Наткнулась на американском ТТР-форуме на "дешевый и простой" способ сделать ТТР похожим на супермото: заднее колесо от DT125X (17" x 3.5"), переднее от XT125X (17" x 2.5")
I have just converted my 1997 TTR250 to a "Supermoto" .... It was relatively straightforward and CHEAP, once I figured out which wheels to use!
For the rear, I fitted a DT125X (17" x 3.5"), which more or less bolted straight on! All it required was a slight modification to the TTR wheel spacers. No extra parts were required at the rear end.
For the front, I fitted an XT125X (17" x 2.5"). Two new wheel spacers were required, plus a new brake caliper bracket(*), two spacers and two slightly longer bolts.
Front Wheel Spacers
22 O/D x 15 I/D x 10.0mm Long (Left / Brake Disc Side).
22 O/D x 15 I/D x 36.0mm Long (Right Side).
Brake Caliper Spacers (two required)
20 O/D x 10 I/D x 5mm Thick.
These fit between the fork leg and the replacement brake caliper mounting plate. You will also need two slightly longer bolts to mount this new plate. The size of the replacements is M10 x 1.25 (Metric Fine) x 45mm long.
That's all there was to it!
Note that the spindle sizes on both of these wheels are identical to the TTR (i.e. 15mm front and 20mm rear), so I used both TTR spindles in the conversion. I got both of the wheels on Ebay!
The tyres are Continental Escapes: 120/90-17 on the front and 140/70-17 on the rear. If anything, the front one is just a fraction too wide, as there is very little clearance between the forks. You may have noticed I've had to lift the gaiters out of the way! The rear tyre is just fine, but don't go too much wider than that! Actually, you could probably just about squeeze in a 150 wide, but it would be pretty close to the chain.
*Please note that I will soon be in a position to be able to supply the stainless steel brake caliper mounting plate, which I had to have specially made to enable me to fit the standard TTR caliper on the slightly larger XTX disc. It is the only complicated part required and I can have a small batch manufactured if there is likely to be any interest in them. 
, интересно было как он выглядит и стоит ли переделывать в мотард, понел что не стоит))) ,а продавать пока не буду нравится мне уж больно ттр да и тем более этим летом его купил. Видите я хочу больше ездить по асфальту, тогда куплю хорошую дорожную резину а то шипы жалко. Кто знает какую лучше поставить? Я езжу 70% асфальт и 30% бездорожье без "говна". 
