gearing on a 125

[Henry]

what kind of hear combo should i run on my rm 125? right now it is 13/50, but i just read that, that combo is good for a 250. what do you run?

[KKXR400R]

Originally Posted by Henry

what kind of hear combo should i run on my rm 125? right now it is 13/50, but i just read that, that combo is good for a 250. what do you run?

I think it would be all preference on this one. On her 125 with a six speed tranny Tracy ran a 13/53 on the tight stuff and a 13/50 on the wide open stuff I think we even ran a 49 at one time but ran into a lil bogging.

What kind of riding do you do?

[Henry]

MX track

[KX02]

13/50 seems like awfully tall gearing on a 125. Do you know what the stock gearing was? On my last 125 I ran two more teeth than stock on the back sprocket, 12/51.

[Henry]

Originally Posted by KX02

13/50 seems like awfully tall gearing on a 125. Do you know what the stock gearing was? On my last 125 I ran two more teeth than stock on the back sprocket, 12/51.

i dont know what the stock gearing was,but when i got the bike it was 13/49, now it is 13/50, and it is a six speeder.

[the_privateer]

i run 13/51 ride 50% track 50% woods and have always liked it on my yz (6 speed also) you can look up the stock gearing on [Only registered and activated users can see links. ]

[quadfather03]

I bought my bike off an experienced racer/mechanic and it had 13/52. I have never had any problem with this gearing.

[bikepilot]

It totally depends on the track, your riding style and level and the conditions of the day. Its really totally meaningless to say what you should run without knowing all those things. If you find the bike is geared too short go taller and vice versa till your happy, simple as that

have fun

[kwmotocrosspunk]

Originally Posted by bikepilot

It totally depends on the track, your riding style and level and the conditions of the day. Its really totally meaningless to say what you should run without knowing all those things. If you find the bike is geared too short go taller and vice versa till your happy, simple as that

have fun

just remember:

1 tooth in front= 3 teeth in back

[wamxp1mp]

My '06 yz 125 is 13/48 stock I had no problems with trial or track on it with this gearing. My bike as a 144 now runs 14/48 gearing!

My '04 KX 125 had 13/49 gearing on it '02 YZ 125 was 13/49 '01 CR 125 was 13/52.

keep it in the 48 to 52 tooth rear range and your good, you want more snap you add teeth to the rear but it comes at the exspense of top speed and each gear will rev/tap out alittle sooner. Flip it when you take away the teeth.

Try not going past 53 rear thats a pretty big sprocket at the point anything larger will be hard to find and then it might not clear the chain guide. If you get to that point you'd be better off dropping a tooth off the front sprocket a 12 tooth front will have similar effects like adding to the rear.

[Florida 393]

Henry,
I'd agree with the above, we ran 13/52 on John's CR 125 for an MX set up. If you ride several different tracks with some having tight conditions and others with long straights keep an assortment from 49-52, as said above. You can run short lengths of chain with two master links to vary the chain length for the different sprocket sizes and to vary the wheelbase length too.

When John and I pitted for T'Dub and Stevie at a DTX short track they had a rack with about ten sprockets for the track conditions. Several C/S sprockets in the parts box also. However the smaller C/S sprockets have higher acceleration forces on the chain and larger than 14 can get into swingarm clearance problems.

Bill

[wildchild55719]

i run a 13/51 and 52 play around a bit see what you like. I like the 52 the best keeps me out of first less chance of hitting neutral. What are you looking for ????

[Aus_Rider_22]

Bit late on this one sorry, but I always ran 1 of 2 gearing setups. Either 12 or 13 counter sprocket with a 50 rear sprocket. Depending on track, conditions and my mood! Experiment and I am pretty sure you will find some ratios will compliment certain tracks or situations

[Henry]

thanks i think eventually im gonna swith to a 53 tooth in th rear.

i just got the new issue of MXA and on the back the advertising for renthal it has a picsture of Mike Alessi's bike and says he runs 13/52 on a 250f, dont you run a lower gearing on a 250f because they alreeady have the tourqe?

[leaper]

i got my 95 cr125 at 12/52. Pulls very very hard

[CRacer659]

hey sorry to go through it like this but Im a new member and I dont know how to start a new post in this forum. Could someone please enlighten me?

[RoostRM125]

Go to the section that obtains to your topic and go to the top left it says "new thread".

[RoostRM125]

While on this topic. Why is it bad to run a larger tooth rear sprocket such as a 53 or 54 obtaining to the chair sliders and rails?