PV1
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Lost regen with new tires

Fri Jul 18, 2014 3:02 pm

My new Continental's came with a surprise, no regen! I don't get any error lights, but going above 25 MPH or turning to the right disables regen until I stop. Since the car needs aligned (1/8 inch difference, toed outwards), I'm wondering if that is the problem. The i-MiEV now pulls to the right, though all tire pressure equals.

UPDATE: The front left tire is larger than the right side. The size numbers are the same, but the left is larger.

UPDATE 2: Nevermind, I mis-measured. Both fronts are the same. Would slightly smaller rear wheels cause that? I thought only if the rear was spinning slower that regen would cut back.
"Bear" - 2012 Diamond White Pearl ES with QC - 2/21/2013

"Koorz" - 2012 Cool Silver Metallic ES with QC - 1/5/2015

"Photon" - 2017 Bolt EV LT in Orange with QC - 7/31/2017

Solar-powered since 10/10/2013

PV1
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Re: Lost regen with new tires

Fri Jul 18, 2014 6:32 pm

Okay, now that I've studied the car's behavior and came off of my panic, I have a better grasp on what's going on.

Since the rear tires are smaller in circumference, the speedometer reading is now 5 mph faster than before (used to be 1-2 slow, now it's 2-3 fast). The front tires are the same size, so the car is suddenly seeing the rear tires going faster all the time, which I believe is disabling regen. That doesn't make much sense to me unless I can see how the car's coded, but if the rear tires go slower than the front (hittting bumps, slick roads), regen will get cut back then brought back up. Maybe the car is programmed to cut back regen if speed difference front to back is 2 mph or more, but not set to disable regen only if the rear tires are going slower, just a general 2 mph difference. Funny thing is, if I go around a turn for about 3 seconds with the wheel past the 10 or 2 o'clock position, regen would come back.

I've adjusted my tire pressure to help make the situation better (44 on the back, 36 on the front), but it's still not right. I'll call the local dealer (not the one I bought from) tomorrow morning to see if I can get an alignment and the speedometer calibrated. I'm not sure if the car will make it to the other dealer the way it is right now.

One interesting note, if I coast down to 25 mph or less and tap the throttle, regen comes back, even on straight stretches.
"Bear" - 2012 Diamond White Pearl ES with QC - 2/21/2013

"Koorz" - 2012 Cool Silver Metallic ES with QC - 1/5/2015

"Photon" - 2017 Bolt EV LT in Orange with QC - 7/31/2017

Solar-powered since 10/10/2013

melloyello
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Re: Lost regen with new tires

Fri Jul 18, 2014 9:48 pm

Can you try disable traction control and see if that helps any? that's a real bummer that the regen system is so sensitive. I was hoping to try some different size tires, but i guess we'll have to figure out how to deal with this first..

PV1
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Re: Lost regen with new tires

Sat Jul 19, 2014 5:21 am

I'll try turning off ASC on my drive this morning. I've tried turning it off before, but regen would still cut out when I hit rough bumps when stopping.

Maybe turning it off before even moving would help.
"Bear" - 2012 Diamond White Pearl ES with QC - 2/21/2013

"Koorz" - 2012 Cool Silver Metallic ES with QC - 1/5/2015

"Photon" - 2017 Bolt EV LT in Orange with QC - 7/31/2017

Solar-powered since 10/10/2013

PV1
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Re: Lost regen with new tires

Sat Jul 19, 2014 6:18 am

Anybody tried to have their speedometer re-calibrated? I've been told it can't be done.

Can the MUT-III perform this?
"Bear" - 2012 Diamond White Pearl ES with QC - 2/21/2013

"Koorz" - 2012 Cool Silver Metallic ES with QC - 1/5/2015

"Photon" - 2017 Bolt EV LT in Orange with QC - 7/31/2017

Solar-powered since 10/10/2013

Don
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Re: Lost regen with new tires

Sat Jul 19, 2014 11:45 am

PV1 wrote:Would slightly smaller rear wheels cause that?
You've changed the size of the wheels??

Details please

Don
2012 iMiEV SE Premium, White
2012 iMiEV SE, White
2017 Chevy Volt Premier
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PV1
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Re: Lost regen with new tires

Sat Jul 19, 2014 12:07 pm

Sorry, I meant tires. The New tires are 175/55R15, stock are 175/60R15.

We changed the rear tires back to the Dunlops, and now it works. I didn't realize how much difference there was between the two. I'll try to return them and get a pair of rear Dunlops. The front Continentals are great, though the car pulls to the right since it needs aligned. Speedometer is spot on.
"Bear" - 2012 Diamond White Pearl ES with QC - 2/21/2013

"Koorz" - 2012 Cool Silver Metallic ES with QC - 1/5/2015

"Photon" - 2017 Bolt EV LT in Orange with QC - 7/31/2017

Solar-powered since 10/10/2013

JoeS
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Re: Lost regen with new tires

Sat Jul 19, 2014 4:18 pm

Turning off ASC does NOT turn off regen.

What it does is eliminates the occasional pesky regen intermittence. For example, going into a downhill curve on a bumpy road with regen slowing the car - regen unexpectedly releases (and starts selectively applying brakes?). Disconcerting, but safe.

IMO, the car handles great in spirited driving on rough curvy roads with ASC off.

I like having ASC for my wife and I like having the ability to turn it off. Thank you Mitsubishi for providing this disable switch.

I noticed no difference in regen with my properly-sized Yokohama AVID ENVigors. I'm going back to Dunlops when these wear out.
EVs: 2 Wht/Blu SE Prem., '13 Tesla MS85, 3 156v CorbinSparrows (2 Li-ion), 24v EcoScoot(LiFePO4)
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GdB
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Re: Lost regen with new tires

Thu Aug 28, 2014 5:28 pm

PV1 wrote:Sorry, I meant tires. The New tires are 175/55R15, stock are 175/60R15.

We changed the rear tires back to the Dunlops, and now it works. I didn't realize how much difference there was between the two. I'll try to return them and get a pair of rear Dunlops. The front Continentals are great, though the car pulls to the right since it needs aligned. Speedometer is spot on.


PV1, Please specify what size combination of front and rear causes regen to be lost. The posts are not clear on that.

Those of us considering upgrading the front's need to know how much front to rear wheel % diameter mismatch does not affect regen.

New the difference is 4%.

If the engineers were being nice and the ABS allowed, they would have designed the system to allow new fronts and worn rears, or new rears and worn fronts. If that is the case the maximum range of % difference might be:

Diameter
front rear
(in) (in) % rear/front
21.9 23.3 6.39% worn front
22.4 23.3 4.02% new
22.4 22.7 1.51% worn rear
My EVs: Mitsubishi Zero (2012 Mitsubishi i-MiEV and 2014 Zero S 11.4 Motorcycle)

PV1
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Re: Lost regen with new tires

Thu Aug 28, 2014 6:04 pm

145/65R15 on front, 175/55R15 on back. The 175/55 are smaller new than worn out 175/60R15. Currently, I'm running new 145/65 up front with worn out 175/60 on back and it's fine. Much more than that will likely cause it to cut out again.
"Bear" - 2012 Diamond White Pearl ES with QC - 2/21/2013

"Koorz" - 2012 Cool Silver Metallic ES with QC - 1/5/2015

"Photon" - 2017 Bolt EV LT in Orange with QC - 7/31/2017

Solar-powered since 10/10/2013

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