I pulled the triple tree and noticed the lower part is cast iron/steel. Is there an aluminum replacement? Is it a good/bad mod?

 

Not sure that aluminum will have the strength to endure. There is a lot of leverage/stress involved in the lower. Can't really see it anyway, so I would find a better return on my time/money than messing with the lower triple's engineering.
Ern

 

Thanks. The only thing I found thus far was a full set (upper and lower) from some racing company that costs around $1200, definitely NOT worth that.

 

does the upper one endures less stress than the lower ?
there is an upper on ebay for 90$, but I am quite doubtful about replacing the original one with this..

 

The stock upper is aluminum (seems to be).

 

Almost all of the bearing load is on the lower and the shaft. the longest part of the lever is between your lowers (the fulcrum) and the axle. That (and cost) is why it is made of steel. The upper doesn't handle nearly the load and can be effectively made from aluminum, as it commonly is.

I'm actually surprised you CAN make one out of aluminum (although, I'm NOT surprised at the cost).

Ern

 

why you wanna polish it or something.......id go with powdercoat instead and forget about it...hell you could chrome it tooo.... polishing it seems like the only reason you would want an aluminum lower

 

Just the basic idea of trying to get rid of any excess weight (provided it doesn't cost $$$ or make the bike unsafe). I asked only because it was something I came across and wanted an explanation of why it was steel vs aluminum.