Sur Ron Tuning. aka geek speak.

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Twist
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Sur Ron Tuning. aka geek speak.

Post by Twist »

All righty now I have a Sur Ron X e-bike and other than clipping the limit wire on it, it's set up just like they ship it: max regen/engine braking
and an application of brakes shuts off the throttle/engine.

So, a couple of observations after my first couple of rides on it:
- it's a little quirky from off to partial throttle in sport mode. In EP it's smooth but just doesn't have a much power. In sport mode the power comes on so hard that it's hard to keep traction.
- Riding around tight obstacles with a minimum radius turn it's awkward with the brake/engine interlock (apply the brakes shuts off the engine).
- When hopping over an obstacle like a log, there's no fly wheel effect and worse, when I bring the front up with throttle and then shut the throttle the region/engine braking kicks in and a dead stop happens.

I could see for trail riding having the region/engine braking on would feel right. But for crawling around in the woods over and around obstacles I'm thinking no/very little engine brake/regen and disabling the brake engine interlock seems like it would be better.

It seems like with the regen/engine brake turned off there's still no flywheel effect to carry me over. Different throttle technique required to pop up the front and then hold some throttle?

Fortunately, the bike is programable so I'm seeking out the local experts here - Stephen, Sam, others? - how have you tuned your Sur Ron to make it a rideable trials trainer?
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Re: Sur Ron Tuning

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The two most important days in your life are the day you were born and the day you figure out why. - Mark Twain
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Laoch
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Re: Sur Ron Tuning

Post by Laoch »

Add a clutch and you’ll be fine.
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Re: Sur Ron Tuning

Post by Twist »

Laoch wrote: Sun Feb 07, 2021 5:07 pm Add a clutch and you’ll be fine.
Yeah, that's the obvious disadvantage to these e-bikes, but I haven't learned how to use it properly on the trials bike anyway :) But, there's no feathering the clutch with some revs on it. I'm wondering if when I disconnect the brake interlock then when I drag the brakes while holding some throttle it'll work out some of the slow speed awkwardness. It'll also enable holding some front brake while spinning up the rear.
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Re: Sur Ron Tuning

Post by Bucho »

Ive ridden some of the other guy’s Ebikes enough to get some of what you are talking about.

Yes, you need to keep the throttle on when hopping over a log/obstacle. Yes, no “flywheel effect” to get the back wheel over. I just about went over the bars first time I tried hopping a log on Ken’s old EM.

Some techniques will need to be a little different. But I still think you are getting good practice on balance, and basic body mechanics. Riding every day/week in your neighborhood will help. Vs having to haul your bike hours away
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Re: Sur Ron Tuning

Post by smdub »

You have found what I think is the Achilles heel of the SurRon - throttle response. It's slow/laggy and has a very nonlinear curve. I mapped it it out voltage vs angle and it's sort of parabolic. Very 'ebike' like (smooth off the bottom) and not motorcycle like. The electronic throttle is a little more linear than the cable one but you can't eliminate the deadband at the start w/ that one. I was working on a couple solutions - the most straightforward was to put a uP inline w/ the throttle to be able to program the curve. Never got that far before I went to the Nuc24F controller. It has great throttle response and you can program the throttle curve too. The oem throttle response is what holds the SurRon back from being truly great IMO.

I unplugged both my brake interlocks so I can drag them at slow speed but after hurting myself several times practicing wheelies (I think I even bruised/cracked a rib), I hooked the front brake disable back up. You need SOMETHING that emulates the safety of pulling in a clutch. Else if you slip and go WFO, even if you grab both levers the bike won't stop and will hapilly drag your ass hanging off the side of it clear across the yard to the scene of the 2nd accident. I like to drag the rear brake in slow stuff so that's the one I opted to disconnect. Plus need to use the rear brake to modulate a wheelie and not have it just cut off power. The connectors are under the key switch panel. Easy to get to, just unplug one. I might put them on small toggle switches so can configure them on/off on the fly depending on who is riding.

RE clutch: W/ more power, faster throttle response, and a snappier throttle curve you don't need it. Ken's old EM had a similar problem as the SurRon hopping logs (but not as bad.) It took some learning the timing. You'll get used to it. Takes a big pump of your legs and a fistful of throttle earlier than you expect. I haven't done much hopping w/ the Nuc, but it'll lift the front end 'right now' w/ just a little throttle snap.

