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Possible gearing change ??

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Hi guys.


I'll start of with what I have which is


ICS M4 with stock motor, M100 spring, mosfet & 7.4v Lipo


JG G36C with high speed motor, M100 spring, mosfet & 7.4v Lipo


Each sector gear has a delay chip but other than upgraded piston (plus head) & cylinder head then there pretty much stock otherwise.


I'm after the pros & cons of swapping out standard gears for 16:1 gears in both rifles please

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no cons for 16:1

actual ratio is about 17.25:1

compared to 18.65 on 18:1


not quite a true 11% more like 8%

but no real extra strain on motors


would be all I'd go with a speed motor - they are quick but get warm on semi spamming


13:1 or 12:1 would be best only if you got torque motor


next time you swap out a motor try and get a Big Dragon M160 motor = mental !!!

faster than a shs torque and like a speed motor but with plenty of grunt like torquey one


Back to 16:1 gear sets, I'm 99% certain it is only the spur gear that really changes slightly

most sets seem to use a 10 tooth bevel to spur gear

and pretty damn sure the sector gears are same or nigh on the same



If owt goes crunch, you "should" have the possible option of using old bevel gear

and/or a spare sector gear that could be used to experiment with Short Stroking...


Most gears use 10 tooth bevel, though the odd curve ball like G&G and some other makes do 9 or 8 teeth bevel that results in 20 or 22:1 ratios

Real speed freaks search out the 11 teeth bevel gears but mostly 10 teeth are used in most sets....


Other higher speed sets use spurs & sector gears that are not so compatible

eg: 12:1 sector or spur gear goes crunch - you are f*cked - new set required


OK some gears may not mesh 101% butterly smooth with other gears but on 16:1

you "should" be able to use old 18:1 bevel & sector if it goes crunch and tetth break after a mega box lockup

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Cheers duck, I knew you'd come to the rescue lol


But yeah, it's usually the spur gear that's got more or less teeth

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On the same topic of gears

what's the difference in speed gears against torque gears and what brands are good and what are crap?

Reason for question I have a G&G gr25 and want to increase the fps.

Looking at upgrading the piston, piston head and the spring any suggestions? Been looking on amazon but being new to airsoft I don't know what brands to look out for and ones to avoid

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Far as I know, there's no real difference between high speed & torque gears but again from my understanding, low ratio gears need a torque motor to turn them better when using high rated springs


To increase fps - better airseals on nozzle, cylinder head & piston head plus a higher spring (ie m130 or m140)


If your making a DMR then you'll need to lock the gearbox to single shot by taking the nub of the selector switch that pushes against the little spring that gives you semi & auto

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On a stock weak ferrite motor,

to pull heavier springs over the m100 to m110 normal rating

you may/will need torque gears with ratios above the normal 18:1 gears used in most stock guns

otherwise weak ferrite motors may struggle on m120+ springs

Note not all ferrite motors are that weak but they do not have the raw grunt/speed/response that neodym motors have


On higher torque gears your trigger response will be lowered

and do not even consider 32:1 gears crap at all - way too lame and will need a half tooth rack on piston

it just ain't worth the hassle....


In fact even the helical cut 200:100 & 300:1 gear sets are not worth it

Lozart and some others tried to use them - one of them is about a 23:1 set and think the other is about 27:1

but can't remember which is which - to be honest unless you are gonna try and pull something really daft

eg: 600 fps upwards with a m180 spring or something

you will be fine on stock gears but use a high torque neodym motor


Most DMR people will be sticking with m130 to m140 springs so 18:1 gears will be fine

though cheap nasty cheapo stock gears should be replaced if going nutz


Higher speed gears help in increasing rate of fire & response but not quite as much as you might expect

a 12:1 gear set should offer a 50% increase in rof but in reality often this is say 45% at best

as the motor is having to work a little harder especially at from standstill


I think your G&G 25 uses just a conventional v2 gearbox - not an extended v2 or v2.5

but don't quote me 101% - sure the G&G m14's use std piston/cylinder

and think the sr25 use normal cylinder/piston lengths too


if this is correct do not be tempted to get a great bit long STFU barrel

longest you can go is around 450/469mm - ak size length but tbh

numerous DMR's stay at 400mm or so

long barrels mean little over this length - most stuff is all down to bucking n hop n a good clean barrel all set up very well


