|
|
Post by lesbaldry on Aug 25, 2010 21:36:46 GMT
Gear diffs seem to be the latest craze,but do they work? Having spoke to drivers who have tried them,GD's seem to be one of those "personal feel" things,some hate em some love em! From the Photons and my point of view,its always been a easy to drive and stable car,fast on large flowing track but has always suffered off power understeer in the tight slow twiddly bits,especially on tracks like ours!no mater what I changed on the car I could never "get it in" with any speed,always having to wait for the car to slow befor it would turn in well. Our SLCC round gave me a chance to fit gear diffs front and rear. First a GD was fitted to the rear and tested,initially the car felt a little loose but a change in oil and a slight adjustment to my thumb Expo soon sorted this  .There was little or no change to my steering prob but what was very impressive was the punch .The direct drive of the GD (zero ball slip) seemed to give my 17.5 13.5 acceleration for the first 2 mtrs out of a slow corner. Time for one in the front! in my ignorance and taking advice from another forum I had filled both GD's with heavy shock oil,this proved to be wrong in the rear as well as the front,this oil allowed the front GD to spin the inside unloaded wheel up very easily causing "diffing up" and lack of drive out,a quick change of oil transformed the car,not only did I have the turn in I was always after but also the punch out like a spool but with better steering control,the front tyres were now not grabbing any surface change as a spool would and that's got to help on our bumpy track. GD's do alter the handling some so I did have to alter my chassis set up a little but this was easily sussed.Are they an advantage? certainly for me and the Photon so far,probably as good as 0.3sec a lap but only time will tell at other tracks. Other advantages are,theres no drive shaft chatter so less wear,so far next to no maintenance,its easier to change oil viscosity than rebuild a ball diff and no overheating balls and plates to alter your handling during a race. disadvantages,a little lively to drive in very low grip  |
|
|
|
Post by darrenoakley on Aug 25, 2010 21:56:42 GMT
In my limited experience with rc racing I found that running in the rear made it grip much better and power down quicker. I did feel a little looser on entry but this could have been due to the set up being for running a ball diff. I haven't tried it in the front but will probably wait till we go indoors to try it now. I have to admit after running for a couple of meetings I opened it up to give it the once over and it was so easy to service( after I found the gear I dropped on the floor at bashley  Need to talk to you about oil weights for the front though Les |
|
|
|
Post by lesbaldry on Aug 25, 2010 22:39:58 GMT
. It did feel a little looser on entry GD's do make the car feel a little "squirly" under hard braking especialy when braking and turning at the same time,this is due to the way the gear diff works,the unloaded wheel will spin up more easily on power than with a ball diff but but do the opposite during braking (lock up) , there are three cures for this,a simple one is to run a little more rear droop (more up lift) to keep the rubber in contact with the tarmac during the chassis roll or rear to front weight change. Darren dont try and run the GD in just the front,trust me it dont work chap...as soon as you hit a blip dot and/or get one front wheel air born with power on it will "diff up" and you will loose all drive to the front for a split second causing you to spin out with out any warning  !! Fitted in just the rear with a spool up front is fine or as a balanced pair front and rear only!!! |
|
|
|
Post by mattsedgley on Aug 25, 2010 23:14:57 GMT
I feel left out without being able to have a gear diff in the poomacher yet!  |
|
|
|
Post by lesbaldry on Aug 25, 2010 23:22:51 GMT
I feel left out without being able to have a gear diff in the poomacher yet! Un like my tight corner phailing Phuton the Schuy Poooie dont seem to need one chap!! ;D |
|
|
|
Post by mattsedgley on Aug 25, 2010 23:29:23 GMT
haha!! just cause one bloke says it doesnt need one means i might never have one! shocking!
|
|
|
|
Post by shaun207 on Sept 4, 2010 12:05:42 GMT
just received my gear diff , will be going in for next week ..
what differences of weight do you use for carpet and tarmac ..
|
|
|
|
Post by darrenoakley on Sept 4, 2010 13:56:24 GMT
I leave the stock 20000 in for bashley but Les would be the best advise on this as he has done most of the testing.
