V7C Front Tire Size Question

[Moto Fugazzi]

My 2009 V7C feels twitchy at higher speeds with the stock tire (100/90-18 Pirelli Sport Demons), and I'm contemplating changing to a 110/80-18. Any ideas on what the results may be if I change to this size?
Suspension has been modified and set up properly with Mupo front fork cartridge emulators and YSS rear shocks.

Ken

[oldbike54]

 Interesting question . Not sure that a 10 MM increase in tire width will make the bike more stable . The effective tire sidewall height will be the same , so no change there . Have you checked the neck bearing adjustment ?

 Dusty

[Moto Fugazzi]

Interesting question . Not sure that a 10 MM increase in tire width will make the bike more stable . The effective tire sidewall height will be the same , so no change there . Have you checked the neck bearing adjustment ?

 Dusty

Excellent question in response to my interesting question. I did check the bearing adjustment, and all seems to be good. There also doesn't appear to be any freeplay in the neck bearings, but I'm also not 100% sure I'm adjusting and checking things properly.
Keep in mind that I'm comparing this to my 2004 V11 Sport which is rock solid at high speeds. I ride the V7 so infrequently that I don't remember how it should ride from the factory...maybe this is normal for this small framed lightweight bike?
Ken

[oldbike54]

Excellent question in response to my interesting question. I did check the bearing adjustment, and all seems to be good. There also doesn't appear to be any freeplay in the neck bearings, but I'm also not 100% sure I'm adjusting and checking things properly.
Keep in mind that I'm comparing this to my 2004 V11 Sport which is rock solid at high speeds. I ride the V7 so infrequently that I don't remember how it should ride from the factory...maybe this is normal for this small framed lightweight bike?
Ken

 Sterling response to my ... Oh shoot , we are sounding like those two chipmunks that couldn't resist being overly polite and complimentary to each other
 
 Making a comparison between a V11 Sport and a V7 might be unfair . Still , maybe try leaning over the bars at speed to see if it helps . Seems the V7's can benefit from a bit more weight on the front . Good luck Ken .

 Dusty

[Moto Fugazzi]

Anybody else have comments, suggestions?
Steering head doesn't feel notchy or have excess free play, so I think the bearings are good.
Ken

[Moto Fugazzi]

I found a cool website that calculates the differences in tires. I really shouldn't notice a difference at all.
Ken

https://www.tacomaworld.com/tirecalc?tires=110-80r18-100-90r18

[oldbike54]

 Sorry Ken , still just me . There has been lots of discussion about raising the forks to deal with this problem . A few months ago , I ran some figures past a professor buddy , math shows that the difference in feel comes from a change in weight distribution and not fork angle . Try raising the forks 10 MM .

 Dusty