What you need to decide is if you will use this as a DMR @ 425-450fps locked to semi

or AEG @ 349.999fps and keep full auto


Now according to G&G it comes as a 510mm barrel on the GR25 Sniper

or a slightly shorter 465mm on the SPR version


Shorter barrel would probably be best if turning into DMR as you have a normal V2 box

yes you could just scrape by on volume on a 510mm barrel but if trying to shoot heavier 30gms

then I would be looking at a bore up kit for piston cylinder and possibly only half correct AoE

to try and ensure a decent amount of air volume is created for the mofo 510mm barrel

Some say it will be ok - but it is pushing it on that longer barrel on a normal v2 gearbox


Your accuracy comes from bucking/hop/barrel - roughly in that order unless something is badly out of whack

Your fps, rof & efficiency & reliabilty comes from the gearbox (and a decent motor to pull heavier springs)

plus good wiring, mosfet, lipo on deans etc......


The list is quite long and a classic example of where do start/stop


You need to decide what type of gun you want

improve the bucking area - see what you gun is shooting at fps wise

increase spring and service gun with a few minor tweaks to improve seals

and after that then go from there.....


Not everybody likes the DMR role of hanging back, 30m single shot, doing less, crawling around

but providing good overwatch & support can make or break a game

but not as easy as many think, often many choose to forget this for a game of soldiers and go back to getting stuck in


If you get your gun shooting well out to 50 or 60m as an aeg - that is pretty bloody good and can kick ar$e in most situations

However getting accuracy is not quite as easy as slapping in a madbull barrel n crap


get your gun @ 349.99 fps with good bucking/barrel and see how you go

gearing if you wish 16:1 is a minor improvement that std guns will pull no problem

when you want to go faster there is a bit more homework to be done as going above 20rps

will lead to over running or double cycle if say above 25rps on m100 setups


So I say to anybody decide on what you want, how far you want to go and do it stages at first

very easy to screw it all up - done this & still doing this so if you want it to work & last

then go steady and see each improvement bit by bit

rather than replace everything - make it go like f*ck and wonder why she smashed herself to bits so quickly


bucking - maybe flat hop, clean barrel or replace with a decent barrel if yours is crap

but try just cleaning the stock barrel first and fix any leaks - see how she shoots - then decide on next stage


Also try experimenting with different bb's - at least 0.25's up to 0.30's on 350fps aeg's

(there are some inbetween weights like 0.23 & 0.28 but usually many use .25's at least for woodland)

note some makes are great and some are crap - plus some guns hate some makes but other guns love them

decent ammo helps but what weight & make - you will have to have a go yourself and see what works/doesn't


Jeez - am I on a bollox roll today

now I understand why my keyboards break quicker than my guns

soz - got carried away - again

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Thanks that is a whole lot more info than I expected.

I don't wand to build a dmr just want to increase the fps as it's currently around the 230 fps,

But and this was my initial thinking "change out the stock piston/head, oh will iv got the gearbox apart I'll install a bigger spring not too much bigger than stock, umm will the gears cope I'll change them just in case. No idea what I need I'll ask the guys on the website"

I did just that and your advice has set me stright change one thing at a time.

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Thanks that is a whole lot more info than I expected.

