You can get Shinko Cheater 505 and 525, as well as the Dunlop I put on my CRF #2 in both 18 and 19, but generally speaking 18" does offer more enduro options, while 19" ends up as a slightly lighter wheel that turns easier.
-
Hello ES! We could use some help to get us past the finish line on building the new knowledgebase for the forum.
Can you donate? Please see our fundraising page. Thank you!
RMZ250 (hard)enduro build
- Thread starter Balgaroth
- Start date
Second ride today. I noticed that if the bike loose too much speed on the steep hill it will then slow down and eventually stall. Is this normal ? I guess it also happens with ICE bikes but I was not expecting it, especially not beeing able to restart from where I stopped as the bike doesn't have the power. All this seems weird to me as even with my 125 usually the problem is finding traction to restart, and on the eRMZ I run a almost slick MX tire with 1bar of pressure (vs my 125 which has tubliss at 3psi and fresh tires). Even switching to the Sport map (330A line, 680A phase) in some cases it wouldn't move. After that even in the flat or low incline the bike felt sluggish at low speeds, ok once it gained a bit of speed.
Because of this I checked my temps and found that motor and ESC were around 70°C (30°C outside temp), could it be that the motor and ESC were too warm which would cause fade or even some sort of limp mode ? Currently I have a 13/48 transmission, would going to 13/50 or even 13/52 help with this ? Because of this I also tried to do some starts afterward and again it feels really soft in almost all maps and above 10 or 20kmh the bike feels very powerful. So is this a ebike thing ? Is this due to my chain/sprocket combinaison ?
My ratio in speed are 100% from 0 to before 6000 rpm I think, so I don't see what else I could do there. Maybe the throttle setup ? I don't see why that would be the case as when the bike dies down on a steep hill, even with full throttle it won't do anything.
After that I went for more flow single track sections (up and down) and the bike was really good in daily mode. The suspension is way too hard, I need to check the Sag front and back but I used less than 200mm today, true I didn't do any real jumps but I would expect to see a little vit more travel used.
Today spin was 21.5km for 810m of elevation in total, the battery was roughly at the same discharge than for the previous ride. I have a little bit of regen which feels somewhere between a 2t and 4t ICE bike which feels good.
Because of this I checked my temps and found that motor and ESC were around 70°C (30°C outside temp), could it be that the motor and ESC were too warm which would cause fade or even some sort of limp mode ? Currently I have a 13/48 transmission, would going to 13/50 or even 13/52 help with this ? Because of this I also tried to do some starts afterward and again it feels really soft in almost all maps and above 10 or 20kmh the bike feels very powerful. So is this a ebike thing ? Is this due to my chain/sprocket combinaison ?
My ratio in speed are 100% from 0 to before 6000 rpm I think, so I don't see what else I could do there. Maybe the throttle setup ? I don't see why that would be the case as when the bike dies down on a steep hill, even with full throttle it won't do anything.
After that I went for more flow single track sections (up and down) and the bike was really good in daily mode. The suspension is way too hard, I need to check the Sag front and back but I used less than 200mm today, true I didn't do any real jumps but I would expect to see a little vit more travel used.
Today spin was 21.5km for 810m of elevation in total, the battery was roughly at the same discharge than for the previous ride. I have a little bit of regen which feels somewhere between a 2t and 4t ICE bike which feels good.
pwd
🚴♂️ Mega poster
Cool build. Yes, the behavior you describe sounds like the controller was scaling back power to prevent overheating. How was your battery performing during this climb? If the battery voltage was dropping/sagging too much; the controller might also scale back the power to protect the battery.
A larger rear sprocket would help too.
A larger rear sprocket would help too.
In fairness I didn't think about checking the battery. But the battery is rated for 330A continuous (Bak 45D, 26p11s) and the problem was happening early in the ride when tye battery was probably 95% full and in daily or sport mode. During the first ride I had the same issue when riding with Eco mode (50% of 330/680A) and switching to Daily (75%) would solve the issue. Today I tried some steeper stuff and that's when I noticed the issue and a switch to Sport (100%) wouldn't solve it.
Tomorrow I will try to do some Starts in my street to see if I still find the first 5/10m to be soft when the bike is cold. It could have been soft from the beginning but with a leg in the cast and not riding for more than 3 months everything felt fast when testing in the street and during my first ride
Last point, I went in my Fardriver app to check all my setting and saw that Power rating is at 5000w. Could that be a problem ? I think that's what the app put as default and I haven't touched it since. I run a 138v3.
