Put SPT's on yesterday

[Balthazarr]

Jury is out thus far.
However, after leaving America's Tire/Discount Tire shop, I noticed quietude which was somewhat of a relief from the worn T1-S'.
They'll charge you $136 a tire for a 23/40/18, but I told them of TR price of $109 and $11 for shipping so they gave them to me for $120 each. YMMV
Something else i noticed when I got up to fwy speed is my steering wheel shook a little and the car felt like I was riding on a pogo stick.
Changed my shock settings to full soft since I bumped them up a few weeks ago.

Didn't get to test the change at speed since I was in the middle of a traffic snarl for 90% of my journey home on the fwy.

Seems a tractor trailer decided to flip over so avg speed was 5 mph for 40 min.
Didn't have a chance to check the pressure until this morning which was a minimum of 3 lbs under on each wheel.
That is probably due to the cold night since these were installed in the mid-afternoon.
Still, 32/31/30/29 is quite a variance from the 34 F/36 R I requested.
Checked the torque on the bolts last night and they were spot on.
Tech insisted that BMW specified 95ft-lbs, but I got my way with 82.
He wasn't too happy about having lost the battle (pissed off written all over his contemptuous smile) and it was kind of lengthy as he admonished me that the wheels could fall off. :stickoutt
I will report back after a few days use.

[synthply]

I assume you're talking about Kumho SPTs? I've had them since the summer and I think they are a great tire for the price.

[Rud]

Mine were slightly out-of-round when I first mounted them. Ran them that way for a week or so and then took them back and got them rebalanced once they had worked themselves back into shape.

They are pretty susceptible to overnight flat-spotting, too, like most soft tires.

Other than that, mine have treated me well. :)

245/40-17 on a 17x8 wheel.

[JBgotM]

have had mine for probably 10k+ and still loving them

[Balthazarr]

I'm glad someone's happy.
I have a question:
why do they only spin balance to 35mph? (Discount Tire)
Surely any non-uniform distribution of mass is going to be more pronounced at a higher speed.
Anyway, I'm going out now to eat so I will take the fwy and get up to reasonable speed since making some changes.

[Balthazarr]

Back and it still rides like a Honda on the fwy.
Just called them up and rep said their machine might be out of calibration.
:rolleyes

[BuchbrunnM3]

I am running the SPT in a 245/35/20 and 275/30/20 on my 5er and like them alot. Nice tire for the money...

[Balthazarr]

After I inspected the wheels, I found that the red dot which denotes the heavy spot on the tire and the valve stem were not positioned as they should be on a couple of them. Checked the fronts only since even with one, I was taking the car back for a rebalance.
The weights are supposed to be opposite those two points (according to what I was told by 2 of the reps on different days) and THOSE two points should not be more than 6" apart.
I guess to place the dot and valve directly opposite would balance better, but the weights might not be small enough to compensate so that's why they do it this way. (my guess)
There are two balancing methods: static and dynamic.
They chose static in my case the first time so this time they did a dynamic balance and had to place weights in two different spots.
One on the inside lip or flange and a second farther out close to the spokes.
This, evedently, is the more accurate method.
They had to separate the tires and move them circumferentially on the wheels for this.
Why this wasn't done the first time is beyond me as I was the only customer they had at the time.
Again, the laser balance machine spun to 35mph and I was assured this was all that was necessary.
Be that as it may, I just know the ride is much, much better and I think I picked up some good tires.
The acid test will be tomorrow when I get on the 710.

[sirius600]

Again, the laser balance machine spun to 35mph and I was assured this was all that was necessary.
Be that as it may, I just know the ride is much, much better and I think I picked up some good tires.
The acid test will be tomorrow when I get on the 710.

Most places only have the equipment to balance up to 35mph. A proper high speed balance will spin the wheels at 80mph. Besides, what do you expect from a place with "discount" in the name. :shifty

[Balthazarr]

Most places only have the equipment to balance up to 35mph. A proper high speed balance will spin the wheels at 80mph. Besides, what do you expect from a place with "discount" in the name. :shifty

You know this for a fact do you?
Rep told me that 35 mph is for safety concerns of shop personnel.
We'll see when I get the car over 120mph whether or not it is sufficient.