I don't wand to build a dmr just want to increase the fps as it's currently around the 230 fps,


F*ck me that is $hit !!!


you got air pi$$ing out eveywhere on that one

if it was some lame ar$e spring you'd be going 10 to the dozen even with a lame G&G motor


now the GR25 uses or should a long metal mofo hop unit

and a mega long mofo nozzle too


How old is the gun and if you bought new ??

just saying speak to retailer if quite new


if old then see if still has the spring on hop unit pushing it back to gearbox to seal it

(they can come adrift or just dissappear)


separate the 2 halves of gun and look at hop unit/barrel - check spring is there on the nipple/lug pushing it back to box to seal


Also check nozzle condition - plastic mofo length - could be chipped or cracked

it's a long bastid like the friggin' hop unit - normal v2 box but some bitch decided to use bespoke hop/nozzle ffs

an Aug type nozzle "might" fit as they are quite long but this is still a silly guess at best

(replacement nozzles can be sourced from Z1 or LWA + others)


check whilst you got the 2 halves separated - see if bucking looks ok though it may look ok

but could be damaged/torn/worn - see if the bulge from the nub pressing down is working at least

you could have a torn bucking or probably a couple of issues so see if owt looks iffy


then try to cycle gun - leaving nozzle fully released - max nozzle showing

(this may have to be half cocked or nearly ready to fire coz moment piston fires

by the time cut off lever kicks in the nozzle is starting to retract again to load a bb)


anyway try and get nozzle as far forward as possible right up against the front of gearbox

now place the hop against the box and you should feel the nozzle sealing - should feel a bit of resistance

and suppose you could blow down barrel with hop pressed against box - should seal

pulling barrel/hop a smidge away - and I mean a smidge - you should have about 1mm before you lose seal


I'm trying to give you some ideas where to look for such a big leak

before you go nutz and rip box open - a fair bit of loss is likely to be hop related

could be also inside box but reckon 75% is going to be outside the box

(though cracked nozzle - cracked piston or damaged o-ring is going to need opening of gearbox)


the piston head on G&G's is crap imho but not that bad to lose that much compression

especially on a long barrel where you would expect if anything a bit of creep or slightly higher fps than shorter barrel guns


conduct numerous tests and examinations on the hop sealing against box - it could be badly aligned causing nozzle to seal off centre

often the box can tip backwards and nozzle rides high, rubbing on hop at 12 o'clock - but usually you would see some tell tale signs

marks on nozzle or bits of black where nozzle was rubbing.....

look at gearbox sitting in receiver - if pulled backwards & upwards you can begin to see the lines may not be true to each other

also where the trigger is underneath a gap appears in front of trigger - another indicator the box was gone backwards and up at front


How does the box sound - trying see if something has broke inside box like piston/spring even

but still think most is going to nozzle/hop area related


let us know any history of this gun - anybody ripped her open before and bodged it up

how old is it etc....


and if possible take some pictures - I'm not an expert on G&G 25's - don't own one

but maybe others might have had one and can shed some light on their common faults a bit


do some basic checks like see how the hop seals against box etc....

yes some ptfe will help to stop or reduce some leaks but only if they need them and it is easier if you know where the main fault(s) might be


don't think it is a blowback box - the G&G pbb boxes can crack a bit easier than the normal non blowback boxes

but you will see quite quickly if box is cracked at front....


My money is on the nozzle & hop not meeting that they are nigh on divorced let alone seperated

the spring can be missing - but some small o-rings infront of hop can help push the hop back to box and seal properly


I am not a guru on these long nozzle long hop and long cylinder head mofo's

so I am not the best person to advise - not gonna fill ya with bull$hit in an area I know f*ck all about

(shut up the rest of ya)


What I do suggest is you run some tests and examinations yourself

post some pictures up in a new thread so the experienced GR25 chaps out there can concentrate on helping you further


a quick searchy brings up pi$$ poor seals could be inside the box on the weird long mofo cylinder head

but check that hop unit seal first - then move onto testing other areas like inside box afterwards
do some checks - post some pics I'm sure it is a daft $hit seal causing this drop

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Thanks dude.

What is mofo?

Right I will check the hop up first.

