Front fork - fixed to suspension?

Workshop tales, trials and disasters.
Maintenance tips, techniques and myths.
Technical discussion, description and outright lies

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?
TethAdam5
 
Posts: 121
Joined: Fri Jan 25, 2008 2:23 pm
Location: Perth, WA

by BNA » Mon Apr 14, 2008 11:40 am

BNA
 

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.
Litespeed Classic - 3Al/2.5V titanium tube set, Record 9-speed groupset, Open Corsa Evo CX
Alchemy Diablo - Columbus Zonal tubing, Ultegra 9-speed groupset, UltraGatorskins
Gitane Rocks T1 - U6 tubing, Deore/XT groupset, CrossMarks
User avatar
LuckyPierre
 
Posts: 1432
Joined: Fri Jul 14, 2006 4:37 pm
Location: Canberra, ACT

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!
TethAdam5
 
Posts: 121
Joined: Fri Jan 25, 2008 2:23 pm
Location: Perth, WA

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

Mate,
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.

Cheers, Gerard
Thanks heaps.
BMC 4Stroke 03. (web nazis won't let me put a third picture up :()
Voodoo Dambala 29er.
FELT AR4 Carbon.
User avatar
glawrence2000
 
Posts: 235
Joined: Tue Oct 17, 2006 12:49 pm
Location: Annandale, Sydney

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.

Rod.
RodC
 
Posts: 10
Joined: Tue Apr 01, 2008 4:52 pm
Location: Melbourne - Out East


Return to The Shed

Who is online

Users browsing this forum: Exabot [Bot], swaz



Popular Bike Shops
Torpedo 7 Torpedo7 AU
Ground Effect Ground Effect NZ
Chain Reaction Cycles CRC UK
Wiggle Wiggle UK
Ebay Ebay AU

“Bicycles BNA Twitter
“Bicycles BNA Facebook
“Google+ BNA Google+
“Bicycles BNA Newsletter

> FREE BNA Stickers
> BNA Cycling Kit