Blasphemy - 180 60 rear "cruiser" bias ply tire!

Joined
Aug 23, 2022
Messages
349
Age
54
Location
Nova Scotia
Loving the new tires!! 180 60 on the back. Gearing is much improved!

I'll try to be concise but there are a lot of points I'd like to share...

Credit to Van Pool (Facebook)who shared a lot about tires with me. He used to work at Michelin.

Tire size calculator and comparison charts are good, but not the full story. Not all tires are created equal - in size!

My previous tire (slightly worn) was less than the mathematical size. It was a Pirelli Angel GT2 @ 180 55.

New tire is a Bridgestone Battlecruise BT50 "cruiser" tire. AND it is bias ply, NOT radial. The Bridgestone is a 180 60, and it is larger than mathematical size (as measured by circumference.

So, although I was supposed to gain only 2.8% gearing reduction, I ended up gaining 4.98% difference! And when leaning, the larger radius of the riding surface keeps circumference larger and rpms lower. Yay!!

Okay, now some comments on the results...

- Gearing is lower, by 5%. It is wonderful, and I am not so rushed to get out of 1st gear in the city, and on the highway I can cruise at 115kph @ 4000rpm. The bike could use another 5 to 7 percent, for my liking... But the 4.98% gain is excellent...

- Cornering - Okay, yeah, this is a bit of a "lazy" tire... But it still has a good lean angle, and I actually seem to sense more rubber confidence during strong lean cornering. The sidewall is taller, and riding surface is a larger radius, so of course it's gonna be lazy, but also you get a much larger contact patch for more confident turning.

- Wait...!! "It's not a radial...?? You're gonna die...!! The Matrix will self destruct!!" Yes, it is not a radial. But this back tire rides really nicely... Seems softer and more smooth. When I did some research, I actually found a pro racer who liked a bias tire with a radial. The front tire for this bike series is radial, rear is bias ply. Drives nice and smoothly, and the back is rated for 19,000 miles!!

- Some interesting things... The bike seems more stable on the highway with less shaking/swaying due to wind buffeting from side or when behind other vehicles. I attribute to greater stability due to the gyroscope diameter being bigger. And less wind buffeting because perhaps (just guessing here) ground effect is less with the back raised close to a cm. (Look up helicopter ground effect.)

That's all I can think of for now, but I'll add to it later if I remember.

Oh, yeah...

Who is this tire good for...?? For people who have some nice mild twisties but also ride 120kph and higher on big highways.

Who is this not good for...? For example, if I still lived in Japan, I'd likely run a 180 60 sport touring tire, or a 170 60 size of this tire, to return the bike to being more nimble.

Oh, last thing... Gas mileage... Way better! Getting fuel economy at 125kph that I used to get at 110 kph. (Parasitic drag is likely expontial, so as long as the gearing has enough power and torque for a given speed, any more rpm is simply losing fuel economy due to more cylinder fires per minute and more parasitic drag from the engine.) my first tank, I got 525kms and 47.5 mpg (riding 110kph to 125kph including 2 up riding), compared to 40mpg (driving slower 100 to 115kph with no 2 up) on my previous smaller tire. I'm at 4000rpm at 115kph (true speed).

BTW, I test drove a Kawasaki Concours yesterday. In overdrive, it runs at 3000rpm at 110kph.

To all you "Honda engineers are perfect" fanbois, quite simply, Honda did not do a great job on the gear ratios.

One last addendum...

I could NOT put the bike on the centre stand with my former tire without help from a second person. I can, relatively easily, put the bike on its center stand by myself.

Now, all you naysayers, load up your ammunition and tell me how I'm gonna break the matrix by using a bias ply "cruiser" tire on back with a radial up front, and tell me again how wrong I am about the gearing choices Honda makes (and please continue to ignore my real world experience with the Japanese culture, and with my former Shadow 750 gearing belt drive mod and my tire size change on my 2nd and present st13).

To those of you who are interested in new information and extending our knowledge of this bike, I hope this information is helpful.

Blessings to you all!

Ride safe!

Photos are of Musquodoboit, Nova Scotia.

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I'll be interested to hear how many miles you get out of it. Presumably, the bias tire should wear better than a radial.
 