I brought the gun second hand, told it was about a year old only used a few times (or so I was told)

I'll post pictures as I don't think I'll be able to tell the difference between any broken part worn so will have to rely on you guys for your opinion.

I want to do it my self for 2 reasons 1 cost and 2nd to learn.

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OK looking at the barrel and the hop up how does it go together as I have a rubber washer that seems to do nothing in its current location

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Thanks dude.

What is mofo?

Right I will check the hop up first.

I brought the gun second hand, told it was about a year old only used a few times (or so I was told)

I'll post pictures as I don't think I'll be able to tell the difference between any broken part worn so will have to rely on you guys for your opinion.

I want to do it my self for 2 reasons 1 cost and 2nd to learn.

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That rubber o-ring just provides a little backwards pressure as it offsets the hop unit and inner barrel from the outer barrel as well as holding the inner correctly in the outer. Just makes sure it's seated correctly and feeds properly. Should be a spring too.



In the current way you have it you've almost certainly lost your hop nub if you've not removed it before the barrel came out. This is a problem. Tap the hop unit and see if a small black tube comes out.


To reassemble

  • Put green rubber tube (your hop up rubber) on the end of barrel with the narrow end pointing towards the open end of the barrel
  • Rotate green rubber tube thing until it drops into a groove underneath the barrel and can't rotate
  • Turn the hop off fully
  • Slide grey hop unit over top of barrel with the long end pointing towards the far end of the barrel
  • Look down barrel and try to align the 'window' of the barrel so it's facing up in line with the taller part of the hop unit. Take your time with this
  • Push the green plastic clip (barrel retention clip) onto the barrel. It will fit into the groove in the hop unit
  • Remove the small metal retention clip on the second 'cog'
  • Remove the second cog and the first cog - the first cog being the one of similar size
  • Turn barrel upside down so the tall end of the hop unit is facing downwards (this is so gravity holds the nub in place)
  • Pull green plastic lever outwards slightly until you see the groove in it
  • Place hop up nub onto groove. Usually your hop up nub is a small black cylinder (about 4-5mm long). If you've lost it you need another
  • Push green plastic hop lever up unto place and make sure that nub doesn't fall out
  • Keeping the hop lever pushed down slightly, replace both of the cogs from before
  • Replace the metal retention part on the second cog
  • Look down the barrel again and press the hop lever down slightly until the bucking protrudes into the barrel. Double check that it's aligned properly like before as this is important in making sure your BBs fly straight
  • Push the brass collar down into the hop unit (this stops the barrel from rattling around)
  • Push the o-ring down as well (doesn't need to be tight or anything as it'll be pushed into place when you put the barrel and hop unit back


There are a billion videos on this. Consult them if you're still not sure. Just put in 'airsoft hop reassembly'.

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inside the hop is a little bit of plastic - the nub

don't loose that ffs it goes in the arm and presses down on bucking...





uhmm ergh I didn't quite mean strip down the hop completely I mean see if looks shagged

but there is no spring on the hop unit pushing it back to box like I said


M4 type - short version of your hop:




see the spring - well you will need more than just one little o-ring

that little o-ring is more like a stabilising o-ring or one used to steady it in a tube barrels are shipped in


you have the brass collar used to steady the barrel at hop unit end

but that o-ring I'd say is not gonna do much to push hop unit backwards

not that the spring is that brilliant - see if you can find a similar spring maybe in a clicky ball point pen or something

or add more o-rings

whilst assembling bucking/hop a bit of ptfe wrapped around bucking - but very thinly done

you can't wrap metres round bucking or she won't go in the hop but helps to stop leaks around bucking/barrel in hop

google this mod and also the cylinder head mod - ptfe is very good for stopping leaks if done with care


Also I did say make a fresh post to help attract other clever mofo's

(mofo = motherf*cker but used in lighthearted terms)

a good posting place would be:


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Connected in side the hop up unit when I rotate the "cog" the arm drops there is a small black thing that's lowers is the the bit you say I'm missing?

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