iMiEV tyre wear status

Mitsubishi EV Interest Group
User avatar
acmotor
Senior Member
Posts: 3603
Joined: Thu, 26 Apr 2007, 03:30
Real Name: Tuarn
Location: Perth,Australia

iMiEV tyre wear status

Post by acmotor » Mon, 05 Aug 2013, 05:28

That might be hard data to get hold of.
I'm not thinking that the tyres would make even a few % difference. More than that would be wishful thinking. It must be hard to make tyres that actually work (rain, handling etc) yet provide low rolling resistance. Given too that rolling resistance is a small component of EV power consumption, actually reducing it by a few % is not likely to extend range by an amount I can see !
Compare the size of tyres on a volt with the tyres on an iMiEV. That tells me the tyres are not big players in range.
But yep, some concrete data would be interesting.

Ah good info on the tread depth.
So depending on how worn you are prepared your tyres to get (towards the wear indicators at 1.6mm)

fronts Dunlop Enasave 2030 145/65 R15
rears Dunlop Enasave 2030 175/55 R15

front at ~0km 6.2mm, at ~28,000km av. 4.1, min 3.5mm so 61,000km at must replace 1.6mm based on av. wear.   39,000km if based on worst wear so far.

rear at ~0km 7.2mm, at ~28,000km av. 5.2, min 4.4mm so 78,000km at must replace 1.6mm based on av.wear. 40,000 if based on worst wear so far.

I can see tyre shopping coming up !
iMiEV MY12     110,230km in pure Electric and loving it !

unheardofinstruments
Groupie
Posts: 86
Joined: Tue, 26 Jun 2012, 15:08
Real Name: ron Berry
Location: Nimbin
Contact:

iMiEV tyre wear status

Post by unheardofinstruments » Mon, 05 Aug 2013, 05:49

I thought kW/km was a readout? Wouldn't electric make seeing the difference easy? I had seen claims of 10% of rolling resistance so about 5% of drag at 80 so 21k instead of 20 better range is possible. They seem to work by reducing hysteresis losses by putting silicon in the rubber. The roll on test video I saw seemed to be substantially better. It would be good to know if there was a lot of brand to brand variability too. Efficiency counts.

User avatar
Simon
Senior Member
Posts: 431
Joined: Sun, 19 Aug 2007, 19:38
Real Name: Simon
Location: Perth WA
Contact:

iMiEV tyre wear status

Post by Simon » Mon, 05 Aug 2013, 06:05

On my Niki (not an iMiEV) I used to be able to goto work and back on 8.5Ah-10Ah until I got new tyres and now it is more like 12-13Ah! Image

The new tyres are 5mm wider though..

With the old tyres I could rely on using 0.75Ah/km hypermiling and with the new tyres it is hard to get below 1Ah/km.
Last edited by Simon on Sun, 04 Aug 2013, 20:07, edited 1 time in total.

User avatar
acmotor
Senior Member
Posts: 3603
Joined: Thu, 26 Apr 2007, 03:30
Real Name: Tuarn
Location: Perth,Australia

iMiEV tyre wear status

Post by acmotor » Mon, 05 Aug 2013, 07:17

There is something in that Simon ??
Tyre (mis)alignment is amplified by increasing tyre width remember. Have you checked wheel alignment front AND rear ?? Is front too toed ?
There is a small rolling diameter difference between old and new tyres and if you change width did the rolling diameter change ? These could add up to a small apparent increase in energy as the km indicated on odometer changes or torque/current suffers a small increse if comparing same trip.

You really need to get used to talking Wh/km i.e. energy/km not Ah (although I guess you use an Ah counter ?) Without us, or you, knowing the realtime voltage involved it is hard to compare energy usage. e.g. lower temperature effects etc in winter.

This may be a good test ground (if you set up to read Wh/km plug to wheel). Do you have any spare rims ? Can you fit 'slicks' for a trial ?
The difference you observe so far is scary ! But I would expect it is more complex than just tyre construction.
iMiEV MY12     110,230km in pure Electric and loving it !

