Integrated HS fork transfer

[amator]

I have an easton ec90SL fork from a frame with an integrated HS that i want to transfer to a conventional headset bike... can this be done? just want to see how a different fork rake would change the handling.

[Dave]

I have an easton ec90SL fork from a frame with an integrated HS that i want to transfer to a conventional headset bike... can this be done? just want to see how a different fork rake would change the handling.

Sure it can be done, but the crown race would need to be changed to match the headset. The steering tube length must also be long enough to work on the other frame.

Unless you know the exact axle to crown race length of both forks, you may get more than a change in the rake. A longer or shorter fork will also change the head tube angle and the steering trail.

More rake will make the steering a bit quicker and less will slow it down a bit. Changes to the HTA could double that effect or cancel out the expected changes, so don't ignore it.

[amator]

Sure it can be done, but the crown race would need to be changed to match the headset. The steering tube length must also be long enough to work on the other frame.

Unless you know the exact axle to crown race length of both forks, you may get more than a change in the rake. A longer or shorter fork will also change the head tube angle and the steering trail.

More rake will make the steering a bit quicker and less will slow it down a bit. Changes to the HTA could double that effect or cancel out the expected changes, so don't ignore it.

the crwn race is taller for Integrated or a different diameter?

Id better go read up how to measure actual fork length to ensure variables arent too many.

[Keith A]

In general, the Easton EC90 SL fork should be able to used on both frames with integrated or standard (threadless) headsets. However, you do need to make sure that the Easton's fork length is appropriate for the frame you want to put this on. Here's the link (http://www.eastonbike.com/PRODUCTS/FORKS/fork_ec90_SL_'08.html) Easton's website for this fork.

[amator]

In general, the Easton EC90 SL fork should be able to used on both frames with integrated or standard (threadless) headsets. However, you do need to make sure that the Easton's fork length is appropriate for the frame you want to put this on. Here's the link (http://www.eastonbike.com/PRODUCTS/FORKS/fork_ec90_SL_'08.html) Easton's website for this fork.

Thanks.
It states that axle to crown is 365mm... Im having trouble finding the length of the reynolds ouzo pro-peleton. Reynolds site shows 300mm for regular ouzo pro but not sure whether measurement procedure amongst manufacturers uses a norm

[dave thompson]

Thanks.
It states that axle to crown is 365mm... Im having trouble finding the length of the reynolds ouzo pro-peleton. Reynolds site shows 300mm for regular ouzo pro but not sure whether measurement procedure amongst manufacturers uses a norm
IIRC, Reynolds forks have a 370MM axle to crown distance.

[amator]

Thks Dave.
Ok... I need a translation on how this would change the handling charcteristics; HT as constant.

Current reynolds Pro peleton- 45mm rake (370mm)
intending to swop EC90SL - 43mm rake (365mm)

My intention is to slow down the handling a little hence the 43mm, but would 5mm less fork length turn it back the other way round?

[Dave]

Thks Dave.
Ok... I need a translation on how this would change the handling charcteristics; HT as constant.

Current reynolds Pro peleton- 45mm rake (370mm)
intending to swop EC90SL - 43mm rake (365mm)

My intention is to slow down the handling a little hence the 43mm, but would 5mm less fork length turn it back the other way round?

The shorter fork would make the HTA about .3 degree steeper and cancel out the change in trail from the smaller rake. The would be no net change in the trail.

[amator]

The shorter fork would make the HTA about .3 degree steeper and cancel out the change in trail from the smaller rake. The would be no net change in the trail.

Assuming the same rake, wouldnt a shorter fork shift the intersection to the ground backwards thus increase the fork trail and make it slower turning and more stable?

[Dave]

Assuming the same rake, wouldnt a shorter fork shift the intersection to the ground backwards thus increase the fork trail and make it slower turning and more stable?

Maybe this drawing will help. http://www.phred.org/~josh/bike/trail.html

Your are confusing front-center and wheelbase changes with changes to trail.

An unavoidable result of changing fork length or rake is a small change to the front-center and wheelbase. The change to the F-C from a 5mm shorter fork would only be about 1.5mm. Changing the fork rake from 45 to 43mm also reduces the front-center by about 2mm, for a total of 3.5mm. Changing the front-center distance by a few millimeters is trivial, when you consider that the wheelbase is nearly 20 times larger than the trail value.

Trail is an entirely separate issue. Trail is the horizontal distance between a line drawn through the center of the steering tube to the ground and a vertical line through the front axle. The formula for trail is (R/tanH) - (rake/sinH), where R is the tire radius and H is the head tube angle. A shorter fork makes the head tube angle steeper and a longer one will make it more shallow.

Notice that in this formula, the first half of the equation is the trail without the effect of fork rake and the second half is the reduction in trail due to fork rake. This demonstrates how all fork rake results in a reduction in the maximum trail. Without some amount of rake, all bikes would steer really slow.