another wheel/tire question
 

actually 3 questions:


1. have the opportunity to purchase Y spoke 20's with tires that are mismatched: continentals upfront and michelins in back. Is this an issue for the AWD system? in general?

2. Any way to estimate how many miles are actually on the tires? seller is saying 12k miles...

3. i have 3rd row so no spare. What do others here do when swapping the rock hard runflats to regular tires? I'd rather not drive around with a tire in the back :) although in the past 8 years and 4 cars I dont ever recall having to replace a tire... but murphy's law will strike - i just know it.

20" Runflat Question
 

If you're interested, I'd love to get rid of my runflats for all seasons and I'm in NYC if you're interested in purchasing. My runflats have about 2K miles on them.

-mixed brands: not a huge deal, imo. You may notice some
wheel imbalance/shimmy, slight handling diff. and probably
different wear, over time. My hunch is the wheel 'puters
will compensate and if you aren't hanging 10 on corners
or autocrossing it, no biggie. Otoh, why does the seller
have 2 brands of tires, F & R?

-if there is decent tread left, who cares what he says
the mileage is? If there is ~12K on them, you may get
another 10ish out of the set; maybe less. No way to
accurately est. tire mileage, imo. Every tire joint will
have a diff. opin. You are looking for good, even wear
across the width, though the rears may show more
wear on the inside tread area due to camber: and that
may be why there is a pair of diff brand on rear.

-No RFTs, no spare...it is a risk, but many of us do it
in other cars. Buy a can or two of non-flammable air
supply or, a can of "Goop", have cell phone, and
roadside service. I've had nearly a dozen tire repairs
in our '01, over 3 diff sets of tires, in 7 years; none
have been "out on the road".
My 50Ct is up...
GL,mD

1.Should not be a huge issue. You may get some vibration if the tread pattern is really mismatched. It is recommended you run all 4 tires the same brand and model.

2. Tread depth gauge is the best indicator. You will need to know the depth of the tire new to try and gauge what is left on the tire. You can buy a tire depth guage for $4.00 at your local auto store. I think it's more important to know how much tread is left since we all drive differently and that will affect tire wear.

3.Many people will use the tire flat repair green goop. BMW sells the Mobility kit, but you can put one together yourself for 1/3 of the price. A decent air inflator, can of slime tire repair, some work gloves, rag, digital tire pressure gauge and your set. Airman make a decent kit for about $35.00. Unless you want to cary a jack and a patch kit this seems to be the only option.

I looked at the tires and didnt notice any weird wear but to my untrained eye the grooves in the thread didnt look very deep and certainly shallower then the grooves on my RFT 18's with 10k miles... estimating milage aside, isnt there a way to tell if the tires have "life" left with a coin? whats the trick there? thanks.

I think 3/32nds is the min, rec'd...
A simple cheap azz tread depth gauge will show actual or,
do the Lincoln Head Penny deal: hold penny opposite of
Lincoln's head, insert into tread. If you can see "any" of
the top of Lincoln's head, they are close to gone, imo.

Tread depth plays a huge role in wet road traction, less
so on dry pavement. If you think the remaining tread is
suspect, it probably is. Maybe reduce offer considerably,
as you may be looking for tires. I recall our decades in NY
where the local insp joint would look hard at tire tread,
come annual insp. time, unless one paid him off.
GL,mD

will pick up a tread depth gauge now that i know it exists :)

Anyone know the orig depth on these 2 tires?

also, forgot to ask about the tire pressure sensor.... those who switched to non RFT tires - did you put the sensor on?

Michelins are probably 10/32nds. Not sure on the Conti, but they will probably be tclose if not the same.

Yes I had them throw the originals in the non-RFTs - they wanted to charge me extra but was free in the end. I should really test them though.. let some air out and see if it complains. I guess I should read how sensitive they are (difference in psi) until they do raise a red flag, unless someone knows off-hand.

I dont know if this is common knowledge but http://www.tirerack.com/accessories/...tkit/index.jsp shows that using the sealer may damage the tpms sensor... I also did a quick google search and there is a some talk about this issue in other car forums.