Kawasaki VN750 Forum banner

Pics - Upsize & Stock Tires (Side by Side)

36K views 67 replies 38 participants last post by  Shade 
#1 · (Edited by Moderator)
Well, I purchase the Metzler ME 880 Marathon tires and since I had both stock and the upsized tires available I snapped a few shots for comparison.

Front - Upsize 110/90 - 19 on the left; Stock 100/90 - 19 on the right




Rear - Upsize 170/80 - 15 on the left; Stock 150/90 - 15 on the right


 
See less See more
4
  • Like
Reactions: VIVERE175
#2 · (Edited)
Both the front and rear oversize tires do look noticeably wider than the oem sizes.

The front oversize does also appear enough taller to account for the reported correction of the speedometer.

My calculations of the diameter and circumference of the OEM and oversize rear tires indicate they are almost identical.
These pictures also seem to verify those calculations. :smiley_th

Thanks for the pics Duece. Very informative.
 
#3 ·
... worth viewing 4 sure..... very educational w/ our own eyeballs !

tyvn Duece
 
#4 ·
I've read up on them and seen them on other bikes but never saw a side by side comparison and thought it would be valuable to many who are thinking about upsizing. BTW, the tires make the bike feel more stable both riding straight and handling curves.
 
  • Like
Reactions: VIVERE175
#7 ·
Thanks for the info and pics, really helped me decide on the larger Metzeler tires for my bike. Already did front tire, lots of life left in rear tire, may be a while before I get the larger Metzeler there.
 
#8 ·
in the last pic be sure to take that part off the rim with the 7 holes in it and lube it up with moly 60 as well as the drive splines before reinstalling! there is a snapring that holds it in!
 
#9 ·
Lube was completely done prior to installation of rear wheel. :smiley_th
 
#10 ·
You got your 150's in man? How's it run????
 
#11 ·
I have ME880s, but in the stock size, which IMO are already two big, especially the rear. My Harley Road King has a 130/90-16 rear tire, but the outside diameter is no bigger than the 150/90-15 on the Vulcan, and it is noticeably narrower. The stock rear tire on my 1985 Goldwing is the same as the Vulcan 750, 150/90-15, but the GW is way bigger. The 150/90-15 just looks out of proportion compared to the size of the Vulcan. I think the 130/90-16 would look much nicer. To me, the sidewall on the Vulcan's rear tire just looks too wide, like something that goes on a dragster. One of the things I loved about '70s bikes were the narrower tires and larger diameter rims, especially the rear. I also like the look of the Mean Streak, with it's 17" diameter rear rim and narrow sidewall. To bad it has to be so slow. Kawasaki should have put an inline four in it.
 
#12 ·
This post was super helpful in me picking the size of my new tires. Up-sized all the way around for me.
 
#16 ·
Ok, I need to learn up here before I get a ticket. I just upgraded from stock to 110/90-19 in the front and 170/80-15 in the back. I notice the revs are higher now and I thought they were supposed to be LOWER. I must be speeding all over the place or something is wrong. How far off is my speedo?

Thanks in advance,
 
#17 · (Edited)
The speedometer is read off the front tire so the rear doesnt change it at all, just the engine rpm's per mph. On the tire size, the first number is the wideth is millimeters, second is the tire height is mm's, third is the wheel size in inches. The second number on the rear went lower which means you put a smaller diameter tire on, hence raising the rmp of the rear tire as the front stays the same. The wider the tire the lower the height is regardless if the wheel wideth stay the same. But as for the how far off is the speedometer, mine is 5 mph off at 55 acording to my GPS.
 
#18 ·
Thank you - ok well in Deuce's picture the back 170 looked a hair taller than the 150 - so my confusion must be coming from that 5mph you informed me about. I think that clears it up! Thanks again!
 
#19 ·
On the speedo drive wheel, whenever you gho a larger OD, it will lower your read MPH...ie the tire makes fewer rotations to travel the same distance. A slight increase in OD on the VN would probably compensate for the existing error, but going TOO large an OD would cause the speedo to read slower than actual.
I used to stop by local area speed trap officers and ask em to clock me....once at 30, once at 45, once at 55....most local cops will do it for ya.
 
#20 ·
Hmmm..... good idea asking the local boys to hit me with radar. Thanks!

My main issue here in moving to bigger tires is getting lower RPMs at the same speeds (better gas mileage), but with both gauges moving in different directions I became confused to the success/failure. :zzz: That radar idea should be helpful. Thanks, guys!
 
#22 ·
My main issue here in moving to bigger tires is getting lower RPMs at the same speeds (better gas mileage),
I totally understand those thoughts, as Id like to myself.....to accomplish that, you'd need a rear of a larger OD...the front does nothing for gas milage, as it is not the drive wheel, unless you own a Rokon....