Are you running front and back or just back ?
I am sticking one in the front too as soon as my oils turns up. In a hope to stop chatter and drive shaft wear.
|
|
|
|
Post by yellowshark on Sept 4, 2010 15:30:18 GMT
Just received my new diff ring refurb tool. Can't wait to fit some silky smooth new balls to my diffs  |
|
|
|
Post by ginge on Sept 4, 2010 15:44:24 GMT
i've just put new diff rings in mine so i can say i've got smooth Balls ;D  |
|
|
|
Post by yellowshark on Sept 4, 2010 16:18:10 GMT
Technology may have stopped me playing with my brushes but blowed if I am going to spend copious amounts of money to stop playing with my balls ;D
|
|
|
|
Post by lesbaldry on Sept 9, 2010 21:29:58 GMT
Technology may have stopped me playing with my brushes but blowed if I am going to spend copious amounts of money to stop playing with my balls ;D Brill ;D ;D ;D |
|
|
|
Post by lesbaldry on Sept 9, 2010 21:52:59 GMT
just received my gear diff , will be going in for next week .. what differences of weight do you use for carpet and tarmac .. Its early days Shaun,My experience with the GD's is limited to Bish Bash and a couple of testing runs at west London. My only advise would be to stick to what you read forum wise with the Photons diff as the same wt/cst oil feels completely different in the Spec R diff, ie 2,000 oil has roughly the same feel as 10,000 oil in the Photon diff Rule of thumb is, thiner oil gives better traction,thicker gives more mid to high speed steering but will make the car push on entry and be a little loose on exit.....start thin and work up,thats what I did for Tarmac,but do change the "fitted " oil ,as its way to thick for the rear GD but way to thin for a front GD on Tarmac....hope this helps some |
|
|
|
Post by shaun207 on Sept 9, 2010 22:08:56 GMT
cheers les , its all fitted for tomorrow night ( on carpet ) with 10.000wt as advised on rctech , ill see how it goes !! ..
ill be in touch in the week for the photon off you ........ oh yeah !!!
|
|
|
|
Post by justchris on Jan 20, 2011 9:52:51 GMT
Gear diffs seem to be the latest craze,but do they work? Just thought i would bring this up again. Just downloaded 4 set up sheets for tc6 and only one has the ball diff. 1/ if a gear diff is better why is it not standard in kit 2/The above sheets have all different makes of components from different maufacturers - e.g. losi, pistons, x-ray rollbars, hpi springs, etc, etc As some of you know, I am going to a workshop at RCLazy to assemble my TC6. Is it really necessary to purchase off Terry all of these things to make the car as good as they say it is? Surely this is not an Associated TC6 but a car made up of various manufacturers parts (ferrari don't walk to the mclaren garage for wheel nuts and then go to the Red Bull garage for the brake discs). This does seem wrong to me as I just wanted to run the car straight out of the box standard as Jason does but using Les's help on the suspension and shock oils. It seems unfair to me that it seems such a good car and used parts from other cars and manufacturers. Is it just me or is this normal in the expensive end of this hobby? ?? |
|
|
|
Post by martinchallis on Jan 20, 2011 13:09:40 GMT
its pretty normal mate, Every setup that i have read for the MI4 CX requires "M Flex C Hubs" and a "Narrow Hex" neither of which were supplied with the kit - im sure they do this so they make more money I will say if you are planning on racing at various tracks a full HPI spring set would be a good idea, although other tuned spring sets are available |
|
|
|
Post by Reuben on Jan 20, 2011 13:11:19 GMT
Ooooo Chris that is a super touchy post, so I will tread carefully.
Most if not all cars should work well out of the box as they are. My advice, which is limited to two chassis that have been new in box (Mi4 and T3), would be to just run the car as it is out of the box for your first meeting before adding anything.
if you start adding stuff straight away, how do you know what it is doing to the kit in kit format? how do you know its making it better or worse?
The danger is, if you add to much to beging with, you start questioning why it was added in the first place, and then you become scared to take it off, incase it makes the car bad. Ide say it is better to start with a base car and tune it to yourself or have others help you tune it to your preference - rather than starting with a pre-tuned car and trying to re-tune it to fit.