User avatar
acmotor
Senior Member
Posts: 3603
Joined: Thu, 26 Apr 2007, 03:30
Real Name: Tuarn
Location: Perth,Australia

iMiEV tyre wear status

Post by acmotor » Mon, 05 Aug 2013, 07:41

unheardofinstruments wrote: I thought kW/km was a readout? Wouldn't electric make seeing the difference easy? I had seen claims of 10% of rolling resistance so about 5% of drag at 80 so 21k instead of 20 better range is possible. They seem to work by reducing hysteresis losses by putting silicon in the rubber. The roll on test video I saw seemed to be substantially better. It would be good to know if there was a lot of brand to brand variability too. Efficiency counts.


Wh/km is usually a plug to wheel measurement representing the full energy cycle including recharge. It is usually measured externally (at least the Wh). Some EVs will display a Wh/km number but clearly not plug to wheel.

Agreed, efficiency counts. I am a skeptic though of 5 or 10% claims.
iMiEV MY12     110,230km in pure Electric and loving it !

User avatar
bladecar
Senior Member
Posts: 445
Joined: Tue, 05 Jul 2011, 16:32
Location: Brisbane

iMiEV tyre wear status

Post by bladecar » Mon, 05 Aug 2013, 15:00

Hi AC,

I really enjoyed your treatise regarding generators and ev's.

I was wondering if you would like to expound on a standard method (including specific instrumentation) in order for us all to discuss our various car's kW/km figure.

User avatar
Johny
Senior Member
Posts: 3729
Joined: Mon, 23 Jun 2008, 16:26
Real Name: John Wright
Location: Melbourne
Contact:

iMiEV tyre wear status

Post by Johny » Mon, 05 Aug 2013, 15:18

Just on the LRR tyres issue. When I put the Vogue on the road as an EV the first thing I did was to have Hancook Enfren LRR tyres put on it. I had only driven it for about 60 km prior to that but my feeling is that there is some small gain from the LRR tyes but if my existing tyres were OK, I certainly would not spend money to change them over.
I think putting about 10% more air in standard tyres might get pretty close. I wish I'd collected more data but the tyres I had were pretty bad and a tad unsafe.

dgj4710
Noobie
Posts: 3
Joined: Fri, 20 Sep 2013, 03:10
Real Name: David Glynne Jones
Location: Australia

iMiEV tyre wear status

Post by dgj4710 » Fri, 20 Sep 2013, 16:32

My wife and I have just acquired our 'new' MY12 iMiEV. The tyre pressures were in the mid-high 20's when the car was delivered, and the handling was very squirrelly.

As with my other cars since the late 90's I've had the tyres nitrogen-inflated.

The key benefits of nitrogen inflation are:

- tyres run cooler (less wear)
- tyres hold pressure for longer (typically 3-6 months)
- slightly lower energy consumption

On both my Mazsda's (121 Metro and Mazda2) tyre pressures have typically held up for at least 3 months (less than 1 psi drop) and up to 6 months before topping up.

The issue with the iMiEVs small tyres is, I suspect, that they have a higher surface/volume area ratio than a larger tyre, and consequently will lose pressure faster for the same air loss rate.

I had the iMiEV tyres nitrogen-inflated at Bob Jane TMart, who use the Nitrogen Express system. It costs $20 for an initial fill, and top-ups are usually $5 (although if you're a regular customer they may not charge for this).

With the iMiEV I had to go back for a top-up a week later, as the tyres lost a few psi (I think this was because they don't actually flush all the air out when they refill, and the tyres were warm). The tyres are now holding presure at 36.5 psi all round.

I use an Accutire MS-4021B Digital Tire Pressure Gauge to check tyre pressures when they're cold (US$12 + shipping on Amazon).

I'll report back in a month on how the tyre pressures are holding up.

I'll submit another post soon on why iMiEVs have differential tyre sizes.

User avatar
Johny
Senior Member
Posts: 3729
Joined: Mon, 23 Jun 2008, 16:26
Real Name: John Wright
Location: Melbourne
Contact:

iMiEV tyre wear status

Post by Johny » Fri, 20 Sep 2013, 16:43

I had new Tyres put on my 48 year old rims in December 2012 when I put the Vogue on the road. They are 185/65R13 so not very big - although obviously larger than the iMievs.
I checked pressure in them for the first time as week ago - all exactly 28psi.
I upped them to 33psi.

