300ex gearing?

[emaxxjeremy]

well i do mostly trail riding and dont really care to go super fast anyway. i am looking for the punch. what gearingshould i be going for? i was thinking about dropping a tooth on the front, as that always helped my street bikes come to life.
also having a tough time deciding between the white bros and hmf pipes?

[ZSK]

Either pipe will help, whichever one is cheaper I'd move on it. For gearing, I always ran stock gearing with 20" tires and it was what I needed.

[Trevor]

With my 20' rear tires I am running 13/36 and I find it perfect. I hit a top speed of 95 kph and it is perfect for tight woods trails.

[300ex13]

Originally posted by Trevor
With my 20' rear tires I am running 13/36 and I find it perfect. I hit a top speed of 95 kph and it is perfect for tight woods trails.

what is the conversion for that in mph??? i run 20'' razrs and stock gearing and does good...i suppose it could be better but its fine for me now

[Trevor]

I think it's arround 55 mph

[bwamos]

Stock gearing works great on 20" tires.

But, if your running 22" tires (stick size), look at swaping the front sproket to a 12-tooth.

A pipe + filter + rejet will wake the 300ex up a lot. I'd look at full system on the 300ex, not just the silencer. You'll want a header too. The stock header on the 300ex is very restrictive.

[POW 352]

ok i got stock gearing in the front and down 2 in the rear so basically adding topend i only have a white brothers e series exhaust small over bore with 11:1 compresion drop in web cam 20" tires and i can pull 4th gear wheelies down the road


this is a power wheelie im still standing on the pegs none of that grab bar crap

[emaxxjeremy]

sweet pic
are you running a full e series or a slip on?

[POW 352]

i've got the full system thing really pulls some monster wheelies

[bwamos]

Originally posted by POW 352
ok i got stock gearing in the front and down 2 in the rear so basically adding topend i only have a white brothers e series exhaust small over bore with 11:1 compresion drop in web cam 20" tires and i can pull 4th gear wheelies down the road

this is a power wheelie im still standing on the pegs none of that grab bar crap

(20*3.14)/(22*3.14)= 0.91 ratio.
12/13 = 0.92 ratio

So your 20" rear tire is doing about the same thing as a 12 tooth front sprocket w/ 22" tires as far as dropping down the "gearing".

If he's got the 22" tires still, he'll need to drop down to a 12 tooth front sproket to match your low end pull.

[ZSK]

Originally posted by bwamos
(20*3.14)/(22*3.14)= 0.91 ratio.
12/13 = 0.92 ratio

So your 20" rear tire is doing about the same thing as a 12 tooth front sprocket w/ 22" tires as far as dropping down the "gearing".

If he's got the 22" tires still, he'll need to drop down to a 12 tooth front sproket to match your low end pull.

On paper that's correct but in practical application it's not. You're dealing with such a small motor and torque output that weight is an issue. If you drop to a 20" tire the gearing will effectively be the same as a 12 tooth and 22" tire but you're dropping rotational mass. A 300ex with 20" tires will be quicker than a 300ex with 22" tires and a 12 tooth sprocket simply because of the reduced rotational mass. On larger quads such as the 400ex or YFZ's, you won't notice this as much.

If your riding terrain permits, you could drop to an 18" rear tire and go up to a 14 front sprocket and be quicker than the 20" stock gearing, or 22" 12 tooth. Much of it is math but a lot of it is also practical applications.

[TRXRacer1]

Originally posted by ZSK
On paper that's correct but in practical application it's not. You're dealing with such a small motor and torque output that weight is an issue. If you drop to a 20" tire the gearing will effectively be the same as a 12 tooth and 22" tire but you're dropping rotational mass. A 300ex with 20" tires will be quicker than a 300ex with 22" tires and a 12 tooth sprocket simply because of the reduced rotational mass. On larger quads such as the 400ex or YFZ's, you won't notice this as much.

If your riding terrain permits, you could drop to an 18" rear tire and go up to a 14 front sprocket and be quicker than the 20" stock gearing, or 22" 12 tooth. Much of it is math but a lot of it is also practical applications.
True but way over thought. For his needs I think the advice already given is fine.

[bwamos]

20" 6-ply is heavier than a 22" 4-ply also. ;) There's lots of factors.. rotational mass is an issue.

Just keeping it simple though.

If he wants 22" tires for trail riding clearance, go with a 12 tooth front sproket.

If, he doesnt need the clearance a 20" tire is better. Heck, go to a 14/36 setup with an 18" tire in that case. ;)

[emaxxjeremy]

i am running 20" razr 2's and they are in fact way heavier than the original tires.
i am trying too hard, i think, to make this something its not. i wish i had gone bigger from the get go, but i didnt. so now i'm stuck either sell this and lose my arse, or pour money into it to make it feel bigger.

[Flo Bee]

Originally posted by bwamos
20" 6-ply is heavier than a 22" 4-ply also. ;) There's lots of factors.. rotational mass is an issue.

Just keeping it simple though.

If he wants 22" tires for trail riding clearance, go with a 12 tooth front sproket.

If, he doesnt need the clearance a 20" tire is better. Heck, go to a 14/36 setup with an 18" tire in that case. ;)

I'm 14/38 currently with 20" Holeshots.

In 5th gear I hit the factory rev limiter hard.

I'm going to a 15/36 today to see what that does.

[Butters]

i have a 14t, but i plan on getting 20'' tires. that way it is about the same as stock gearing.

[Flo Bee]

14/36 is the hot ticket with my 20" Holeshots from my initial test ride today. Makes for much more usable gearing.

[kd5sfq]

A 12/38 will add to the low end but will probably put you in the rev limiter on top end if you drop your tire size by much.

[1998300ex]

I ride a 98 300ex with 20 inch holeshots and i was wondering what gearing would be good for mx. I have the stock gearing right now but i am wondering if there are any good gearings for mx racing. thanks

[bwamos]

Originally posted by 1998300ex
I ride a 98 300ex with 20 inch holeshots and i was wondering what gearing would be good for mx. I have the stock gearing right now but i am wondering if there are any good gearings for mx racing. thanks

On 20" the stock gearing should be about perfect.. maybe a hair tall. If you think it's too tall, try a 12/36 setup.

[1998300ex]

thanks man, i might just try that and if i do ill post how it was on here.

[SidewaysSam]

So would you change the gearing any with 18" on the rear?

[bwamos]

Stock gearing on the MX track with 18" tires and a stock bore motor is perfect, IMHO.

If you're riding in more open areas, I'd put a 13/36 ratio on it, or a 14/38.

Gearing:
13/38 is stock
13/36 = 5.6% taller
14/38 = 7.6% taller

22" + 13/38 gearing = 23.63" per rotation of front sprocket. Top speed 55 mph (reference only)
18" + 13/38 gearing = 19.34" 22% drop. Top Speed 45 mph
18" + 13/36 gearing = 20.41" 16% drop. Top Speed 47.5 mph
18" + 14/38 gearing = 20.82" 13% drop. Top Speed 48.5 mph
18" + 14/36 gearing = 21.98" 8% drop. Top Speed 51 mph