> Folks

> I have a 15 year old Giant Yukon MTB and a Trek Road flat bar racer. I
> like the stance of a MTB and I am principally a commuter so when the MTB
> seemed too old (and there was coin in my pocket) the flat bar racer seemed
> a sensible move. Trek bike is 2 years old. They have a similar frame size
> and are both in excellent condition. (I think...)

> Question is this.

> I can ride the MTB endlessly and feel fine when I get off it. These days
> when I ride the Trek I end up with almost crippling back pain.

> Do I consult my friendly bike shop guy? See a medico? I'm not sure whether
> the skinny wheels and structure of the flat bar racer mean more road
> vibration ends up in my back whereas,  the MTB has reasonably fat tyres
> which seem to soak more of the vibrations up. (The MTB has no suspension)

> Any thoughts?

> Cheers