Gearing suggestions for 03 450


9 replies to this topic
  • TeamPrecisionIT

Posted May 05, 2009 - 04:14 AM

#1

I have been running rather tall gearing on my YZ (14f 46r) and have noticed that was a bad idea. I did it to in a sense 'tame' the bike down a bit since it was my first four stroke motocross bike. Anyway, the chain and sprockets have worn down and I am much more comfortable on the bike and just ordered up a 14t front and a 51t rear. I run the taller front sprocket to try and cut down on wear and tear on the drivetrain. I think I am going to buy a couple more rear sprockets to try and find the right gearing for the tracks I ride, what would you guys suggest for spares/test sprockets? I use steel sprockets which are relatively inexpensive and it shouldn't be too big of a deal to get three or four of them and try and find the happy gearing for each track.

Damian

  • grayracer513

Posted May 05, 2009 - 05:30 AM

#2

With a bike like the '03, gearing really is just not that critical, frankly. Stock, they came with a 14/48, and with a little effort, you could put the bike in third and leave it there on many MX tracks.

Changing from the stock gear is necessary only in the case where your particular venue has a turn or jump or other situation where you always feel like you are in between gears. In that case, change the ratio one way or other to, say, extend second gear farther, or to bring third in sooner.

On my '03, I ran 14/49 in the tighter trail areas and tracks, and 15/49 in the desert and the roomier tracks. It worked out pretty well most of the time.

  • Ga426owner

Posted May 05, 2009 - 11:00 AM

#3

I still use 14/47 and prefer it to 14/48 (stock) .....I can use each gear longer and 3gear only for almost 70-85% of the track. I do not ride on tight smaller tracks so this works well for me and with the power my 470 puts out.

Grey I know you have explained why 15/49 setup...is this helping to extend the sprocket/chain life as compared to 14/47?

  • grayracer513

Posted May 05, 2009 - 11:16 AM

#4

Grey I know you have explained why 15/49 setup...is this helping to extend the sprocket/chain life as compared to 14/47?

15/49 is "one tooth" higher than 14/47, two higher than stock. When I set the bike up with it, I wanted higher gearing for the desert, and I needed a rear cog anyway, so I tried to buy a 46. Since it wasn't immediately available, I went with the more or less equivalent 15/49 combo. The good thing about that is that it gave me the flexibility of using the 14/49 when I wanted to.

If you compared your 14/47 to a 15/50, the ratio would be nearly the same, but you would get marginally/technically/nominally less friction losses and chain/sprocket wear with the larger gears, since the chain doesn't pivot as far, and more teeth on the front share the load. It will also drag on the slider less, but probably drag on the lead edge of the lower guide more. It makes more difference as you get smaller. It's a bigger deal switchingh from a 14 to a 13 than it is from a 51 to a 14.

  • TIG88

Posted May 05, 2009 - 01:17 PM

#5

I have a 13/48 combo. What is this roughly equal to with the 14 font sprocket? Would it be better to swtich back to the 14t front sprocket, and a larger one in the back?

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  • grayracer513

Posted May 05, 2009 - 02:09 PM

#6

The relationship is roughly 3:1, so a 13/48 is "the same as" a 14/51. Divide the front into the rear for the ratio:

48/13=3.69:1
51/14=3.64:1
(difference of 1%. Changing one tooth on the rear is more like a 2% change) Bear in mind, this is not the overall gear ratio, just the secondary reduction.

As I said, it's technically a little better to use the bigger cogs, but it isn't a real big deal until you go smaller than 13. The 12's don't last long.

In the rear, your concern becomes clearance at the lower guide. 53 seems to be as big as is practical there without modifying the guide.

  • TIG88

Posted May 05, 2009 - 02:11 PM

#7

The relationship is roughly 3:1, so a 13/48 is "the same as" a 14/51. Divide the front into the rear for the ratio:

48/13=3.69:1
51/14=3.64:1
(difference of 1%. Changing one tooth on the rear is more like a 2% change) Bear in mind, this is not the overall gear ratio, just the secondary reduction.

As I said, it's technically a little better to use the bigger cogs, but it isn't a real big deal until you go smaller than 13. The 12's don't last long.

In the rear, your concern becomes clearance at the lower guide. 53 seems to be as big as is practical there without modifying the guide.


Thanks alot!

  • TeamPrecisionIT

Posted May 05, 2009 - 07:40 PM

#8

Gray thanks for the substantial info.

  • Ga426owner

Posted May 06, 2009 - 07:10 AM

#9

15/49 is "one tooth" higher than 14/47, two higher than stock. When I set the bike up with it, I wanted higher gearing for the desert, and I needed a rear cog anyway, so I tried to buy a 46. Since it wasn't immediately available, I went with the more or less equivalent 15/49 combo. The good thing about that is that it gave me the flexibility of using the 14/49 when I wanted to.

If you compared your 14/47 to a 15/50, the ratio would be nearly the same, but you would get marginally/technically/nominally less friction losses and chain/sprocket wear with the larger gears, since the chain doesn't pivot as far, and more teeth on the front share the load. It will also drag on the slider less, but probably drag on the lead edge of the lower guide more. It makes more difference as you get smaller. It's a bigger deal switchingh from a 14 to a 13 than it is from a 51 to a 14.



thanks Grey - it is coming back to me now....stupid old age :excuseme:

  • grayracer513

Posted May 06, 2009 - 10:46 AM

#10

...stupid old age :excuseme:

You can't use that excuse yet. You have to go farther.





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