I'm probably going to wire a wrist tether like the OSET and trials bikes. Still need to determine the polarity required to tie into the shut off. FWIW, OSET uses the opposite polarity (normally open vs normally closed) so I need to determine which kind to order to emulate the brake sw.
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Re: Sur Ron Tuning

Post by Twist »

That makes a lot of sense to me to just disable the rear e-brake and leave the front interlock enabled. I think my next time out on it I'll have that done as well as turn off regen so it'll coast on whatever momentum I put on it. The programming mode is both or nothing so to just do the rear I'll pull the sensor wire for it.

I definitely need better tires on it. I've ordered a Shinko SR241 for the rear. My goal for that tire was more about leaving less trace that I've been there than getting better hook up. I may regret that decision as hard as the torque comes on when I put the spurs to it. I've done days of practice in my back yard landscape on the Beta without any trace I've ridden there. 10 minutes on the Sur Ron and it looks like Travis Pastrana has been there :killingme:

Bucho, there was a pretty comical moment the first time out in my back yard trials loop. I went to pooch the front up over a rock step that I'd been over a hundred times on the Beta and the next thing I knew I was teetering on going over the bars with my hip mashing the horn button. It was a real "what the....oh, right..." moment.

Well, I figured since firebolter got his new Sur Ron the same day that we'll be learning all this together and It's definitely helpful to tap in to the knowledge you guys have that have been riding the bike.
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Re: Sur Ron Tuning

Post by Firebolter »

Twist wrote: Mon Feb 08, 2021 5:26 am Well, I figured since firebolter got his new Sur Ron the same day that we'll be learning all this together and It's definitely helpful to tap in to the knowledge you guys have that have been riding the bike.
I haven't had a chance to ride yet. Pulled mine in and have it up on the stand for now while I set it up. Definitely want to turn off regen to get more freewheel and use of momentum. My small time on ebikes reflects most of what everyone has said, gotta blast more and carry through over obstacles. My time on Dave's Alta was like that, very easy to break the back end loose and you had to be ready for the motor to cut off when you chopped the throttle and the instant "braking" effects-

I am not trying to replace my ICE bikes, no way-But, I do want to be able to run out of my house and go for a hour or so spin on some fun stuff and be back home for the afternoon and not have to spend 5-6 hours driving every time I want to go blast some-I am working on a top secret loop on my peninsula and it is looking good. My GF and I walked part of the loop Saturday and man, it is a playground with lots of undulation and is down in a valley and has a large bowl with hills to play on. Really nice grade in and out, so nothing too extreme to drop into this valley. It is right off the side walk in through trees, kinda hidden if you didn't know it was there. The closest houses are way up (200+ feet) on the top and not near the edge, so super stealthy for a ebike. We have a lot of wooded sections that have game trails but no people since this is a 55+ community, I am the only "kid" in the woods! Lot's of deer tracks, so I just followed the deer trail down the valley and it goes all the way to the South river.

The Sur Ron is a cheap (relative) option to open up more riding, albeit somewhat different. Easy to hop up and a simple design. Jumping is jumping, roosting is roosting!

Mike Pool, this thing would be PERFECT to run from your house over to the farm, run the loop a couple times, then back home to eat lunch and charge it up and then do an afternoon loop before dinner!
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Re: Sur Ron Tuning

Post by Firebolter »

smdub wrote: Sun Feb 07, 2021 10:44 pm Else if you slip and go WFO, even if you grab both levers the bike won't stop and will hapilly drag your ass hanging off the side of it clear across the yard to the scene of the 2nd accident.
While I know that is not supposed to be funny, the visualization of that as I read it and having experienced a few "Whiskey throttle" endeavors myself, I couldn't help but laugh my ass off! :killingme:
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Re: Sur Ron Tuning

Post by smdub »

IMO, it's more the tire pressure thats an issue tearing up the yard. Not fair comparing a bike tire at 20psi w/ a fat wide one at 5psi. An SR241 has a stiffer sidewall than the oem bike tires. You will have to run very low pressure. Will either need a rim lock or look into a bike tubeless system like Stan's sealant to prevent slipping the tire on the rim and tearing the stem.

W/ all the recent rain/snow the ground isn't in as good a shape as it was even a month ago. My fat SR241 will tear up the yard in the current conditions even at low pressure w/ TuBliss.
Stephen (not Steve) - '20 Husky 701LR / KTM '20 500 EXC / '17 150 XC-W / '21 E-XC / '21 890R / '19 Sherco 300FST / Sur-Ron LBX / Segway X160 / Sur-Ron Ultra Bee
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