Spare Wheels

SPARE TIRE

With over 22K miles on our Mitsi I decided to swap left and right tires as the front left one is wearing a bit more on the outside resulting from my high-speed onramp/offramp escapades. Anyway, while I had the car up in the air I pulled out the 'temporary' spare tire from my Gen1 Honda Insight and tried it: it fits both the front and the rear! The bad news is that it is a 14" tire. Not to worry, I have two Insights so for longer trips I'll be packing both tires plus a lightweight jack plus wrench/socket, in addition to the collection of power connector adapters and extension cords and portable EVSEs... sheesh, over 100# of 'stuff' just to venture outside one's comfort zone in an EV. Hey, we thought our iMiEV front tires are skinny? - check out the photo of the Insight's emergency spare next to the iMiEV's front tire. The Insight 'temporary' spare is labeled T115/70014 88M and the very lightweight alloy wheel is labeled 14/4T 32. The car is up on jackstands in these photos.

It looks like your tire is worn out, Joe - I can see the wear bars worn flush. Time for a new pair

Don

Looks like motorcycle tires.

JoeS, you must like to slide you I-MiEV around a lot. I've got close to 22k miles on my I-MiEV and still have plenty of tread left.

The new i3 from BMW is equipped with the skinny tires. Another I-MiEV first copied by competition. Funny no one is complaining about them on a BMW.
http://www.greencarreports.com/news...kinny-tires-to-boost-efficiency-and-cut-noise

Don said:

It looks like your tire is worn out, Joe - I can see the wear bars worn flush. Time for a new pair

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Don, thank you for pointing that out and if our record drought continues I could probably get by on slicks. :roll: Note the very even treadwear pattern despite running these tires at 60psi. Since I AM in the market for replacement tires (the default being our stock Dunlop Enasave) and I like my stock alloy wheels, my priority is a tire with the lowest rolling resistance, willing to sacrifice handling, noise, comfort, treadwear, etc. Anyone have any suggestions for the latest and greatest?

MLucas, I keep telling y'all that I live on a winding road and enjoy throwing our iMiEV around. Our iMiEV's low CG really makes it fun to drive in the hills; however, most of the miles are by my wife who is a sedate hypermiler. Perhaps running at 60psi has something to do with it? At least my tires fared better than the 12Kmiles Barb got: http://myimiev.com/forum/viewtopic.php?f=26&t=1490

MLucas said:

The new i3 from BMW is equipped with the skinny tires. Another I-MiEV first copied by competition. Funny no one is complaining about them on a BMW.
http://www.greencarreports.com/news...kinny-tires-to-boost-efficiency-and-cut-noise

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Wonderful observation! Have to remember that one.

JoeS said:

Note the very even treadwear pattern despite running these tires at 60psi

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I think if you showed that tire to anyone with any expertise in tires, they would immediately tell you it has been run severely overinflated. All of the tread in the center is gone, while both outer edges still have tread - Pretty much the exact opposite of what you see on most worn out tires. The outer edges are designed to 'bite' in to prevent the tire from sliding sideways, so they are usually the first to go when the tire is run at the recommended pressure

I don't think you're gaining 1/10 of one percent in added range by running 60 psi over a more reasonable pressure like 45 or 50, but I do think it's costing you some in handling and definitely some tire wear. This car understeers pretty heavily, so it needs all the help in front that it can get. Keep in mind that your wife drives it the majority of the time and it's probably just your trips down the hill which caused this unusual wear. If you drove it every day, those tires would have probably been shot at about 10K and you'd be thinking much differently about how overinflating them has worked out

Try 50 in your next set and see how that works out. The manufacturer recommends a maximum of 51 and probably for a good reason

Don

JoeS said:

SPARE TIRE

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That's a coincidence. One day last week, I spent all day (and $8 for toll roads) in a auto parts "junk yard" looking for a SPARE TIRE for my favorite car.



The SpaceSaver temporary spares T125/70D15 and T135/70D15 with 100 mm four lugs from some old Toyotas, Hondas, and VWs seems to fit the iMiEV.


My OEM front tire is 145/65R15 with a 24.4" [Edit: 22.4" Thanks Don.] Overall Diameter. [Edit: Don also points out that chart revolutions per mile is wrong.]



The SpaceSaver spare T125/70D15 has 22.1" Overall Diameter. The T135/70D15 spec is 570mm or 22.4".

http://mcgrefer.com/sizeinfo/1357015

Now the interesting part:
At the junk yard I put the T135/70D15 on the front left and set out for home which was forty some GPS miles away. My RR was 9 more than the GPS so I felt safe. After hypermiling for 14 miles my RR was only 2 more than the GPS. I expected the difference to increase, but it was deceasing and fast. It was starting to get dark. At this rate I wouldn't make home. Or possibly get stuck in a toll tunnel.

Then the TMPI (tire monitor pressure sensor indicator) on the dash lit up. I pulled into a McDs and put the OEM wheel/tire back on. The T135/70D15 was warm to the touch but looked like it had good pressure. In a short distance the TMPI went out.

