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Yz 250x gearing and ratios

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I just got off the phone with tm designworks and wow did I just learn a boat load of info about gearing and gear ratios. Don't bash on me but I just learned that dividing the back sprocket tooth count by the front count u get your gearing ratio. On my 2017 it came stock with 14/50 which is 3.57. Now I'm at 14/51 which is 3.64. I like it, but I was just told that by lowering the rear sprocket tooth count it will definitely save on wear of the chain guide which I never realized. He told me going to a 13/48 would raise me to 3.69 and help me lug third better since now my gearing is lower.

 

So this brings me to my next question. What are people with the 2017 yz250x running for gearing and what kind of riding do u do? I'm running harescrambles. I also have a gnarly pipe as well as a 10oz flywheel weight. Thanks.

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Going to a smaller diameter countershaft sprocket, the tighter the turning radius so the harder it is on the chain.

 

Say using similar final drive ratios like :

13/48 : 3.69 

14/51 : 3.64

Running the 14/51 would be easier on the chain.

 

The downsides to running much larger rear sprocket (53+) is reduced ground clearance,

perhaps the need for a longer chain and, that the stock chain guide likely isn't ideally designed for running sprockets that large.

 

Here's a handy online calculator: http://www.sprocketcalculator.com/

 

Edited by mlatour

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I have just switched to 13/50 from the standard ratio 14/50. I think overall its a step in the right direction, but maybe a bit too low now. However it sure makes the bike lug better and pull from low down when riding in the tight stuff, plus when going  flat out in 5th gear its more than fast enough for me on a dirt bike...

Thinking that 13/48 might be a good compromise? I have found over the years that a 13 tooth may be a bit harder on the chain and guides, but not by much. Most other brand dirt bikes seem to come standard with a 13t countersprocket anyway.

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See he never told me that about causing more wear on the slide. Not anything about turning radius and being harder on the chain. What do you mean by being harder on the chain? When I had my 07 CR 250 I ran 13/50 and I loved that combo. It's true u learn something new everyday.

 

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You can also change the ratio 

with tire size / aspect. 

The ratio also changes as a tire 

wears / tire circumference size /

revolutions per mile

Do a search on 

Tire Size Calculator

...it explains it all. 

 

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After a fair bit of testing, I have settled on 14/51. At 14/52 my bije was too jumpy and required too much shifting. I can't imagine 13/50 working for me. I ride anything from tight first gear trails to faster 3rd and fourth stuff. Fifth is used for transfer sections. I find it a bit too low at times, but it reminds to not ride like an idiot on forest service roads that connect our trails.

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Ride mostly track and initially ran 13/49. Switched to stock, which made riding less exhausting. But then the step from 3rd to 4th is too big for my taste, so went back to 13/49. 

This is what I really dislike on my X (which is a WR250LC, actually) - the gap between 3rd and 4th. The YZ250 has even steps between the gears, the X is kind of awkward in this aspect. 

But maybe I should have corrected the squish finally, a bit more grunt and getting on the pipe a tad quicker would help. 

 

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Look up at mcgradybrandt's earlier post,

13/48 is for all purposes identical to a 14/51.

(but, as mentioned a smaller countershaft sprocket will always be a bit harder on the chain

tougher on the slider and, likely to wear faster than a larger one)

Edited by mlatour

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And on the same token having a 51 rear tooth is causing more wear on the guide and is more susceptible to being hit by a rock.

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Ride mostly track and initially ran 13/49. Switched to stock, which made riding less exhausting. But then the step from 3rd to 4th is too big for my taste, so went back to 13/49. 
This is what I really dislike on my X (which is a WR250LC, actually) - the gap between 3rd and 4th. The YZ250 has even steps between the gears, the X is kind of awkward in this aspect. 
But maybe I should have corrected the squish finally, a bit more grunt and getting on the pipe a tad quicker would help. 
 

I hate third to fourth as well. It's like I open her up in third and then I need fourth but I'm nearing the end of the straight. So I don't shift but I'm winding out.
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I run 13-48 with a shorter chain and 13-49 with regular chain lengths for tight stuff..
 

Glad u mentioned chain lengths. With running 13/48 will I have to come up with a different chain tension or can I still run what the manual suggests???

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3 hours ago, Hondaracer1318 said:


Glad u mentioned chain lengths. With running 13/48 will I have to come up with a different chain tension or can I still run what the manual suggests???

You can certainly still get adequate chain slack.. I cut an already stretched Oring chain and had no problem with slack....I really like to run my rear as far forward as possible and this compliments that but it's not totally forward to the max.... although 13-49 with the stock YZX chain is the sweet spot for me in the tight stuff..

To add, I have no problems with gaps in gearing with this setup and can stil hit 70 if I need to for some reason in the deserts..  

Edited by Nevada Al
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Here is a short video with the 13-49 gearing in some single track  putting in 1st and 2nd to give you an idea if you listen to the engine... 

 

And one going a bit faster..Not racing though and I'm not sure what terrain racing you do? Harescrambles are probably much different here in NV to what you race.. I haven't raced the 250x in the Idaho tighter stuff yet but will probably stay at 13-49 for that.. 

 

 

Edited by Nevada Al
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Dude thanks. 13/49 sounds nice. Being at 14/51 right now I dislike it in a way because I can't run third out of a corner coming down a hill at my practice track I have to click second then hit it then click to third and fourth. I want to run third everywhere. That is my lugging gear. When I had my Honda CR 250 I loved 13/50. I would be able to blip the throttle in third and lighten that front end right up. And I ran a 13oz fww on that bike. Now I just feel like I need more bottom, more pop.

In those videos especially the first one do you use a lot of clutch work, sounds like you do but I could be wrong? In that type of riding which I don't quite see I would click third and lug her if I had the right gearing and blip that throttle on getting over little stuff. I don't want to go to second. And I never run first. But this last race I had to run first. So I know my gearing is messed up.

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I run the stock setting 14/50. It originally felt like I wanted to add a tooth the the rear....but after adding a GYTR flywheel I kept the gearing stock. 

 I ride mostly singletrack and some doubletrack, tight hilly stuff into a slim few open long sections. I am happy with the gearing and personally feel it is a good mix of both worlds. 

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I'm running 13/50 on my x and it works well for me,I ride a lot of tight s.t. and can pretty much run second like an automatic where as with the stock gearing I found myself shifting back and forth between 1st and 2nd alot.i also added a 13oz stealy weight at the same time so I'm sure that helped alot.i haven't noticed any more wear on my guide than stock.i love first for the super rocky steep stuff,seems to be alot easier on my clutch and bike temp stay lower than stock gearing.ill take the wear on my chain and guide rather than my clutch and motor.

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Well I want either 13/49 or 13/50. This sucks because I don't want to make the mistake of getting a size to small and then say I wished I got the 50. Like I said before I've ran 13/50 and damn was there a lot of pop, but that was on a 2007 CR 250 it was great. I guess I'll try 13/49.

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