Bicycle Tutor

My daughter wanted me to put a different set of handlebars on her mountain bike and I am just wondering how you get the brake levers onto the new handlebars. The old bars were somewhat normal mountain bike bars that allowed me to loosen the levers and slide them off the end of the bars. The new set of handlebars have the curled up ends on them (look like ram horns...lol) with foam gripping area, so cannot slide them onto these bars.
The brake levers are made of some kind of fiberglass or heavy duty plastic and I am afraid if I try to spread them open enough to slip them straight onto the handlebar the material will crack and ruin the brake lever. How do you go about installing these plastic brake levers? Do you heat up the plastic so it won't break when spreading the clamp to slip onto the bar? Do you somehow get that foam grip off the end of the bars, to allow sliding the levers along the bar? If so, can't imagine how these grips come off...they are on the bars pretty good. Any help appreciated.

I have always had to remove and grips and slide the break levers on that way. A method that I use to remove handle grips is, I insert the plastic straw attachment for a can of GT85 or WD40 and insert that down the side of the grip and spray it and pull the straw out and the same time and it should coat the inside of the grip and you'll be able to pull it out.