I got home with RR=1. The T135/70D15 pressure was 21 psi without a TMPI sender. That's why it was warm to the touch, but WHY WAS THE TMPI INDICATED? All four OEM tires with TMPI had 50 psi.

FiddlerJohn said:

...The T135/70D15 pressure was 21 psi without a TMPI sender. That's why it was warm to the touch, but WHY WAS THE TMPI INDICATED? All four OEM tires with TMPI had 50 psi.

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Perhaps none of your tires has TMPI sender.

Perhaps the sensors are the ABS/ESP ones.

See "Indirect TPMS"

Would the i-MiEV be happy with a spare tire whose diameter is significantly different from the opposite tire? Wouldn't this potentially confuse the traction control?

FiddlerJohn said:

My OEM front tire is 145/65R15 with a 24.4" Overall Diameter.

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The chart doesn't jive with your 24.4 number, does it? The Revs/Mile is way off too

Now the interesting part:
At the junk yard I put the T135/70D15 on the front left and set out for home which was forty some GPS miles away. My RR was 9 more than the GPS so I felt safe. After hypermiling for 14 miles my RR was only 2 more than the GPS. I expected the difference to increase, but it was deceasing and fast. It was starting to get dark. At this rate I wouldn't make home. Or possibly get stuck in a toll tunnel.

Then the TMPI (tire monitor pressure sensor indicator) on the dash lit up. I pulled into a McDs and put the OEM wheel/tire back on. The T135/70D15 was warm to the touch but looked like it had good pressure. In a short distance the TMPI went out.

I got home with RR=1. The T135/70D15 pressure was 21 psi without a TMPI sender. That's why it was warm to the touch, but WHY WAS THE TMPI INDICATED? All four OEM tires with TMPI had 50 psi.

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I *think* the iMiEV's computer did that to you, on purpose

It monitors the ABS signal from each of the 4 wheels, so it noticed your left front with the smaller tire was turning lots more revolutions per mile than it should be, so it *knew* that one was very low on air, which triggered the TMPS indicator on the dash. The RR meter also calculated in the extra drag on the car running with a nearly flat (so it thought from it's calculations of the Revs/Mile) so it knew you were not going to be getting the 'normal' miles/watt hour and it was alerting you to the fact that you weren't going to be getting the range you expected

These darned 'smart cars' are pretty tricky, aren't they?

Don

Don. You're right. You point out three issues that I missed. Thank you.

Don said:

... The chart doesn't jive with your 24.4 number, does it? The Revs/Mile is way off too ...

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The chart says 22.4, but I typed 24.4". That's a typing error. Both Revs/Mile are way off. Yep. You're right again.

Now the most interesting part:

Don said:

... It monitors the ABS signal from each of the 4 wheels, so it noticed your left front with the smaller tire was turning lots more revolutions per mile than it should be, so it *knew* that one was very low on air, which triggered the TMPS indicator on the dash. The RR meter also calculated in the extra drag on the car running with a nearly flat (so it thought from it's calculations of the Revs/Mile) so it knew you were not going to be getting the 'normal' miles/watt hour and it was alerting you to the fact that you weren't going to be getting the range you expected

These darned 'smart cars' are pretty tricky, aren't they?

Don

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Yes! "Pretty tricky."

Does the i-MiEV have BOTH hardware TMPS AND "indirect TMPS?" That seems unnecessarily redundant. Barbagris also suggested "indirect TMPS." I guessing that the i-MiEV only has indirect TMPS.

My original point was -- these cheap 100mm, four lug, T135/70D15 Temporary Space Saver wheels and tires make a useable emergency spare tire for the i-Miev. AS IS! With the proper air pressure, the 22.4" diameter of the Temporary Space Saver is the same as the OEM tire.

Even better. Could these cheap Space Saver wheels be mounted with snow tires? I'm even considering mounting four new LRR tires on these wheels as backup spares.

FiddlerJohn said:

Even better. Could these cheap Space Saver wheels be mounted with snow tires? I'm even considering mounting four new LRR tires on these wheels as backup spares.

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There are a few in this size, at least in Europe:
http://www.tyres-pneus-online.co.uk/car-tyres-135-70-15.html
But the load index is only 70, seems too low.

I picked up four Gen1 Honda Insight spare wheels. They all mounted and I drove around a couple of miles, but I'm not sure if the front wheels did seat properly although they torqued up ok. Certainly make excellent spare tires, but need to replace them in pairs. Weigh only 13.4# (6kg) vs. Mitsu F 24.2# (11kg) and R 28.9# (13.1kg) using Yokohama AVID ENVigors with 5K miles on them. Speed difference: iMiEV=40mph, GPS=36mph. The regular Honda 14" wheels did NOT fit the front as they hit the brake caliper housing.

:lol: Joe, that's great (but please say you're going to paint the wheels)! I've been wanting to try a smaller-radius tire/wheel combo on the rear axle for two years now. Since you did it first, please answer the $64,000 question; did 10% smaller tires result in 10% faster acceleration, or is available power vs load exactly that, and tinkering on the margins is nothing but a rounding error? Even on my series-motored dragster, which makes peak torque at stall, the tire diameter has a negligible effect...