A lot of the Xray setups at present also have gear diffs in, I tried the gear diff a few times and only liked it once. But if the setup sheets are to believe - I should be usign the gear diff and changing other parts of my setup to account for it? but ide rather not.
|
|
ianlloyd
Lapping the Back Markers
Posts: 932
|
Post by ianlloyd on Jan 20, 2011 13:51:18 GMT
Well I don't know anything about gear diffs as opposed to ball diffs but on the subject of why do we need to add loads of extra bits to make cars work straight out of the box.....I tend to agree with Reuben. Run the car as per kit and then decide if you feel you need to change something. Just because someone else uses a "part" that is not included in the kit does not mean it is necessary to make to car work for you.
Obviously once you have run the car in kit form, trying other special parts may well show an improvement in your times but you need to be very carefull about this as sometimes we are spending too much time listening to what other people say and not enough time actually proving those parts work for you.
|
|
|
|
Post by yellowshark on Jan 20, 2011 14:12:04 GMT
Better off buying an XRAY Chris then you won't have to spend out replacing with better parts from other cars ;D
|
|
|
|
Post by yellowshark on Jan 20, 2011 14:28:53 GMT
I agree with Reuben. Unless you are top class you need to get used to your NEW car first. Inevitably it will handle differently to whatever you had before - even if that was an old (in terms of age) model of the car you just purchased.
Why is the diff not stnd. Firstly just because some setup sheets have the gear diff in does not mean the majority do. Secondly maufacturers build to a price point, which means compromise and I suspect few manfacturers are shipping gear diffs as standard. It is quite possible that those setup sheets represent people who are trying the latest fad and not actually representing the setup that woudl give them the best performance (they may do I am just presenting an alternative perspective)
Setup sheets. Not restricted to setup sheets , the Internet gives everyone the capability to be appear an expert when they are not. I cannot believe some of the posts I see which are written in a very assertive way and give the impression the idiot knows what he is talking about. (take this post for example ;D)
Also setup sheets basically mean nothing unless you are driving on the same track, with the same powerplant, with the same tyres, with a similar driving style and have the same various hop ups (not all are always noted on setup sheets).
Which is not to say they are not useful, they are. But don't treat them as being God. EG Les and Craig drove the XRAY 008 with totally different setups at Bashley.
|
|
|
|
Post by Martin Young on Jan 20, 2011 20:08:22 GMT
As said above give the car a go as standard. The TC6 indoors (not run mine outdoors yet) is good without the need to buy anything. It's always the driver that let's mine down.
As for gear Diffs, I like the feel and the reduced maintenance but I don't think I go any faster with one in the car.
IMO and definitely for my driving the top drivers setup usually have way too much steering anyway.
|
|
|
|
Post by Reuben on Jan 25, 2011 17:06:20 GMT
My gear diff skips one side, if i hold the right wheel and spur, I can turn the left making it click, It doesnt click the other way (holding the left).
also sometimes when turning the left side outdrive it feels like it jams.
Am I right in thinking its the gears that have gone?
|
|
|
|
Post by Martin Young on Jan 25, 2011 17:16:54 GMT
If it clicks when you try and make it slip without doubt its jumping teeth, a gear dif should not slip at all in either direction. If the teeth on the gears are not damaged then they must be worn excessively. The problem with the type of gear diff used recently you have very little adjustment by shimming so once they go it new gears unfortunately (at best).
Hope that helps
|
|
|
|
Post by Reuben on Jan 25, 2011 17:28:01 GMT
yeh the teeth "look" ok, ill see if i can shim it, if not, new gears.
Shame because it transformed the car again sunday - its definitely a love/hate track specific thing. Some tracks it makes you go slower, others it really gives your those extra tenths
|
|
.There was little or no change to my steering prob but what was very impressive was the punch .The direct drive of the GD (zero ball slip) seemed to give my 17.5 13.5 acceleration for the first 2 mtrs out of a slow corner.
!! Fitted in just the rear with a spool up front is fine or as a balanced pair front and rear only!!! 
