gearing for mx track

[140pitracer]

I'm trying to figure out best gearing for my pitbike for mx and sx tracks. I'm having a ton of problems coming out of a corners into jumps. The main place i ride is switchback mx in pa in there indoor track. i have a ssr sr140tr the gearing on it is 16/41 on a 420 chain thanks in advance

 

[gottagetacheaperhobby]

If you need more punch out of the corners try dropping your front sprocket 1 or 2 teeth. From memory 1 tooth smaller on the front is equal to going up 3 teeth on your rear sprocket.

 

[motovert24]

on my pitbikes i always changed the front sprocket for every track. 15t front sprocket seem alright for most tracks on the 184/190cc.
for a small private supercross like track i used a 13t, for a larger big bike kinda of supercross style track a 15t. for big wide fullsize bike track like ride park i use a 16t.
for a 140 depends on what track but i think a 14t or 15t front sprocket would be what you are after.
never changed the rear sprocket as my lxr always had sprocket coming loose issues and was just better to bolt it and loctite so it wont come undone
small front sprocket = more acceleration less top speed
larger front sprocket = more top speed less acceleration
smaller rear sprocket = more top speed less acceleration
larger rear sprocket = more acceleration less top speed

 

[140pitracer]

Thanks for the info i'm going to buy a 13t 14t 15t and test them out an see what works best with each track.

 

[my67xr]

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With your bike having a 16T front sprocket now,
you would want the chain adjustment so that the axle is right forward.
if this is the case then you should be able to adjust your axle rearward for the smaller front sprocket's and be able to use the same chain.
Make sure you get the matching locking plate and a couple of decent M6 x1mm high tensile bolt's too.
Some front sprocket's have different pattern bolt hole's so your original locking plate may not fit the new sprocket's.


Check your chain hasn't stretched too when you swap the new sprocket's over
To do a quick check you can grab a link at the rear middle of the sprocket and see if you can pull it away from the sprocket much, if it's stretched you see a bit of a gap between the sprocket and chain.
Or you can unclip the joiner link and take it off, then lay it out on something flat and clean with the pin's sitting parallel to the ground, a good chain won't be able to curve much side to side
Also check for tight and or broken link's

These are timing chain's but same thing, top is new, bottom is well worn,
if they can curve like the bottom one then it's time to replace it