19" wheel vs 18"

[Shaw520]

I have installed 13/52 sprockets (SX400). Although it is much better than stock, the gearing is still a bit tall for my likings. My question is, will the 18" wheel make a noticable difference in the final drive? And what are the advantages of 18"/19". Please feel free to describe your own experiences with 18" vs 19", and the conditions where you feel one is better the other. Thanks!

 

[kciH]

The 18" wheel is supposed to be much less succeptible to flats. The 19" wheel is supposed to corner easier. Enduro/CC=18" MX/SX=19" The diameter of the wheels is usually the same once there is a tire on it. The 18" tires usually have a higher aspect ratio which makes up for the smaller diameter rim. I'm sure it's not exactly the same, but it's close.

 

[Strick]

I am about to go 18" on my 400. The response above I agree with completely. I do not believe it changes the height at all. The sidewall on the 18" is taller and less susceptible to flatting. I believe the 18" also has a larger footprint on the bike (more bite to the ground).

I have several rims ready to go I just need the hub. I am ordering it tomorrow. I will let you know any performance differences once laced.

 

[Bonehead]

The 19" came from motocross, Reason weight, the 19" and the 18" have the same overall height. Honda got this from NASCAR; one pound of moving mass is worth 4-horse power. A 19" tire weighs 1 to 1.5 lbs. Less Than an 18" tire.
The 18" has more sidewall and is less susceptible to flats under low air pressure and that’s why enduro bikes still have 18" wheels.

 

[Shaw520]

Hmm, some very interesting responses;
KciH, I measured the circumference of each, and they are almost identical.(the 18" I have has some wear on it)
Bonehead,...The 19" tire IS noticably lighter, just by picking it up!
I guess if I want to lower the final drive more, I will have to install a 54t rear sprocket, (longer chain required). I know some guys have used 12t counter shaft sprockets, but, I have been told that this puts too much stress on the counter shaft itself. Thanks Guys

 

[Idaho Charley]

Countershalf torque stress would be the same with either a 12, 13, or 14 tooth sprocket. However, the smaller sprokets cause higher stresses on the chain due to the tight bending radius: Also higher stresses are placed on the individual teeth of the countershalf sprockets, since the chain is in contact with fewer number of teeth on the sprocket.

 

[Ramski]

Just get a KX500 and you won't have to worry about power loss with a 18". ;)

If it wern't for these darn desert rocks, I wouldn't be too concerned about going with a 18" wheel. Now that there are some great tires out there like the Dunlop Desert AT 739 you can get by with a 19" in off road without worrying about flats. I run a 18" just to be even more safe. Never had a flat yet!

 

[Layton]

Originally posted by Ramski
Never had a flat yet!

You shouldn't have said that. :uh: