Dual 420's instead of one 530??

[avendlerdp]

Hello all-

I posted up on the "Meet and Greet" area with a bit of info about my ride.  It's a pavement car powered by a CBR900RR engine.  More info:

http://dtsfab.com/index/index.php?topic=1070.0

The off road world attract way more creative minds so I am going to pick your brains here...

I am running a 14-49 rear ratio with a 530 chain.  The big problem is, due to space constraints, the center to center distance of the two sprockets is only 8.5 inches.  This makes for a stupid short 530 chain and not enough wrap around the big sprocket.  After about 8 hours the chain is worn out.

So, what I think I am going to try and do next is dump my 530 chain setup and go with a dual 420 rig.  With a 420 chain the sprockets will be a lot smaller and that will make our short center to center distance more viable.  I already know that there are no true 420 duplex chains that can be used externally.  The industrial duplex chains need to be in an oil bath.  There is no way for me to make a chain case for the budget this car needs to be built on.  The rules are strict and since the car is one of the fastest we get inspected very carefully by the surprisingly smart judges.

I think it's possible to simply run two 420 o-ring chains right next to each other on identical sprockets.  I would simply cut the teeth off my 530 sprocket and bolt a pair of 420 sprockets onto either side of the now toothless 530 one.  That takes care of the rear.

I guess for the front I could turn down an existing counter sprocket and weld a couple of 420's on there too.

I think the big issue is: Is it possible to get two sprockets that are truly identical?  The tooth timing must be dead on or the two chains will have different tension.

Who can make sprockets like this without charging an arm and a leg?  Will two 420's be strong enough to deal with 120hp?

Thoughts??

Thanks!!

[Boostinjdm]

what you are talking about is double singles to single chains side by side.  I mentioned it in my pilot thread and Whiplash also has a thread that it has been discussed.  Look through the last couple of days worth of topics and you will see it.

[avendlerdp]

Thanks for the reply.  I checked out those other threads and there was some good information.  It looks like there are a couple of people who might be able to make the sprockets.  I will contact them.

I think the twin 420 idea could be a bit better then any 530 solution because we have to use such short chains .  By using 1/2" pitch chains there is a gain in ground clearance.  Also the 420 chain will have a lot more links for cooling.  Also one can use a 14 tooth front without needing a giant rear sprocket. 

I'm going to look into this further and keep you all posted.  In my application the car runs at speeds between 50 and 100 mph for 8 hours at a time stopping only for fuel/driver change.  If the twin 420's work for me I would venture to say they would be good for anything with less then 150 hp.

Oh, and here is a pic of the car running at Thunderhill Raceway.