Jump to content

New sprockets query

Recommended Posts

I'm in the process of changing the front and rear sprockets on my 2011 TTR250.    It's currently fitted with the OEM Sunstar 44 tooth rear and 14 tooth front but I'm changing to a Supersprox 13 front and a 50 rear.   The original chain is a DID 520V2 O-Ring chain which I'm also changing.

My first question is, the original front sprocket has rubber on both sides but the aftermarket ones I'm replacing them with does not.  Does that matter ?  The second question is regarding a new chain, will any type of 520 oring chain do or is there a specific type I should use.  Considering I changed the original sprockets I suppose using another DID 520V2 isn't really that important now.





I bought a 30mm socket especially for the job and it worked a treat.






I'll wait till the new chain is fitted before torquing up the front sprocket.   Believe me, the original took some getting off !


Edited by steve99

Share this post

Link to post
Share on other sites

Glad you got yours off ok... I had to take my bike up to a neighbor with a BIG impact to get my front sprocket nut off. My smaller impact wouldn't get it to break loose. Don't forget to bend the little tab over to keep your sprocket nut from coming off. My new front was a JT sprocket and did not have the rubber stuff like yours in the pic, neither did the old one.

Stock sprockets on mine were 13/52 and it used a 110 link chain, but I changed the rear to a 50 tooth. With my old chain and front sprocket my rear axle snail adjusters were all the way at the max and the chain was still too slack. When I put the new 13t front on and new 110 link chain the adjusters are between 12 and 13 on the snail adjusters, so there's not much more adjustment for stretch. You can use any 520 chain... regular roller, o-ring, or x-ring. I just put new sprockets and a new DID DZ2 520 roller chain, just because the roller chain is less drag on the motor, but may switch it out for an x-ring DID VX2 since I don't have room for a bunch of chain stretch. 


Share this post

Link to post
Share on other sites

Bikes that did not originally come with O-ring chains might have some clearance issues

behind the front sprocket and engine case (you don't want to be rubbing away aluminium from the case)


My CRF250X originally came with a narrow VT2 style chain, while a 'regular' width O-ring physically fits,

case clearance is a tad too tight for comfort (in case of packing with mud, rocks, branches etc.) 


On some models, thin 'spacers' are available which move the front sprocket outwards to gain clearance but...

that likely will cause chain alignment issues with sliders, rollers, guides and rear sprocket.


The DID VX2 is narrower than most typical O-ring chains and is especially made for

tight fitting applications that were initially designed for regular non O-ring chains.


If anyone is considering a gear change to better suit their usage, here's a handy sprocket / ratio calculator 

link: http://www.sprocketcalculator.com/

While the chain link counts isn't exact for all bikes, it gives you a good idea if a shorter or longer chain will be needed.


An experienced rider can certainly feel a 1 tooth change of the rear sprocket, especially in slow technical terrain.


Edited by mlatour

Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with: