Upsizing Rear Tire to 190/55 (w/ pics)

[Fred W]

What we really want to know is what it the increase in circumference? Cause that will directly translate into more miles per tire with all else remaining equal (which it might not).

Has anyone ever tried downsizing the rear to a 170/60? Five bucks cheaper for a PR2 and it might have a performance improvement in turn-in, if'n you believe the geometrical pundits!

 

[str8]

What we really want to know is what it the increase in circumference? Cause that will directly translate into more miles per tire with all else remaining equal (which it might not).




Has anyone ever tried downsizing the rear to a 170/60? Five bucks cheaper for a PR2 and it might have a performance improvement in turn-in, if'n you believe the geometrical pundits!

I calculated the circumference at 1978mm vs 2012mm. See post #34. Obviously this is meaningless, as fossilrider pointed out, lots of manufacturing tolerences. Top speed should have measured the circs of those 2 tires when he took the picture!

Maybe, next time try the smaller size. Won't be able to impress my friends though.

'Cept I have no friends.

 

[Fred W]

'Cept I have no friends.

Finally, an opinion unbiased by peers.

 

[Spud]

You'll also rack up less miles on the odo, helping resell value--or do we need to oversize the front too?

 

[Chiefblueman]

I happen to have a very low mileage, about 1k, 185/55-17 PR2 on my Fz1 and a 195/55-17 PR3, about 500mi, on the Feej. Using a cloth tape and both inflated to 40 psi the tale of the tape is 67.5in or 1714.5mm for 185/55-17 vs 69.25in or 1758.95mm for the 195/55-17. Measurements taken at the middle of the tire, repeated 3 times. Represents about a 2.6% difference in circumference. Both bikes run 5.5" rim widths.

 

[str8]

I happen to have a very low mileage, about 1k, 185/55-17 PR2 on my Fz1 and a 195/55-17 PR3, about 500mi, on the Feej. Using a cloth tape and both inflated to 40 psi the tale of the tape is 67.5in or 1714.5mm for 185/55-17 vs 69.25in or 1758.95mm for the 195/55-17. Measurements taken at the middle of the tire, repeated 3 times. Represents about a 2.6% difference in circumference. Both bikes run 5.5" rim widths.

-edit-

 

[Fred W]

You'll also rack up less miles on the odo, helping resell value--or do we need to oversize the front too?

No, just the back. The speedometer/odometer is driven off the rear drive.

I happen to have a very low mileage, about 1k, 185/55-17 PR2 on my Fz1 and a 195/55-17 PR3, about 500mi, on the Feej. Using a cloth tape and both inflated to 40 psi the tale of the tape is 67.5in or 1714.5mm for 185/55-17 vs 69.25in or 1758.95mm for the 195/55-17. Measurements taken at the middle of the tire, repeated 3 times. Represents about a 2.6% difference in circumference. Both bikes run 5.5" rim widths.

Too bad that they weren't the same model tire (PR2 vs PR3). But in any case you can still see that the difference in circumference is fairly insignificant.

 

[Chiefblueman]

Doh! Must remember to write things down. I typed the wrong numbers. They should be 77.5 in/1968.5mm vs 79.25 in/2012.95mm. 2.25% difference.

I'm blaming it on my buddy in my avatar.

Str8, your calcs were quite accurate. Was your edited post aimed my way?

 

[str8]

Your numbers seemed low. Also, I was going to ask you if they were the same brand of tire.

Still learning to read.

 

[Top_Speed1]

What we really want to know is what it the increase in circumference? Cause that will directly translate into more miles per tire with all else remaining equal (which it might not).




Has anyone ever tried downsizing the rear to a 170/60? Five bucks cheaper for a PR2 and it might have a performance improvement in turn-in, if'n you believe the geometrical pundits!

I calculated the circumference at 1978mm vs 2012mm. See post #34. Obviously this is meaningless, as fossilrider pointed out, lots of manufacturing tolerences. Top speed should have measured the circs of those 2 tires when he took the picture!

Maybe, next time try the smaller size. Won't be able to impress my friends though.

'Cept I have no friends.

