EXR/MXR Maps

Watt Fun

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Eldridge Iowa
#1
I recently purchased a 2018 MXR that will be used for GP races. I currently own a 2019 EXR and it feels that the MXR is made for higher top end in maps 1&2. A few of these races have endurcross sections where the low end power would be best. I am guessing that a change in sprockets would be the best solution?
 

Watt Fun

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Eldridge Iowa
#3
Thank you for the reply. New to Alta but I love these bikes.

Is the front sprocket the same as any other manufacturer like Honda, KTM etc? I would like to drop as much on the front as possible because I see the back is already a 53t. I plan on just gearing the bike super low because I don’t need a ton of top speed anyway.
 

TCMB371

The Silent Assassin
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#4
The front sprocket is standard KTM style. The MXR has a 12T front sprocket stock. I'm not sure if anyone has tried smaller than a 12T in the front (maybe alta employees have), but you may run into issues with quicker chain slider wear and maybe some chain binding since its a smaller radius.
 

Watt Fun

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Eldridge Iowa
#5
The front sprocket is standard KTM style. The MXR has a 12T front sprocket stock. I'm not sure if anyone has tried smaller than a 12T in the front (maybe alta employees have), but you may run into issues with quicker chain slider wear and maybe some chain binding since its a smaller radius.

Good point. I will check that out.
 

strider

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NE Oklahoma
#7
I find it odd that you feel the MXR has better top end. IIRC the EXR has a 13T front sprocket and the MXR a 12. So the EXR should have higher top end no?
 

Judaslefourbe

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#8
I find it odd that you feel the MXR has better top end. IIRC the EXR has a 13T front sprocket and the MXR a 12. So the EXR should have higher top end no?
One thing to keep in mind also is the butt-dyno lies: you might think you run out of steam when you are actually in the HP (as opposed to torque) portion of the RPM and your performance is not falling off. Josh Hill fell victim to that trap more than once.

Hopefully that makes sense.
 

Fod

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CA
#9
One thing to keep in mind also is the butt-dyno lies: you might think you run out of steam when you are actually in the HP (as opposed to torque) portion of the RPM and your performance are not falling off. Josh Hill fell victim to that trap more than once.

Hopefully that makes sense.
I guess at his level of jumping into another zip code and landing on a postage stamp...he needs to rely heavily on his butt hair senses.
 

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