Don
Site Moderator
Posts: 2733
Joined: Thu May 10, 2012 3:55 pm
Location: Biloxi MS

Re: Lost regen with new tires

Fri Jun 29, 2018 8:11 pm

I *think* even a small difference is enough to inhibit regen if the rears are smaller than the fronts by any amount - With the rear wheels turning more revolutions compared to the front than the computer thinks is normal, it assumes (I assume) that the rear end has lost traction, so adding regen to that mix would be dangerous

MelloYellow put rears on which were about 2% larger than the fronts he was using and had no problems with regen

When Carolyn poked a hole in a rear tire, I put a 195/55R14 on the car to get it home and had no regen . . . . and no other warning lights either. The car drove pretty much normal, but boy did it coast!! . . . . even in B mode

Don
2012 iMiEV SE Premium, White
2012 iMiEV SE, White
2017 Chevy Volt Premier
2014 Ford Transit Connect XLT SWB wagon, 14,000 miles
1979 Honda CBX six into six

Don
Site Moderator
Posts: 2733
Joined: Thu May 10, 2012 3:55 pm
Location: Biloxi MS

Re: Lost regen with new tires

Fri Jun 29, 2018 8:29 pm

kiev wrote:i love regen and wouldn't want to give it up, but would like to go bigger front and rear.
I am going to put 175/55R15's on the front and 185/60R15's on the back in the not too distant future. I'm relatively sure those sizes will work and not affect regen. I'm having a pair of 15 X 5.5 Mini wheels cut and rewelded to be 5" wide for the fronts . . . . I really don't want to use spacers front or rear which would upset the scrub radius. I'll let you know how it works out

Don
2012 iMiEV SE Premium, White
2012 iMiEV SE, White
2017 Chevy Volt Premier
2014 Ford Transit Connect XLT SWB wagon, 14,000 miles
1979 Honda CBX six into six

GdB
Posts: 145
Joined: Tue Aug 12, 2014 4:06 pm

Re: Lost regen with new tires

Mon Jul 02, 2018 9:18 pm

jray3 wrote:
GdB wrote:There are so many combinations that I prefer to share my excel file with the calculations. It also has a lot of other useful stuff including range calculations.
http://files.fm/g/woponqe#aa/9624Mpg_mph_imiev.xlsx


Wow GdB, that's not a spreadsheet- it's a quick reference bible for all i-MiEV performance questions!
THANKS :ugeek:


I have an improved version which includes battery rate effects from the Yuasa report.

https://drive.google.com/file/d/0B2R9j5ABY2mLdFYyRVJYNWU0WWM/view?usp=sharing
My EVs: Mitsubishi Zero (2012 Mitsubishi i-MiEV and 2014 Zero S 11.4 Motorcycle)

PV1
Site Moderator
Posts: 2929
Joined: Fri Apr 27, 2012 4:22 pm
Location: Pittsburgh, PA
Contact: Website

Re: Lost regen with new tires

Tue Jul 03, 2018 7:07 am

The car allows enough difference in the tires for the tires to wear differently without disabling regen, but changing the ratio of front circumference to rear circumference outside of the really narrow window will disable regen. Koorz has new rear tires and nearly worn out fronts and the regen is starting to drop out at any slight bump in the road. Bear has half-worn rears and new fronts and is fine.

I forget which size I tried then (I think they were 175/55R15 rears), but it was enough to cause no regen at higher speeds. If you switch to tires that have a different circumference, make a similar change for the other two tires. This will maintain regen, but it will throw the speedometer off.

I'd take over-zealous regen cutout over it not cutting out at all when there is wheel slip. I almost wrecked the Bolt because of it this past winter (front tires slid under regen going through a roundabout: never use the Bolt's L mode when the roads are slick :? ).
"Bear" - 2012 Diamond White Pearl ES with QC - 2/21/2013
Solar-powered since 10/10/2013

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

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

Driving electric since 2-21-2013.

GdB
Posts: 145
Joined: Tue Aug 12, 2014 4:06 pm

Re: Lost regen with new tires

Tue Jul 03, 2018 8:12 am

PV1 wrote:I almost wrecked the Bolt because of it this past winter (front tires slid under regen going through a roundabout: never use the Bolt's L mode when the roads are slick :? ).


Make sure you understand what features disable stability control. If it was me I would go to the dealer and ask for it to be harder to stability control. There is virtually no safety benefit, unless you have the driving ability and you have to escape extreme danger.
My EVs: Mitsubishi Zero (2012 Mitsubishi i-MiEV and 2014 Zero S 11.4 Motorcycle)

PV1
Site Moderator
Posts: 2929
Joined: Fri Apr 27, 2012 4:22 pm
Location: Pittsburgh, PA
Contact: Website

Re: Lost regen with new tires

Tue Jul 03, 2018 5:17 pm

I think it's an oversight in programming, as the regen paddle in D will also cause it to slide, even with all safeties on. Leaving it in D and using the brake pedal doesn't have the issue. But enough about the Bolt.
"Bear" - 2012 Diamond White Pearl ES with QC - 2/21/2013
Solar-powered since 10/10/2013

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

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

Driving electric since 2-21-2013.

Return to “Wheels - Tires”