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Old 12-18-2007, 10:24 PM   #31
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O.K. If my math is correct, 25/69 will put you at a 1.735 (40.4mm) roll out. Once again, if my math is correct, that's more than double the RO you would want to keep that 6x1 healthy.
BTW I am pretty sure a T1 gearbox ratio is 2.125

Which with those calculations: 69T Spur, 25T Pinion, 63mm Tyres this is what I got:
Spur/Pinion Ratio: 2.760
Gear Ratio: 5.865
Rollout: 33.746mm

I think that is correct, lol. Could be wrong. Also what would the RPM on a 6 turn be roughly? Does anyone have an idea?
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Old 12-18-2007, 10:26 PM   #32
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FK05 internal ratio is 1.77.
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Old 12-18-2007, 10:27 PM   #33
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I know the touring cars at indoor tracks (with foam tires around 56mm) hit 65-70 kph on a 90 foot straightaway without damaging the motors, 7x1 usually (pre-brushless). Overall final drive ratio about 10 to 1. Not sure what your internal ratio is, I think about 1.7:1. If this is correct, then you would need about a 3.5 spur to pinion ratio to get to an overall final drive of 6to 1 to let you hit 100kph.. Since your tires are bigger, you need to gear down a little more, though, around 10-12%. Soooo, this works out to about 3.9 to 4.0 spur to pinion ratio, or maybe 70 spur/18 pinion. If your internal ratio is different, you can adjust accordingly.

So, that's where I would start and not be too worried about blowing up the car. Even if it's a little slow, you can always gear up!

Sounds like fun!!! Good luck.
Hi Larry Brown, I just put up the gearbox ratio of my T1. It is 2.125

What gears do you reckon I could put to get my T1 going at about 80-100kp/h whilst still having not too much strain on the engine. It seems you know a bit about this stuff lol. I don't. Thanks your help will be much appreciated Cheers guys
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Old 12-18-2007, 10:28 PM   #34
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oooops, sorry guys. I have been corrected. 1.77 the gearbox ratio is. Cheers
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Old 12-18-2007, 10:29 PM   #35
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I agree w/ Larry. Run it and post a vid.
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Old 12-18-2007, 10:33 PM   #36
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Soooo after all the talking and discussion.

If I were to put a 48p 70t spur and a 48p 18t pinion running in my T1 with my Epic 6 motor in it. Would I be looking at speeds over 80km/h?

All you guys have been a great help. Thanks
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Old 12-18-2007, 10:35 PM   #37
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But atm I am running a 86t Spur with a 25t Pinion. Aren't I gearing down if I put what Larry said?
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Old 12-18-2007, 10:37 PM   #38
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Guess my estimate was close enough so the 18 pinion and 70 spur can be used without too much damage to the motor. If you are familiar with electric motor tuning, set the timing rather mild, maybe in the range of 6 to 10 degrees, to keep the motor from overheating.

Have fun!!
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Old 12-18-2007, 10:39 PM   #39
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Guess my estimate was close enough so the 18 pinion and 70 spur can be used without too much damage to the motor. If you are familiar with electric motor tuning, set the timing rather mild, maybe in the range of 6 to 10 degrees, to keep the motor from overheating.

Have fun!!
I would be gearing down though wouldn't I? I currently have a 86t spur, 25t pinion.
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Old 12-18-2007, 10:39 PM   #40
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Didn't see your recent posts.

Yes, the 70/18 is gearing down from 86/25. Have you tried the 86/25?
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Old 12-18-2007, 10:40 PM   #41
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http://www.gearchart.com/index.cfm?f...n=chart.create

good place for rollouts and ratios of most cars

will even tell u ur speed but does not factor in effiicency loss to wind resistance and such, also to get to the crazy speeds the motor will have to be perfect condition with new brush and trued armature

hope that helps
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Old 12-18-2007, 10:43 PM   #42
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Pie has a good point. These are race tuned motors with NEW batteries, driven by some of the best in the world. Everything has to be in peak condition.
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Old 12-18-2007, 10:44 PM   #43
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Didn't see your recent posts.

Yes, the 70/18 is gearing down from 86/25. Have you tried the 86/25?
Yes, I have tried 86/25. The motor runs good, no strain whatsoever. But, I want much more speed. lol. How about if I try 70/25 for now? Cheers
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Old 12-18-2007, 10:49 PM   #44
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What the hell, go for it!!
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Old 12-18-2007, 10:54 PM   #45
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What the hell, go for it!!
Ok, I'll go for 70/25. I'll also attach a camera to the car.

Thx again all, will have fun trying this out. I will purchase the Robinson 70t Spur tomorrow. And thry this project soon. Vid will be up just after chrissy. lol. Take care, have fun
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