Attachments
This is weird. If it can wheelie from standstill it should have no problems starting up at a hill. Maybe it's something with sensors, where it can't readily apply full torque if it doesn't see the motor move into a "correct" position? My bike definitely feels that it's working more uphill, but I'm pretty sure that if it got too steep to ride it would just raise up with me rather just bog down.
Wheeling is mostly technique rather than power I guess. I can do pivot turns in all the modes (165/340Amp to 330/680Amp) but as with ICE bikes I use my front brake and pump the fork. As for the bogging down it stops but if I unweighted the bike or push it a little bit it tries to go with me. So it is still alive but it isn't able to either create forward motion, or brake traction, in scenarios where either would usually happen but then I don't have a clutch to load up the flywheel so maybe it is a ebike characteristic once they run out of steam.
Yesterday I tried to modify few parameters : PC13 race mode, turned off roll assist and everything I don't use of need, experimented with throttle parameter too. It seems to help a little bit but not much. The throttle mode set in sport made the bike very twitchy but did nothing on the steep incline test I did.
For the testing I found a set of stairs (roughly 45° steep) and tried to climb them, step by step from a stand still, seated on the bike. In eco mode I could manage 2 steps I think, in daily I could get to the point where the bike is on the stairs (back wheel trying to climb the first step) but it wouldn't climb further unless helped a lot. In sport mode (330/680amps) it also got stuck once the bike is fully on the stairs but you can feel the bike trying to move and if I unweighted the bike a little bit I was getting a little bit of wheel spin and it would go up.
So am I asking too much to my setup ? Either I am missing a parameter in the Fardriver ESC to increase start-up torque, or 330/680Amp is not enough for what I am planning to do and I will need to get a bigger contrôler to feed it more phase amps, and go with a bigger sprocket meanwhile.
Yesterday I tried to modify few parameters : PC13 race mode, turned off roll assist and everything I don't use of need, experimented with throttle parameter too. It seems to help a little bit but not much. The throttle mode set in sport made the bike very twitchy but did nothing on the steep incline test I did.
For the testing I found a set of stairs (roughly 45° steep) and tried to climb them, step by step from a stand still, seated on the bike. In eco mode I could manage 2 steps I think, in daily I could get to the point where the bike is on the stairs (back wheel trying to climb the first step) but it wouldn't climb further unless helped a lot. In sport mode (330/680amps) it also got stuck once the bike is fully on the stairs but you can feel the bike trying to move and if I unweighted the bike a little bit I was getting a little bit of wheel spin and it would go up.
So am I asking too much to my setup ? Either I am missing a parameter in the Fardriver ESC to increase start-up torque, or 330/680Amp is not enough for what I am planning to do and I will need to get a bigger contrôler to feed it more phase amps, and go with a bigger sprocket meanwhile.
The controller can limit motor power with a temperatur sensor , when the windings reach 140°C , it drops power down to near zero at 160°C, the outside of the motor may still be at 70°C,
Slow driving with high phase current is heating up the motor very fast.
Reducing the gearing will help a little, if topspeed then is to slow, you can get probably more revs with weakening field.
The controller also limits output power when it gets to hot. Mine starts limiting at 80°C and cuts off at 100°C.
I have a temperature controlled fan installed, which kicks in a t 50°C and cools down the 721800.
The 72680 is a tiny controller with much less cooling capacity, it may overheat in a few minutes with high phase currents.
When you enter "cacu" for temperature sensor then the controller uses the "rated power" for calculating the motor temperatur.
But you can try and raise the value.
The controller can also limit current through "LowVolWay" setting.
To see if your battery is limiting run a screen recorder whilst the Fardriver app is displaying the meters.
Last edited:
Hi, I checked temps when riding last time and it was around 70°C for both the ESC and the motor. I believe the temperature comes from the sensor inside the 138v3 70H and in the app I have selected the sensor n°5 which seems to be giving the right temps when cold and is the one usually suggested for this motor.
Yesterday testing took few seconds for each tests, there is no way temperature could have been an issue if the motor and ESC only went up to 70°C in much longer draws and also higher outside temp.
I have seen some people mentioning "torque coefficient" as a parameter that could help. Do you know anything about this ?
Sorry changed my post above, when I saw you had posted a screenshot with KTY Sensor in the app.