JoeS said:

I picked up four Gen1 Honda Insight spare wheels

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Neat!

If there was an iMiEV in San Juan PR, this is EXACTLY what it would look like! I couldn't believe the number of Japanese cars running around on 4 compact spares the last time I was there - It seemed like for every 20 or 25 cars you saw, at least one had them. Evidently, there's no law against it

Don

The Gen1 Honda Insight spare wheel has the following designation cast-in: 14x4T 32

I don't even know how to look for LRR tires that would fit this rim, as I was wondering if there are any 14" tires with an OD that might be close to our iMiEV's stock size.

I still need to make some precise measurements to see if there is an interference between the i-MiEV front wheel hub outer ring and the Insight wheel hub opening, because it's not just a matter of diameters but also the protrusion from the plane where the wheel bolts on. At worst, it would take a very slight opening-up of the rim's ID on a lathe. Like I said, it bolted on OK and should certainly usable as a spare. Have a pair of these in a Rubbermaid box ready to take on longer trips. Now, for a small lightweight jack...

If there appeared to be a problem on the fronts Joe you could certainly alleviate it by just removing the steel collars from the front hubs - The only reason they are there is to prevent someone from accidently putting a rear wheel on the front. With the collars removed, the inner bore would be the same front and rear so anything which properly fits the rear hubs would also fit the fronts

Don

jray3 said:

:lol: Joe, that's great (but please say you're going to paint the wheels)! I've been wanting to try a smaller-radius tire/wheel combo on the rear axle for two years now. Since you did it first, please answer the $64,000 question; did 10% smaller tires result in 10% faster acceleration, or is available power vs load exactly that, and tinkering on the margins is nothing but a rounding error? Even on my series-motored dragster, which makes peak torque at stall, the tire diameter has a negligible effect...

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jray3, sorry, just noticed your question. I drove around on these skinny wheels and tires simply to find out if they would work on the i-MiEV. Did not floor it and, besides, I probably wouldn't have noticed a 10% difference in performance. I have now put two of these wheels into a rubbermaid box together with a jack and lug wrench and toss this box into the car every time I take a longer trip. After the ASC discussion on the other wheels thread, I see that I need to take a drive with only two of these undersized wheels on the car to make sure that disabling ASC will still allow me to get home.

Don said:

If there appeared to be a problem on the fronts Joe you could certainly alleviate it by just removing the steel collars from the front hubs...

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Of course! I'll pull one off and see what's under there, as the secondary function it might be performing is to keep the dust out of the wheel bearing - if so, I'll see if I can find a non-oversized replacement at the local car parts store.

Don and jray3, these spacesaver rims (14x4T 32) are so lightweight as to possibly make them quite attractive for everyday use - any idea as to how to find out what their load rating is and if there are any LRR tires that would fit? Yes, Jay, I would repaint them if I were to try using them daily. :roll:

JoeS said:

Don said:

If there appeared to be a problem on the fronts Joe you could certainly alleviate it by just removing the steel collars from the front hubs...

Click to expand...

Of course! I'll pull one off and see what's under there, as the secondary function it might be performing is to keep the dust out of the wheel bearing - if so, I'll see if I can find a non-oversized replacement at the local car parts store.

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No need. They don't have anything to do with covering the wheel bearing - The wheel bearing is not accessible from the outside like it is on a conventional car. You'll see when you get in there . . . . the collar has no other purpose other than to make it impossible to mount a rear wheel on the front. When it's removed, the front and rear can both use the smaller diameter wheel bore

Don

TEMPORARY SPARE TIRE

This is a huge thread which I have scanned but not read it all carefully so if my unbridled enthusiasm is about old news and unwarranted, I apologize.

Now I'm not driving around without a spare tire. Call me old fashioned, or whatever, I'm just not doing it. In fact it was one of the larger concerns I had when considering buying the car (no spare???). After an exhaustive search of specs etc. The information led me back to my own garage and my wife's 2013 Honda Fit. I just returned from a test run with the Fit's stock temp spare (15in steel wheel) on the front. Then a second drive with it on the rear.

Front: The tire is much larger dia than the Miev front tire, but it clears everything lock to lock on the steering and fender wells. I tested it with the traction control off and everything went fine. It didn't even feel very strange having a larger tire on one side of the front end. Didn't test it with traction control on. I'm sure there would be issues since I have heard the traction control kick in on some corners I have taken since having the car.

Rear: It is also taller by a smidgen sitting side by side with the OEM Rear. I drove farther and faster with the rear temporary on and regen worked flawlessly. The temp tread in noisy (of course) but that is the only issue. (traction control off on this test drive too). Rolling circumference must be very close to the OEM tires. Even though it is taller it squishes more under load pulling it's rolling circumference down a bit from a static measurement

The wheel is steel and has a flared center bore so the collar on the front hubs did not pose a problem for it. It clears it and snugs right up to the hub.

One workable temporary spare for both ends of the car

Aerowhatt

I'll be moving related posts into this new thread. This will encompass both rims and tires, specifically for use as Spare Wheels (not to be confused with alternatives for primary wheels or snow tires).