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Old 04-06-2007, 06:31 PM   #13831
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yes been checked & replaced with new ones.

when you look close the slop is clearly in the chassis/ diff cover housing that holds the diff bearings, but the plastic in these does not look like it has been rubbing or spining in there or any wear at all!!!!

and i have double checked that the bearings are the correct size too....
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Old 04-06-2007, 06:35 PM   #13832
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I had the same thing happen and a new diff cover fixed it.
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Old 04-06-2007, 09:16 PM   #13833
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That's killing me. You're gonna make me go tear apart my car and see if it does that. It needs to be done, but I've been dreading it since the asphalt doesn't start here for two more weeks. I'm gonna tear it apart tomorrow and I'll get back with you. I swear it doesn't look normal though.
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Old 04-07-2007, 12:58 AM   #13834
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Just checked mine. There's a bit of play in mine as well, but nowhere near as much as shown on the video. Quantitively speaking the end of the outdrive on mine moves through a total of maybe 3/4mm. But most of my play seems to be coming from the bearing (I've put in some cheap metal sheilded bearings on the diff as I could never get the OEM ones rolling free enough) rather than the chassis.

My gut feel is that you shouldn't be getting much more than this otherwise you will have problems with the handling. The belts actually loosen up and tighten up during use depending on what the motor is doing. So you'd get the diff both being held firmly in place (eg under acceleration), but then moving around it loosens up as you transition from acceleration to braking and vice versa. Can only guess that this would mean a somewhat erratic transition.

Some more ideas looking at the design of the chassis. Its only a fairly thin peice of fairly thin plastic lip that holds the bearings in place. My guess is that the chassis is unlikely to wear around the bearings enough to cause the play. However the plastic edge or lip that holds the bearings may progressively soften with use resulting in the play of the diff. This sounds consistent with how DrOlds fixed the problem (though my guess temporarily) with a new diff cover, as half the lip that retains the diff has been replaced with new stiffer plastic....
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Old 04-07-2007, 01:46 AM   #13835
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yeah i forgot to say mine as about the same, definatly not as much as in the video that was posted.

could be more in the video as to like you guys said bearing wear and posibly a very loose belt as well.


i am going to order the graphite diff covers and see if that cuts down the slop even more.
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Old 04-07-2007, 06:58 AM   #13836
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Well, i took apart the chassis and there is no evidence of wear on either the main chassis plate or diff cover and the bearings are good to. Stumped I put the car back together as you would normaly and the movement has seem to completely gone. There seems to be only a little bit of play now. Maybe thats just the way they are designed?
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Old 04-07-2007, 10:07 AM   #13837
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I have no movement at all in my car. Weather the car is taken apart or put together, there is no movement in my front, or rear drive gear. One thing I thought of though, is this car on a graphite chassis, or the cheap abs plastic one? My car is a graphite plus and I have a good set of bearings in it.
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Old 04-07-2007, 03:14 PM   #13838
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mine is just the cheapo rtr xxx-s, so yeah maybe that why mine has movment
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Old 04-07-2007, 08:54 PM   #13839
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You can get the graphite chassis from Stormer for a little over 50 bucks. That will give you a much lighter and stiffer chassis. I would advise you to get that. It would really help with your setup and eveything.
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Old 04-11-2007, 02:14 AM   #13840
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Default How to increase directivity ?

Hi guys,

Here is my question : is there a way to increase the directivity of the XXX-S, mostly at low speed ?

Any idea is welcome.

Thanks.

