Tire size versus gears

[Kingwood Raptor]

I just removed my stock wheels/tires (20x10x9/21x7x100) to Holeshot MX4 19x10x10 and MX6 20x6x10. I know it cost me some top-end speed and would like to know what front/rear gears it would take to get the speed back? I do alot of dirt drag racing..

[Colorado700R]

IMO you went the wrong direction in tire size (Raptor's torq already makes allot of wheel spin with stock size tires), but you know your set-up and tracks better than me.

I'd go 15 front and 40 rear to start



Aaron

[Kingwood Raptor]

Thanks for the input.. This is the set up ITP suggested for my riding conditions. They said that these tires hook up really well on loose/hard packed dirt. Of course I bought the largest tires in the MX line. I knew this would hurt my top end but figured if I could get it to hook up better then i would make up the top end speed in the gears.

[Colorado700R]

the problem I see for you is that the raptors don't rev up as fast like 450s, but they have more torq available sooner.  I understand that top speed isn't much of a concern in short drags, but I'm afraid your really gonna get left behind on the launch because the smaller tires are gonna spin easier even with the good ITP MX knobs.   

[Kingwood Raptor]

  I just dropped $700 on this set up.

[Colorado700R]

I just dropped $700 on this set up.

The gears will help some    and I think I suggested the wrong size for the rear    38 is stock I believe so 36 maybe?


Aaron

[Kingwood Raptor]

So 15/36 would be a good starting point?

[Colorado700R]

I think so, but I'd like to see what some of the other dirt draggers here have to say before you go purchase anything.

[Peelz]

colorado is correct. I would go up a tooth on the front sprocket (they're cheaper).  Then you will get all your top end back plus some. Especially if you have any engine mods. The taller front sprocket will keep you in gears longer before you have to shift which is good for dragging with the great torque of the big bore raptor.

[Kingwood Raptor]

Just go up one in the front and leave the rear alone?

[Colorado700R]

I'd still go down in the rear with your tire size.  With your mods a 15T front is a good with stock tires, but won't be enough with your smaller tires.

Aaron

[Peelz]

Didn't notice the mods in your sig. . you got plenty of power to pull that off with smaller diameter tires. Go down one in the rear. Hell, just buy one, then check it out. Not enough, go for the other. i might start with the rear. Hey I will go find the gearing calculator. Just a sec.

[Kingwood Raptor]

Thanks for the support...

[Peelz]

try this: put your #'s in and see what the difference in speed is versus stock, smaller higher gears. This one is stickied at R.F. maybe we should here?

http://www.dansmc.com/mc_software1.htm

wait..not quite what I was looking for. Try it and see, I will keep looking, I want to look into changing mine as well.

[Colorado700R]

Wilco Peels

Also, I just did a little research the 15T will run you about $10 from RMATV.  The rear will run anywhere from $20 for a cheap steel. to near $60 for a Renthal.  If you were gonna try out two diffrent rears, and get the quality parts, you might just want to buy 2 20-21 inch rear tires for about the same price?

Just a thought