Just air in them I'm afraid - but 9 months.....

dgj4710
Noobie
Posts: 3
Joined: Fri, 20 Sep 2013, 03:10
Real Name: David Glynne Jones
Location: Australia

iMiEV tyre wear status

Post by dgj4710 » Sat, 21 Sep 2013, 03:06

The differential tyre sizing on the i/iMiEV is a stability and safety design function.

Dynamically the iMiEV is a mid-engined car, with a front-rear weight distribution around 45-55 and a low polar moment of inertia, due to the 200 kg battery located in the middle of the vehicle.

The low polar moment of inertia allows the car to turn more easily. The downside is that the vehicle is potentially less stable when turning.

When Rover were developing their mid-engined BS prototype sports cars in the 1960s they encountered a problem with the car in corners when they backed off the throttle, with a rapid transition from understeer to oversteer that could result in a snap-spin if not controlled. It turned out that the change in relative tyre slip angle as the load came off the rear tyres and transferred onto the fronts was enough to initiate the understeer/oversteer transition and possible spin.

The solution was to fit narrower tyres at the front, and this solution is widely used in mid-engine cars to provide the required level of stability in turns.

Fitting wider tyres to the front of the iMiEV while leaving the rears at the original width will make the car more likely to oversteer in turns when the throttle is lifted, particularly if you're using the B setting with aggressive regen.

dgj4710
Noobie
Posts: 3
Joined: Fri, 20 Sep 2013, 03:10
Real Name: David Glynne Jones
Location: Australia

iMiEV tyre wear status

Post by dgj4710 » Sat, 21 Sep 2013, 03:42

In 1974 I bought a Citroen GS station wagon that had 145R15 Michelin XZX's all round. I went nuts and fitted 'wide' 155R15 XAS's (the first radials with an asymmetric tread pattern). The GS had the full hydropneumatic suspension system and cornered like it was on rails.

The GS wasn't as heavy as the iMiEV (950kg vs 1100kg kerb weight), but it made the point that you don't need wide tyres for very good handling.

Narrow tyres also have a significant advantage in the wet, and I've already noticed that the iMiEV is very surefooted in wet conditions.

Now that I think of it, the Citroen GS would be a great EV.

User avatar
Jeff Owen
Groupie
Posts: 157
Joined: Thu, 13 Nov 2008, 15:53
Real Name: Jeff Owen
Location: Brisbane

iMiEV tyre wear status

Post by Jeff Owen » Sat, 21 Sep 2013, 03:58

dgj4710 wrote: Now that I think of it, the Citroen GS would be a great EV.

There is one in Brisbane.

User avatar
offgridQLD
Senior Member
Posts: 1825
Joined: Tue, 23 Jul 2013, 16:05
Real Name: Kurt
Location: Fleurieu Peninsula, SA

iMiEV tyre wear status

Post by offgridQLD » Sat, 21 Sep 2013, 04:32

It's all relative.I think the imive has rubbish handling compared to cars that handle well.Take it on a track with some one willing to drive it on it's limits and do the same with a good sports car and you will soon see how bad it is.It's drivable though and gets the job done. It's
not a sports car that's for sure.

kurt
Last edited by offgridQLD on Fri, 20 Sep 2013, 18:34, edited 1 time in total.

User avatar
acmotor
Senior Member
Posts: 3603
Joined: Thu, 26 Apr 2007, 03:30
Real Name: Tuarn
Location: Perth,Australia

iMiEV tyre wear status

Post by acmotor » Sat, 21 Sep 2013, 07:44

Interesting observations on tyres there dgj4710.
Tyre sizes, I can run with you on that. It is good to hear a plausible explanation.