Cheers.
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Old 04-11-2007, 06:44 AM   #13841
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ok guys
this is it
i have had enough
loosened the belt
clearned all the bearings
fully charged a 4.2 battery
changed pinion to 38, 34, then back to 41,,,,,,, (oh spur is a 86 tooth)
and stll a ttoi (10 year old son) was on my back all the way
i dont under stand

the two cars have the same 540 motor( I even swapped the motor when the kid was gone for some food, that did not work...)
(very bad dad)
am i just wasting my time with a losi xxx s in a 540 motor class.......
however i have purchased a spur gear adaptor which is on the way (maybe if this will help at all i must say i really dont know now ....)
help.., help.., help.., help.., help.., help., sos., sos,.sos,.a
a newbie is distress help here.....

now can any of the losi gurus help me out here
do i just need to move to modified with a brushless
or what do i do here
sorry for the long post
thanks
mnnesh
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Old 04-11-2007, 07:43 AM   #13842
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Minnesh, your gearing is WAY off compared to what i and other people run in stock at our club. I run a 86 spur and around a 25 pinion. Try that mate, the gearing u have now to me (I may be wrong) sounds wayyyyy off.
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Old 04-11-2007, 07:56 AM   #13843
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Quote:
Originally Posted by minnesh
ok guys
this is it
i have had enough
loosened the belt
clearned all the bearings
fully charged a 4.2 battery
changed pinion to 38, 34, then back to 41,,,,,,, (oh spur is a 86 tooth)
and stll a ttoi (10 year old son) was on my back all the way
i dont under stand

the two cars have the same 540 motor( I even swapped the motor when the kid was gone for some food, that did not work...)
(very bad dad)
am i just wasting my time with a losi xxx s in a 540 motor class.......
however i have purchased a spur gear adaptor which is on the way (maybe if this will help at all i must say i really dont know now ....)
help.., help.., help.., help.., help.., help., sos., sos,.sos,.a
a newbie is distress help here.....

now can any of the losi gurus help me out here
do i just need to move to modified with a brushless
or what do i do here
sorry for the long post
thanks
mnnesh

if you swaped the motor and are sure its not the motor,

then it must be something you are over looking / have not relised.

are you running standard 63mm rubber tyres (diameter)

is it a tight or open large track?

have you double checked the end points on the controller then re set the esc setup?

have you tried the battery out of the tt01?

is the car or body scraping on the track?

what is the total rollout?

are the diffs too lose and slipping?

have you pulled out the motor & tryed the roll test to see if the car drive line is stiff or binding at all?


I will be able to work it out as my xxx-s is one of the fastest in 540 and i have been to heaps of clubs/tracks with very fast / experienced drivers that run high end cars, & my xxx-s is still up there with the fastest.
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Old 04-11-2007, 08:22 AM   #13844
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Minnesh, dont give up on XXX-S yet. Its an old design, but its still more than adequate for 540 ad dare I say stock club racing as well.

Interesting how your comparing it with your sons TT01. I've got both and at the start found that the TT01 accelerated much faster, virtually no difference in top speed, but Losi had much better control and handling. However since sorting out a few things with suspension and drivetrain, have found that Losi is much better in terms of both speed and handling. In fact, I find the TT01 really slow and hard to drive now compared to the Losi....

But its actually good to hear that you've got both as you've got something to compare with. I still think that something's too tight in your drivetrain. So pull the motor out of both, and give them both a little push and see how far they roll. If the TT01 rolls a lot further than the Losi, then you've got something too tight in the Losi drive train. If they both roll a similar distance check that you haven't got your diffs and belts aren't too loose (you may be loosing a lot of speed if one or both are slippin).
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Old 04-11-2007, 08:51 AM   #13845
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Blin,

I run a little bit tighter diff in the front(assuming you're running on carpet) That gives me more on power steering. If you want more off power steering, you need to run your diff as loose as you can without causing the drive gears to slip. I run a 13.5 brushless in the stock class(brushed and brushless together) with the sintered rotor, so it has so much more torque that I have to run my diffs a little stiffer.

Minnesh,

You need to check and make sure that everything run smooth when the car is ready to put on the track. Check and make sure your diffs are smooth and make sure your wheels turn freely with no stutter when you turn them by hand. If you tighten your wheels to tight, the car will run slower.
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