Coolant_Leak

iTrader: (18)

just ordered a set of staggered sumitomo's

after mounting the tires on my wheels i see that the they are not directional? they are labeled (outside) (inside)

my concern is that the tread pattern isnt mirrored like other non-directionals...

one the left the circular tread points to the rear of the car.
and on the right side. the circular tread points to the front of the car...

just want to know if its supposed to be like that... or they sent me 4 left tires...

Howard Coleman

iTrader: (6)

based on your post i checked the 4 HTRZIIIs on my car and found 2 correct and 2 backwards.... yet all showing "outside."

the circular grooves start near the center of the tread and should roll towards the outside.

these grooves unlike, say a Toyo Proxy, are not the primary grooves in the tire. the circumfrential grooves and outer tread blocks are key. so unless you are in a rain situation i doubt if it is much of an issue. that's probably why they aren't labled as directional.

that said, it is incorrect. i have another 4 new HTRZs and will see what i have in the stack. i ordered 8 and had 4 sent to Tire Rack for shaving.

i have sent an email to Sumitomo Tech and will let you know what i find.

BTW, i love the tires. i was bedding in a set of Hawk DTC60 pads for a track day a couple of weeks ago and the tires and RacingBrakes just about put me thru my racing belts w not a squeal.

hc

owen is fat

arent the azenis directional like that?
they have a groove that needs to be on the outside edge of the car
but the tread pattern (arrows or slashes) can be forward or trailing, that doesnt matter.

Coolant_Leak

iTrader: (18)

thanks for the replies.
i just thought it would be strange because the grip say making lefts and rights would not be identical. due to the "different tread"

here's an image that i edited to reflect what it looks like.




maybe the design was made for left to right rotation to even wear?... it seems strange to me that it would look "backwards" like this.

will be awaiting the response you get howard coleman. i'll be going to the track in the FD for the first time this winter, so i dont want any surprises.

Howard Coleman

iTrader: (6)

i received the following response from Sumitomo:

"You are correct that the HTRZ III has a directional element, but the impact of running the tires on one side backwards is very minor compared to the advantages of being able to rotate them. Directional, asymetric tires with a staggered fitment would require 4 different sku's on a particular vehicle. As a practical matter, that's impossible to manage during manufacturing and through the supply chain. Further, the marginal benefit to performance is minimal. Note that Bridgstone RE050a and Continental Sport Contact3, popular OE tires, have the same characteristic."

that is what i suspected. a modest compromise made so most buyers would be able to rotate their tires without dismounting as well as significant manufacturing/warehousing cost savings much of which are clearly passed on to the buyer based on the friendly pricing.

while i have yet to track the tires i have an entire (wisconsin) season on them.

lots of aggressive driving. i run 255/35/18 fr and 295/30/18 rear. at 1.2 degrees neg camber and a touch of front toe-in the wear pattern is perfect.

i will post a few pics of the tires so you can judge for your selves.

2 weeks ago i was getting ready to go to Blackhawk Farms for a test day and was bedding in a set of track-only Hawk DTC60 pads. lots of stops from 80 mph. combined w my RacingBrakes (ABS removed) i was totally shocked at the decel Gs pulled by my HTRZIIIs. dead straight and not any noise from the tires. i really can't wait to get them ontrack.

unfortunately, i came down w some viral deal that flattened me for 2 weeks and i missed the last 2 track opportunities. oh well.

back to the tires...

the item that makes them "directional" is minimal and primarily operative while driving in rain. if you look at the tires you will see four large circumferential bands.... they do all the heavy lifting re drainage. my tires are shaved to 6/32 and work just fine in the rain.

good luck ontrack and let's hear from you after...

howard

Howard Coleman

iTrader: (6)

here's the RR, 295/30/18 today. 'was shaved to half tread depth at Tire Rack. even while run at neg 1.2 degrees camber it looks symmetrical and new. a happy tire at 2700 miles. fronts look exactly similar. run at 29 psi fr and 27 psi rear set cold. tire still is nice and soft as specs out at 54 on my durometer. don't buy the 300 rating as a direct expression of tire softness...

inside tread blocks completely intact.

ditto outer

Coolant_Leak

iTrader: (18)

ty for the feedback, howard.
cant wait to break these new tires in this weekend.

par your instructions i think i need to deflate my tires a bit..to "29 psi fr and 27 psi rear set cold." the guys at discount tire max loaded it i believe...

thank you for all the suspension/tire information