I am running a 16-43 setup right now as many of you know. On Comp hill at Dumont on the Banshee side I am pulling right around 8 to 8200 R.P.M. On the steeper side I pul around 7700 to 7800, all this in 3rd gear. Whould it be to my advantage to go to a 16-42 or a 15-42? I am thinking I can utilize the torque of the 720 to pull the 16-42 and i would be right on the power band. On the other hand I am not exactly sure what to do. Anyone have any ideas for me?

 

17/35 and I'll race you for pink slips[img]i/expressions/face-icon-small-happy.gif[/img]

no really I'd try the 15/42 I think your sweet spot is around 8000-8500 stay in the power band man!

 

My 720 setup is a little different than yours, I have Web 109 cams, TM 45 and stock valves (not sure if you have the 40/34 valves) so my sweet spot is a little lower in the RPM range and my DS seems to like taller gearing while utilizing all that torque. My 720 seems to like 16/40 with 22's or 17/40 with 20's. My riding conditions are also far different than sand drags, I always seem to be reaching for 6th gear. I would definitely try the 15 tooth front sproket considering how much sand zaps the power of a quad and the fact that you're drag racing and only in 3rd gear on the hill, just my $.02. One more thing, 17/40 with 22's puts a prety sizeable grin on my face appraoching triple digit speeds on the backroads.[img]i/expressions/face-icon-small-happy.gif[/img]

 

how much tire spin are you getting on that hill?

 

Hard telling Sandman. I should have tried Annihalater's 10 paddles and see if it made a difference. But Big Baja's rig had some new Double buff 25" 10-paddle extreme's and he was pulling the same R's as I was. He was running 15-42's I think.

 

i've switch to some 10 paddle and they help a lot on the hill, also ran some 12 and they were to much, 25 seems tall.

 

When I first got to Dumont I was running the 15/40 and was pulling the hill in 4th (a little low on the RPM though.) I was getting smoked on the hill.

Changed the front sprocket out to the 16 and was now pulling 3rd up the hill (a little high on the R's for my engine though.) 8200 to 8300 RPM in 3rd I was at about 6100 RPM in 4th. It was much stronger in 3rd. I think if I had a 38 or 39 rear sprocket I would have been a bit faster and my R's would be a bit slower.

 

has anyone checked out gearing that would let them pull thru fourth. that was the same problem i was having at sand mt. couldn't pull 4th and 3rd was reving hard. i also did some checking i was getting about 12 mph slower than the gearing calulator said the speed should be unless jeff radar gun was off[img]i/expressions/face-icon-small-smile.gif[/img] which has me wondering about that

 

Sandman:

Every hill is different! Ideally for the fastest speed I think you gear for wherever you go so you are in 3rd gear at about 7700 RPM. This means anytime you go somewhere you have to change the gearing (probably front and back!)

As for flat drags. . . don't know. I would think whatever you can pull in 5th but, maybe some guys have found it better to gear to pull in 4th? Dunno. Don't run them.

I'm sure the gearing calculator is for no slip. Heading up a sand dune / Mt. there is sure to be quite a bit of slip! I would think Jeff's Radar gun was right.

All these changes seem like a pain but, I can tell you I picked up an easy 5 lengths at Dumont by staying in 3rd and had I made a rear sprocket change to keep me around 7500 to 7700 RPM I think I could have picked up another couple lengths.

 

that was the thing at sand mt. if i had npt worked on my quad all that time i could have worked the drive train. but hey is great fun there. i was thinking of droppping one in the front to pull thru 4th. not much chance of hitting 5th on that hill. can you guys actually pull 5th with gearing that high? i'm lower and seem to be at about 8500 in 5th on the flats, and that was with the 8 paddle. well at least it's all fun[img]i/expressions/face-icon-small-smile.gif[/img]