home made 2spd gear box

[coachgeo]

may not be strong enough for our applications but it might open up ideas

http://www.thepixelpump.com/widdershins ... ission.php

[pietenpol2002]

All in the interest of being creative - right?

How about this as a 2 speed option instead? Mount the differential shown below in lieu of the front jackshaft.

http://www.surpluscenter.com/item.asp?i ... powerTrans
http://www.peerlessgear.com/node5380.aspx?pid=300845
http://www.geminikarts.co.uk/files/Peer ... 100120.pdf

Attach 2 different sized sprockets on opposite sides of the differential. Those 2 sprockets would drive 2 differently sized sprockets on the rear jackshaft to provide the desired ratios. Mount the higher ratio rear sprocket on an overrunning sprag clutch so that the rear sprockets drive independently of one another allowing the higher ratio sprocket to freewheel when the other is engaged.

http://www.vxb.com/page/bearings/PROD/K ... Mgodc2oA5g (or if you've got deep pockets, go with a Formsprag)

Then mount disc brakes on the 2 front sprockets that are actuated alternately of one another.

http://www.racemotorparts.com/productim ... _Break.jpg

Braking one side of the differential would allow the other sprocket to turn and conversely....................................
And of course there would be a final drive sprocket on the back jackshaft to drive the rear wheel.
The one down side would be the lack of engine braking with one of the ratios due to the sprag clutch.
Probably only weigh a hundred pounds and cost a thousand dollars.

Just needed to exercise the brain a bit before I turn in for the night.

[redlined_b16a]

the diff idea is pretty nifty.......but when a diff is ran as you are talking about,locking one side with a brake and allowing the other side to rotate only,it develops a lot of friction which causes a lot of heat.You would then need one way/cam bearings somewhere in there.

[boutje]

Look at the victoria bergmeister gearbox.
That is a 4 speed with chains.

http://www.v35-bergmeister.com/html/pc_gear_shafts.html

[Diesel Dave]

may not be strong enough for our applications but it might open up ideas

http://www.thepixelpump.com/widdershins ... ission.php

That's exactly how the early 2 speed Morgan 3 wheelers worked, 2 chains to the rear wheel providing the Hi and Lo ratio's and a dog clutch between the 2 driving sprockets. They used to handle the power of the sporting V twins for racing.

I think the earliest was 1915....