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Gear ratio

dermotcdermotc Posts: 3
edited June 2010 in MTB beginners
Hi guys, new to the forum so please excuse me if this is posted in wrong place

I have just purchased a Giant Boulder and love it

I mainly use it on roads (my primary goal is fitness) but I find that downhill I run out of gears

I have a SR Suntour 22/32/42 up front and a Shimano TZ07 14-28 at the rear with a KMC Z51 chain

I have managed a pedalling top speed of approx 34mph but my legs were travelling like egg whisks

I have been looking around and wonder if the easiest option would be to replace the rear with a Shimano HG30 11-28 ( ... elID=40480)

Am I correct in assuming this would give me approx 27% more road inches per crank turn?

Would there be any issues to look out for?

Thanks, newbie


  • redveeredvee Posts: 11,920
    A 14-28 rear gear spread is most likely to be a freewheel and not a cassette like you have linked to on CRC. Have a look at the inner ring on the block and it will have markings along the lines of MFZ........, if so this will confirm a freewheel. To go from freewheel to casette will mean a new wheel.
    I've added a signature to prove it is still possible.
  • njee20njee20 Posts: 9,613
    A TZ07 is indeed a freewheel not a cassette, so you would have to replace the rear wheel.

    You could do the chainset, unlikely you'll have replaceable rings, but again it's not particularly cheap.

    I'd just be content with being able to pedal up to 30-ish mph frankly, if you want to ride on the road perhaps think about changing for a road bike or hybrid in the future.
  • dermotcdermotc Posts: 3
    Thanks for the replies guys

    Think I might start saving for a road bike
  • supersonicsupersonic Posts: 82,708 Lives Here
    Have a look at the third option on this page: ... 20Page.htm

    The 11-34 freewheel.

    You would need a new longer chain though.
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