Jump to content
Sign in to follow this  

Changing gear ratios in the field

Recommended Posts

Everyone would agree I'm sure, it would be nice to change gear ratios in the field. Having a high/low range would be sooooo awesome! Anyone thought of a way to easily do this? What if.....(brainstorming)

A pair of rear sprockets were welded together [like 41 & 47], (and a pair of front sprockets [14 & 15]) so that one could just move or replace the chain for the secondary gear ratio. Maybe a larger chain could be mounted if a chain tensioner was used.

Share this post


Link to post
Share on other sites

Why not just take the sprockets off a ten speed bike? Just imagine the versatility with that!

I guess you would have to rig up seperate shifters for the gears though.:applause:

Share this post


Link to post
Share on other sites

i know that some really really old enduros had a little sprocket and a big sprocket attached to each other on the rear and they both could run on the same front sprocket

Share this post


Link to post
Share on other sites

That's a neat idea (the sprocket welding one :applause: ). But you'd have a couple of problems that would seem to make it undoable. First, there isn't enough room on the countershaft for two front sprockets. You'd have to make the inside diameter of the outer sprocket large enough to get the countershaft nut on. And that would leave you with what might be a very weak sprocket.

Also, if you could do such a setup, when the chain is on the outer sprockets, the angle through the chain guide would be pretty weird.

Share this post


Link to post
Share on other sites

Also, if you could do such a setup, when the chain is on the outer sprockets, the angle through the chain guide would be pretty weird.

i thought the same thing but i guess it worked, it was on like a late '60s yamaha enduro it was really really really old has anyone seen this?

Share this post


Link to post
Share on other sites

Also, if you could do such a setup, when the chain is on the outer sprockets, the angle through the chain guide would be pretty weird.

That's why I was thinking a chain tensioner might work instead of a chain guide.

Share this post


Link to post
Share on other sites

I have one of these with the dual sprockets and still ride it, had it since 1980. I'll get a picture of the sprockets sometime tomorrow. Takes about 5 links in and out of the chain with two master links. Tops out about 35 mph with the big one and 55 with the small one.

DSCN0604.jpg

Share this post


Link to post
Share on other sites

I would guess the DRZ400 chain would not like the angle to the 2nd rear sprocket

Share this post


Link to post
Share on other sites

I would suggest strapping a big wrench to the tail of the bike and carry a spare CS sprocket. It only takes about 10 minutes to switch one out. That seems like the logical choice to me.

Share this post


Link to post
Share on other sites

Love my 14/47 combo for offroad, but I'd love to try 16/41 for freeway. Anyone tried that?

Share this post


Link to post
Share on other sites

I don't have a drawing or anything, and this is just off the top of my head, but how about this as an idea...

Use two rear sprockets - one enough larger in diameter that its center could be cut out leaving just the teeth and enough of the ring to hold the teeth together, with the cutout sized to just slip over the teeth on the smaller sprocket. On the inner diameter of the larger "ring sprocket" you could grind/mill/file "half holes" that would line up with the valleys of the smaller sprocket's teeth. Several short grade 8 bolts with nylock nuts could hold the larger ring on the smaller sprocket and also serve to keep both sprockets aligned and everything from slipping. In effect, you would be running the smaller rear sprocket until the larger was needed, at which time it could be slipped over the small sprocket and bolted fast. The chain would continue to be properly aligned.

Uh oh, I just thought of a good reason this wouldn't be such a hot idea. :eek: You'd have to remove the rear wheel to get the larger ring on. Or, come up with a way to hold the large ring securely out of the way. And, there's the issue of whether the chain adjustment cam would be able to cover the two sizes.

Prolly I should just delete this post, but I'm going to leave it in the spirit of brain storming, hoping it will trigger a better thought in someone else. After all, nothing ventured, nothing gained. Keep the thoughts coming - we may come up with something useable sooner or later.:applause:

OK, how's this? Maybe a couple of custom rear sprockets could be produced, where the inner diameter of the larger sprocket has actual teeth milled in it that would fit precisely over the teeth of the smaller sprocket. Shouldn't be a problem for a CNC water jet rig or something similiar. That would result in better distribution of the forces of acc/decel, less wear, more reliability, etc. The outer sprocket could even be made in two semi-circular pieces that could be bolted together onto the inner sprocket, or maybe also have interlocking tabs. Some technical issues to solve I'm sure, but that would take care of the "how to get it on" issue I mentioned above.

I'm smelling something good here...:lol: :lol:

Share this post


Link to post
Share on other sites

for what its worth.... Sidewinder (others might too) makes a rear sprocket that can be changed without removing the wheel, they come in two pieces that lock together.

Share this post


Link to post
Share on other sites

Here are pics of the dual rear sprocket. alignment on the small sprocket is pretty good, the large sprocket is offset. It spends far more time on the small sprocket. I put in an extra 5 links with two master clips to use the big sprocket. It uses a non o-ring 420 chain. I have 7000 miles on it, its on its second chain and original sprockets. Both bolt to the cush drive with the same bolts. Probably could be done on the DRZ, line up the sprocket you would use the most and just accept running a looser chain and increased sprocket and chain wear due to the mis-alignment when using the other one.

sprocket1.jpg

sprocket2.jpg

sprocket3.jpg

Share this post


Link to post
Share on other sites

Those Yamaha Trail master 100's had a round doohickey you could switch from high ratio to low ratio. Really all it did was make up for a motor that didn't make much hp. I can't complain though It helped me heal from the most painful thing that still has happened to me. That was the year my dad died.:applause::lol: :lol:

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×