Holy 14T - Sweet Spot!

[Philip]

Judaslefourbe posted this at the EMF Alta forum a while back:

"One thing you need to consider with EVs is the motor efficiency also. The Redshift sweet spot is between 6,000 and 8,000 RPM."

That's a very valuable info!

Unfortunately for MX and single track, this sweet spot is way above the average speed:



And gearing the bike up would make things even less efficient from the motor's standpoint.

So, perhaps, for the longest range in such conditions, one might want to gear the bike down to 11/53 or lower, and use Maps 1 and 2.

 

[snydes]

gprix1: I don't see how you will be able to do 60 miles of 80% single track unless you are swapping bikes, swapping battery or charging in between sprints.
I get about 35 miles on tight single track with some dirt road connectors mixed in.
I have gotten as little as 22 miles in severely technical terrain.

Hey MXR's, how do you like your foot pegs?
The EX foot pegs are no good and am considering swapping with aftermarket (YZF 250 fit) but based on threads herein the aftermarket pegs will angle forward a bit and I would rather get MXR pegs if they are good in wet mud conditions.

@Fod (if memory serves) I think swapped his MXR pegs out for some ankle savers, maybe he’d be willing to sell his. I hear he needs funds for a new chain slider...

 

[Philip]

Even on a smooth paved road 60 miles is not likely, unless you are descending from a high elevation or have a strong tail wind.

I just read that Alta advertises 60 miles of city commute and 4 hours of trail riding for the 2018 Redshift EX.

That's quite optimistic. According to Wikipedia:
Studies that have relied on self-measurement, including those from Internet surveys, consistently reported a higher average length than those that used medical or scientific methods to obtain measurements.

 

[Fod]

@Fod (if memory serves) I think swapped his MXR pegs out for some ankle savers, maybe he’d be willing to sell his. I hear he needs funds for a new chain slider...

Ha ha, But honestly the aftermarket yz250f pegs that fit are a better option. I do need my handicap pegs!

 

[Fod]

That's a very valuable info!

Unfortunately for MX and single track, this sweet spot is way above the average speed:

View attachment 481

And gearing the bike up would make things even less efficient from the motor's standpoint.

So, perhaps, for the longest range in such conditions, one might want to gear the bike down to 11/53 or lower, and use Maps 1 and 2.

This is great info but from what Fog and I have been seeing on our local track is that gearing up is for sure more efficient. The track speed range I would guess is 12 to 45mph range with average speed roughly around 30.

 

[Philip]

This is great info but from what Fog and I have been seeing on our local track is that gearing up is for sure more efficient. The track speed range I would guess is 12 to 45mph range with average speed roughly around 30.

This is probably because less power is being wasted on the wheelspin when the bike is geared up. The wheelspin is a huge battery drainer.

Also, we have no idea how significantly that "sweet spot" becomes unsweet outside of that 6-8K rpm range. Perhaps the motor is still efficient enough there.

 

[gprix1]

gprix1: I don't see how you will be able to do 60 miles of 80% single track unless you are swapping bikes, swapping battery or charging in between sprints.
I get about 35 miles on tight single track with some dirt road connectors mixed in.
I have gotten as little as 22 miles in severely technical terrain.

Hey MXR's, how do you like your foot pegs?
The EX foot pegs are no good and am considering swapping with aftermarket (YZF 250 fit) but based on threads herein the aftermarket pegs will angle forward a bit and I would rather get MXR pegs if they are good in wet mud conditions.

Duncan, it appears worse than that. I finally got the bike out for some testing and was hitting just a little over 20 miles and definitely couldn't get over 30 miles using map #1 on single-track. There are some races where we are able to stop in the pits between loops. I'll run the bike at those but the rest I'll probably be using my 300XC.

 

[Mark911]

I did some quick calculations one day and figured a full battery has about the same "relative" energy as about 3/4 gal of gas. I was allowing the Alta major efficiency numbers so 3/4 might be high depending how you ride.

 

[metallic88]

so what sprockets fit the alta or from what bikes?

 

[snydes]

I’m seeing 2014 KTM front and rear. Didn’t see mention of a model just 2014 KTM.

 

[Rix]

I’m seeing 2014 KTM front and rear. Didn’t see mention of a model just 2014 KTM.

Kevin told me that our sprockets are compatible with a 2014 KTM SXF 250.

 

[Rix]

That's a very valuable info!

Unfortunately for MX and single track, this sweet spot is way above the average speed:

View attachment 481

And gearing the bike up would make things even less efficient from the motor's standpoint.

So, perhaps, for the longest range in such conditions, one might want to gear the bike down to 11/53 or lower, and use Maps 1 and 2.

There is definitely something to this. My first ride two days ago, I was pushing a quick pace in the desert on a mix of hard pack and sand washes in Map2. At about 19-20 miles, my battery meter indicated I had about 20% charge remaining and I was 7 miles away from home. I got on the pavement and rode home keeping my speed between 40 and 45MPH. At the house, my battery meter registered 1 less bar. It would appear with my stock 13/53 gearing, the efficiency sweet spot is right around 40MPH.