made the switch toPR3 55 rear tire today .

[Jeremy Mitchell]

Well, I might not be a "looker", but I really do not have orange skin, green hair, and tiny arms....

Then maybe some Kawasaki green platform shoes are what you need.......... 

[Coomers]

1/2 inch, 3/4 inch, those numbers seem a little high. What is the exact height difference from a 50 to a 55 rear?

[Jeremy Mitchell]

1/2 inch, 3/4 inch, those numbers seem a little high. What is the exact height difference from a 50 to a 55 rear?

About a 1/2 of an inch in overall height for most tires so that equates to about 1/4 inch of increased ride height on the rear.  I would guess that the seat would go up about 1/8 inch since it is close to the mid point of the bike.  It didn't go up enough for me to notice but I am 6'2'' with a 33-34 inch inseam so it wouldn't make a difference anyway since I'm not proportioned like an oompa loompa.     Sorry Maxtog and ZG, I couldn't resist.

[Steve D]

So I’m looking at the specs between the 50 and the 55 and I see that the 50 starts with 7 mm of tread depth and the 55 only starts with 5 mm.  What’s that about?  That’s almost 30% less tread…is that going to mean 30% less mileage?  Oh and by the way the overall height difference is about ¾” but that only will make the seat about 3/8” higher.

[Jeremy Mitchell]

So I’m looking at the specs between the 50 and the 55 and I see that the 50 starts with 7 mm of tread depth and the 55 only starts with 5 mm.  What’s that about?  That’s almost 30% less tread…is that going to mean 30% less mileage?  Oh and by the way the overall height difference is about ¾” but that only will make the seat about 3/8” higher.

I measured my Angel and PR2/PR3's and they all (all 4 that I have bought) measured between 6.7-6.9 mm with my micrometer.  Must be a misprint.

[Bourne2Ride]

I was just about to start a thread on this topic. Over the weekend I ordered the PR3s. What a difference then the old Battleax. The bike is much more responsive and confidence inspiring. I can't believe I waited 9K miles to switch. While I thought the Bridgestone's were adequate; but I quickly found out you don't know what you don't know. I'm sold on my choice of replacement rubber. Looking forward to many miles of travels.

[claggie]

New to the bike and forum.  Thinking of doing this.  Quick questions:

1.  Do you need to switch the front tire as well on a new bike?  Or, could I just change the rear?  If I do need to change the front, what tire size specifically?

Thanks,
Chris

[Jeremy Mitchell]

New to the bike and forum.  Thinking of doing this.  Quick questions:

1.  Do you need to switch the front tire as well on a new bike?  Or, could I just change the rear?  If I do need to change the front, what tire size specifically?

Thanks,
Chris

I would suggest changing the front since the brickstones aren't that great to start with.  You will want a 120/70/17.  Michelin PR2, PR3, or Pirelli Angels are what most of us use and they are all great tires for the money.

[Gearhead82]

New to the bike and forum.  Thinking of doing this.  Quick questions:

1.  Do you need to switch the front tire as well on a new bike?  Or, could I just change the rear?  If I do need to change the front, what tire size specifically?

Thanks,
Chris

If you still have the OEM Bridgestone tires, I would be more concerned about swapping out the front before the rear.  You won't have any problems if you switch out only the rear, but the OEM rear tire isn't a terrible tire.  The OEM front tire on the other hand is a joke.  It's shaped oddly and wears quickly and unevenly.  I would swap out both tires if you can.  If you plan to only do one at a time, I would replace the front one first.  I swapped to the 190/55/17 PR2 rear and 120/70/17 (OEM size) PR2 front at about 3000 miles.  I saved the old rear as a spare.

[jjsC6]

And a higher tire = higher seat... which is a *HUGE* negative for those of us trying to get the bike as low as possible.  Just saying...

Have you done the math?  The difference is so small I would challenge anyone to tell the difference if they didn't know that a taller tire had been put on.  First of all, the difference in radius (which is what raises the bike) is maybe 1/3 inch.  But only the rear tire is taller, and you don't sit directly over the rear tire.  Lets say you sit 2/3's of the way back between the front and rear tire.  You now multiply 1/3 * 2/3.  That comes out just slightly over 2/10's of an inch.  Hold your fingers 2/10's of an inch apart and tell me if you think that really makes a difference.

BTW, I switched to a 55 last year and I'm never going back.   

[W14]

Chris,

Whether or not you should change you stock tires depend on your riding style and the condition of your tires, IMO. I would not change the tires because others say they are not good tires. On the other hand, if you are an aggressive rider doing a lot of twisties and can tell the difference between the performance of one set of tires versus another, do what is best for you.  I, for one, cannot tell the difference between the stock tires and the PR2's I now have on the bike. I do know that the PR2's are lasting longer, 5k on the stock front tire, 10K so far on the PR2.  I also know that the front PR2 is very loud for a Michelin

Just my opinion.   

[Viking]

Did someone say math?

190mm X 55% = 104.5mm
190mm X 50% = 95mm

104.5mm - 95mm = 9.5mm

9.5mm ÷ 2 = 4.75mm

4.75mm = .12065"

So, a little less than 1/8" (.125").


That does seem rather insignificant at first glance; however, we all know that small changes can translate into significant performance values.


It does increase the distance per revolution a bit, which would help with the speedo error (as already mentioned).

Circumference = pi x diameter = pi x (17 + (104.5 x 2 x .0254)) = 70.0845" for the 55 series tyre.
Circumference = pi x diameter = pi x (17 + (95 x 2 x .0254)) = 68.5684" for the 50 series tyre.

Cheers

[wally_games]

Did someone say math?

190mm X 55% = 104.5mm
190mm X 50% = 95mm

104.5mm - 95mm = 9.5mm

9.5mm ÷ 2 = 4.75mm

4.75mm = .12065"

So, a little less than 1/8" (.125").


That does seem rather insignificant at first glance; however, we all know that small changes can translate into significant performance values.


It does increase the distance per revolution a bit, which would help with the speedo error (as already mentioned).

Circumference = pi x diameter = pi x (17 + (104.5 x 2 x .0254)) = 70.0845" for the 55 series tyre.
Circumference = pi x diameter = pi x (17 + (95 x 2 x .0254)) = 68.5684" for the 50 series tyre.

Cheers

I was following until you divided by 2. Isn't the 9.5 mm how much taller the bike's rear end would be? Now if you're saying that the seat is about half way between the tires and the seat would be .12 higher, then I follow.

[feelergaugephil]

I'm still on stocks, friggin hate them!, I had the 08 with Pilot powers 2 and could scrape the hero blobs but these stock tires suck! but I'm not pushing any curves hard yet until I change them for my trip to Arkansas in June, if I change them now it will mean another set of tires before I go away!!!!

[Viking]

I was following until you divided by 2. Isn't the 9.5 mm how much taller the bike's rear end would be? Now if you're saying that the seat is about half way between the tires and the seat would be .12 higher, then I follow.

Excellent observation; you are of course correct.
Since the calculations already omit the wheel, it is not necessary to divide the profile delta by two.
A direct comparison of the two profiles should yield an increase in height of 9.5mm, or 0.243" (a little less than 1/4").

I believe the circumference calculations remain as previously stated.

Cheers!