Drivers

[SledFreak]

How many tooth driver is the drive axle on the Apex? 10 tooth? Aslo, what is the caculation used to figure out what the actual top speed is on these Apexes? Some guys are using stock gearing with turbos and they are pulling close to a 135-140mph. I would think our sleds are way over geared.

 

[Srxspec]

9 tooth drivers

The formula to figuring out MPH at a 1:1 ratio with 9 tooth drivers is as follows:

(Clutch RPM / Gear Ratio) X (22.68/12) X (60/5280) = MPH

Or use the chart I attached. You can enter your engine rpm to find your clutch speed towards the bottom and then enter in your gearing from there. This will require Excel to view the attachment.

 

[ROCKERDAN]

Srxspec....can you help me out and give up the answer for our apexs with 24/38 gearing?...i mean the thoeretical top speed.

Ive also heard 135/145mph with stock gears...if this is true then Ill be adding a 23 top tooth gear soon!

one thing im wondering,does yammie gear them tall to help REDUCE track spin at holeshot?....The attack has 23 gearing but longtrack,maybe the increased traction of attack allows yammie to go with 23 top gear.

Im assuming a 23 geared apex rtx would need some major studding to hook.

Dan

 

[Srxspec]

Stock Apex gearing motor spinning 10,700 rpm.

1:1 clutch ratio: 117 mph
5% Over Drive: 123 mph (roughly the % of OD that the Yamaha clutch will shift out stock)

Stock Apex gearing motor spinning 11,000 rpm.

1:1 clutch ratio: 121 mph
5% Over Drive: 127 mph

I ran 23 tooth top gear in RTX with the stock Ripsaw and 144 studs down the middle and it worked pretty good. I then changed to a 1" Hacksaw with 144 studs down the middle and struggled with hook up. I've since gone to a 128" Ripsaw with 154 studs down the middle and traction is excellent.

 

[ROCKERDAN]

hmm...why are there so many discrepancies here?.....ive heard several SC and turbo guys who run 140 with stock gears..and most guys who do the math keep coming up with 115-120 range...why???????..

are you guys running turbos at 135-140mph onn the gun??????????..or dreameter???


thanks
dan

 

[SledFreak]

My buddy has a turbo 310hp and he blew the track @131 mph on the gun, with stock gearing.