For the VN, you'd need to measure the space available with the rear shocks fully compressed....you could actually get away with a 16" rim if you replaced the shocks with non-compessable struts. Hurts my azz just to think about it...

And now, to decrese RPM at same speed, you'd need 1)to change final gearing...forget it, I looked into it. 2) add a higher 5th gear (possible, but cost not worth the result). 3) rigid out the rear and go to a 16" rear wheel...I'll pray for yer kidneys. 4) go with just a slightly larger diam rear tire, but you will have less "off the line" performance, and honestly, the result wouldnt be worth the expense IMO....if you mostly ride hiway, then ya...go for a higher profile rear tire....but you'll find out you may bog some from a stoplight (then you'll slip the clutch, and burn that out)...

For a VN to be more fuel efficient ?...go with an FI (fuel injection) system instead of the carbs, and update the antiquated ignition system for a guaranrteed good spark at all RPM ranges.

Ive gotten as much as 59 mpg with my 85, stripped and modded properly....
..a larger diam rear tire might raise me to 64 tops.
 
#23 ·
Ive gotten as much as 59 mpg with my 85, stripped and modded properly....
Ok, so bottom line here is that the RPM's are essentially the same; when I noticed my RPM's higher than they were with the old tires, it really meant that I was actually rolling faster than the speedo was reading, correct?

Thank you
 
#25 ·
when I noticed my RPM's higher than they were with the old tires, it really meant that I was actually rolling faster than the speedo was reading, correct?
If your RPMs were higher at the same indicated speed, the only thing that could cause that would have been a smaller OD rear tire. BUT....since you changed out the front too, the comparison wouldnt be visible.

Do yerself a favour...get clocked by a cop at 3 different speeds.

Your larger front, will show you going slower at same RPM....larger rear, should decrease RPM at same speed....shouldda done one at a time, lol....rear first...that'd tell ya the actual RPM drop at same speed. Then a larger front would correct the speedo error.

Sorry...I did a lot of acid back in the day....sometimes a lil tough to git the gist of what Im sayin. ;)
 
#26 ·
LOL - we are both saying the same thing, bro, just backward from each other. Maybe the pot got to me, too LOL :beerchug: YES, the same RPMs are now showing a slower speed. I was just curious if anyone knew exactly what the difference was. I'll have to get clocked, hopefully not in a bar. :blah:
 
#28 ·
According to Cycle World's road test they did on a new VN700...30 indicated was 29 actual....and 60 indicated was 55 actual. I suppose a math whiz could figure out the exponetial differences and apply a percent formula. But just a guess, 45 indicated would then show 42 actual, and inversely, 90 indicated would show 82 or 3 actual. I dunno, I did better in chemistry, lol.
 
#29 · (Edited)
So, it is close to what an old post which "Diane" wrote....approx. 10 % over.

WilliamTech :smiley_th
 
#31 ·
Not to be "untechnical" but if you just keep up with the flow of traffic you'll probably be fine and safer and not get a ticket. If you're all alone on the road, just don't get caught. :smiley_th

I always assumed my speedo was showing about 8-10% off but even when I would ride faster to do the real speed limit, cars were still flying past me. Now that I have the oversized shinkos, they still fly past me. So I just get in with the flow and try to stay out of their way.
 
#32 ·
I have been running Dunlops for years. When I first got my Vulcan I almost slid out because of that Spitfire. It aint too round and the side edges get hard over time. Not much contacting the road. If anybody has them now I would advise getting rid of them.
 
#35 ·
Pirelli Night Dragon tire

Mounted a Pirelli Night Dragon 170/80/15 rear tire yesterday and took a 30 mi ride to check it out. Since they are a tad taller (and with thicker tread) than stock tires I'm showing about 2mph faster @ 5000 rpm. It makes the bike feel very light and agile on both turns and straight roads. Much more agile than the origional factory tires which I had before. I'm more confident on sharp curves but the bike seems almost too responsive on straight road, perhaps that will change after more miles.

No clearence problems once installed but since I'd heard reports of it being tough to get this wider tire past the final drive and I wanted to relube the splines I removed the final drive and mounted the wheel and final drive as an assymbly. 2 extra minutes to get it all lined up and it fits like a charm.

At this point I highly recomend this tire. If I think about it I'll update this review in a few months after a few thousand miles.
 
#37 ·
Yea, Pirellis cost a bit more but a flat tire or lost traction could ruin my day so paying an extra $30 is worth it to me for giving my butt a little more safety. I'll just drink cheap beer for a few weeks to make the money back.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top