Never tried to change torque coefficient. I went for a bigger controller, as the 72680 was to weak for a fast start with my BLDC Hub Motor in my 190kg heavy scooter. Now I can rach 30kW from the battery at 30km/h , with the 72680 I reached 20kW at 40km/h.
More current equals more tourque
Never tried to change torque coefficient. I went for a bigger controller, as the 72680 was to weak for a fast start with my BLDC Hub Motor in my 190kg heavy scooter. Now I can rach 30kW from the battery at 30km/h , with the 72680 I reached 20kW at 40km/h.
More current equals more tourque
I need to see if I can find another solution than changing the controller. Aside from this very specific issue I am pretty happy with the bike with the current controller/esc combo. I haven't once used the daily mode (75% of 330/680amp) and felt the need for more power for woods riding. In sport mode, even with decent grip the bike tends to be hard to control. Most like I will only use this mode for MX tracks, going for a bigger controller to not even use 50% of it in most riding scenarios doesn't sound like a solution to me. I might ask on the FarDriver FB group, if I get any useful information and results I will report back here.
I think I had a similar problem at first on my ktm. Back then I thought 7-1 or even 6-1 was a good number for gearing on a dirtbike with qs 138, and I also only had 500 phase A. (which also seemed like a good number at the time) Changing gearing to 8.x-1 (something between 8 and 9 to 1) solved it.
It is a long time ago that I rode that bike though, so I cant really say if I would be happy with the torque today. (probably not
)
The low end is very sensitive to phase amps and gearing.
It is a long time ago that I rode that bike though, so I cant really say if I would be happy with the torque today. (probably not
)The low end is very sensitive to phase amps and gearing.
Unless my math is wrong (possible, it isn't my strong suit), I think I am already in this ballpark. 9 to 1 is 0.11. My current setup with the internal ratio of 2.35 to 1 and 13/48 final drive gives 0.42 x 0.77 = 0.11.I think I had a similar problem at first on my ktm. Back then I thought 7-1 or even 6-1 was a good number for gearing on a dirtbike with qs 138, and I also only had 500 phase A. (which also seemed like a good number at the time) Changing gearing to 8.x-1 (something between 8 and 9 to 1) solved it.
It is a long time ago that I rode that bike though, so I cant really say if I would be happy with the torque today. (probably not
The low end is very sensitive to phase amps and gearing.
Going all the way to 13/52 would give me 0.105 or 9.5 to 1 which would be better but by your recommendations my current gearing is already ok.
The controller has a locked rotor detection, probably that kicks in earlier with more phase current settings.
When I had installed the 72680 my scooter was not starting slow, but now with more then double the phase amps, it does accelerate much faster, but you still see a slower acceleration from the standstill.
Measurements are with the same 10kW hub motor done with a 10Hz GNSS
721800
72680
When I had installed the 72680 my scooter was not starting slow, but now with more then double the phase amps, it does accelerate much faster, but you still see a slower acceleration from the standstill.
Measurements are with the same 10kW hub motor done with a 10Hz GNSS
721800
72680
I did a quick test in the garage, trying to spin the wheel with the rear brake applied. I can stop the motor from starting (basically what happens in the stairs) in Eco and Daily mode but I can't do it in Sport mode. I experimented more in Eco mode and noticed that despite my phase amp being setup at 340A (50% of 680A), I was getting between 290A and 307A with the throttle fully twisted. I double checked my throttle parameter and the controller was reading full throttle when I read these phase numbers. At start-up with full throttle I should get 100% of the phase amp number for a given map. Solving this could solve my problem, or at least access full power in Sport mode which should be enough in most cases. I will need to test what happens in Sport mode in the stairs to make sure this also happens when that map is on.
Otherwise I tried to change the RatedPower of the motor which didn't make a difference. I also tried to change Speed KI from 9 to 18 which is a parameter for heavier vehicles but it didn't change my phase amp value with the brake test either. I will need to replicate this in the stairs and also during starts.
I do not think that you will notice a 10% change in phase amps.
My 72680 did only 630pA.
If I set it higher I got phase current errors.
It also had jittering at top speed with field weakening activated, which I never got solved.
I had to reduce max rpm to get rid of.
Probably 20kW @120kph for longer duration was to much for this small controller.
But it did a good for 5000km with 115kph and up to 22kW power.
With the 72680 I tried a lot of things (also PID settings) to get it starting faster, but nothing noticeable happend, i could only change power and behaviour after the controller had reached max battery amps.
