24" tt bike forks question

[T&B Workshop]

Hi there bit of a random question but does anybody on here have a time trial bike with a 24" front wheel that they'd be willing to measure the forks on for me? I've been asked to build a set of forks for such a bike but am having trouble finding out what the axle to crown and trail measurements should be to achieve the correct geometry...

 

[FINNEY1973]

Hi, I can hopefully help you with this one.

Top of fork crown - centre of wheel spindle = 310mm
Top of fork crown - bottom race of headset = 8mm
Bottom of fork crown - space to top of tyre = 12mm (using very shallow reach brakes)
Fork rake = 42mm

Pictures here: viewtopic.php?f=23&t=302444

If you need any further info I'll try my best to get it for you.
Cheers

 

[T&B Workshop]

Thats brilliant, exactly what I needed to know! Thanks a million! It's an old Joey Mcloughlin Cougar, will try and get pics up when its all together.

 

[FINNEY1973]

Re:

No drama, glad it helped.

People always enjoy a 'build' on here so some photos as your going along would be good. Seems you have a very decent project on there with a decent bit of provenance.

 

[pigman]

Re:

Wont fork rake and trail be individual to your frame's head angle. you can't just copy someone elses. Or can you? I'm no framebuilder

 

[FINNEY1973]

I'm no builder either, and with lo-pro's they would appear to be very complex with all the angles. Agreed, the angle of the headtube should dictate the rake, all of mine have shallow rakes. Is the wheelbase used as a starting point?

 

[Midlife]

For lo-pro's the head tube angle is pretty relaxed so you can have a shallow rake fork and still have plenty of trail, in general lo-pro's run a lot of trail which makes them self centre well but are a bit of a pain to corner......

Shaun

 

[FINNEY1973]

but are a bit of a pain to corner......

Shaun

That's half the fun Shaun

 

[T&B Workshop]

The plan is to measure up properly to get it spot on, however its useful to have a general starting point to work from, especially as stuff like this isn't exactly common!

 

[pigman]

...but are a bit of a pain to corner......

Shaun

Rubbish, it's well known that timetrialists can't corner .. don't blame the bike