But, Nitrogen ? sorry, it is like oxygen free copper wire for loud speakers. Technically different but just not that important. A scam at $20 ! You'd have to back those claims with real data. Like most of those sort of things, if they were really so good then everyone would be into it or Vic Roads would have added it to the compulsary list. Image
e.g. temperature rise in a tyre would have to be 99% from rubber flexure and <1% from fill gas. If the fill gas were pure nitogen and say 20% less heat generated (why ?) then that could be a 0.2% difference. That is a stone's throw in 100km if it were actually true.
A tyre filled with helium would deflate faster (IF there were leakage issues) than Nitrogen ('coz of relative molecular size) but then you could also fill a tyre with Argon or Xenon for a lot less than $20.
Then there are questions of nitrogen embrittlement of the rubber.

Surely the main reason for using nitrogen would be to maintain more contant pressures with temperature change ? This is worthwhile, however checking tyre pressures and adjusting for load and speed is more important for most road users.

Feel free to convince me otherwise.

I think the rubber compounds of LRR tyres may be worth a few % in energy saving, but perhaps at the expense of $,life and grip.

Hey Kurt, the iMiEV handling is fine by me. You don't have to spend all your time getting away from your own exhaust smell ! Image
iMiEV MY12     110,230km in pure Electric and loving it !

User avatar
offgridQLD
Senior Member
Posts: 1825
Joined: Tue, 23 Jul 2013, 16:05
Real Name: Kurt
Location: Fleurieu Peninsula, SA

iMiEV tyre wear status

Post by offgridQLD » Sat, 21 Sep 2013, 15:28

Well perhaps rubbish was to harsh. At low speeds (sub 80kmh) I find the steering is quite sharp. I will give it that. I just don't think it's the kind of car you associate or that you would expect performance handling and that's fine.

Snap throttle off over-steer isn't good for the general public but I could live with it. My old hill climb civic was a shocker for that but as long as you are aware of it its wasn't to bad and it did take a lot to get to that point.

What are the stock rears on the Imiev 175 with 145 front. I guess you could up the width of both front and rear to keep the balance. I wouldn't want to go much bigger than 195 on the rear.as i fitted a set of Honda 6 inch mags with 195/50/15 and that was about the limit. The front needs a 5 inch rim max and it needs to be a 16 inch to clear the strut.

So perhaps a 195/16 on the rear and a 165/16 on the rear a and fiddle with the profiles to get the RD correct.

I'm probably just going to stick with what it came with. Save the money for more PV Image

Kurt.
Last edited by offgridQLD on Sat, 21 Sep 2013, 05:29, edited 1 time in total.

User avatar
g4qber
Senior Member
Posts: 1733
Joined: Sat, 31 Jul 2010, 06:27
Real Name: Joseph
Location: Perth
Contact:

iMiEV tyre wear status

Post by g4qber » Thu, 03 Oct 2013, 02:13

32,457 km grey imiev tyre treads measure :-
depths in mm
groove    left    2    3    right    
RR        4.6    4.6   4.6   4.5
LR        4.4    4.6   4.3   4.4
RF        2.5    3.4   3.3   3.3
LF        3.4    3.9   4.1   2.5

Acmotor suggests under inflated
And toe out
I shall send car to tyre specialist some time

Thanks acmotor
Last edited by g4qber on Wed, 02 Oct 2013, 21:57, edited 1 time in total.

User avatar
acmotor
Senior Member
Posts: 3603
Joined: Thu, 26 Apr 2007, 03:30
Real Name: Tuarn
Location: Perth,Australia

iMiEV tyre wear status

Post by acmotor » Wed, 04 Dec 2013, 07:02

Another set of measurements at 43,080km in iMiEV....

depths in mm    [0km new] (27,000km) 43,000km

groove    left                     2                   3                   right    
RR        [7.2] (4.8) 4.3   [7.2](5.8) 5.3   [7.2](5.7) 5.2   [7.2](4.7) 3.9
LR        [7.2] (4.9) 4.3   [7.2](5.8) 5.2   [7.2](5.7) 4.8   [7.2](4.4) 3.7
RF        [6.2] (3.6) 2.6   [6.2](4.3) 3.3   [6.2](4.3) 3.4   [6.2](4.2) 3.6
LF        [6.2] (3.5) 3.3   [6.2](4.6) 4.1   [6.2](4.7) 4.2   [6.2](3.8) 3.5

Tread wear indicators are at 1.6mm

Interesting this is very similar extra wear as g4qber found on his RF tyre.

