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Old 11-21-2009, 05:08 PM   #31
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I was thinking of something like a ball diff in a sealed case but yeah, just a theory/possibility.

I wonder how something like a Losi Smart diff would work on a 2wd vehicle?
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Old 11-21-2009, 11:42 PM   #32
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Quote:
Originally Posted by Davidka View Post
I wonder how something like a Losi Smart diff would work on a 2wd vehicle?
I don't think it would work well. Generally in 2wd you want as free and "open" a diff action as you can get. Anything that limits diff action off-power kills the cars turn-in and if it locks up on power it does donuts unless traction is insanely high, then it doesn't turn at all. With the Serpent pro-diff on 2wd on road cars, most people kept it very soft. If traction was really good, you might tighten it up a bit.

Still, with just the right tuning so it just got a bit stiffer without locking it might work well in certain conditions.
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Old 11-23-2009, 11:17 PM   #33
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Here is a post from one of the French designers of 2wd classic 1/8th onroad cars about gear vs. ball diffs:

In fact ball diff is a good solution for 2WD cars, but without suspensions the chassis is so rigid that it's very difficult to have a constant set up. For 5 minutes for example, the diff will be constant but for a 30 minutes use, in general we observe a degradation of slip on because of vibration and unscrew of the diff even if it has been set very hard at the beginning. So that, gear diff have been adopted. With gear diff, depending on the track you will drive, it's better and more constant. In general you have to consider to let your diff enough free and use a soft grease (but not silicon grease that is sticking) and to prevent too much forward drive lost, you play with the tyres shore to reduce this effect (between 37 and more shore for rear tyres & 48 and more shore for front tyres). But it's also a question of how you drive. But don't forget also that during the run grease will heat up and gear diff will be more free. Outside temperature will also play, I mean if you leave in a place where you have regurlarly around 80F, your option should be to adapt a harder grease.
That's also the pleasure of these cars to find the good set-up, and believe me, when you have it, it's a real pleasure to drive.
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