Thanks for the analysis.
Although I'm an analytical personality, I have never found myself pursuing gear ratios, tire circumference, radial vs bias, etc.
However, much of your handling description mirrors my experience with the Vredestein car tire.
Except, maybe due to a rounder shoulder than most CTs, I don't find a "lazy" cornering turn in.
I do agree that the 1300 could use a taller top gear (no 6th gear!) for interstate travel.
I am a MPG measuring fanatic, and have noticed no real difference before and after mounting the CT, with or without towing the trailer.
As I've said many times, once I worked past my unfounded, stubborn skepticism about going Dark, everything has been positive.
With one minor exception being having to loosen the front fender when mounting the rear m/c tire up front, to move it up and allow installation, and then refitting the fender.
 
At least is surpasses the bike's load rating of 72 minimum, coming in a a rating of 75.

Was there a cost savings over a standard replacement tire? What drove you to this tire? Did you consider doing a car tire on the back instead?
 
My previous tire (slightly worn) was less than the mathematical size. It was a Pirelli Angel GT2 @ 180 55.

New tire is a Bridgestone Battlecruise BT50 "cruiser" tire. AND it is bias ply, NOT radial. The Bridgestone is a 180 60, and it is larger than mathematical size (as measured by circumference.

So, although I was supposed to gain only 2.8% gearing reduction, I ended up gaining 4.98% difference! And when leaning, the larger radius of the riding surface keeps circumference larger and rpms lower. Yay!!

- Gearing is lower, by 5%. It is wonderful, and I am not so rushed to get out of 1st gear in the city, and on the highway I can cruise at 115kph @ 4000rpm. The bike could use another 5 to 7 percent, for my liking... But the 4.98% gain is excellent...
Math R hard. If you went from a 180-55-17 to a 180-60-17 then it is a only 2.8% change as you first noted (from your non stock size tire). The change is all in the tire outer diameter, gears ratio's didn't change.

180-55-17 size tire o.d. (77.8968") equates to 813.39 revolutions per US (5280 feet) mile. 5280 x 12 = 63,360 inches in a mile. 63,360 / 77.8968 = 813.39 revolutions per mile.
180-60-17 size tire o.d. (80.1231") equates to 790.78 revolutions per US (5280 feet) mile. 5280 x 12 = 63,360 inches in a mile. 63,360 / 80.1231 = 790.78 revolutions per mile.

813.39 - 790.78 = 22.61 less revs per mile.

22.61 / 790.78 = .02859 change. 2.9%

If you care the 180-60-17 is a ratio reduction of 1.0% from the stock ST tire size of 170-60-17. The 170-60-17 turns 805.71 revs per mile.

I'm glad your math gives you 4.98 to 5% change! Go ride it and tell us how it does over 10,000 miles.
 
Last edited:
I found this calculation sheet on another page (scroll down for corrected version). The tire cross section and aspect ratio are factors in the calculation. If these are hand measured, versus what the "factory" numbers show, they would then change the speed in gear and the relative ratio of the gearing for the bike, to the road, it would seem to me.

Then I noticed there are several versions of the sheet in this other link with corrections made on the fly, as I described above.

ORIGINAL HERE: https://www.st-owners.com/forums/threads/st1300-gearing-tech-info.130196/
 
The increase of tire life span will probably be due to bias construction and a "harder" tire.

I committed the error of going off on a 5 day ride with a tire (bias and higher mileage) I'd never used. During the rain, it would step out on me. Vert nerve racking. I felt I wasted the vacation because I had to carefully ride the curves in fear of the rear tire sliding out on me. It came off when I got home never to be used again.
 
Honda engineers used to produce quality products. Now, like most companies, Honda is run by bean counters and lawyers. The final product has been re-designed to make it easier and cheaper to produce. The majority of the production needs to make it through the life span of the warranty with as few/cheap, if any, recalls.
 
I entered many a post on the 180/60 17 that I used on my st1100. Got 18,000 miles on it, still has good tread on it. At the time the price was only a few bucks more that a T31 now the price has more than doubled. Matched it with a 130/70 H50 on the front.
 
The increase of tire life span will probably be due to bias construction and a "harder" tire.

I committed the error of going off on a 5 day ride with a tire (bias and higher mileage) I'd never used. During the rain, it would step out on me. Vert nerve racking. I felt I wasted the vacation because I had to carefully ride the curves in fear of the rear tire sliding out on me. It came off when I got home never to be used again.
It wasn't a Bridgestone. I had no problems with mine in wet weather. I watched an interview with Nickey Hayden who won more races in the rain than anyone else at the time. He was asked why he was better in the rain his answer was that he rarely used the rear brake.
 