Then I moved forward and upgraded to the 721800 ignoring the ND96850 I had bought a year before, because a 25% phas amps and tourqe increase was to less for me.
Now I´m running 1400pA and 400bA, if I ever will install a bigger BMS, I will try to raise the phase amps to maximum, which will probably bring me in the mid 5 seconds range.
My 72680 did only 630pA.
If I set it higher I got phase current errors.
It also had jittering at top speed with field weakening activated, which I never got solved.
I had to reduce max rpm to get rid of.
Probably 20kW @120kph for longer duration was to much for this small controller.
But it did a good for 5000km with 115kph and up to 22kW power.
With the 72680 I tried a lot of things (also PID settings) to get it starting faster, but nothing noticeable happend, i could only change power and behaviour after the controller had reached max battery amps.
Then I moved forward and upgraded to the 721800 ignoring the ND96850 I had bought a year before, because a 25% phas amps and tourqe increase was to less for me.
Now I´m running 1400pA and 400bA, if I ever will install a bigger BMS, I will try to raise the phase amps to maximum, which will probably bring me in the mid 5 seconds range.
Yeah we don't have the same issues I think. For instance I don't use field weakening right now and don't feel like I need any more top end. Also I don't need more power to ride the trails I do, even in 50% mode it is decent and I don't need more than the 75% mode.
The only thing I need is to get more torque at 0rpm to probably 10rpm. I might change my daily mode to 100% line and 75% phase to not have to switch back and forth between modes. With 100% phase the power is almost enough, so if it is 10% less than it should, squeezing these last 10% is probably enough.
If I can't find an ESC setup doing that I will go to 13/50 or 52 and call it a day.
The only thing I need is to get more torque at 0rpm to probably 10rpm. I might change my daily mode to 100% line and 75% phase to not have to switch back and forth between modes. With 100% phase the power is almost enough, so if it is 10% less than it should, squeezing these last 10% is probably enough.
If I can't find an ESC setup doing that I will go to 13/50 or 52 and call it a day.
New ride today, I mostly did some hill climbs to test and try to solve my problem. For 16km and 900m of elevation I used 25% of my battery, this seems pretty good to me and even when fit do 3 times that on one spin will be more than enough. Also I checked the battery temp throughout the whole ride and it didn't change, this is great news as the bike was working well (more on that later).
I also played with my throttle setup as it was a bit jittery when off the throttle. For instance when popping the front wheel to pass a gap/rut I would have to be very careful to not wiskey throttle when off the gas. To solve this issue I increased my low throttle value to have a little bit more dead travel. Now I have much less unwanted throttle input when riding off the throttle (rolling downhill for example). Because I had to up my line amps I needed to make my throttle curve more manageable too. I experimented with the LQ setting which is basically moving the mid point of your throttle. The auto learn put it at 329 which means it was 0.329v from the 0 point of the throttle. Considering my low throttle is 1.1v and high throttle is 4.1v that meant that I was getting 50% of the power with 10% of throttle input (3v of throttle travel, 4.1v-1.1v). I now put the LQ at 1000 which gives me enough throttle snap but makes it a lot more manageable.
Regarding the torque issue, I tried the Torque coefficient which changed nothing in the stairs, nor on starts so I reverted to the default parameter. I tried Power rating again with these 2 tests and again it changed nothing. I forgot to try the Speed KI values again, instead I simply put the max phase amps (680a) in my daily map (250a line) and went for my ride to test all these mods. The bike worked very very well and except some very steep hills were I stopped and tried to restart, the bike was perfect. I also tried max speed on a fire road climbing slightly, I got 85kph in daily mode which is plenty enough and that's without FW. Overall the motor and ESC were between 60 and 70°C for the whole time, even after climbing 500m of elevation in one go. The battery temperature never move even at the end of this climb.
I think I will get a 52t rear sprocket to get a little bit more torque and maybe reduce my line amps a little bit in order to keep everything a little bit cooler. That would bring my top speed around 80kph which is still plenty, probably too much for my style of riding.
Other than that I was very impressed with the bike. Even with rubbish worn out tires, a very stiff fork, and a very unfit/out of practice ride the bike allowed me to clear all the hill climbs that I normally just about manage with my KTM when fit and riding regularly. Honestly, if I don't restart racing I think I will just keep the Suzuki. It is easier, super fun, doesn't make any noise, no air filters, oil, petrol to deal with. I wasn't sure if I was wasting my money or not when I started this project but today I am 100% convinced and the bike will get even better once setup properly. Happy days !
