Another Satisfied Double Darkside Convert

After reading many well-written posts from experienced Goldwing riders who have crossed over to the Dark Side, I decided to take the plunge one tire at a time. Prior to crossing over, I had put about 15,000 miles on my GL1800 since I bought it, so I have a good feel for how it handled with the first and second set of Dunlop D250’s.

About 1,500 miles ago, I had a Michelin Primacy Alpin installed on the rear, and started with 30 psi. I used 3 ounces of Dyna Beads. My first sensation was how the tire wants to remain perpendicular to the pavement. The crowns on Interstate 5 between Portland and Seattle are sometimes very steep, and crossing between the crown and the car tire tracks can give you a very funky wiggle that you need to be prepared for. The same is true when coming to a stop. If the pavement is not level, the bike requires some man-handling and firm contact between my boots and the ground. It took about 200 miles before I began to like the Alpin, but I now love it.

When I lean into a curve, I have the sensation of sitting on a substantial chunk of treaded rubber and I can “feel” the large contact patch as the sidewall flexes slightly. While in a curve, the tendency for the Alpin to remain perpendicular to the pavement actually provides a feeling of stability which is hard to describe. If I sense I have too much bank angle for the curve, I can just “let up” a little, and the tire reduces the bank angle. If I want more bank, it just takes a tiny amount of lean into that large contact patch.

The positive experience with the rear gave me confidence to proceed into the hallowed grounds of the Double Dark Side. About 400 miles ago, I had a Battlax BT45 “rear” installed on the front, and started with 38 psi. I used 2 ounces of Dyna Beads. Living in the Great Northwest, I ride often in heavy rain, so I decided to mount the BT45 in the normal direction, as I wanted to maximize the potential for the tread to disperse the water.

The only handling difference between the D250 and the BT45 is a little more stability at walking speed with the BT45, and this is especially handy when riding 2-up.

There is now a light buzz in the front end and hand grips at about 14 and 28 mph, and this buzz was not present with the D250. It ONLY occurs at these 2 speeds, and is not detectable at any other speed. And, I only sense the buzz if the bike is fairly close to upright, and not while leaning in a curve. The buzz is barely noticeable during acceleration, but I feel it while holding a constant 14/28 mph or decelerating through these values.

My theory is that the BT45 produces noise pulses similar to a knobby tire, and those pulses occur at a frequency which causes the front fork/suspension to resonate. This is even more logical when you consider that the tire RPM is twice as high at 28 mph than at 14 mph, and now you have frequencies occurring at multiples of the other. I don’t have a theory about why it is not present during acceleration or in curves.

For the benefit that the BT45 provides in terms of thick rubber and tread pattern, a little buzzing at 2 speeds is an easy compromise. Since many streets have a speed limit of 30 mph, I actually don’t mind the 28 mph buzz, as I can decelerate from a higher speed limit to just below 30 by waiting for the buzz.

My bike has always had the “Goldwing Handlebar Wobble” at 42 mph, and these new tires did not affect this at all. It is interesting that 42 is a multiple of 14, so it is possible that the BT45 noise just happens to excite a natural instability in the front end due to the straight bearing I am planning to have a new tapered head bearing installed and I will post my findings.

There are many twisties in this area, and they will often be wet and sometimes slimy with moss or leaves. This is where the Alpin/BT45 combination really shines. The extra confidence gained by the thick rubber and tread pattern has not resulted in me riding faster, but the enjoyment level is higher because I have more of a sense that the tires will grip the road much better than my former tires. Knock on wood, but I have never had a blowout on a motorcycle. When I am 2-up on the Goldwing at 75 mph on the interstate, surrounded by vehicles, I want as much rubber between me and the nasty stuff as I can get. This was my primary reason for wanting to explore the Dark Side. There is no substitute for thick rubber with lots of tread.

My D250’s are heading to the recyclers, and I am a firm believer that the Dark Side is the Best Side.

Nice write-up, thanks.

I also just went DD on my VTX. I'm on my 3rd CT and wanted to get more miles out of the front.
My buddy that rides a ST1300 talked me into trying a Michlin Pilot 3 rear on the front.
I only got 200 or so miles on it so far, but no problems. Did find it interesting that I now need less counter-steer in corners and it doesn't "stand - up" coming out of a corner as quick as it did. Different, but liking it!!

Ride Safe,
Craig

I am a Darksider on my Vulcan 2000 and about to need a front tire replacement. Any idea what size rear I could put on my bike, reverse the tread pattern or leave normal?? Thanks.

Street--Find the same size rear as your front. Or as close as possible.
Craig

A 150/70-17 is not the same height as a 150/80-17. The 150/70 is over 1" shorter than the stock 150/80 tire.

-------------------------Tire Size Comparison-----------------------
Specification Sidewall Radius Diameter Circumference Revs/Mile Difference
150/80-17 ---- 4.7in --13.2in -- 26.4in -- 83.1in ---------- 763------ 0.0%
150/70-17 ---- 4.1in --12.6in -- 25.3in -- 79.4in ---------- 798----- -4.5%

there. all edited

Well you got it right! I did a lot of research before I did mine. Same set of tires except I run 32 psi on the PA3 with 3 oz dyna beads. Also did the Traxxon full monty. No more tire cuping and after 17,000+ miles this year they still look brand new. My scooter vacation took me through 9 state and 5,000 miles this summer all the way to Seattle. I rode in more rain than I had in my MC career and they grip like velcroe. Now riding in the rain doesn't bother me.. Gear Up! My GL 1800A is an '05 and I got it last January with 20,000 miles, a garage ornimate. I'm fixing that fast. My old E3's were trashed after 6,000 and I decided I wasn't going to spend $300 for a set of tires every 6-8,000 miles. I still have my old 1200 I and I wanted to get it over to the dark side as well so I am soaking in the info here. I love the fact that the PA3 doesn't have that shoulder bump that many have mentioned with other CT choices. Love the Darkside and shall not be lured back... the force is too strong here!

try running 40 PSI in the BT45. I have the same setup and don't get any buzz.