Best Map for least sensitive throttle.

[Alta_mxr]

I’m currently geared 13-50 on 18’ MxR. I have been struggling a bit with pretty loose conditions. Like a dry gravelly or dirt up hill. With no clutch to feather it breaks the rear tire loose easily. And once it starts hard to stop and get going again. Tried in map 1. Thinking to try map 2 next time out. Using pretty gummy tire with tubliss and 7psi. Another problem area is a narrow trail that drops off on the edge if u lose the rear wheel off the path you can’t just crawl back on very easily. When not on the Alta which isn’t very often anymore I ride a 250xc 2t which is noticeably better in these 2 areas.

 

[Philip]

I think Map 1 is your best bet. To prevent or limit the wheel spin you need just barely enough of power to get you up that hill. The less extra power you have -- the less wheelspin you can produce. My 2c.

Do the two bikes have the same rear tires?

 

[Alta_mxr]

I think Map 1 is your best bet. To prevent or limit the wheel spin you need just barely enough of power to get you up that hill. The less extra power you have -- the less wheelspin you can produce. My 2c.

Do the two bikes have the same rear tires?

Yes exact same tires. Tubliss and psi same. It’s really not a trials type problem like spinning over a solid object like a root or rock. It’s when the ground is loose like fine dirt or gravel that’s the problem. The point between enough to keep climbing and not spinning is hard to manage or find with just the throttle. It has plenty of power it’s just when it breaks loose it won’t settle down and get traction again like my other bike. Its like I need a wider power delivery at the lower end of the throttle turn. Or some kind of electronic clutch

 

[Philip]

What you need is a "Tractor Map". Ask Lyndon Poskitt where he got one.

 

[Philip]

I am not much of a hill climber, but I found it a lot easier to do on the Alta compared to my 2-stroke Husky. Climbing dusty/gravely/rocky uphills in Arizona that is.

But I know what you are saying, when the traction is low the Alta's rear tire just keeps churning steadily, not stop-and-spin-stall like on an ICE bike. Shutting down the throttle or using the LHRB are the only options.

 

[Alta_mxr]

What you need is a "Tractor Map". Ask Lyndon Poskitt where he got one.

I’m sure that got taken out of his van too

 

[snydes]

Yeah, the better question is where is it now.

 

[WoodsWeapon]

Surprised your having traction issues at 7psi with Tubliss.

 

[Alta_mxr]

Surprised your having traction issues at 7psi with Tubliss.

That’s what I’m thinking. Traction to all out spinning is like a light switch with this thing a bit. In the right conditions. Up hill and loose. I see Lyndon doing it too in some of his Erzberg training vids. I’m hoping there is a tractor map and we can load it too for enduro type up hills.

 

[Fod]

How about running more sag? Are the rear rim scrubs the same on both bikes?

 

[Fog 25]

I would like to see what would happen if you went back to a 53 rear and try it on the same trail. I think the bigger rear socket might give you more down force on the wheel so more traction.

 

[Alta_mxr]

That’s lower gearing would spin even more. I love the Alta compared to my 2t Ktm except for pretty steep up hill loose ground. I think the instant torque is too much in a bad traction situation. I would think they could do some kind of traction control based on wheel spin and motor load or feed the front wheel speed into the computer to compensate for the touchy throttle and keep it moving forward. Like I say it would be cool for a map that maybe would only give you half the available power but still be in a full twist of the throttle. You would switch to it only when you are going into those kind of situations. All this discussion would mainly be for off road technical riding. The Mx tracks I have ridden would never be an issue. And I guess that’s what the bike was designed for. This off road stuff will come over time I think. The Erzberg experiences will definitely expedite things

 

[Fog 25]

What size gearing is on your 250xc 2t?
I know its lower gearing. I suggested the bigger sprocket because with the torque of this motor I think it will turn the rear wheel slower, creating more traction and down force. With the gearing you have 13/50 is like going is like going down 7 teeth on the rear from stock, which would be taller gearing making the rear tire spin faster. Like I said it would be interesting to see if the larger rear sprocket on the same trail would increase traction. The only way to know is by trying it.

 

[Kurlon]

My understanding is they do a form of TC by simulating flywheel effect. In simple terms the map may say X RPM @ Y Throttle means dump 50A into the motor but it's also watching the rate of RPM climb and backing off the power to match a rate of increase limit? So what you want is a map with more simulated flywheel.

 

[Oded]

I think that with time, you'll get used to it. Since you are coming from ICE clutch equipped bikes, you are used to tame the throttle with the clutch.
With the Alta it is all about controlling the throttle with your right wrist. Something that is far from being natural for ICE riders.

That said, perhaps my EX's maps are completely diifferent from the MXR, not sure.

 

[Mark911]

You need to realize that the most difficult motor mode to control is very low speeds. The controller needs to know the rotor angle just like your ICE bike needs to know the crank angle, only much more accurately. At zero and very low rotor rpm the exact angle is difficult to determine and startup algorithms are needed to get the motor spinning. In my experience, even the best startup algorithms can't quite match the low speed torque delivery of a trained hand and clutch.

 

[Alta_mxr]

I have read through the dyno demystified thread but can’t find how rpm relates to throttle position. Has anybody tach’d the countershaft at various throttle positions in the different maps? Like 1/8-1/4-1/2-3/4-wot. Maybe I should take that on
Gotta get a tach.

 

[Mark911]

In general, max Torque/HP dyno tests are performed at WOT as would be expected. If you just want motor rpm at specific throttle openings (the load should be kept steady) it's not difficult to get ball park numbers. Just mark your throttle grip and clamshells at 1/8, 1/4, etc. Run down a level (long and safe) road and check your speed (mph) at each increment. Then do the math. Calculate/measure rear wheel diameter, gearing, and the final internal gear reduction (it's on the Alta website) and you'll find the motor rpm for each throttle position given the load imposed. Change the load and the results will change as well.

 

[Alta_mxr]

Ok disregard all my previous posts. Went to a decent up hill tried all the maps multiple times and the winner is map 3. Not sure why but the best map for me on a loose PNW hill climb is map 3. It still spins maybe even sooner than map 1 but it doesn’t over spin. You can actually keep progressing forward while controlling the spin with the throttle. And as you progress up if the ground tightens up you actually stop spinning mid hlll as well.

 

[Josh402]

Try a wider wheel/tire that 450 bikes use. The Altas use 250f sized rear tires.