I also played with my throttle setup as it was a bit jittery when off the throttle. For instance when popping the front wheel to pass a gap/rut I would have to be very careful to not wiskey throttle when off the gas. To solve this issue I increased my low throttle value to have a little bit more dead travel. Now I have much less unwanted throttle input when riding off the throttle (rolling downhill for example). Because I had to up my line amps I needed to make my throttle curve more manageable too. I experimented with the LQ setting which is basically moving the mid point of your throttle. The auto learn put it at 329 which means it was 0.329v from the 0 point of the throttle. Considering my low throttle is 1.1v and high throttle is 4.1v that meant that I was getting 50% of the power with 10% of throttle input (3v of throttle travel, 4.1v-1.1v). I now put the LQ at 1000 which gives me enough throttle snap but makes it a lot more manageable.
Regarding the torque issue, I tried the Torque coefficient which changed nothing in the stairs, nor on starts so I reverted to the default parameter. I tried Power rating again with these 2 tests and again it changed nothing. I forgot to try the Speed KI values again, instead I simply put the max phase amps (680a) in my daily map (250a line) and went for my ride to test all these mods. The bike worked very very well and except some very steep hills were I stopped and tried to restart, the bike was perfect. I also tried max speed on a fire road climbing slightly, I got 85kph in daily mode which is plenty enough and that's without FW. Overall the motor and ESC were between 60 and 70°C for the whole time, even after climbing 500m of elevation in one go. The battery temperature never move even at the end of this climb.
I think I will get a 52t rear sprocket to get a little bit more torque and maybe reduce my line amps a little bit in order to keep everything a little bit cooler. That would bring my top speed around 80kph which is still plenty, probably too much for my style of riding.
Other than that I was very impressed with the bike. Even with rubbish worn out tires, a very stiff fork, and a very unfit/out of practice ride the bike allowed me to clear all the hill climbs that I normally just about manage with my KTM when fit and riding regularly. Honestly, if I don't restart racing I think I will just keep the Suzuki. It is easier, super fun, doesn't make any noise, no air filters, oil, petrol to deal with. I wasn't sure if I was wasting my money or not when I started this project but today I am 100% convinced and the bike will get even better once setup properly. Happy days !
Quick update, I swapped the rear sprocket from 49t to 51t and took the opportunity to also put a brand new chain on the bike so that the whole transmission is now made of new items. This will help not wearing out some new parts faster than it should du to the use of an old chain.
Regarding the performance of the bike, I dropped the phase amps to 630A for the daily mode, the bike feels similar to what it was feeling like before but it should reduce the stress on the controller a little bit. I kept sport mode with 660A, interestingly, in those hard enduro situations when you are stuck and try to restart from a stand-still even switching to the sport mode doesn't seem to help much compared to the daily mode or to when I was running the 49t sprocket. It seems that this is really a downfall with my setup. Maybe a bigger controller would help but for 99% of the time it is perfect as it is, and I wouldn't really want to have to deal with 1000A phase for the 99% of my riding. So far the workaround I found is to back-up slightly (even 5cm) in order for the motor to start spinning and then the power/speed picks-up.
When going full hard-enduro (aka climbing a 50m hill in 10min lol) the controller ended-up at 90°C. The very high amps of start-up combined with the lack of airflow are definitely the explanation. That day wasn't super hot, around 25°C, and it didn't trigger the temp warning but I think I will need to add a fan for next summer. The motor never seem to go above 50°C regardless of the type of riding.
Other than that I changed the linage bearings which massively reduce the slop in the rear suspension, there is still some slop left which comes from the swingarm bearings. It wasn't obvious before, it will get fixed soon. I am also in the process of changing rotors/pads/caliper pins to refresh the braking system which is currently in a very poor state. I installed a Tubliss in the front tire, surprisingly the grip is excellent a 0.6bar , even with the dried-up Maxxis tire so i will keep it on fr now. I also have a Tubliss for the rear with a Starcross 6 in decent shape. Currently I am ridding an old Razorback, dried-up and basically slick (4mm left on the main knob) but somehow the grip isn't bad in most conditions. It seems that electric bike have a lot more grip than normal bikes, or at least the lack of noise allow you to avoid wheel spin. You can feel the lack of drive when the ground is very soft but it is still very manageable.
