a general question needing an in-depth answer-

[treelimb]

IF a knowledgable KDX rider has one.
FIRST and FOREMOST-Finally got my bike back from the suspension czar that did it up.FEELS GREAT.thanks to all that had been wondering and I am unaware of any.But anyways----
I had to install a DUNLOP 739 120/100-18.WHEW!!!!! What a great big huge knobby.It was a barely used hand me down,FREEEEE of charge,(THE BEST HAND ME DOWNS I KNOW OF) and I got it just in time to run a local but huge,4 times per year/old school type/mx.
I installed it yesterday morn and was late enough for the race to not be able to practice but still able to race. All of those I knew in attendence were mesmorized by the IN YOUR FACE SIZE and asked me how much pressure i was running(11.5lbs.).Had me tripping on it from that point forward because it does look too big for my bike.
Now for the question because i know you are ready-
IS that tire too big and did it possibly slow me down a tad or more? I sure felt as if it did and my finish, 14th out of 32 riders/2 motos- BUT the class was for 40-49 year olds and I was pitted against 400's and 450's as well as whatever else,made me feel that way.
Have I become mesmorized myself and just tripping on the size for an excuse OR is the tire detrimental to the performance? MAN IT LOOKS HUGE and I have gone outside to view it several times AGAIN today already.
I gots to know.
Thanks in advance.
treelimb

[thebleakness]

I think it's in your head. I've never noticed a speed difference in any size tire I've run, just different riding characteristics. If it did really slow you down all you had to do was twist the throttle some more and pick up speed. I run 120/100 Maxxis Desert ITs on my KDX and I have fairly tall gearing and love 'em.

[skipro3]

I always ran the 120 on my KDX. It can turn that tire without any problems. If you want to steer with your rear tire, it's not the best to have though.

[2001kdx]

I think a 120 width tire a little fat for a KDX. You're supposed to feel significantly less wheelpsin/more traction with a wider tire, and what comes with that is a less-snappy feeling bike, along with less turning ability. I run a 110 on my RM250 - But I did however pick a BN 120 D756 for 10 bucks. I'll have to try it next year!

[KarlP]

I think 14th out of 32 when up against 400 and 450's on a MX track is fine. Sounds like you needed a little time on the track with your new suspension. What were those bikes doing on an "old school MX track" anyway? Your ride may be somewhat "old school", those aren't. Ask 'em to go for a ride on some ST with you, HA.

I had a XR200 once that I put a monster tire on. It must have been a 130 or 140. It looked cool, though. That slowed the XR200 down, if you can believe it. I had to take a grinder to the knobs on the sides to clear the swingarm. Foolishness.

I run a 120 on my KDX. No problem.

[treelimb]

STILL ISO more comments/opinions.THANKS for those up to this point.W/O re-reading all the comments,I must answer one question-the reason(s)the big bore KTM's and all else were on this old school mx track is because by old school,the owners of said track (runninbrandmx when googled)have set the track up per pre-super cross stuff.MAN it is a beautiful sight seeing all those vintage(pre'74/pre'84) and the moderns racing.They have separate classes for the vintage BUT for all else the classes are by age-20-29;30-39;40-49;50+so forth.The track is well over a mile in length w/plenty of thrills for all,a chick class,PLUS plenty of pretty chicks to view and eye scr--!!
FYI-I have a 1997 KDX200 that I race as well as a 1987 KDX200 just to ride and look at,purging thoughts of my air cooled days since I am pushing 47 years young.
BTW-THANK YOU for the compliment of doing pretty good against those big bores!! I felt that way initially but must have gotten TOO mesmorized by that 120/100-18 real big knobbl-y that I fought to mount on my KDX yesterday morning.
More comments PLEASE;THANKS in advance.

[Indawoods]

110 is optimal. I am running a 120 right now and it is too big.

[2001kdx]

You'll lose turning agility with the 120! Too stinkin big! It comes stock with a 100 I believe.

[thebleakness]

I never liked the 110 or anything smaller, it didn't hook up like I wanted at all. With the extremely dry rock hard conditions here a smaller tire is annoying and doesn't have the footprint of a 120.

I've raced desert/woods ST on my 220 and I'm 3rd overall in a 250/450 class for the year. There's about 60+ riders in the class.


Karl, I think you would be surprised at how well my 450 rides ST. Even the technical trails up here the 450 does pretty darn well and as soon as it gets any sort of rythem it shines.

[MXOldtimer]

I'm running a 110 Maxis IT and it has a much larger appearance both in width & height. I would think a 120 would really give the KDX the stinkbug (KTM) look & feel with being jacked up in the rear.
Maybe the Maxis IT's just run larger?

[kawagumby]

I run a 120 dunlop and it does not impair brake sliding (anymore than any othe new tire) or make the bike a stinkbug (adjust fork height for that) or any of that stuff...LOL.... I like the larger footprint.
If you want to lose some unsprung weight back there, toss the worthless kick stand.