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

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Holy shazitts, that's a lot of meatloaf! You might need a tractor trailer tire and much more suspension :eek:

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Ho hum...benn running 190/55 ever since I got the FJR. Been flamed about the slower turn in [not noticeable,run a couple pounds more pressure]..As mentioned-rpm's are lower, mileage higher, looks better....All manufacturers list a 5.5 inch rim as acceptable fitment for a 190. A 200 is interesting but the tire is designed for a 6 inch rim and may be pinched so much that there would be no width gain. Hope someone tries it and posts up. Could always send the wheel out to Kosman and have it widened-we could maybe run a 240 [and it wouldn't be square..] Fat bottomed girls make the world go 'round..
+1

I bean run'in 'em since I got the bike. I wuz drag'in pegs on mah test ride, so I immediately went to a 190/55 ta get sum ground clearance.

The 190 makes the bike "turn in" bettah fer 2 reasons;

1.) The tire's "pinched" so it actually has a "pointier" profile than a 180.

2.) it raises the rear, which also makes the pig bike turn in bettah.

I go back to the 180 in winter cuz I want the bike lower, (Don't need the extra ground clearance fer the wet, cold winter months.) and I have a proper shock/spring out back now. ;)

 
So you changed the rear tire, and it affected your speedometer accuracy? I am surprised.
Why? The FJR speedo reads off the tranny, not the front wheel like most other (old-style) bikes.
Good point but I don't see it as much (RPM lowering to Speed) as a couple of others. For me as I documented way earlier on this thread it was actually noticeable but not by much!, and I used the GPS 60mph mark as only ~100-200 less rips.

Prior to fatsiding the rear, my speedo was reading about 3 mph faster than GPS, now it's pretty darn close.

 
Just finished mounting this tire on my bike. The original 180 measured 190 in width. This new 190 measures, drum roll please, are you ready,....180 in width. :dribble:

 
Just finished mounting this tire on my bike. The original 180 measured 190 in width. This new 190 measures, drum roll please, are you ready,....180 in width. :dribble:
Shoulda went with a PR2 :)

My 190 is definitely wider, I would say 10mm is prob spot on.

 
Any of you "Fatsiders" riding two up? Any observations shared would be appreciated as I'm already closely watching my Conti Motion (rear has only 2600 miles :angry2: ) so going back to my tried and true PR2, but interested in a fatty.

 
**Had a PM on this so I thought I would resurrect this thread from the graveyard**

So Springtime equals time to open up KJ's garage for sum mancave shoptime. (usually this costs me money but this time it was for a friend and it's all on his dime this time!). So he buys both a 180/55-17 and a 190/55-17 rear with the dealer agreeing to take back the non mounted one. After waffling, he decides to upsize like I did prior (OP, me- last summer). I thought I would snap a pic this time as many were all wondering the actual (real look) size differences. On my FJR; I went with PR2's, he having a sportbike went with PP's. As you can see, an easy inch on height, maybe 3/4" on width. Hope this helps :)

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The height of the new tire can be calculated from the Aspect Ratio_Old tire: 180/55

New: 190/55ZR-17

The aspect ratio New tire "55" indicates that this tire size's sidewall height (from rim to tread) is 55% of its section width "190mm". Old tire was 55% of 180mm.

.55*190 = 104.5

.55*180 = 99

104.5-99 = 5.5mm increase in height from tread to rim. X2 for total increase is 11mm => 0.433071in.

So just shy of a 1/2in increase in overall (un-sprung?) height.
Well stated, Jason. If there is an inch actual difference when measured, I suspect it's in comparing the worn tire that was replaced to the new replacement. A new tire comes with maybe a quarter inch of tread. Wear that to a sixteenth, and you've reduced the diameter of that tire by 3/4". Compare that to the new 190, and that could be over an inch difference.

 
Check your math, I think you meant 3/8".

FWIW, Michelin's literature puts it at .48", mounted.

 
I have a PR3 190/55 on now. Mounted up, it's not any wider than my last tire (Storm 2 180/55) when comparing the distance it is from the brake caliper strut.

It definately is bigger around, speed on GPS is prolly within 2 mph of what's indicated on the bike; it was never that close with the any 180/55's that were mounted prior.

 
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