Last point, it seems that my battery (bak 45d, 26s11p) allows me to ride for roughly 40km and 1500m of elevation. Definitely enough for some evening ride, just enough for an afternoon ride but nothing more. This is ok for me as this is the intended program for this bike. In the future if I would go with some 5A cells or above to get a little bit more of a safety margin but sine the bike is already 110kg I will not go with a bigger pack.
Regarding the performance of the bike, I dropped the phase amps to 630A for the daily mode, the bike feels similar to what it was feeling like before but it should reduce the stress on the controller a little bit. I kept sport mode with 660A, interestingly, in those hard enduro situations when you are stuck and try to restart from a stand-still even switching to the sport mode doesn't seem to help much compared to the daily mode or to when I was running the 49t sprocket. It seems that this is really a downfall with my setup. Maybe a bigger controller would help but for 99% of the time it is perfect as it is, and I wouldn't really want to have to deal with 1000A phase for the 99% of my riding. So far the workaround I found is to back-up slightly (even 5cm) in order for the motor to start spinning and then the power/speed picks-up.
When going full hard-enduro (aka climbing a 50m hill in 10min lol) the controller ended-up at 90°C. The very high amps of start-up combined with the lack of airflow are definitely the explanation. That day wasn't super hot, around 25°C, and it didn't trigger the temp warning but I think I will need to add a fan for next summer. The motor never seem to go above 50°C regardless of the type of riding.
Other than that I changed the linage bearings which massively reduce the slop in the rear suspension, there is still some slop left which comes from the swingarm bearings. It wasn't obvious before, it will get fixed soon. I am also in the process of changing rotors/pads/caliper pins to refresh the braking system which is currently in a very poor state. I installed a Tubliss in the front tire, surprisingly the grip is excellent a 0.6bar , even with the dried-up Maxxis tire so i will keep it on fr now. I also have a Tubliss for the rear with a Starcross 6 in decent shape. Currently I am ridding an old Razorback, dried-up and basically slick (4mm left on the main knob) but somehow the grip isn't bad in most conditions. It seems that electric bike have a lot more grip than normal bikes, or at least the lack of noise allow you to avoid wheel spin. You can feel the lack of drive when the ground is very soft but it is still very manageable.
Last point, it seems that my battery (bak 45d, 26s11p) allows me to ride for roughly 40km and 1500m of elevation. Definitely enough for some evening ride, just enough for an afternoon ride but nothing more. This is ok for me as this is the intended program for this bike. In the future if I would go with some 5A cells or above to get a little bit more of a safety margin but sine the bike is already 110kg I will not go with a bigger pack.
I am planing to sign up for a local race, not sure what the right term is in English but it is like a MX race but the track is created on the day in a grass field. This is typically 15min of training and 2 races of 15min. So Saturday I went to a local MX track in order to test the battery range when used at a faster pace than my usual riding style, and also get some info on how the motor and controller will react to such use.
The track was prepped but it rained a lot which resulted in some thick deep mud, the first runs were absolutely horrible and just to move through was a struggle lol. Once the track developped a bit and some rut appeared it was much nicer but some spots were still slowing the bike down quite a bit. Here on the activity it says nearly 1h20min of ride time but actual track time was closer to 50min if I look at the speed/heart rate graphs. This is good enough for the type of race I am considering and a quick recharge during the day will give me 100% certainty of not having any troubles with the battery.
Regarding the motor and controller, it went the opposite of riding enduro. In this case the controller stayed cooler (roughly 50° avec 12min of MX riding at 20°C outside temperature) and the motor warmer (around 70°). This is totally acceptable and considering the conditions, again it won't be an issue to use the bike for this type of race or some MX days in general. Other than that the bike behaved very well and you could really tell that the suspension were setup for this lol.
Other than that, I got the chance to test the Starg Varg EX of a friend. The bike felt much heavier when riding than my eRMZ but this could be explained by setup choices such as tubliss with low pressure and enduro tires, a lot of engine braking and low power. I only got the chance to do one lap with the 35hp map and I can safely say that this is much slower than either of my maps, at least down low. It would be interesting to test different power setting in the future to see where I am at in reality.
