Gif
Posts: 217
Joined: Mon Jun 06, 2016 12:24 pm
Location: Bottom right hand corner of Wales

Brake Pad and Tyre Wear

Thu Aug 10, 2017 11:55 pm

So my i3 went in yesterday to have the recall done on the potential fuel line problem. No issues there and I got the car back washed as usual. They did the cursory service checks while it was in.

After 15k miles, it was reporting 3mm across every tyre which didnt surprise me but I'm not sure what the depth they had to start so not sure how much wear / life that represents. Anyone got any idea?

The more surprising thing was a report of 50% brake pad wear on the front :shock: Now given that I don't drive like a saint, I would expect some wear but the vast majority of my braking is done on regen so 50% sounded pretty high. Anyone got any experience of replacement yet?

theothertom
Posts: 188
Joined: Mon Mar 20, 2017 6:08 am
Location: South Carolina

Re: Brake Pad and Tyre Wear

Fri Aug 11, 2017 4:53 am

Hi Gif and welcome to the forum.
I don't know about the tyre tread depth when new but 50% brake wear seems excessive. Maybe they measured it wrong ?

rtanov
Posts: 117
Joined: Mon Oct 20, 2014 10:55 am
Location: Cincinnati, OH, USA

Re: Brake Pad and Tyre Wear

Fri Aug 11, 2017 7:04 am

The EP600 tires (19 inch) when new are 9/32" for the 155 size (front) and 10/32" for the 175 (rear) which is 7.1 & 7.9 mm. The legal limit here in the US is 2/32" which is ~1.6 mm, so you have quite a bit more than that. My tires after about 19k miles and 2.5 years are probably close to what you have left ~4/32". I'd say there's still some life left in them, although they show their age on the wet pavement.

The break pads have sensors - if it's not triggered I would not replace.
2014 BMW i3 REx
2014 BMW i3 BEV - retired

Gif
Posts: 217
Joined: Mon Jun 06, 2016 12:24 pm
Location: Bottom right hand corner of Wales

Re: Brake Pad and Tyre Wear

Fri Aug 11, 2017 7:21 am

theothertom wrote:Hi Gif and welcome to the forum.
I don't know about the tyre tread depth when new but 50% brake wear seems excessive. Maybe they measured it wrong ?

That was my first thought on the pads in terms of a pure guess measurement without any knowledge of their original thickness. Unless they are excessively soft, I can't see how I can have gone through 50% in 15k on a car with very strong regen.

Up until recently I had two tonnes of diesel Ford Kuga in my garage. I had only just replaced its front pads at 35k miles and I drove that harder with no regenerate at all.

Gif
Posts: 217
Joined: Mon Jun 06, 2016 12:24 pm
Location: Bottom right hand corner of Wales

Re: Brake Pad and Tyre Wear

Fri Aug 11, 2017 7:28 am

rtanov wrote:The EP600 tires (19 inch) when new are 9/32" for the 155 size (front) and 10/32" for the 175 (rear) which is 7.1 & 7.9 mm. The legal limit here in the US is 2/32" which is ~1.6 mm, so you have quite a bit more than that. My tires after about 19k miles and 2.5 years are probably close to what you have left ~4/32". I'd say there's still some life left in them, although they show their age on the wet pavement.

The break pads have sensors - if it's not triggered I would not replace.

So that makes my tyres 81% worn on the front and 77% worn on the back based on 1.6mm min. That gives range of around 19k for a set of fronts and 20k for a set of rears. Pleased with rears on that basis what with the obligatory traffic light dragging :oops: Fronts are a bit disappointing as I don't drive it hard in and out of corners.

Not changing the pads, must be a lot more wear in them than implied I think.

MikeS
Posts: 698
Joined: Thu Jan 16, 2014 8:29 am
Location: Brighton UK

Re: Brake Pad and Tyre Wear

Fri Aug 11, 2017 9:30 am

Just had my i3 checked over after 17K miles and no mention of any significant wear on the brake pads…..
BMW 3 Series 2005 - Aug 2014
BMW Z4 35i 2009 - Mar 2014
BMW X1 Mar 14
BMW i3 Sep 14

brastic
Posts: 32
Joined: Thu Apr 27, 2017 11:29 am
Location: San Jose, CA

Re: Brake Pad and Tyre Wear

Fri Aug 11, 2017 4:18 pm

The tires on these cars wear fast. It is just nature of the beast. At least the tires are cheap. Well compared to my M3. My guess on the brakes is that they were not read correctly. Some BMW dealers are still learning how to work on the i3. As others have stated, the wear is measured by the car and there is no reason to replace till you either hear it or the dash tells you.