Loving the new tires!! 180 60 on the back. Gearing is much improved!

I'll try to be concise but there are a lot of points I'd like to share...

Credit to Van Pool (Facebook)who shared a lot about tires with me. He used to work at Michelin.

Tire size calculator and comparison charts are good, but not the full story. Not all tires are created equal - in size!

My previous tire (slightly worn) was less than the mathematical size. It was a Pirelli Angel GT2 @ 180 55.

New tire is a Bridgestone Battlecruise BT50 "cruiser" tire. AND it is bias ply, NOT radial. The Bridgestone is a 180 60, and it is larger than mathematical size (as measured by circumference.

So, although I was supposed to gain only 2.8% gearing reduction, I ended up gaining 4.98% difference! And when leaning, the larger radius of the riding surface keeps circumference larger and rpms lower. Yay!!

Okay, now some comments on the results...

- Gearing is lower, by 5%. It is wonderful, and I am not so rushed to get out of 1st gear in the city, and on the highway I can cruise at 115kph @ 4000rpm. The bike could use another 5 to 7 percent, for my liking... But the 4.98% gain is excellent...

- Cornering - Okay, yeah, this is a bit of a "lazy" tire... But it still has a good lean angle, and I actually seem to sense more rubber confidence during strong lean cornering. The sidewall is taller, and riding surface is a larger radius, so of course it's gonna be lazy, but also you get a much larger contact patch for more confident turning.

- Wait...!! "It's not a radial...?? You're gonna die...!! The Matrix will self destruct!!" Yes, it is not a radial. But this back tire rides really nicely... Seems softer and more smooth. When I did some research, I actually found a pro racer who liked a bias tire with a radial. The front tire for this bike series is radial, rear is bias ply. Drives nice and smoothly, and the back is rated for 19,000 miles!!

- Some interesting things... The bike seems more stable on the highway with less shaking/swaying due to wind buffeting from side or when behind other vehicles. I attribute to greater stability due to the gyroscope diameter being bigger. And less wind buffeting because perhaps (just guessing here) ground effect is less with the back raised close to a cm. (Look up helicopter ground effect.)

That's all I can think of for now, but I'll add to it later if I remember.

Oh, yeah...

Who is this tire good for...?? For people who have some nice mild twisties but also ride 120kph and higher on big highways.

Who is this not good for...? For example, if I still lived in Japan, I'd likely run a 180 60 sport touring tire, or a 170 60 size of this tire, to return the bike to being more nimble.

Oh, last thing... Gas mileage... Way better! Getting fuel economy at 125kph that I used to get at 110 kph. (Parasitic drag is likely expontial, so as long as the gearing has enough power and torque for a given speed, any more rpm is simply losing fuel economy due to more cylinder fires per minute and more parasitic drag from the engine.) my first tank, I got 525kms and 47.5 mpg (riding 110kph to 125kph including 2 up riding), compared to 40mpg (driving slower 100 to 115kph with no 2 up) on my previous smaller tire. I'm at 4000rpm at 115kph (true speed).

BTW, I test drove a Kawasaki Concours yesterday. In overdrive, it runs at 3000rpm at 110kph.

To all you "Honda engineers are perfect" fanbois, quite simply, Honda did not do a great job on the gear ratios.

One last addendum...

I could NOT put the bike on the centre stand with my former tire without help from a second person. I can, relatively easily, put the bike on its center stand by myself.

Now, all you naysayers, load up your ammunition and tell me how I'm gonna break the matrix by using a bias ply "cruiser" tire on back with a radial up front, and tell me again how wrong I am about the gearing choices Honda makes (and please continue to ignore my real world experience with the Japanese culture, and with my former Shadow 750 gearing belt drive mod and my tire size change on my 2nd and present st13).

To those of you who are interested in new information and extending our knowledge of this bike, I hope this information is helpful.

Blessings to you all!

Ride safe!

Photos are of Musquodoboit, Nova Scotia.



actually there is only a 1% difference if you calculate it by the recomended tire size. You put a smaller tire on then complained about gearing now you put a larger than stock size on it's a lot different, ya think?
 
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