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Old 03-11-2012, 11:21 PM   #1
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Default Super Nitro RS4 Gearing Help

I'm undertaking a new project and need some help!

I've built a brand new SN RS4 and I''ve installed the Wolf adapters to run 1/8th on-road large rear tires and the smaller dia 1/8th fronts.

The stock SN RS4 tires are the same diameter front and rear.

Common sense tells me I need to run a different sized pulley for the front and rear. Does anybody have any experience with this? If I was smart enough there's probably a formula to figure this out but I don't know where to start?

Thanks for any help
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Old 03-12-2012, 12:58 AM   #2
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The responses you get for this "Project" you're undertaking should prove interesting.

I have One season of experience running 1/8th scale (Mugen MRX4X), so with this in mind, questions about the Tires you intend to run, along with the front and rear Diffs need to be answered. First, I assume that the SN could only fit 8th scale width Front Tires in the Rear as well as the front of the car, (I can't imagine 8th super wide rear tires sticking way outside the body). Then consider the difference in Front to Rear diameter split, (MRX4X kit default is 69 mm frt, 76 mm Rr), this coupled with the standard Front Oneway diff, Rear spool, near 3 HP of .21 race engine power, are some of the basic elements that determine how the cars steer, (not to mention the "Agressive Driving Style" required).

You might be able to find, via the search function, a link that was posted in these forums that explains "Overdrive" and how this relates to car handling. Also, Mugen Seiki's website could possibly offer their overdrive chart as well as Serpent's site. As others chime in, this could at least get you started.
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Old 03-16-2012, 09:28 AM   #3
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Thanks, el salvador

The plan is to run the HPI GT-One Proceed body instead of the GT-One RS4 body.

The wheel base is 300 mm so that works perfectly. The rears are flush with the outside of the body and the fronts are inboard about 15 - 20 mm so it's not that bad. Looks really good actually.

I did a test and here's what i came up with. I stuck an unbent staple in the rear parallel to the axel and I did the same in the front.

I lined up the staples top dead center and then rolled the car forward until the rear tire staple was again top dead center. The staple in the front tire was forward of top dead center by about 5mm! The belts did not pop or bind. I think I'll leave it!!!

This is a merely a parking lot toy I should have mentioned.
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