I have the feeling that basing the power feel of a bike on the simple formula "line amp x Voltage" is less than ideal because this puts my eRMZ at 31kw which is 40hp (without any losses), maybe the SV at 40hp would feel like my bike but I am doubtful. For instance, my daily mode (23Kw, 250A line, 640A phase) feels basically the same than my full power mode, at least all the way to half max speed. If I look at my activity log the fastest I went was 60kmh. This tells me that even on a MX track I am not using the top speed of the bike, making the Line Amp rating somewhat irrelevant, but if I go "phase amp x voltage" it gives me 80hp which I don't think is accurate either. It also goes to show that I could gear down even more to get more low end grunt and maybe reduce the heat in the controller when riding enduro.
The track was prepped but it rained a lot which resulted in some thick deep mud, the first runs were absolutely horrible and just to move through was a struggle lol. Once the track developped a bit and some rut appeared it was much nicer but some spots were still slowing the bike down quite a bit. Here on the activity it says nearly 1h20min of ride time but actual track time was closer to 50min if I look at the speed/heart rate graphs. This is good enough for the type of race I am considering and a quick recharge during the day will give me 100% certainty of not having any troubles with the battery.
Regarding the motor and controller, it went the opposite of riding enduro. In this case the controller stayed cooler (roughly 50° avec 12min of MX riding at 20°C outside temperature) and the motor warmer (around 70°). This is totally acceptable and considering the conditions, again it won't be an issue to use the bike for this type of race or some MX days in general. Other than that the bike behaved very well and you could really tell that the suspension were setup for this lol.
Other than that, I got the chance to test the Starg Varg EX of a friend. The bike felt much heavier when riding than my eRMZ but this could be explained by setup choices such as tubliss with low pressure and enduro tires, a lot of engine braking and low power. I only got the chance to do one lap with the 35hp map and I can safely say that this is much slower than either of my maps, at least down low. It would be interesting to test different power setting in the future to see where I am at in reality.
I have the feeling that basing the power feel of a bike on the simple formula "line amp x Voltage" is less than ideal because this puts my eRMZ at 31kw which is 40hp (without any losses), maybe the SV at 40hp would feel like my bike but I am doubtful. For instance, my daily mode (23Kw, 250A line, 640A phase) feels basically the same than my full power mode, at least all the way to half max speed. If I look at my activity log the fastest I went was 60kmh. This tells me that even on a MX track I am not using the top speed of the bike, making the Line Amp rating somewhat irrelevant, but if I go "phase amp x voltage" it gives me 80hp which I don't think is accurate either. It also goes to show that I could gear down even more to get more low end grunt and maybe reduce the heat in the controller when riding enduro.
Varg has adjustable throttle curves and "maps". If it was artificially limited, it could definitely feel slower. Incidentally I rode one yesterday as well and it definitely didn't lack power compared to what my QS138 can produce with 690pA. I have much lower final gearing, though.
That's not accurate for power, no. Phase current is a reasonable predictor of torque, which at very low RPMs will largely translate to the acceleration force. At higher RPMs where the engine starts ramping the torque down, the battery draw is a good proxy for what to expect. Stark with the high voltage system can outperform a 72/96V just because it can generate both large torque through massive reduction as well as large power through high top RPM - we basically have a smaller powerband and have to choose between top speed and low rpm pull.
Clearly the SV is a superior package overall and can be setup differently which will have a massive impact on how the bike feels. In this case I was not impressed by the power and power delivery but like you said it was probably more a setting thing, I mean the massive engine braking alone was not my cup of tea lol. Once you also add gearing in the mix it is even harder to compare. It would be fun to take the bike to a dyno just to see how the controller numbers translate to power numbers we are used to.
Regardless, the more I ride my eRMZ and the more I love it and don't regret the time and money spent. Yesterday I put the rear tubliss and a new rear tire and sometime next week I should be able to fully refresh the brakes. Actually the brakes were the biggest issue at the MX track, I need to pull so hard on the lever that my right hand gets tired pretty quickly and forces me to stop earlier than I'd like to. The super worn out rear tire wasn't ideal for traction but honestly it was still manageable and wasn't causing much fuss.
Regardless, the more I ride my eRMZ and the more I love it and don't regret the time and money spent. Yesterday I put the rear tubliss and a new rear tire and sometime next week I should be able to fully refresh the brakes. Actually the brakes were the biggest issue at the MX track, I need to pull so hard on the lever that my right hand gets tired pretty quickly and forces me to stop earlier than I'd like to. The super worn out rear tire wasn't ideal for traction but honestly it was still manageable and wasn't causing much fuss.
Theoretical question for those more knowledgeable than I am: if I am only using 70% of my bike speed range (0 to 70kph with a top speed of 90kph), would a smaller gearing help with battery range ?
