Losi XXX-S

Old 02-15-2003, 01:44 PM
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Default More Rear Traction Needed

Tomorrow I will be racing at a track that I have had problems with in the past with I major loss of rear traction. I have tried just about every Sorex tire, even some that should have been to soft but still it looks and feels as if the rear tires just arent hooking, like driving on ice. I will probably start with the stock setup with 50wt oil front and rear and diffs. I remember it feeling like the car was sliding not just in the turns but on the straight it would actually feel drifty. Does increasing rear tow increase total tracion or just on power traction? Any help would be appreciated.

Blake
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Old 02-15-2003, 01:46 PM
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Blake, what inserts are you using with those sorexes?
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Old 02-15-2003, 03:04 PM
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I have always used the medium b's(thin) and I am racing stock. It is a smooth untreated lot.

Blake
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Old 02-15-2003, 03:21 PM
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Does increasing rear tow increase total tracion or just on power traction?

Rear toe in increases rear side bite. It works by inducing a slip angle to the tyre so only requires the car to be moving forward to have this affect.
There is a secondary effect in that you are also changing the direction the wheel is applying power in. This means that you have less forward drive and that toe in increases sideways traction more when on power than when braking.

The ultimate limiting traction when you car is about to fly off the track will be less with toe in though. This happens because once the slip angle of the tyre reaches a certain value the traction starts to decrease. The outer wheel always reaches this value first. With toe in when this happens the inner wheel has had it's slip angle reduced so will be producing less traction than it would otherwise.

For this reason toe in should only be added to solve grip problems on corner entry and exit or straight line stability. It will not help mid corner.
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Old 02-15-2003, 03:41 PM
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thanks for the info DW, i am having the most problem with corner entry so i will give the rear hubs a shot.

Blake
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Old 02-15-2003, 04:51 PM
  #5346  
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Blake, if you can get a hold of one, get the XXX Main tuning guide. Bar none the best money you can spend on RC. Once your in the ball park where the car is manageable this guide will help you get it locked down. TTYL.

Gary
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Old 02-15-2003, 06:05 PM
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Blakesrc: Is the the rear end slipperry on entry, mid-corner or exit cornering? I have read the XXX manual sveral times and I think I could try to help the best I can.
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Old 02-15-2003, 10:24 PM
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Default aluminium screw set

Hi,

Is there anyone offering an aluminium screw set for XXX-S ?
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Old 02-15-2003, 11:33 PM
  #5349  
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ong- Trinity put a kit together, but it's blue.... I thought I saw a red one somewhere but I can't remember.......

Blakesrc---- reduce rear droop, use less front toe. slightly tighter front diff, reduce rear anti-squat, increase front kick-up, lower rear rollcenter.....all will work.... droop will have the most powerful effect, front toe and diff settings will be more suttle and will add steering on corner exit. if you choose front kick-up you can reduce the amount of caster at the hubs to yeild the same total chamber
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Old 02-16-2003, 04:39 AM
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Blakesrc: the biggest issue you are looking at is going into the corner you are slowing down and all the weight is being transferred to the front of the car so the first thing I would do is reduce rear droop like IMPACTPLAYR said. 2nd Depending on where your shock positions are you could stand the fronts up right more 1st and then you lay the back shocks down, in this case you are trying to stiffen the front up to keep the weight in back. You could aslo use a spool diff, this will make the car push more but give you more exit steering on-power. Hope this helps!
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Old 02-16-2003, 09:51 AM
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are you using a front sway bar? if not give it a try. I had problems with rear traction due to the wrong foams(was trying to run "front only" tires on the rear) and this really helpled me out. start with middle and then go stiffer. rob
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Old 02-16-2003, 10:18 AM
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can someone point me in the right direction. Im looking for roll out calculations. or should I say how to figure roll calcs. thanks rob
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Old 02-16-2003, 11:23 AM
  #5353  
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Originally posted by Gary Fliegel
Blake, if you can get a hold of one, get the XXX Main tuning guide. Bar none the best money you can spend on RC. Once your in the ball park where the car is manageable this guide will help you get it locked down. TTYL.

Gary
I absolutely agree.

The XXXmain guide is actually a reprint of Martin Crisp's (Mpoweredracing.com) guide; I'm assuming he sold the rights for it to XXX-Main. But it is well written and WELL worth the money. It was what changed me from a back of the pack runner to a moderately fast guy overnight; knowing how to set my car up (and how to make proper adjustments on the fly) made all the difference.
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Old 02-16-2003, 12:10 PM
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blackflag--- you could have just done a search for roll-out..... here it is though........

FDR (spur/pinion * trans ratio)
---------------------------------------- = Rollout
tire diameter * 3.1416
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Old 02-16-2003, 04:16 PM
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[QUOTE]Originally posted by ChristopherKee
[B]KO Racer -

As you can see... your Speedo has a good home it fits perfect and I still have the same wire you put on... I'm glad you flaked off all the blue.. I like the look better.


christopher......looks great where did you get the motor heat sink clamp?

here is a shot of the front of my car now and i have had no problems .
Attached Thumbnails Losi XXX-S-front-xxxs.jpg  
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