2 Speed Gearbox for any Car!

[Nick Goodall]

Haven't ever seen one of these myself..... can't really see how it works?

http://cgi.ebay.com/TWO-SPEED-TRANSM...QQcmdZViewItem

[Stu]

It's just a centrifugal clutch & one way roller bearing, neat.
Is this similar to the mechanism that was on the PB Mini-mustang?

[Stu]

Advert claims this "It provides racers with more steering control over sharp corner(s)"

[Nick Goodall]

It sort of makes sense..... if it has two gears i assume the first is very low ratio which should mean you get a really responsive car in the "lower" gear so should be easy to get on and off the power.

Sounds like quite a good idea anyway - and not exactly expensive either!

[Chrislong]

Have I read that right, the gearbox is 1 & 8:1

So that means, 1 rev of the motor, = 1 rev of the pinion,
then in 2nd gear, 1 rev of the motor = 8 rev of the pinion?

Wow, that will mean will have to drop pinion size, the the 1:1 is ultra low, as the high is ultra high.

It quotes "higher torgue, acceleration, top speed" but really, torque will be improved on the 1:1 but 8x less on the 8:1, therefore acceleration fast til it engages to 2nd gear, and top speed will be improved over a very long distance, so long as not running in long grass or uphill, as it will just bog down.

It'd be like setting off in my real car in 1st, going to red line then going to 5th.

Mental. if it was 1 & 3:1, it may be worthwhile for offroad. (although illegal by BRCA)

[Nick Goodall]

Chris, i guess it wouldn't be as bad in a real car if you had the equivalent of say 1000bhp though like our 1/10th buggies as they would still accelerate pretty quickly even at the higher ratio wouldn't they?

I guess it would be good on certain tracks - would be cool to see it working anyway

[Stu]

Originally Posted by Chrislong

(although illegal by BRCA)

I don't think it would be illegal, there is no rule making it illegal, so therfore it must be legal?

Anyone......

[LiamD]

No 2-speed gearboxes for electric cars as far as I know. (in relation to BRCA rules)

[Stu]

Is there a rule?
Which section?

[Chris Doughty]

thats quite a clever little device!

not sure it would improve laptimes though, plus it would hang the motor out quite a way to one side.

clever idea though!

[albertobdq]

2 speed transmision are banned for electric cars. The reason why... maybe too much speed, I don't know

Many years ago you can buy 2 speed transmisions, very similar to the ones used nowdays on gas touring cars. HPI, Yokomo and schumacher produced themm in fact schumacher went one step further with 3 speed.

Around a decade ago we clocked a HPI RS4 with 2 speed tranny at 80 km/h with six 1700 mAh SCR cells

[Chrislong]

Originally Posted by Stu

Is there a rule?
Which section?

Can't find my BRCA handbook, must be with the Efra one somewhere...

There was a two speed made for the Cat 2000, i think it was initially made for another car first, it was a dual spurgear type idea like on IC tourers, but I remember then it was illegal so i never bought one and I never saw anyone try one either, I just saw pictures.... and since then, BRCA had no reason to reconsider the rule, although i can't quote it (sorry)

[Oscar]

Originally Posted by Chrislong

Have I read that right, the gearbox is 1 & 8:1

Read again Chris, 1:1 and 1.6:1

[Chrislong]

Originally Posted by Oscar

Read again Chris, 1:1 and 1.6:1

Hey John,
The seller really has screwed up the page. the title definatlely states 1 & 8:1, but in the text it specifies:

Low speed = 1.6:1
High speed = 1:1

Anyway, this seems a bit more like it, I suppose it means to use it, you would be able to gear up so the 1:1 is higher than the overall ratio which is usually run, as the 1.6:1 will easily take care of the standing starts/low speed corner exit.

I still don't want one tho.

[Nick Goodall]

Originally Posted by Chrislong

Hey John,
The seller really has screwed up the page. the title definatlely states 1 & 8:1, but in the text it specifies:

Low speed = 1.6:1
High speed = 1:1

Anyway, this seems a bit more like it, I suppose it means to use it, you would be able to gear up so the 1:1 is higher than the overall ratio which is usually run, as the 1.6:1 will easily take care of the standing starts/low speed corner exit.

I still don't want one tho.

Nothing to do with the amazing amount of room you've got in both X Cars??

[WheelNut]

I've heard a couple accounts from people who have had 2 speeds in their electric cars and from what they say there is no benefit. Since an electric motor has basically a flat torque curve there is no need to keep the motor in a certain range of RPM like you need to with a nitro engine. An electric motor will basically accelerate the same from 5000rpm to 10000rpm as it will from 15000rpm to 20000rpm (on a dyno of other device where load doesnt increase with rpm like it does in a car). Not to mention this device is going to add weight and make you motor stick way out of the back end of your car.