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

[FJRat]

These forums are worse than a bar is to a drunk

So now that I am talked into a 190...let me run this o

by the clients on the bar:

Since I just trimmed half inch of my seat, if I put a 190/55 and installed a 15mm lowering link (sold by LustRacing) then I would gain the benefit of the 190 and keep the desirable seat height... does that make sense?

Of course, as my girlfriend would say: here I am again farting around with a perfectly perfect motorcycle...can you hear her: "why do you always have to change everything"

To which I always reply "Ah shut up you dumb woman, can't you see I am man" (on the inside). On the outside I say: "Oh honey common..."

 

[Fred W]

Come on guys. I sucked at math in high school. But even I can cipher this one out:

Comparing 180/55-17 to 190/55-17:

55% of 180mm = 99mm

55% of 190mm = 104.5

Let's call it a 5.5mm difference in sidewall height. The sidewall height is what lifts the axle (and the rest of the bike), so the difference at the axle will be 5.5mm. But the front axle remains at the same height, so the 5.5 difference at the rear axle will be roughly halved at the seat, for a grand total (seat) lift of 2.25 mm, or less than a tenth of an inch.

Maybe if you don't wear skivvies that day you'll make up for it?

 

[FJReady]

Fred, Check your typing. You meant to compare 180 vs. 190 right?

Or are you using those French 185/195 tires?

either way it is a small number

 

[palerider]

Come on guys. I sucked at math in high school. But even I can cipher this one out:
Comparing 185/55-17 to 190/55-17:

55% of 185mm = 101.75mm (Michelin says they are 99 mm)

55% of 195mm = 107.25mm (Michelin says they are 104.5)

Either way, let's call it a 5.5mm difference in sidewall height regardless of the actual dimension, The sidewall height is what lifts the axle (and the rest of the bike), so the difference at the axle will be 5.5mm. But the front axle remains at the same height, so the 5.5 difference at the rear axle will be roughly halved at the seat, for a grand total lift of 2.25 mm, or less than a tenth of an inch.

Maybe if you don't wear skivvies that day you'll make up for it?

What I really need is a sixth gear.

 

[FJRat]

its always best to get the right data before the rant

190 ==> 104.05

180 ==> 99

I thought this refers to the width, not the height, or did I get that wrong also?

 

[maggot]

I think the difference is exaggerate because owners are going from a worn out 180 to a fresh 190, where the difference would be doubled.

of course it'll be taller, probably an inch, and easier to put on the center stand.

 

[Redfish Hunter]

its always best to get the right data before the rant
190 ==> 104.05

180 ==> 99

I thought this refers to the width, not the height, or did I get that wrong also?

I agree. It ALWAYS best to get the data right first.

Now, when you say you thought "this" refers to the width... What exactly is "this"?

I will go very slowly and repeat what so many others have already typed.

180/55 ZR 17 means:

180 is the width in millimeters of the inflated tire.

55 is the aspect ratio or percent. In this case the distance from the edge of the rim to the outside of the carcass. Simply put, this is the height of the tire from the rim. 180 x 0.55 = 99 millimeters

17 is the rim diameter in inches.

If your sole purpose here is to be argumentative it is working. You are arguing with perhaps the most useful mind on this forum. I don't see that helping you in the future at all.

 

[FJRat]

Well no, I am not trying to argue...I am just a little dense about these things and smarter at others...like anyone else.

I think you are right in that I missed the message, cause I finally understood it on your post, at the same time I recall having heard it before. I was a little mixed up on the width and 'aspect ratio'.

So, the differ between the diameter of the 190/180 is 104.5--99 = 5.5

Split that diameter in half would imply the 190 tire is actually 2.75mm higher ... I see what you all mean by this being an insignificant smidgen

If I put a 15mm lowering link I would actually lower my bike 12.25mm (having installed a 190 plus the link)

FRED, check my Math here!!!

Well shoots, if I do that then I can probably put my stock seat back on which is more comfortable than the one I lowered.

...and I thank you gentlemen for your patience...I try to absorb as much as I can as fast as I can...some of you better versed than meself on these context, I appreciate your feedbacks.

But wait, I have one more inquiry (not an argument). Would not that 190 be a little taller than the numbers indicate given that is being pinched by a rim that was designed for a 180? and would this not be the reason why folks find the 190 more nimble to handle in transitions?

 

[Redfish Hunter]

Sorry, but you are still off.

You don't have to "split the diameter in half". In THEORY the 99 mm distance would be from the edge of the rim to the ground. It would not be across the diameter of the entire tire.

I hope this helps.

Yes, there is a great deal of bulge from running a 190 width tire on our rim. How much? Depends on the tire. The only way to really know would be to install the 180 and measure it, then using the same brand/type tire in a 190 install and measure that one.

 

[Fred W]

My number skills are great. My memory, not so much.

I just used 185 and 195 by mistake, should have been 180 and 190. I have no idea why I used those numbers.

All the calculations were correct. Fixed my post, now that my big mistake has been found and quoted several times.

PS - that was in no way a rant.

