Drz250 Thread

[mendydrz]

Originally Posted by JamesK

Can anyone offer some advice on what rear sprocket I would need to give my Djebel 250 more lower pulling power to get up steep hills?

I've read on Thumper Talk that the DRZ400 rear sprocket is a direct swap for the DRZ250, so that should open up the available parts to choose from.

My best advice would be to leave the rear sprocket as it is.
Best off going gown a tooth in the front easier to change as its held in by a circlip. Maybe even 2 teeth and flat stick it in second.
When I put a 12 tooth on mine it's top speed was about 85kmph but it climbed anything in second and third
That way you can change it easily before taking on the hills and switch it back over for the trip home

[tdrrally]

i run a 13/46 on the road its ok off road, some times a 15/46 but its to tall for any off road use

i run a 13/49 off road its very good but 12/49 sounds like its worth a try

[privateer2010]

Here is a good little calculator to help you decide. You enter the number of teeth on the front and rear currently running and then the number for what you are thinking about changing to. It calculates the % of change you can expect to gain or loose. I have been changing out just the front sprocket when tackling steep off road riding, I go down one tooth and leave the rear alone. It is easier and you get an instant 7% or so of gain in low end grunt. Plus if you need to you can still run on the road. Here is the site:

http://sprocketcalculator.com/

[tdrrally]

3:1 is near stock gearing for a stock d/s drz/djebel 250

[mountainduro]

I found this useful information at TT:


According to the official parts fiche, the
DR-Z250 has a 13 tooth front sprocket. It
has always had that front sprocket.
To figure out how changes in tooth count
will affect the bike, take the ratio of the
front tooth count over the rear tooth
count. Thus, stock is
13/49 = 0.2653
If you change to a 51 tooth rear, the new
ratio is
13/51 = 0.2549
The percentage change in mechanical
advantage is
(0.2653 - 0.2549) / 0.2653 x 100 = 3.9%
If, instead, you change the front from a
13 to a 12, the new ratio would be
12/49 = 0.2449
The percentage change in mechanical
advantage is
(0.2653 - 0.2449) / 0.2653 x 100 = 7.7%
Because there are fewer teeth in the
front, the change of one tooth is a bigger
percentage change. However, 12 teeth is
a fairly small sprocket and requires the
chain to bend more quickly. That is why,
when I upgraded my DR-Z250, I added 2
teeth in the back, rather than dropping
one in the front. I also changed the
chain, but the stock chain should be able
to fit with a 2 tooth increase in the rear.
Going to a 53 in the rear will get you a
7.5% mechanical advantage. However,
the stock chain may no longer fit. Is
7.5% enough to loft your front wheel? I
don't know, but it is a step in the right
direction.


And...

Front Rear Rpm Kph Mph
14 41 4500 100 62
14 41 4950 110 68
14 41 7800 173 108
14 43 4700 100 62
14 43 5200 110 68
14 43 7800 165 103
15 46 4700 100 62
15 46 5200 110 69
15 46 7800 166 103

[tdrrally]

the big advantage to the 13/49 is its easy to change the front to a 15 for the road and back to the 13 for off road

with a 15/49 it sings a bit at 55mph but is ok.

i like the 15/46 for road use

[mountainduro]

Originally Posted by tdrrally

that is for the us market drz250 right ?

As I see,I guess so.

[tdrrally]

cool.

i guess gear is a personal thing like suspension

what works for in the desert may not work for some one else on a muddy mountain

its the riden that the most important

[AlexD92]

For those of you who have fatbars, where have you relocated your ignition key switch?

[tdrrally]

i have bolted mine to the upper triple bolt before

it was on the right side, just behind the headlight

[1zero]

Originally Posted by tdrrally

cool.

i guess gear is a personal thing like suspension

what works for in the desert may not work for some one else on a muddy mountain

its the riden that the most important

Interesting and varied opinions on these sprocket combo's it's def a personal preference thing.
My findings are:
Off road riding only, I average 23Kph, with std 13/49 gearing I found i could never be in the right rev range with this gearing, changing to 13/51 made 2nd 3rd 4th gears at the sweet spot for speed/revs/traction etc.
And yes agree also that a smaller front sprocket makes for harder work for the chain to do it's 180 deg wrap around the smaller 12T, cheers guys.

[mountainduro]

Originally Posted by AlexD92

For those of you who have fatbars, where have you relocated your ignition key switch?

Hi Alex this is what I did,just put a little bushing between the switch and the clamp so it can tighten the bars
and a larger bolt.
.
I still owe you my front suspension graphic explanation.
:)

[JamesK]

Thanks for the great advice guys on the sprockets. Based on the posts, I guess I'll try to switch the rear out to either 51T or 52T. My chain whilst still in good condition in terms of free movement of the links and no perceived kinking is at around 80% of max out adjustment so I figure it should stretch across even a 52T. However, I'll shop around to see if I can also pick up a 12T front sprocket and a 51T rear, just so I can play around and see what works best for me.

I read on the TT crossover thread that the DRZ rear sprocket is the same as the DRZ400 so that should open up more options for finding one.

[tdrrally]

dr250/350 non cush drive is the same too

[JamesK]

Hey guys, need some more WOTL, this is my first chain bike, so I'm a noob at anything to do with the chains and sprockets, as in what's good and what's not.
Here is what I've dug up on eBay, what say you? I'm not looking to spend mega bucks by going to Alloy and competition level components, just good quality stuff. This stuff is going to cost me a pretty penny anyway by the time I re-ship it to Japan...

Chain (I believe the O-Ring types are supposed to be better right?)
http://www.ebay.com/itm/150905303146

520 Pitch 112 Links chain with master link. Will the 112 link chain stretch over a 13T (OEM)/52T combo?

Sprockets:
Rear 52T: http://www.ebay.com/itm/220634697162
Rear 51T: http://www.ebay.com/itm/330449933225
Front 12T: http://www.ebay.com/itm/330449844220

Thanks for your help.