In Reply to: Sumitomo HTRZii - first impression (longus) posted by DHoang on August 15, 1999 at 10:07:43:
: Removed SP2000E @30k miles and Just had 235/45/17 SUMI's [shipped from TireRack] mounted yesterday on my E39. Cost for mount+bal=$60.00. Yes, independent tire reseller threw in two 2" rim scratches on my 2pce wheels for free, even though I paid $20 extra for touch free mounting. Might sound crazy, but this is peanuts compared to NTW/NTB dropping my Porsche 944 off of their lift,with 1/2 car on lift and other 1/2 6" from the concrete, gouging the galvanized underbody with one of the lifting arm.
: Living in the rural/country , I typically drive through my county road route about 5 times a week and thus am very, very familiar with the only roads going into and out of the next big town. Almost immediately out of my garage, this 20 mile [one way] trip gives me access to some fairly spirited driving with only the cows and buzzards to contend with. Tires now have about 100 miles worn in. So here's what's going on...
: 1) Very evident that worn SP2k's grip and track far better than new Sumis, but I am beginning to wonder how much longer I can handle the floatiness of these new babies. At 30 mph, If I twitch the steering wheel to and fro [ around 2-1/2" circumference of the steering wheel ] the car reacts about 1/2 second later. I don't remember this condition when I first drove my new car w/ new SP2k's. I know for certain that the old sp2ks behaved more responsively than current setup.
: 2) Front end alignment has recently been performed five weeks ago by BMW dealer, yet New tires seem to be wandering, not wanting to track straight on smooth road surfaces, and requiring more input to keep car pinned straight. Is this due to the squirminess of new & deep tread ? Or is it due to new tires trying to wear into a pattern ? I Don't remember this condition with old SP2k's.
: 3) I had wheel weights adhered to the back facing portion of the wheels, so there is no visible weights showing. Took the car up to 110 mph, sustain speed for about 5 secs, and did not feel any apparent vibration. Had about three more miles of open highway to reach limit but I throttled off due to the straight line incaccuracy. Decellerating from stated speed down to 20mph was OK, but not impressive. It felt like the brake pedal got mushy on me. I don't know how to rationalize this, because it doesn't make any sense to me.
: 4) Obviously, new tires absorb cracks and road irregularities better than worn tires, and the new tires indeed do so. The steering wheel jittering when impacting over these patches or railroad tracks don't come through steering wheel as much anymore.
: 5) I had complained to BMW dealer in Jan. when my car had 16k miles about a bearing noise heard when coming to a stop. Dealer said their technician mounted a different set of tires and said that the noise went away, so problem's with the SP2k tires. Well, after re-tiring to Sumi's , the noise is still there and as audibly apparent as before. Road noise when decellerating has not changed. Road noise when accellerating has not changed. Was hoping that overall road noise would be dramatically lessened with new tires, but my first impression is that road noise is borderline marginally reduced to no change at all - as compared to old SP2k's. So I'm now saying to myself " Gee, if my old tires have road noise almost comparable to these new tires, either the SP2K is far better at reducing road noise than I realized, or I am being overly critical with the new tires."
: 6) ASC light comes on at every aggresive turn with new tires - didn't do so with old tires. With more miles, I hope, - I pray - that I get more stick through the curves. If not, I may need to replace them.
: 7) I hear more road noise [ sort of like a high pitch whine] on smooth surfaces than on rough textured pebble surfaces, where the high pitch is lessened to a low grumble. This is odd. I would think that road noise would lessen on smooth, not on rough. I wonder if this has to do with the fancy tapered rain grooves.
: At this point, I am first going to address the bearing noise again with dealer. Then I will reassess these tires when I log 200 miles. SHould I log in more miles or less ? If it were that I determine that the tires are not to my satisfaction, has anyone tried to return tires to TireRack for replacement of like kind vs. different kind ? At how many miles would they take them back ? Assuming that TireRack has a return policy, what other cost would I absorb?
: I welcome all constructive comments. TIA.
A guy I know with an A4 put on SP9000's and really hates their turn in response. He is a serious driver and does lots of track time (although he has R compound for that). He said they are floaty also. I think the ride quality they brag about has a tradeoff-a softer sidewall. They will probably get better with more miles.
Bottom line is this, chew up the Sumi's and get a real performance tire. With most tires you get what you pay for. If you are driving a $50k car, you can spend $150+ for a tire.
I bought Bridgestone RE71's for my track wheels and they are responsive and sticky (140 rating, only $128 a piece). However, as they are 10 years old, they are loud and stiff-riding, but that doesn't matter for what I will use them for. By the way, I have 700 or so miles on them now and they are way stickier than at 100.
For the street, I am going with Firestone SZ50 or the new Yokohamas next time ($160/$170 respectively). Unless I give in and buy the SO2PP's. The car had Pilot SX GT's on it when I bought it. Decent tire, nice riding but pretty low treadware and only VR rated. At $190 each they are not a bargain.
KJK 91 M5