I have been using 40 psi but the wear still suggests under inflation.

It looks like those fronts are needing replacement.
Last edited by acmotor on Tue, 03 Dec 2013, 20:03, edited 1 time in total.
iMiEV MY12     110,230km in pure Electric and loving it !

User avatar
offgridQLD
Senior Member
Posts: 1825
Joined: Tue, 23 Jul 2013, 16:05
Real Name: Kurt
Location: Fleurieu Peninsula, SA

iMiEV tyre wear status

Post by offgridQLD » Wed, 04 Dec 2013, 13:58

Over 40,000km Is not to bad from a set of small tyres that are reasonably heavily loaded for there size.

I have about the same km 41,000 on my 4wd on original tyres. They have had a easy life but will be replacing then after a get back from Adelaide over Xmas. They will have just over 45,000km on them by then and will be just on the limits.

The sedan I had before the Imiev gave me similar life 40 - 50k from tyres always good brand names. (though I most likely replaced tyres a little sooner than there max limits due to them getting a little sketchy during the summer rain with shallow tread.

Whats your plan for the replacements, just going with the same again or trying something new. Perhaps a wheel change Image

Kurt
Last edited by offgridQLD on Wed, 04 Dec 2013, 03:01, edited 1 time in total.

User avatar
acmotor
Senior Member
Posts: 3603
Joined: Thu, 26 Apr 2007, 03:30
Real Name: Tuarn
Location: Perth,Australia

iMiEV tyre wear status

Post by acmotor » Wed, 04 Dec 2013, 15:58

I am tempted to find a 155/60 R15 LRR for the front (specs show same rolling diam and rim as the 145/65 R15s OEM). Dunlop 2030s don't come in that size but there are other brands around.
That would be just a token more tread as the 145s do seem to have worked hard as you note.

The fronts could go a bit longer (still a long way to the wear indicators at 1.6mm) but the uneven wear building up on the RF suggests it is time to shop. I'll check alignmet as well however the wear patterns all round and 43,000km don't suggest there is any issue, to me at least. As mentioned, this RF extra wear is exactly the same as g4qber found ! Coincidence, or something about the vehicle ? edit: though I do think g4qber had some tow out.

The rears have another 10-20kkm in them. Replace those before next winter. It normally doesn't rain in Perth over summer. Image
I don't like going down to the wear indicators though. The tyre wet grip suffers and in a vehicle with no spare(s !) the extra rubber depth is a good buffer from potential punctures.

I might up those rear pressures to 42 psi. I know I push the i on corners at times but I would still expect a more even wear across the tyre.
Last edited by acmotor on Wed, 04 Dec 2013, 05:02, edited 1 time in total.
iMiEV MY12     110,230km in pure Electric and loving it !

User avatar
acmotor
Senior Member
Posts: 3603
Joined: Thu, 26 Apr 2007, 03:30
Real Name: Tuarn
Location: Perth,Australia

iMiEV tyre wear status

Post by acmotor » Wed, 04 Dec 2013, 18:37

This is what I hear...

The dunlop 2030 is around $230 and there is one in Oz. Described as OEM special on iMiEV out of Japan.

Continental do an 'EcoContact 3 155/60 R15 74T' around $130   (the 145 dunlop is load rated 72) the T being for 190km/h (dreaming)
0.4% difference in rolling diam.
It is the standard equipment on (not so)smart cars, but I won't hold it againt the tyre. In stock.

Maxxis MAP1 (not eco) 145/65 R15 is around $105. In stock. Zippie went for those.

Other suggestions ?
iMiEV MY12     110,230km in pure Electric and loving it !

