Acceleration wise yes, but rpm wise the taller the tire the higher the rpm at any given speed

 

Sorry to pee in your Cherrios. When someone asks a question I answer it as exact as I can. When other input may have questionable results about which I know something I will also comment on it... the nature of a forum. It can save money for someone when it comes to performance. Kind of like the MCM when it comes to trying it on a big bore. Others have mentioned it doesn't improve performance. If one wants to ignore it or prove it out for themselves, have at it. It isn't worth actually whining about. Sally forth and learn by hard knocks.

Fact is I am doing exactly that only in the opposite direction some of you do. I am going smaller and narrower to see how it works. It has worked well in the past on small displacement bikes in my past riding. I warn against excessively large tires because I also tried that too on street bikes. Made the slow handling MotoGuzzi handle like a dump truck. First thing the guy that bought it from me did was to take off those fat tires and put on the right size. Had I kept the bike I would have likely done the same, but it was sold while I was in the hospital recovering from an accident (with my permission).

If a rider wants the fat tire look, fine, but expect differences in performance. Same with going smaller, but in my case no one has commented on any experience as to what will happen.

If you don't want to know others' experiences and knowledge I highly recommend against reading these kinds of posts. It will be a spoiler for your experimentation. Kind of like planning on watching a baseball game replay, but watching sports news before doing so, takes a bit of the thrill out of the replay. Personally I will use them to get an idea of what to expect, then make a choice.

As for your comments:

About a KLX being a motocross bike, of course I don't see it as a motocross bike. I see it as a less powerful 250cc motorcycle that weighs more than a motocross bike, both of which make it less likely to be able to handle a larger tire than a 250 motocrosser without losing performance in general.

I've also ridden enough off road to know there are times when it is beneficial to be able to break the tire loose and work it rather than slipping the clutch and risking damage to the clutch. Getting stuck in some mud or sand can be that sort of situation. Rev it up a bit, dump the clutch and spin my way out. Much easier on the clutch and little wear otherwise. Friends and I have "over tired" a bike and found it bogs them down in some off roading. It also makes them more fun to broadslide since it is a bit easier to break loose and modulate.

If you don't understand the comment about it taking more horsepower to pull more weight, to rotate heavier weight wheel, think about it, I'm sure you will comprehend it. If you're just trying to conjure up a smart reply, try again. It didn't work.

Oh, and if I saw your bike with a paddle tire on it in a parking lot I wouldn't say a word, your choice. So quite honestly I could care less about your choice.

But I will comment when someone asks about putting some specific size on their bike - they ask for a reason. Had you started your own thread with the title "I have a 190-60 radial on the back of my KLX and love it" I would have ignored it. But this had to do with confusion about size and if someone is confused on size they likely won't have much knowledge about the pros and cons. My apologies for being knowledgeable and sharing it in a rational way in a forum.

 

I will say it isn't a bad idea though. The bigger sprockets don't wrap the chain quite as much, resulting in less wear. The bigger the sprocket the more teeth the loading is distributed over and the less the chain actually will have to "bend". Less pin wear, less sprocket wear. Not a bad thing. I was thinking that direction with my 650, biggest possible front sprocket, then work the gearing I want with the rear sprocket tooth count.

Does it gain a lot of mileage on the sprockets and chain? Don't really know for sure, but it is mechanically sound thought process.

Then there is the ability to gear even lower with the 14 and 13 with the 45 versus the 42. Lots of playing can be done.

 

42 replies, 858 views. Will we see a 1000 views by Sunday night? possible

By the way, I have one of those manual cam chain adjusters from that guy out in Ohio. It works as advertised and the price was right.

I also did the MCM and I like it. I am not going back on that mod.

 

If you have the largest front and a larger rear to get more gearing and increase chain life, I think that it would get pretty heavy. Does someone have a calculator to see how many links a 16/48 (stock gearing with tallest front) or a 16/54?

 

IMO the 4.10 X 18 on a 250 simply wore out to fast. However, it could have been the Kenda 270 that I chose; 750 miles and it was shot. It was a fun tire and the 250 could spin it easily. At 40mph the tach read 45rpm

Moved up to the 351 and the 4.10 still read 45rpm at 40mph.

A friend gave me a 120/80/18 MT-21; the 351 spins it just fine. What I noticed right away was the drop in engine speed; 41rpm at 40mph. I'm not sure if it is the tire size, tire weight, or both that has lowered the engine speed at any given mph. To me, the drop in engine speed while cruising tar to get to dirt is very welcomed.

 

It's just the opposite actually

Your friend's tire must be taller.



RPM x TD
--------- = MPH
GR x 336

Gear ratio on a motorcycle = primary reduction ratio x trans gear ratio x sprocket ratio

TD = tire diameter

 

Since you brought it up..

The others haven't drilled their air box after doing their big bore have they?

on cutting out the complete top of a CRF 250/400X air box to gain what's described as "serious power" after rejetting.

First step in hot rodding is better breathing

 

I'm confusing myself now...you're right, taller tire, lower revs what the heck what I thinking

 

yeah sarcasm is hard to catch over the internets.

i actually just put on a shinko 241 trials tire 4.00-18 and like it a lot. doesnt look gnarly though but i hope it lasts as long as my 244 did.