I think the difference is exaggerate because owners are going from a worn out 180 to a fresh 190, where the difference would be doubled. of course it'll be taller, probably an inch, and easier to put on the center stand.

Yes, as already mentioned the difference of the 180 and 190 new tires sidewall height is ~ 5.5mm. Normal tread depth on a brand new rear is usually around 7-8mm. So going from a bald 180 to a fresh 190 would be a difference of 12.5-13.5 mm, ie. still only talking about increasing the shod wheel radius by about a half an inch.

That is significant when lifting the bike on the center stand, and probably when calculating the steering angles, but the seat will still only be raised by a bit more than half of that since the front wheel isn't being changed and the seat is between the two wheels.

 

[FJRat]

The other speculation I had was on the use of the 200/50...which according to the calculations appears to be about the same height than the 180; but probably bulge up like a ballon squeezed in the rim...what is the size of the FJR rim?

And, I would suspect the 200 will offer a rougher ride since the wall height is shorter? Does that make sense?

 

[RadioHowie]

The other speculation I had was on the use of the 200/50...which according to the calculations appears to be about the same height than the 180; but probably bulge up like a ballon squeezed in the rim...what is the size of the FJR rim? 5.5 inches
And, I would suspect the 200 will offer a rougher ride since the wall height is shorter? Does that make sense? No

A 200 series tire is NO BIG DEAL. Did ya ever read the Darkside Thread in the NEPRT section?

Us crazy-assed Darksiders are riding on stock-rimmed FJRs sporting a 205/50-17 car tire. Now, if you put one of those on your bike and ran the pressure up to 42psi like you would a bike tire, it probably would ride rough as a Tennessee cob, but "we" don't..."We" use car-application pressures on our Darkside rides, i.e., 32-35psi. Rides just like a motorcycle tire.

Will you perish in flaming plastic and aluminum death if you run a car tire on an FJR??? Probably, but so far, I've gone 46k miles on my original 2009 Michelin Pilot installation, with probably another 15k to 20k left on the tread. I've made my peace with the Moto gods and accept my final crispy destiny.

 

[Top_Speed1]

As Howie says; Darksiding see's even bigger footprints. I guess us fatsiders are just taking baby steps

 

[RadioHowie]

As Howie says; Darksiding see's even bigger footprints. I guess us fatsiders are just taking baby steps

Nah...y'all are just a bunch of man-whores who won't commit to a TRUE relationship.

 

[FJRat]

Darksiding: been there, done that.

I rather ride on motto tires... not that I got anything against CT...It is just a preference for me.

 

[bigjohnsd]

This all be ones even more confusing when one considers the fact that not all 180/55-17 or 190/55-17 are the same width and diameter.

When you compare the various manufacturers 180/55-17 you will find varying tread widths and diameters there is quite a bit of variation. The Avon factory engineer I spoke with at Sturgis last year told me that the only common feature between tires is the rim size. He stated that manufacturers often call a tire a 180 but that it may well be wider than that. He advised that they never calla tire narrower than 180 a 180.

Look on the manufacturers website for diameter and width to make a valid comparison between both brands and sizes and required rim widths.

 

[HotRodZilla]

This all be ones even more confusing when one considers the fact that not all 180/55-17 or 190/55-17 are the same width and diameter.
When you compare the various manufacturers 180/55-17 you will find varying tread widths and diameters there is quite a bit of variation. The Avon factory engineer I spoke with at Sturgis last year told me that the only common feature between tires is the rim size. He stated that manufacturers often call a tire a 180 but that it may well be wider than that. He advised that they never calla tire narrower than 180 a 180.

Look on the manufacturers website for diameter and width to make a valid comparison between both brands and sizes and required rim widths.

This is true. The Metzler SportTech I put on my bike recently is the standard 180/55/17, however, it has a very diffenrent profile than the Angels, PR3s, and just about every other ST tire we saw at SW-FOG. The taller profile of this tire is obvious. I kinda like it.

 

[Top_Speed1]

As Howie says; Darksiding see's even bigger footprints. I guess us fatsiders are just taking baby steps

Nah...y'all are just a bunch of man-whores who won't commit to a TRUE relationship.

HS, these are my g/f's Debbies words EXACTLY! .....hey, I just think you should share the love!

 

[palerider]

As Howie says; Darksiding see's even bigger footprints. I guess us fatsiders are just taking baby steps

Nah...y'all are just a bunch of man-whores who won't commit to a TRUE relationship.

Hmm--"man-whores" is kind of awkward. We need a better word. If you say it fast, it comes out "manures."

Which, come to think of it, describes most of what Howie comes out with.

 

[RadioHowie]

As Howie says; Darksiding see's even bigger footprints. I guess us fatsiders are just taking baby steps

Nah...y'all are just a bunch of man-whores who won't commit to a TRUE relationship.

HS, these are my g/f's Debbies words EXACTLY! .....hey, I just think you should share the love!

Always DID wonder what happened to you after your television career....

You became a bouncer at a titty bar??? :rofl: