EP600 tires tread depth

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rtanov

Well-known member
Joined
Oct 20, 2014
Messages
217
Location
Cincinnati, OH, USA
Can anyone with new EP600's measure the tread depths of the tires and report here.

The depth as reported new is 9/32" for the 155 size but is seems to me that the inside groove might be shallower than the center groove and that is what I am mainly interested in. Bridgestone tech support could not find this info, so it seems that the only way is to just measure a new tire.

The reason I am interested is lease return - as per the BMW instructions the tires will be accepted as good if they have 1/8" tread depth left, and people are reporting that they measure all treads. My center grooves have more than that but the inside groove is less. If this groove was shallower to begin with that might be a case to only measure the center groove; if it were the same depth then I shall be prepared to buy new tires at lease return. I guess I am not the only one with this issue as the 2014 leases come close to ending.
 
Thanks for reporting back. Maybe we should do something about this... cal BMW NA and try to have them change the tire check procedure - they cannot require the tire to have 4/32" on each groove if the new tire only has 5/32" to begin with! If that is the case then we should all be prepared to buy them brand new sets at lease return. I actually have a winter set so have used the original for only half the time, and was pretty confident that I will pass the tire wear test but this does not look good :evil:

BTW, the 175's specs say 10/32" for the central groove, but that's close enough - the important is that the inner groove is 4-5/32" less than the center.
 
Oh, I have time - my lease is up end of February. But I would like to plan and know what I should be expecting. I also have some flexibility with the winter set to control the wear. And we do have to figure this out as a group as it might affect a few of us.

It would be nice if we have good pictures showing the difference in tread depth on the new tires.
 
Hi,

After a visit for the recall, I got a copy of the "Tire Tread Depth" which shows 'red' on the inner grooves:

left_side(*) - right_side
5,6,2, LR ,2,6,5, front
5,5,2, LR ,1,5,4, rear

* - the driver side

The service writer suggested it was the aggressive regeneration. Since the rear, center grooves are shallower than the front, that would be the signature of regeneration wear. But the inner groove fails on all four tires. These tires have +13k service miles and the service writer reports they typically last 15k miles. Tires that were new in June 2016, 10 months ago.

Searching, I found heated, 'tire groove' tools, that have a mix of heated blades. These are typically used in competitions to improve tire performance. Prices range from $90-500 and there are different sizes and shapes, round and square. But they do not appear to have a gauge or stop to limit the depth (Oh give me a hard problem!) So this begs the question, has anyone thought to use a tire groove tool to deepen the shallow, inner groove?

The rubber profile looks OK although the driver-side, rear looks a little raised. But if this happened on our Prius, I would look at putting in shims to give the tires more camber towards the outer tread. In effect, offloading the inner tread to even out the wear. But another alternative is a wheel alignment tool and add the camber without the shim. Anyone look at this approach, adjusting the camber to offload the inner tire tread?

Thanks,
Bob Wilson
 
I'd like to report the results from my BEV lease end inspection - all 4 tires passes. This was the first i3 that the inspector from Autovin did - I pointed out to him that only the center groove had wear indicators and therefore the wear should be measured only on that one and he agreed. If he had measured the inside groove all tires would have failed. Car had 18k miles and almost half of that were on winter tires, so the original tires have less than 10k miles on them.

On a side note - my other REX i3 which just hit 17k miles still has more than 4/32" center thread left on all tires although I drive pretty aggressively. I've had no winter tires on this car so the 17k miles were put on these original tires. I also inspect the tire pressure regularly and try to keep it in spec. I have recently noticed that the tires have noticeably lost some traction on wet pavement - I attribute this to aging.
 
Good news! False-positive

The drive-over tire scanner is tuned for wider tires. The tech took a closer look and he sees no problem.

I will do a tread-temp test this weekend and if they are equal, no problem.

Bob Wilson
 
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