts. The standard Kyosho screws work just fine.
The pillar balls need to be fitted with a hex-key, again in the GPM tradition, no such tool was supplied, even though it's needed.
The GPM oil shocks are just way too hard, the Overland is just too rigid with the GPM oil shocks. They only worked (a little) if I dropped the Overland from about 6-7inches.
When I placed the Overland on an uneven surface, the suspension did not function at all, the Overland would just dangle it's wheels in the air.
Not to be outdone, I fitted the standard Kyosho springs to the GPM oil shocks. They are a little longer, slightly narrower but a lot softer than the GPM springs.
There was an immediate improvement. I then opened the shocks and cleaned them out with motor cleaning spray. The reason I did this is because the GPM shocks ship with a rather thick and tacky grease-like substance inside the shocks. I cleaned it all out.
I then filled two units with GS 25WT silicone shock oil.
The shocks were soft, but extremely slow. I re-cleaned them with motor spray and filled them with a 5WT technical oil I use to lube suspension parts on my other RC cars.
The standard Kyosho springs combined with the very thin technical oil is just what the GPM shocks need to function properly.
As the Kyosho springs are a little longer than the GPM units, the suspension is a little harder than the standard configuration.
With all the new kit installed, I set about to build a track that could offer me airtime (as in getting the Overland airborne)
Landing from a high-speed jump with the "hybrid" GPM oil shocks, the Overland doesn't bounce around on landing the way it did with its standard suspension.
It also doesn't lean so much when cornering, but this makes it a little more prone to falling over.
The suspension is much quieter when you climb up obstacles at speed.
In my opinion, the GPM oil shocks are much better for racing and combined with the GPM ball-diff, the Overland now becomes a very progressive high speed, high flying off road racer.
If you want to clamber up and around technical courses at low speeds, stick with the standard planetary-gear diff, lockplate and standard shocks.
I will buy the Kyosho oil shocks when they are released, for the time being, I'll live with the GPM oil filled dampers combined with the Kyosho springs. It's an awesome combination for high-speed, high-flying jumps.
I am a happy man.
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Mondo
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2003.01.20, 03:29 AM
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#2
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Mini-Zedologist - Fear me
Join Date: Dec 2001
Location: Bristol, England
Posts: 3,610
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Oil Shocks pic
A pic of the GPM oil shocks with the standard Overland springs fitted to them:
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2003.01.20, 05:39 AM
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#3
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None better.
Join Date: Dec 2002
Location: California
Posts: 669
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Good review Mondo, saved me some needless spending
My list of parts for what I want to put in my overland has shrunk:
MZR.com a-bb motor
GPM alloy motor heatsink
GPM alloy battery clips
Kyosho oil shocks
A pickup truck body
larger, knobby tires
I've already got nice NiMH AAA's, and a bearing set, so I think the other upgrades would help it out nicely.
I would like to find some tires that work on hardwood though, as right now the little thing spins like a top in my house, and at my work. And its not controlled spinning either, or I wouldn't care because I'd be able to drift in large circles (where I work, there are large round display tables in the middle of a round hardwood area, and the rest of the store is extreme low pile carpeting).
I'm going to avoid the ball diff, because the thing sucks up enough hair as is, I dont need another part to have to take apart and clean after every battery set...
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2003.01.20, 08:43 AM
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#4
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Moderator
Join Date: Sep 2002
Location: Washington, DC
Posts: 35,480
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very thorough review. i am thinking about getting the gpm shock and using the springs from the kyosho spring set to soften them up. what are your thoughts on this?
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2003.01.20, 10:22 AM
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#5
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Mini-Zedologist - Fear me
Join Date: Dec 2001
Location: Bristol, England
Posts: 3,610
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Hybrid Shocks
Quote:
Originally posted by arch2b
very thorough review. i am thinking about getting the gpm shock and using the springs from the kyosho spring set to soften them up. what are your thoughts on this?
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Arch2b,
I have no regrets over my purchase.
Combining the Kyosho springs with the GPM dampers and adding an extremely lightweight oil make them great for high-flying touchdowns.
I prefer them to the original shocks for this type of use.
As for clambering up and around obstacles, they'll do just fine.
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2003.01.20, 10:37 AM
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#6
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Mini-Z Pro
Join Date: Dec 2002
Location: CHI-TOWN
Posts: 183
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So your saying the ball diff will not be good for climbing straight up a hill. Your can't tightin it until both wheels spin?
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2003.01.20, 10:48 AM
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#7
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Mini-Z Pro
Join Date: Dec 2002
Location: CHI-TOWN
Posts: 183
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Why does it suck more hair?
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2003.01.20, 11:39 AM
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#8
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Mini-Zedologist - Fear me
Join Date: Dec 2001
Location: Bristol, England
Posts: 3,610
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Ball-Diff
The GPM cannot be be tightened until it locks.
If you examine the picture, the collar is on the inside of the axle, there is limited space and the collar doesn't have a lot of adjustment.
It collects more hair as the hub (opposite side to the spur) is prone to collecting the hair and getting caught in the small gap between the hub and motor mount.
As the diff is not sealed, fluff tends to collect in the cavity.
Look at the pics and you'll see where it get's caught on the spur side.
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2003.01.20, 12:57 PM
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#9
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Mini-Z Novice
Join Date: Jan 2003
Location: Dallas, TX
Posts: 40
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So Mondo,
Are the stock shocks super bouncy....that seems to what i have read a few times, i may be reading wrong.
So, as an example, if you land your OL from about 5 - 6 inches, does it rebound up back of the ground, almost like a hop?
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2003.01.21, 07:18 AM
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#10
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Mini-Zedologist - Fear me
Join Date: Dec 2001
Location: Bristol, England
Posts: 3,610
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Overland suspension
NitroNSX
The standard Overland suspension is functional but not brilliant.
I've read that Members have cracked steering knuckles from heavy landings.
The GPM shocks are better for hefty landings, but even when combined with the standard Overland springs, they are a little too hard for climbing over objects at low speed.
It's a matter of choice, if you want to tackle big jumps, the GPM damper/Kyosho sping hybrid shocks are great.
If you need to do some low speed obstacle course type driving, stick with the standard suspension.
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Mondo
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The UberMod is back in town...
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2003.01.21, 09:50 AM
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#11
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Mini-Z Novice
Join Date: Jan 2003
Location: Dallas, TX
Posts: 40
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Mondo
Do you know if the Adjustable Alloy Shock mounts from GPM will work with the standard shocks and screws?
Would it add anything...i.e customization, etc with the standard shocks besides looks?
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