Tire Sizes

[rcers]

I posted a Q about tire sizes for a KDX a few days ago and got several responses about a Mich s12 140/80/18 being to much tire for a KDX.Someone replied that I couldnt get a tire that big to break loose.Am I missing something,when is too much traction not a good thing?(except maybe when trying to throw mud from your tire to clean it?)I am no tire expert,just trying to learn when I can.
THX

 

[Fred T]

Well how about this...

Too much traction is a problem when:

1. the front tire won't stay down going up a hill
2. you can't maintain enough wheelspin going up a hill to prevent the rpms from dropping and end up in too low a gear and (see #1)
3. when cornering and the front tire pushes because the rear won't break loose a little.
4 when you need wheel spin through a tricky mud section
5 when your bike won't pull enough rpm in deep sand so you need to ride a gear low and lose momentum.
6 when you are going through a high speed flat corner and you cannot power slide the bike with out eratic behavior.

I think you should try the Michelin S-12 90/120 instead. That's the one I am using and it's perfect. I know there are others that feel that a bigger tire is better so maybe in different conditions that might be true, but not for me.

 

[jimicarl]

140 just fine

i use the 140 S12, and have no problems. '99 220 FMF Grarly Rev & TC2 silencer, jetted a little lean.

can certainly understand that you need a little spin once in awhile..., but when it's that slick..., the 140 still spins. when the S12 is no longer "sharp", it loses traction & leaves you wishing for a new sharp 140. can only turn 'em around, once.

i've seen 140 M5B's used on similar set up 220's. perhaps better drive than the S12, but not nearly the side-hill grip. and again..., if it's that slick, it still spins.

come late spring, the 140/soft-terrain tire makes way for a narrower intermediate tire.

bottom line..., depends on where/how you ride.

 

[OLD-N-SLOW]

I recently installed a s-12 in the 120/90-18 size. The traction was so much better that i had to make several attempts at the starting line to keep the
front end down. I can see where more traction could be a problem such as in
the exit of a corner where you would have to abuse the clutch more to keep engine on the pipe. Have never tried a 140/... so cant comment on them but
for me 120/... is plenty. In my opinnion if more were better, why wouldnt
125mx bikes come with the same size tire as the 500s.? The 140 may be better in some instances, but for me it does not out weigh the down sides
mentioned by Fred T.
Good luck
Steve

 

[Sage]

when your going to smash into a tree in 4th gear and don't have the option of spinning the rear tire up to get the bike pointed into the inside of the turn.

 

[bcVulcan]

I just bought a 140 but haven't intalled it yet. I'm waiting until after Loretta Lynn's. I'm not gonna let her mangle a brand new tire.
I've never used a 140 before but can't imagine having a problem with too much traction. I certainly understand the points that Fred T made but the issues I run into can usually be corrected with MORE traction.