How Much PSI for my new "darkside" Sumitomo?

Took the leap today - my mechanic installed (with much hassle) my Sumitomo tire on my 03 Swing (ended up putting a tube in it to press it onto the rim, then removed the tube and presto! The tire then mounted itself to the rim). I took a 30-mile jaunt home with 40 psi, but it feels squirrely - like it's overinflated. I plan to decrease in 2-lb increments to find a "feel-good" PSI. Any suggestions?

Hi Slick. From the tire shop, my Sumi was handed to me with 34lbs. I have since reduced that to 30lbs and she feels great. I hope you hear from Bill on this, as he has mucho miles on his Sumi. I'm happy with 30.......and I'd be happy to "BE" 30 again! Take care....Jeff.

I usually have 40-42 on my Pirelli Diablo rear, but already have a Sumitomo ordered when the Diablo says sayonara. I've heard that typically most folks have lower psi in the front than the back -- I wonder if the same holds true for a darkside tire?

Slick-Tenn wrote:

Took the leap today - my mechanic installed (with much hassle) my Sumitomo tire on my 03 Swing (ended up putting a tube in it to press it onto the rim, then removed the tube and presto! The tire then mounted itself to the rim).

That is a simple non-destructive solution.

Do you have any more details on the mechanic's "hassle"??

Slick-Tenn wrote:

I took a 30-mile jaunt home with 40 psi, but it feels squirrely - like it's overinflated.

When did it feel squirrley ... straight or on curves.

Remember for the first 250-300 miles, until the Sumitomo has scrub the mold compound ... the darkside tire should not be pushed or tested in curves especially when wet.

Slick-Tenn wrote:

I plan to decrease in 2-lb increments to find a "feel-good" PSI.

If I want a very responsive counter-steering in twisties, I will run the darkside Sumitomo at a higher pressure 45 PSI ... though the tire will not absorb as much shock.

For the majority of times, I will run the darkside Sumitomo at a lower pressure 32 PSI ... the tire will absorb a significant amount of shock.

honda_silver wrote:

Slick-Tenn wrote:

Took the leap today - my mechanic installed (with much hassle) my Sumitomo tire on my 03 Swing (ended up putting a tube in it to press it onto the rim, then removed the tube and presto! The tire then mounted itself to the rim).

That is a simple non-destructive solution.

Do you have any more details on the mechanic's "hassle"??

Slick-Tenn wrote:

I took a 30-mile jaunt home with 40 psi, but it feels squirrely - like it's overinflated.

When did it feel squirrley ... straight or on curves.

Remember for the first 250-300 miles, until the Sumitomo has scrub the mold compound ... the darkside tire should not be pushed or tested in curves especially when wet.

Slick-Tenn wrote:

I plan to decrease in 2-lb increments to find a "feel-good" PSI.

If I want a very responsive counter-steering in twisties, I will run the darkside Sumitomo at a higher pressure 45 PSI ... though the tire will not absorb as much shock.

For the majority of times, I will run the darkside Sumitomo at a lower pressure 32 PSI ... the tire will absorb a significant amount of shock.

The motorcycle tire (IRC) he took off is wider rim-to-rim. The Sumi is quite a bit narrower (around the rim). It was simply impossible to get both inside beads up against the rim to catch the air. He tried wrapping around the tire with a strap, but the tread wouldn't cooperate. So, he ended up putting in a tube and the tire seated great. The plan was to drive it around for a week or two and then remove the tube. But, we rolled the dice and removed it before putting the wheel back on and VOILA! it seated. About a 90-minute process.

Here is the Sumitomo specifications

http://www.tirerack.com/tires/tires.jsp?tireMake=Sumitomo&tireModel=HTR+T4&partnum=67TR3HTRT4&vehicleSearch=false&fromCompare1=yes

Service Description: 165/70R13
Load Range: 78T SL
UTQG: 560 A B
Speed Rating “T” = 118mph (190kph)
Max Load: 937 lbs.
Max. Inflation Press.: 51 psi
Tread Depth: 9/32"
Tire Weight: 14lbs.
Rim Width Range: 4-5.5"
Meas. Rim Width: 5"
Sect. Width: 6.5"
Tread Width: 5"
Overall Diam.: 22.2"
Revs Per Mile: 949
Country of Origin*: "CN" = CHINACN

Slick-Tenn wrote:

Took the leap today - my mechanic installed (with much hassle) my Sumitomo tire on my 03 Swing (ended up putting a tube in it to press it onto the rim, then removed the tube and presto! The tire then mounted itself to the rim). I took a 30-mile jaunt home with 40 psi, but it feels squirrely - like it's overinflated. I plan to decrease in 2-lb increments to find a "feel-good" PSI. Any suggestions?

THANKS TO ALL WHO REPLIED! I'VE PUT IN 32 PSI AND THE TIRE SEEMS TO BE RUNNING AND FEELING AS IT SHOULD. OF COURSE, GETTING USED TO THE SIDEWALLS FLEXING WILL TAKE SOME GETTING USED TO, BUT I AM THRILLED AT THIS POINT! THANKS AGAIN!

THERE IS NO HANDLING DIFFERENCE, or so we're constantly told, so there is nothing to get used to .

Enjoy the ride of that car tire.

Hi! can anyone put some photos with darkside tires for we can see?

Hi Armelao. I have a pic of my 03 in " Silverwing Topics'. Darkside....yes or no. page two. The pic of your scoot....tell us about it. Thanks...Jeff

Jeff, I still have the picture you sent me do you need it now?

thank´s,i have seen,here in portugal,we don´t practice dark side.

It might just be me (very likely just my poorer riding ability) but I have a lot of trouble with sharp right turns as well as switchbacks. No problem with twisties otherwise. I'm running 33psi in the rear. Do you think I would do better with a lower psi?

30psi

Another caveat: I run quite heavily loaded as I have a 5 gallon tourtank and I also have Ortlieb saddlebags and a full complement of tools since I'm often all over the place by myself. Do you think 30psi would still be fine or should I bump it up a little?

Right now I'm running 34 loaded, and I'm not good on switchbacks AT all.

Hammy wrote:

Right now I'm running 34 loaded, and I'm not good on switchbacks AT all.

Not sure about the air pressure, but try doing some switchbacks sober instead of loaded and you may do better.

I did some research on the Delphi forum and they recommended 38 psi.
I tried several different pressures and 38 psi was the sweet spot.

38 psi for the Silverwing to do twisties... Kinda runs counter to what I've been told that lower psi was actually better. I'll have to give it a shot, but the last time I rode on 40, it was not comfortable at all. Then again, it was when I was still feeling it out. I just hate that I can't do sharp right turns or switchbacks like I used to. It works great for everything else though.

This is the Sumitomo on my '04. I usually run it at about 42psi.

I find that the higher the pressure, the faster the Silverwing responds to the counter steering.

With the Sumitomo tire at the higher 45-50 PSI, the response seems to be immediate.

If I am going to ride very twisty roads, I raise my PSI to 45 for the best handling ... otherwise I run a lower PSI.

Lower PSI provides better shock absorbing.

So for me it depends which balance of the two I would like.

I have an 04 too. Perhaps it would be smart for me to show you what I mean when I say my Swing is fully loaded.

I raised my PSI to 45 a week or so ago. So far I don't feel any 'squirreliness'.

Hey Tim, do you think I'd do better in the twisties with a higher pressure? My Goldwing buddies have been telling me to go lower instead. When you did the Dragon, what pressure were you running?

Hammy wrote:

I have an 04 too. Perhaps it would be smart for me to show you what I mean when I say my Swing is fully loaded

I was loaded with when I went to Ozark ( E52 case packaged, rear seat loaded with camping gear: sleeping bag, Therma-Rest pad, tent, Silverwing cover, small folding camping seat ).

The Ozark had some great twisties. Upper Arkansas 7 was a very interesting ride, it had twisting with the slick tar snakes. The front tire constantly felt like it was slipping out when it hit the tar snakes in a curve and the rear darkside Sumitomo tire did not slip on the curves ... if only the front motorcycle tire gripped like the softer Sumitomo car tire

Well, I bumped it up to 40. What a difference. MUCH more responsive, but also a harsher ride. I do have the rear springs set at 5; maybe I'll set them to 4 and see how it goes. I did feel MUCH better in the few twisties I was using as a testing ground.

I'll get to test these out on a group ride on Saturday to the Delaware Water Gap. I have missed the handling!

Hammy wrote:

Well, I bumped it up to 40. What a difference. MUCH more responsive, but also a harsher ride.

As expected.

Hammy wrote:

I do have the rear springs set at 5; maybe I'll set them to 4 and see how it goes.

As I recall, 5 is the harshest setting. So trying lower settings or pre-tensioning with the PVC plastic collar may help.

Hammy wrote:

I'll get to test these out on a group ride on Saturday to the Delaware Water Gap.

Are you taking US-209??

Yeah, 5 is the hardest setting. What does "pre-tensioning" do? Sounds like would make it even harsher? (turn the volume up to 11 kinda thing) I just hope I don't start bottoming out at 4 (haven't really bottomed out, but going over bumps in the road last night was a little jarring).

As for the Water Gap, I'm dragging for my motorcycle group so I didn't plan the route, but this is what we're doing:

http://goo.gl/maps/Cwqh
and
http://goo.gl/maps/teTz

It'll be a good test.

Let's see, your mechanic had trouble mounting the car tire on your S/Wing, you can't take the twisties or turns very well, car tires on two wheeled vehicles are outlawed in alot of countries for safety reasons, hey it's your Butt, just hope you don't get in an accident and cause harm to others.

Ride Safe.

Gee, thanks. Enjoy your ride too.

Moved to Darkside Car Tire :: Darkside Car Tire Experience