User avatar
offgridQLD
Senior Member
Posts: 1825
Joined: Tue, 23 Jul 2013, 16:05
Real Name: Kurt
Location: Fleurieu Peninsula, SA

iMiEV tyre wear status

Post by offgridQLD » Wed, 04 Dec 2013, 19:26

How dose the 0.4% R dia difference over stock effect the (abs,stability control) You would think there would be some tolerance in it as there is a small dia difference between a new and worn Tyre anyhow. I would go with the continentals over the maxxis (that said Im getting maxxis for my 4wd next change over as there 771's are a good tyre)


Come on we know you realy want some 195 low profile fats all round Image

Kurt


User avatar
acmotor
Senior Member
Posts: 3603
Joined: Thu, 26 Apr 2007, 03:30
Real Name: Tuarn
Location: Perth,Australia

iMiEV tyre wear status

Post by acmotor » Sat, 07 Dec 2013, 08:28

Just asking around, It seems the ABS systems self calibrate and can tollerate reasonable variations in rolling diameters. One obvious example cited was the small diameter temporary spare tyre on some vehicles that can be 10-20% smaller than other tyres on the vehicle, this sort of difference is cated for by the ABS system.

I've ordered the 155 conti's. We'll see how they go.

195 LP fats all round ? does that come with the bluetooth loadable re-map of the VFD settings to 80 kW on the emotor ?   Image
iMiEV MY12     110,230km in pure Electric and loving it !

User avatar
offgridQLD
Senior Member
Posts: 1825
Joined: Tue, 23 Jul 2013, 16:05
Real Name: Kurt
Location: Fleurieu Peninsula, SA

iMiEV tyre wear status

Post by offgridQLD » Sat, 07 Dec 2013, 16:07

Great,
      Only a little bit wider but its a step in the right direction.

It's good to know I should get 40,000km from my factory front wheels as a guide. I was thinking about how people are often concerned about uneven tyre wear when they start seeing the shoulders wearing down a little faster.

Often looking for reasons why like alignment or Pressure. My view is unless it's excessive then it's to be expected and will become noticeable towards the end of the tyres life. If you ever view low speed footage of a car taking a sharp corner at speed. Particularly one with skinny tall tyres and basic suspension like the imiev you will be surprised at how deformed the tyre gets and its a modern wonder they last as long as they do. Expecting them to wear perfectly even wall to wall is unrealistic unless you only drive straight.

Extreme example on a test machine
Image



Image

fats
Image

At least the smoke is coming from the back Image
Image
Last edited by offgridQLD on Sat, 07 Dec 2013, 05:37, edited 1 time in total.

CometBoy
Groupie
Posts: 313
Joined: Fri, 20 Jun 2008, 02:59
Real Name: Bruce

iMiEV tyre wear status

Post by CometBoy » Sat, 07 Dec 2013, 16:17

I’ve actual seen false ABS light triggering using a space saver (50 Km/h rated) and was told the problem is the wheel speed is obviously different on the wheel with the smaller diameter. So the speed difference is what caused the issue.

In your case having the same diameter on all wheels (or pair’s front and back as factory supplied) should be fine especially the small change you are making.

What is the weight difference in the tyres? I’m assuming they are very similar to the originals...

I played with different wider/heavier tyre/wheel combinations on the MightyBoyEV project years ago and could actually measure a w-h/km difference. After using the vehicle for months with the two setups, I can verify it did make a difference in day to day range. Remember the un-sprung mass theories out there....

If interested look here.

Bruce

PS love the photos Kurt!! MightyBoyEV could do that in 3rd! But a good way to break things! Not so our i-MiEV...
Last edited by CometBoy on Sat, 07 Dec 2013, 12:16, edited 1 time in total.

User avatar
offgridQLD
Senior Member
Posts: 1825
Joined: Tue, 23 Jul 2013, 16:05
Real Name: Kurt
Location: Fleurieu Peninsula, SA

iMiEV tyre wear status

Post by offgridQLD » Sat, 07 Dec 2013, 16:30

Interesting Bruce,

2whr - km with your mightyboy. If I got a simular loss/gain with the imiev that would be around 2% as my average consumption is around 100wh km.

Ultimately I would like to have the same size wheels in the Imiev front and back. I can deal with the potential snap over steer of this combination. Though not sure if the trade off in consumption would be worth it especially when I have a once a week commute that is on the 20% DOD limit i like to use as is.


Kurt

Post Reply