Changing the geometry??
Jack04
Posts: 60
Hi,
What does changing the geometry mean if I put 130mm travel forks on a 04 Kona Scrap frame that should only take 110mm...That means I have to change the geomety but ones does that mean and how do you do it??
Thanks Jack
What does changing the geometry mean if I put 130mm travel forks on a 04 Kona Scrap frame that should only take 110mm...That means I have to change the geomety but ones does that mean and how do you do it??
Thanks Jack
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Comments
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You don't have to change the geometry, by having the longer forks you'll raise up the front of the bike and so slacken the angles, putting your weight over the rear wheel and making the steering slower (less responsive). Not to mention you might tear the head tube off the frame if you jump, especially as the frame is both old and not designed for such long forks.0
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It's not just the head angle that will change, your bottom bracket will be higher off the ground and your centre of gravity will move backwards. This can result in your front wheel coming off the ground when climbing.
I thought all the talk about changing geometry and head angles was bike mag hype until I got a stumpy FSR which has Talas RL forks on it. I can change the travel between 100mm & 140mm on the fly, I do it all the time now, drop the travel down to 100mm when climbing which keeps my front wheel on the ground and helps when avoiding rocks etc, up to 140mm when descending to increase travel and push my centre of gravity further to the back.
I was really surprised how much difference 20mm on the fork length could make to the handling of the bike.It's easier to ask for forgiveness than for permission.
I've bought a new bike....ouch - result
Can I buy a new bike?...No - no result0 -
FYI as a rule of thumb every 25mm (1 inch) that the front wheel to fork crown race distance changes the average bike will have the head angle changed by 1 degree."Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
Parktools :?:SheldonBrown0 -
Just for my piece of mind, you can counter the steering speed changes by fitting a shorter stem cant you, but then you have more issues with the front lifting.0
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Not to mention you might tear the head tube off the frame if you jump, especially as the frame is both old and not
this is a bit of a myth
installing a 130mm fork on a frame designed for a 100mm fork will not tear the head tube off...its only a difference of 30mm, most of which is taken up with sag (a longer fork will generally be run with more sag), the difference in leverage is miniscule and certainly no threat to the frame - Kona Scraps were overbuilt anyhow!
what might do more damage is the fact you can ride faster and hit stuff harder with a longer fork..
likewise installing something like a 150mm fork or 170mm (like happened on old DMR Trailstars fitted with Junior T forks - which people used as cheap DH race bikes) will definitely stress the frame both from the extra leverage of the fork and the fact that a much longer fork will encourage you to hit terrain much harder and faster, using the frame outside of its intended usecheck out my riding - www.robcole.co.uk Banshee Factory Team rider, Da Kine UK Team rider, www.freeborn.co.uk www.eshershore.com0