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Discussion Starter · #1 ·
Comrades-

Just wanted to share a tuning tip for Scalextricthat I came across earlier this year as I was prepping about 12 high impct cars for my kids and their friends to run on my track last month. Virtually all of my Scalextric GT Sidewinder sets have the traditional gearing summary of 25.5MM. This is typically a 6.5mm slot.it pinion and a 19MM slot.it spur gear. 6.5 + 19 = 25.5. This arrangement has been fine for 30+ scalextric sidewinder cars that I have converted to my digital track. However, there is one GT car where it just doesn't work so nicely at 25.5. The car is slow and it sounds like something is binding. The Audi R8 GT3 was one of my early Scalextric purchases and that is the car in question. I know have 6-8 of these in different race liveries. I find that 25.5mm is too tight on every model of the Audi R8 GT3 that I converted to digital earlier in the year.

So, I decided to try combinations to get the aggregate down town to 25.25MM and I did that by taking a Slot.it 18mm spur and matching it to a Scaleauto Brass Pinion 12-tooth 7.25MM. Let it run dry on my test block for about 10 minutes and applied gear lube from SCC.

The gear mesh has a slightly different sound than the pure Slot.it pinion and spur combo. It isn't any noisier, just a slightly different pitch.The car was so much faster after the gear change,

Curious if anyone else figured this out already? If so, why didn't you posted it for the rest of us!

Have a great holiday,

Chris
 

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From what I remember, Scalextric sidewinder cars have various clearances between motor and rear axle. I always played around with different Slotit and Scaleauto pinion and gear sizes to get a good mesh.
 

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Kevs Racing Bits
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Changing gearing is just normal practice depending on your motor of choice. It's MUCH easier to talk about gear ratio, doing it your way won't always work as you can get same diameter gears with different number of teeth.

3:1 will be faster than 4:1 but slower to accelerate/brake

4:1 will be slower than 3:1 but faster to accelerate/brake
 

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Discussion Starter · #5 ·
Just a follow-up, this tip wasn't really intended to be about gear ratios and was intended to clarify a gear mesh problem. Personally, I like the way my cars run with a 12-tooth pinion vs. the stock 11. I understand there is a trade-off when I move from a 3.27 (11/36) to 3.0 (12/36) but 3.0 works better on my layout.

My tip was to point out that this particular Scalextric Audi doesn't appear to have the typical Scalextric distance from the motor mount to the rear axle. Pointing out the obvious here, but Sidewinders don't have any adjustment between motor and rear axle. The mesh has to be darn good or the car's performance will suffer noticeably. Most Scalextric GT sidewinders seem to be happy with a 25.5 mesh, but this particular car (the Audi) is happier with 25.25.

I have found 2 ways to get to a 25.25. One way is to use a 6.75MM slot.it pinion and combine that with an 18.5MM Scaleauto spur gear. The second method is to use a 7.25MM scaleauto pinion and an 18MM Scalextric spur gear. Both options work. I have had an easier time tracking down 7.25MM pinions, so my preference was to use option #2.

Only wanted to pass along this set-up tip just in case any users were working on this particular Audi.
 

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Kevs Racing Bits
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You can modify the motor mount slightly to allow motor movement fore/aft, I've done this before and fixed the motor position with a little superglue that held just fine. Releasing the motor was easy enough when I needed to remove it by pushing a slotted screwdriver between motor and mount (where I'd applied the glue) and twisting it.
 

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Good to read that you've sorted the problem with your Audi(s), but for whatever reason I've never had a problem with mine and it's always capable of being at the pointy end of the podium (routed track no magnets) with only a change of rear tyres, and providing I'm up to it at the time.
 
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