Yamaha WR250R Mega Thread

shows right on it....4.00 X 18.

I bought new rubber all round. The rear is 4.00x18 Pirelli MT43 Trials Tire 1347120002(RockyMTNAtv part #), and the front is a 90/90x21 Pirelli MT21 Dual Sport Rallycross - 1035780001.

...that 4:00 looks FAT...and I don't mean like SIC.
Got any idea how tall it measures up against the stock rear tire?

Not really, I'm just following in the footsteps of others like Ramz - http://www.rickramsey.net/WR250Rmods.htm#tires

It was also discussed a few days back, here - maybe on May 6th as that's when I did all my ordering. It's tall enough to warrant gear changes, so I'm doing that too.

Utah how is your bike so clean? It looks brand new... not even any chain grease on your swingarm?

LOL do you ride it or just upgrade it?

I was wondering if anyone would ask this question . I had the rear tire and chain off, it would be sinful not to clean it up with such easy access.

Upon returning from my Utah/Arizona tour I did a 515 mile day which included 250ish on the interstate. Seems like every time I take a long trip, I think of ways to improve the bike, this time it was gearing. There are a number of 8,000' passes you have to do on the interstate, and I'd like to get over them going 75. Dropping down to 65 then shifting is not a fun option, what with all the passholes out there. I also wasn't super happy with the rubber and it is 3,000 miles old, so I'm doing it all in one fell swoop. I think I have replaced everything now, except the radiator guard. All that said, I've ridden 2,800 miles in the last 2 months

I've only gotten on the bike sporadically over the last week and a half. Looks like Thursday I should be able to get out, lot of snow up high still, I wonder about the roads - we'll see.

Very. IIRC it's the same as changing a tooth on the front.

I have removed it before without bending out the peened in spots. I don't think they add a lot of resistance to loosening the nut. Having a friend hold the rear brake or being in a higher gear helps.

The Pirelli MT-43 hybrid trials tire is quite a bit taller than the stock tire on the WR250R. I've been following the discussion on this tire closely. Other inmates here (just a few pages back on this thread - try reading it!) suggest that the difference is at least 1-tooth on the CS sprocket, or 3-4 teeth on the rear sprocket. To me, that is a lot! You should be prepared for the difference if you change just the rear tire and not your gearing.

...I was more thinking about the handling with the fatty rear.
My redumptive experience showed that too tall a rear made the bike real squirrly, especially off road. Pushed the front end.
But at the time I was messing with a lowering link. Removing that helped things alot. Putting on a smaller rear skin made everything just peachy.


FatBob...


LilBob...

Yes, but in his case he already took the chain off, so that won't help.

I do mine with the chain still on, and then as described above.

How big are you (weight/height), and how hard do you ride on dirt? Also, what tire pressure did you ride when it felt squirrly? Did you tire other pressures?

Is it a difference in traction between fat bob and ill bob??? That would be huge and if the back gets traction it would push the front more rather then spin

I'da putta the chain back on.

...I ride SoCal fire roads and desert. That particular day I did sand rocks and whoops. Tire pressure not really realative, I tried it all.
I'm convinced that these lil bikes don't require big Monster Trellerborgs, don't really have the power to spin the rear that much.
A smaller knobby will.
I weigh 175, have silver blond hair and lovely blue eyes....not that that tells ya anything.
Trail Tricks suspension done for my weight and style.
Oh, and I often ear women's undies...

Ear Women's undies???

...yeah, you got a prolem wif dat?

You might have better luck if you mouth them. But to each their own I guess???

I'm not sure

You fellows are silly...