KDXRIDER.NET

Anyone tried a 20" front wheel on a KDX-200 w/ the fork swap?

Few years ago I rode a CR-250F with a 20 inch'r on the front end and was totally shock'd how the thing stuck in corners. It did want to climb a little in ruts but over all the front end was very stable. Since I'm round'n up parts for my swap I can get a 20 inch'r very reasonable and seriously think'n of go'n that route.

What'cha think?


.

How easily available are the tires for them ?? If you liked it and can get decent tires for it, well why not...

I had a 20" front on my KX250 and liked it. It ends up the same outside diameter with the tire as a 21", making the sidewall taller in order to accomplish that. The taller sidewall results in less tube pinch and flat tires. That is why the 20" rim was designed for. I also think it was a wider tire.

Keep in mind, you will need a whole new set of spokes.

skipro3 wrote:I had a 20" front on my KX250 and liked it. It ends up the same outside diameter with the tire as a 21", making the sidewall taller in order to accomplish that. The taller sidewall results in less tube pinch and flat tires. That is why the 20" rim was designed for. I also think it was a wider tire.

Keep in mind, you will need a whole new set of spokes.

Skipro - what you say is true for rear tires in that generally speaking the rear 19 inch tires have the same outer diameter as an 18 inch rear tires with the difference being made up in side wall height. But the 21 inch and 20 inch front tires do NOT share that same trait. i.e. same outer diameters.

EDIT - I may be wrong since I haven't checked into this for a couple of years: I suppose there could be a given tire company that went to an increased height sidewall - but at least during the first couple of years of the 20 inch tire being public there was no increased side wall height tires available.

From Dunlop (739 as an example):

90/100-20
80/100-21

Given the same diameter the 20" sidewall is 'taller' than the 21"..but I don't know what the actual numbers are.

I recall Ski saying he had measured his for difference.

Considering all the different ideas of what aspect ratios mean to different manufacturers..a blanket statement on either side can likely be excepted.

Re: '...and was totally shock'd how the thing stuck in corners.'

That might as well have been the Showa's, no? Or you're comparing to some other Showa'd 250F with a 21"?

canyncarvr wrote:


Re: '...and was totally shock'd how the thing stuck in corners.'

That might as well have been the Showa's, no? Or you're comparing to some other Showa'd 250F with a 21"?

Nahhhhhhh I've owned/rode/raced Cr's & CrF's for some time as well as blue & yellow bikes, no green race bikes.

After riding mine & other CR's the 20"' fit'd CR-250F was so much more planted in turns it really stood out to me. Even in high sweep sweep'rs you could let the rear drift as far as you want'd and the frt just stay'd plant'd. It had a really nice feel to it.
Do'n the 20'r will cost me more than what I want'd to put in a tire/rim but what the hell, the KDX is my play toy.



.

Good Points CC.

When the 20 inch had been out for about a year or so it seemed like a lot of people were contributing better handling due to the lighter weight of the tire/wheel combination. The unsprung weight apparently becomes a factor/or is noticable when airing out a bike (something I know nothing about).

Re: planting in corners - sooo many factors go into cornering .... including a tire's aspect ratio and flex.

I say the 20" and the 21" were the same since the calibration for my enduro computer required me to measure the rolling distance of each. By marking the tire and the ground with a marker, I rolled the bike until the mark on the tire was again in contact with the ground and measured the distance. Both bikes were within an inch or 2 of the other and it never mattered to my computer on an enduro course. In any given 20 mile section, there would be less than a 1/10th of a mile difference from my computer and the posted mile marker. With resets, it didn't matter after that anyway.
That allowed me to install a sensor to the KDX and the KX so I could just swap the computer from one bike to the other without any other changes to keep accurate mileage.