Front fork - fixed to suspension?

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Front fork - fixed to suspension?

Postby TethAdam5 » Mon Apr 14, 2008 11:24 am

I'm working on my old commute bike, it was a cheapo malvern star that is very tough, but after a recent trip on trails in the bush, the jarring of the fixed front fork is not really ideal.

Can I swap in a suspension front fork as an upgrade? Is there anything about the build of more recent MTB frames that stop me from doing this?

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Postby LuckyPierre » Mon Apr 14, 2008 11:40 am

Sadly, geometry is going to work against you. Your frame's geometry, not geometry in general. :wink:
A rigid frame's geometry is based around a known, fixed effective length of the front fork. A suspension fork will be longer, so it throws the geometry out of whack. You would end up with the front of the bike too high and the potential for the tyre to bottom out on the downtube when the fork compresses.
That said, I'm looking at a fork upgrade at the moment, and the cost of a decent fork as a single component is scary compared to the cost of a new bike.
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Postby TethAdam5 » Mon Apr 14, 2008 11:44 am

Yeah, in looking at my bike's fork, I could sort of see that problem arising. thanks for confirming it.

Looks like its a new bike for me!

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Postby glawrence2000 » Tue Apr 22, 2008 11:28 am

I disagree, unless you're riding something very specialised, changes to the geometry of the frame will be negligable.
I'm not saying get a triple clamp with 200 mm of travel, that will feel a little funny, but you could easily get 30mm, 50 or even 80 mm of travel up front without any problem. I know because I've done it and have benefited from the change.
Just make sure you know what size steerer tuber you've got before you go buy one.

I recommend you get something 2nd hand off ebay Like a Rock Shox Tora for example. Won't set you back too much.

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Postby RodC » Thu Apr 24, 2008 4:10 pm

Did it the other way round, replaced a suspension fork on a Trek 7200 hybrid with a fixed Cro-Mo fork to convert it into more of a flat bar road style bike.

Fixed fork is about 30mm shorter than the suspension fork, no noticeable difference to the geometry when riding though and it's certainly lighter and faster.


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