Weighed my 530 and 520 drivetrain tonight...

Stock Chain = 4lb 13.5oz (77.5oz)...................520 Chain = 3lb 8.9oz (56.9oz)
Stock Rear = 1lb 13.6oz (29.6oz).....................Alum Rear = 10.1oz
Stock Front = 9oz............................................... .520 Front = 7oz.
Stock Hubs = 3lb 12.7oz (60.7oz)....................Cut Hubs = 2lb 11oz. (43oz)
---------------------------------------------- ---------------------------------------------
TOTALS..........11lb 1oz (176.8oz)......................................... 7lb 5oz (117oz)

SAVINGS OF: 3lb 12oz. (59.8oz)

I am hoping to save 2lb per tire by going from a standard extreme hauler to a bead to bead and 10" .190 rim to 8" .125 rim. That will be darn near 8lb of rotating mass. Tires will be here Tuesday and I will weight them. Another cool note is my chain and sprockets cost me about $200 and saved me an extra 7oz over Sidewinders $350 "Titanium" set!

The 520 chain was a DID 520VM, which was the lightest x-ring chain I could find. The sprocket is an aluminum 40t from Jeff Ross made by Sprockets Specialties. The hubs were cut down to a yamaha bolt pattern and I got those from Jeff too. This is on an 04 Baja, so my hubs are already lighter than earlier years, I think by a pound or so. Any questions feel free to ask.

 

Congrats and thanks for the info.

I usually try to get most of my go-fast stuff from Jeff Ross as well. [img]i/expressions/face-icon-small-wink.gif[/img]

 

Thanks, hope its worth it and the aluminum rear holds up. Jeff said it will and I trust him. Do you remember the figure that everyone touts? This much rotating mass equals this much horsepower?

 

10lbs per hp.

 

bump, I haven't seen anyone do this before, figured there would be more response. You know de-mystifying the 520 conversion. Did everyone think there would be more of a difference? or no?

 

I went with the same DID 520VM X-ring chain as you, RWR 15t front sprocket, and 40t aluminum rear from On-Dunes. After the conversion I was pulling the same long hills at Sand Mtn NV, at the same RPM that I was previously with 15/42 gearing on 530 parts. My motor also felt like it wanted to rev a little quicker. Nice little pickup if you ask me.

I don't remember the manufacturer of my aluminum rear (something like PPI or PDI if I recall) but it shows very little signs of wear so far. I do run the 520 a bit tighter than my 530 and I think that helps cut down on wear. I have not had to make any chain adjustments so far as a result of chain stretch.

As far as equating rotating mass directly to freed up HP its not that cut and dry. Every component (front sprocket, rear sprocket, and chain contribute differently due to varying centers of rotating mass. The only way to really tell exact HP pickup at the rear wheels would be a before/after dyno run.

 

HOLY )%^)#$%$#... got my new paddles yesterday and weighed them... 8 pounds lighter total (22x11x10 standard Extreme on .190's vs 22x11x8 bead to bead Extreme on .125's). This brings the total rotating mass savings to 11lb 12oz. HOLY #@%$@#% again!

 

What are you running for fronts tires? My comp cut STU paddla brats are alot lighter than my front dune trackers.
I'm having a hard time believing that 10lbs rotating weight is equal to 1hp, I think you are going to see noticeable gains.

 

I run 22x8x10 Sandstars for the front on .190s, not sure on the weight. I would be very interested to see what your STU's weigh, I heard they are around 10lbs, whereas my double buff extremes are 14lbs. Do you dune with your STU's or just drag?

 

JMann you will feel quite a difference in performance with your lighter tires and wheels.I bought some triple buffed 22-11-8 haulers on .125 wheels last year to use just for drag racing on the hill and they work so well i have a hard time going back to my 22-11-10 extremes for duning.From my experience the tire change you made is going to give you probably two quad lengths gain on the hill.