My big wish is for wider tires in the future. I would be willing to give up a bit of range for more lateral grip. I mean, my minivan can out handle the i3 in any corner.

Bawareca
Posts: 39
Joined: Wed Apr 12, 2017 6:40 pm

Re: Brake Pad and Tyre Wear

Fri Aug 11, 2017 10:04 pm

brastic wrote: I mean, my minivan can out handle the i3 in any corner.

It may feel so, but you will need a heavily modified van to out-corner the i3. Given the i3 is not a top performer, the g-loads feel very different in small and a large car.

brastic
Posts: 32
Joined: Thu Apr 27, 2017 11:29 am
Location: San Jose, CA

Re: Brake Pad and Tyre Wear

Thu Aug 31, 2017 3:19 pm

Bawareca wrote:
brastic wrote: I mean, my minivan can out handle the i3 in any corner.

It may feel so, but you will need a heavily modified van to out-corner the i3. Given the i3 is not a top performer, the g-loads feel very different in small and a large car.


Thank you for asking more about this. I had to go look it up. With our minivan, we replaced the stock tires with some summer tires and the difference in handling was noticeable. The i3 is a good driving car, and I do not regret owning it. I hope that we can get some better tires for it, even it means less range. From the C/D test below, the i3 is faster, brakes longer and has the same skip pad numbers. This is what I feel when I drive both cars. It was after replacing the tires on the minivan, where I noticed that my exit speeds on some corners was higher than my i3. Then again, neither of these cars handle like my M3, nor do I expect them to. I hope that BMW will sell us the i3s rims and tires.

C/D TEST RESULTS:
2017 BMW i3 BEV
Zero to 60 mph: 7.2 sec
Zero to 90 mph: 19.0 sec
Rolling start, 5-60 mph: 7.3 sec
Top gear, 30-50 mph: 2.7 sec
Top gear, 50-70 mph: 4.7 sec
Standing ¼-mile: 16.0 sec @ 85 mph
Top speed (governor limited): 92 mph
Braking, 70-0 mph: 184 ft
Roadholding, 300-ft-dia skidpad: 0.77 g


C/D TEST RESULTS FOR:
2015 Honda Odyssey Touring Elite
Zero to 60 mph: 7.7 sec
Zero to 100 mph: 21.0 sec
Zero to 110 mph: 26.9 sec
Rolling start, 5-60 mph: 7.7 sec
Top gear, 30-50 mph: 3.8 sec
Top gear, 50-70 mph: 5.5 sec
Standing ¼-mile: 15.9 sec @ 88 mph
Top speed (governor limited): 120 mph
Braking, 70-0 mph: 178 ft
Roadholding, 300-ft-dia skidpad: 0.77 g
C/D observed fuel economy: 22 mpg

jadnashuanh
Posts: 3450
Joined: Thu May 22, 2014 2:07 pm
Location: Nashua, NH USA

Re: Brake Pad and Tyre Wear

Thu Aug 31, 2017 5:12 pm

On the i3s, the track is wider and the fenders are flared to make them fit, so not sure its wheels/tires will fit without maybe a bunch more cost than just the tires/wheels. Given that each are 0.5" wider, it may mean that you'd only need new rear wheels...the larger ones on the car now would be the same size as the new one for the front. That may mean that there is only one new tire size needed. Note, also, that those are currently summer tires...if you need all-seasons or winter tires, you'd have to go back to the 19" wheels and narrower tires front-rear. WIth the existing car, trying to put the 5.5" wheel on the front will lead to damage immediately after driving. The least expensive way to allow a wider tire without changing the suspension much is the flared fenders...that way, the inner clearances can remain the same. Given that the car is also lowered, that often can limit clearance, too.

Because the center of gravity on the i3 is so low, how the cornering feels doesn't correlate exactly the same to one that has more lean in the corner.
Jim DeBruycker
2011 535i x-drive GT, 2014 i3 BEV

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