Chain is also called America's Tire. What do you have to say about that?;)

[jbnery6465]

was looking into getting the spt's, but i think i might try the asx's, but one issue im concerned about is that if kumhos run true to size. i have 225/40/18 falken 512's on a 18x8 rim, and the falkens run narrow. any one know?

[Balthazarr]

was looking into getting the spt's, but i think i might try the asx's, but one issue im concerned about is that if kumhos run true to size. i have 225/40/18 falken 512's on a 18x8 rim, and the falkens run narrow. any one know?


I have 8" and the 235/40/18's fit just fine.

[jbnery6465]

I have 8" and the 235/40/18's fit just fine.

do have any pics? if i were to install 225/40 on an 8", would it be flush still and not stretched...

[Balthazarr]

I had Pirelli P7's on 8" and the front were 225's.
I thnk I have a couple of pics.

[Balthazarr]

Then again, the tires looked a bit narrow come to think of it wrt the wheel.

[sirius600]

You know this for a fact do you?
Rep told me that 35 mph is for safety concerns of shop personnel.
We'll see when I get the car over 120mph whether or not it is sufficient.

Chain is also called America's Tire. What do you have to say about that?;)

Meh. :embarrasm


Stock M3 rims are 7.5". Is the stock 235/40 the widest you can go on those?

[Balthazarr]

These are 18's not 17's and 8" wide and 235's are as wide as I want to go up front.

[kendogg]

Balthazzarr, I wouldn't worry too much about the balance man, if they balance out to 0 on a machine, then they'll be fine. If your getting odd resonance at varying speeds, they might need to be force-matched, but if they're good to 80-90, they'll be smooth at 120+.

[Balthazarr]

What is force-matched?
All said and done, they behaved much better at 100mph today so I can't complain.

[kendogg]

What is force-matched?
All said and done, they behaved much better at 100mph today so I can't complain.


Force-matching is when you use one of the newer Road Force balancers, I've only used the ones made by Hunter. It has a drum roll that it puts on the wheel, and measures the amount of road force variation - basically, the amount of imperfections in the tires, the rolling resistance, etc., - it measures it in lbs. Normally, a tire with alot of road force, normally 15-18 lbs and up, will exhibit a large increase in noise,a s well as not feel quite 'round' going down the road. Not necessarily out of balance, but out of round. Force-matching is when they take measurements using a road force balancer, make a mark on the tire, and a mark on the rim, break the tire beads, and align those marks. Usually, this will both lower the roadforce, and lower the amount of weight needed to put the tires and wheel assembly in balance. Basically, it makes sure the tire and wheel assembly is perfectly balanced and round before adding weights. Usually only necessary when you experience excessive noise or vibration.

[Balthazarr]

Well, I guess that is what they did then.
I was experiencing some thumping at much lower speeds than 80-90 mph.
They broke the bead on each, removed all the weights and moved the tires around the wheels to position the red mark on the tire wrt the valve and used the laser balancer to determine amount of deflection (I guess in both planes) then added new weights.
I don't know how much each little ssegment weighs, but there were about 7 of them the first time on one wheel I watched them work on.
All I know is, the car rides much smoother than before I took it back to them.

[kendogg]

Well, I guess that is what they did then.
I was experiencing some thumping at much lower speeds than 80-90 mph.
They broke the bead on each, removed all the weights and moved the tires around the wheels to position the red mark on the tire wrt the valve and used the laser balancer to determine amount of deflection (I guess in both planes) then added new weights.
I don't know how much each little ssegment weighs, but there were about 7 of them the first time on one wheel I watched them work on.
All I know is, the car rides much smoother than before I took it back to them.

Each section of most sticky weights is 1/4 ounce. 7 equals 1.75 ounces. If they needed that much weight to get the wheel to balance, then I can totally see your problem. I mounted new 15" Sumitomo tires on these AMG wheels I picked up for the '83 Benz Diesel I just picked up, and one balanced out perfectly no weights, I was quite happy!!!

[Balthazarr]

thanks for the input kendogg