Yep, If I knew u guys were going to get back into this I would have! I kinda thought we hashed this same stuff out in the prior posts

I've super sized 3 rears now to all great reviews from myself and the other 2 owners. In earlier posts; there were other FJR owners who have jumped on this bandwagon, one at least prior to me. I basically got the idea from the BMW K1600 that I originally test drove. I said to myself, both bikes are almost equal in size n weight so why would this not work for the slightly lighter Feej? It does work and quite well in fact. I will add that after the change (new tire syndrome) I did have a high top roll effect until they broke-in a bit, wore off the nibbies... maybe 40 miles of this.

So PR2's on mine, super-sized the rear as mentioned, handles and corners better than evah!

And Yes! it is def taller and wider, whoever said it's not... ya gotta get off the pipe dude

 

[Auron]

I'm doing it for sure.

Since it's a bigger burlier tire, wouldn't it generate less heat, have a bigger contact patch and last longer?

I am wondering if it will go up on the stand for those of us with a Penske and raised the rear a bit.

 

[Fred W]

I'm doing it for sure.
Since it's a bigger burlier tire, wouldn't it generate less heat, have a bigger contact patch and last longer?

I am wondering if it will go up on the stand for those of us with a Penske and raised the rear a bit.

You can figure that out for yourself beforehand. Just measure how much air is under your rear tire now and then subtract (or compare that to) the increase in the tire's radius. Using Chiefblueman's numbers the 180/55 tire has a 12.335" radius and the 190/55 has a 12.613" radius, so the difference will be ~ 0.278" a little over a quarter inch.

 

[mcatrophy]

I'll preface this by saying I don't know if this applies to a motorcycle tyre, but it's true of radial constructed car tyres (on cars).

There is a significant length of tyre flat on the road surface. The tread rubber moves to take the same length as that belt length, regardless of the thickness of the rubber. So the effective rolling circumference of a radial car tyre is defined by its belt underneath the tread, wear has little effect on the circumference and speedometer calibration.

Dunno about a motorcycle tyre, the construction is very different.

 

[wheatonFJR]

Area of contact patch= (vertical gravity load on individual tire)/(pressure in that individual tire)

ie...force pushing down on road=force from road surface pushing back

force=pressure x area

area=force/pressure

 

[RadioHowie]

Since it's a bigger burlier tire, wouldn't it generate less heat, have a bigger contact patch and last longer?

Not as well as one of these will....29,000 miles on the ride home from work tonite. Right now, 28,991.

 

[Chiefblueman]

I'm doing it for sure.
Since it's a bigger burlier tire, wouldn't it generate less heat, have a bigger contact patch and last longer?

I am wondering if it will go up on the stand for those of us with a Penske and raised the rear a bit.

I have the 195/55 and a Penske 8983, goes up on the centerstand just fine.

All this Darksider stuff has me wondering, would motorcycle tires on my car make it handle better?

 

[RadioHowie]

Maybe...well, probably not...but they'd sure as hell wear out faster!

The fallacy of your tongue-in-cheek question is the questionable premise that motorcycle tires somehow guarantee to make your bike handle better.

 

[SoCalFJR1300]

YER GUNNA DIE!!!!!!!!!!!

Naw he won't die, it's a motorcycle tire, and it's used on many sportbikes, also manufacturers actually recommend them.

Hey Howie are you the "Howard" that used to run the ZRXOA??

This is Jerry, Frank Pepito's riding buddy.......just wanted to say "Hello" was wondering how you were?

 

[lnewlf]

190/55 equals-

lower cruising rpm

less speedo error

less miles on the odo

quicker turn in--yup that's right-you just jacked the arse end 1/2 inch which steepens rake and the 190/55 has a sharper profile

easier to put on the center stand

costs more

looks phatt without having a clown CT out back

only @ 2% on the good stuff

Avons run bigger than Michelins ,meebee next tire I'll try the Storn Ultra..

 

[Chiefblueman]

Maybe...well, probably not...but they'd sure as hell wear out faster!
The fallacy of your tongue-in-cheek question is the questionable premise that motorcycle tires somehow guarantee to make your bike handle better.

Just a joke Howie not a *** at your car tire. I think the Darksider thing is cool, I would never have thought of it. However, I'm pretty sure using motorcycle tires on my motorcycle will not make it handle worse.