dunno if anyone's done it this way before, if so, sorry! used a wee 12v compressor to fill a cylinder ( old fire extinguisher), and a ram to shift the gear linkage. two micro switches behind the wheel, wired thru the horn wiring, and that's about it. oh aye, there's a valve thing that lets the ram rest in mid travel, and work both ways, up and down. passed sva today, didn't want to cost anyone time or money till i knew it was ok! think it cost about £130 for the valve and ram. anyone interested and i'll try and get photos from camera to here... could take me a while though!

Sounds good that. Only 1 question, how fast does it react/change gear?

Seen it done with soda stream bottles on a drag bike, that was quick, the gear change as well as the bike.

dunno, mate uses it on his sprint car, and he's about the fastest up here i think. (supercharged gsxr) so it canna be too bad. i've also wired a relay off the up change switch, killing the feed to the coils, so it's foot to the floor, click the switch, no clutch. and an override to get up from first to neutral without conking out!

Mmmm, sounds even better. I was just curious/worried about the cylinder emptying or running low on pressure and leaving you stuck in gear. Have you tried it for long road runs yet? I quite like the idea, but would need reassuring as I break down enough as it is!

not really a new one ...

Was looking at pressured cylinders a few years back and even found some chaps that used them for 5-speed gearboxes (robotized gearbox as it's called)

It all boiled down to reliability and weight, a lot have tried them and tossed them ( and the idea), it's not worth the hassle of calibrating, leaks and the fact that it's quite hard to get the "correct" force to engage without crunching gears if it stops midway.

So, yes it's possible.
But when the compressor has broken down 7 times, the air pressure drops on track etc, they all tend to go electrical ...

But I really hope I'm wrong and that you have found the answer we all have been looking for, anyway please show us a picture
I guess i'm not the only curious one around here

Cheers

It all boiled down to reliability and weight, a lot have tried them and tossed them ( and the idea), it's not worth the hassle of calibrating, leaks and the fact that it's quite hard to get the "correct" force to engage without crunching gears if it stops midway.
never calibrated, no leaks, a wee bit trial and error on position for smooth change. bit vague on reliability - let you know at the end of the summer!

ps used the low pressure warning switch off a lorry's air brakes to keep switching the compressor on when the pressure drops, mate just fills his bottle once for the race, so pressure loss not a prob.

Don't MNR do somthing like that.

Carl

MNR's System

hmm... seemed to have made an arse of the quote in that last reply... those photos could take longer than i anticipated...

If you are going to use on the road, and will need the pressure reservoir topped up, you could use a small Halfords type tyre pump. Just remove all outer casing and use small pressure switch.

Loads of drag/sprint bikes use this system, either with or without a cut out.

ATB

Simon

yeah, that's what i used simon, bypassed the digital readout etc.

does anyone have any pics or schematics of this sort of gearchange? will it work with any type of gearbox? Am just musing about future projects......

still haven't got round to getting photos, might try tomorrow. will work on any bike gearbox.

New to the site. here's another option Pingel electric shifters.
http://www.pingelonline.com/eshifter.htm
Shifter demo videos
http://www.pingelonline.com/shifter_demos.htm
And these guys make a paddle shifter for cars. http://www.westracecars.com/

[Edited on 16/1/07 by mooner]

some pics would be great, not sure this is going to be any good to me, i am prob gonna have to change the gearbox in my saab at some point, as its goona be bolted to a zetec soon and they were only orginally designed for a 3 cylinder 2 stroke engine! so will prob blow it up at some point and was thinking what i could use as a gear shift as a opposed to making a new linkage i could use this compressed air idea, am not sure what gearbox tho, some sort of transaxle, maybe audi or renault.

thanks for the links, they are really interesting though the shifter is abit out of reach for me!

[Edited on 16/1/07 by trogdor]

should be do able to make it DIY

Air bottle
Compressor
Fittings and PU hose
Pressure switch
2 Electric valves
a 2 way cilinder with enough stroke to pull and push..

problem i saw was the compressor at 12volts.. they all get only 2.2Bar (tyre pressure) and it gets a while to get them sow far also durability and duty cycle takes me of trying it.

Used RC servo“s they are positionable and give also fast torque also they can be programmed to move exactly whats needed and not just a hard pull / push!

Tks