Currently I am using 13/51 and after 2 days spent a the MX track I reach top speeds slightly under 60kph. In a good day I don't think I would go much higher than 70/75kph and I definitely don't need to go faster when riding my usual tech enduro stuff. Going down to 12/51 would probably help with tech enduro by keeping phase amp draw a little bit lower. If going 12/51 can also increase ride time in MX (and flow enduro) at the sacrifice of a top speed I am not using that would be great but before I import a sprocket from the US I'd like to have your opinion on the effect on battery range. Because to me lower gearing means that the motor will have to spin faster to ride the same way than before and more motor rpm, to me, sounds like it will use more battery.
Other than that the bike restoration continues, I changed the front disc, pads and caliper sliders before going back to the Mx tracks. First I had to push the pistons back, they wouldn't fully retrackt, I hope it was enough to fir the new disc and pads, spoiler alert, it wasn't... Then I moved on to changing the pins, the top one was loose, the bottom one was tight but didn't make much of a fuss. In fairness neither looked too bad with no obvious signs of wear. News pins, pads and discs all went in without issues but the wheel was hard to go back in because the disc/pad clearance was very tight. I tried to open the lever tank cap but obviously both tiny phillips head screws were seized and just rounded off instantaneously. In the end I cracked the lever banjo bolt open to let some fluid out. This worked fine, but despite all the refreshing the lever feel didn't change a bit and is still spongy. I was hoping that braking power would increase but it isn't night and day even after a full battery at the Mx track. After inspection I noticed that tye pad/disc contact is not good at all, especially on the hub side of tye disc. Not sure what to do at this point, the performance isn't terrible but it is worse than the bremdo on my 2004 Ktm, both in terms of power and feel. Power might improve still once the hun side pad wears flat to the disc but this isn't ideal.
Currently I am using 13/51 and after 2 days spent a the MX track I reach top speeds slightly under 60kph. In a good day I don't think I would go much higher than 70/75kph and I definitely don't need to go faster when riding my usual tech enduro stuff. Going down to 12/51 would probably help with tech enduro by keeping phase amp draw a little bit lower. If going 12/51 can also increase ride time in MX (and flow enduro) at the sacrifice of a top speed I am not using that would be great but before I import a sprocket from the US I'd like to have your opinion on the effect on battery range. Because to me lower gearing means that the motor will have to spin faster to ride the same way than before and more motor rpm, to me, sounds like it will use more battery.
Other than that the bike restoration continues, I changed the front disc, pads and caliper sliders before going back to the Mx tracks. First I had to push the pistons back, they wouldn't fully retrackt, I hope it was enough to fir the new disc and pads, spoiler alert, it wasn't... Then I moved on to changing the pins, the top one was loose, the bottom one was tight but didn't make much of a fuss. In fairness neither looked too bad with no obvious signs of wear. News pins, pads and discs all went in without issues but the wheel was hard to go back in because the disc/pad clearance was very tight. I tried to open the lever tank cap but obviously both tiny phillips head screws were seized and just rounded off instantaneously. In the end I cracked the lever banjo bolt open to let some fluid out. This worked fine, but despite all the refreshing the lever feel didn't change a bit and is still spongy. I was hoping that braking power would increase but it isn't night and day even after a full battery at the Mx track. After inspection I noticed that tye pad/disc contact is not good at all, especially on the hub side of tye disc. Not sure what to do at this point, the performance isn't terrible but it is worse than the bremdo on my 2004 Ktm, both in terms of power and feel. Power might improve still once the hun side pad wears flat to the disc but this isn't ideal.
Attachments
If your disc is dished "in" then I'd replace it even if it's still above max thickness. There are super cheap discs on Aliexpress nowadays, just get a nice matched set front and rear and plop in.
They also sell caliper rebuild kits, but I see you've actually replaced the pins. Greasing them properly and reassembling clean makes a huge change to how the caliper slides and works.
For the screws on the reservoid, it's not technically required to remove the cap to back out the pads - as long as the lever "preload" screw isn't set too tightly, it should be possible to push the fluid back in the level resting position. If the set screw is set too far, it could technically be blocking the return orifice, although I'm not sure if that's realistically possible. Always easy to try out by checking if the lever has freeplay. Even with a stuck piston trying to push the fluid back should push the piston out and allow the extra fluid to overflow into the reservoir chamber.
Similar threads
