SOHC.co.uk Forums > CB500/550
500 K cafe racer conversion - build thread
Ewan 500 K1:
--- Quote from: Johnwebley on September 01, 2013, 01:07:21 PM ---you are working hard Ewan,
I suggest you get it on the road,run it for a while,get used to the feel.bed the tyres and brakes in ,
then explore the handling,
I guess you have some great bike roads around you,
go and have some fun
--- End quote ---
you're right of course John ... but intrigue & curiosity meant I spent some more time on rake and trail today. I decided I wasnt happy with the broom handle .. to much scope for variation in the figures so made a telesopic version which was then fixed to the tripe T in line with ,and parallel to, the headstock. Much more rigid and stable. Pics 1 to 3 below show this. The 4th photo shows how I measured the sides of a right angled traingle to calculate the rake. So .. after much repeated measuring and using three different trail and rake calculators .... I've got some averages of averages:
Old shocks with straight triple T : Trail = 97.9mm (3.9 inches) Rake = 23.8 degrees
New longer shocks with straight triple T : Trail = 90.5mm (3.6 inches) Rake = 22.7 degrees
So still showing a one degree reduction in rake with the new shocks and now a 7.4mm (0.3 inch) reduction in trail. I think I'll get a steering damper to be of the safe side.
Ewan 500 K1:
another (vastly improved, simpler and more accurate) method of finding out what the trail is ...thanks to turbo guzzi and johno on the US site's high performance & racing forum
Step 1. find out what the rake angle is by sitting a bubble protractor / digital protractor / inclinometer against the fork tubes , OR by taking a high definition photo from a long distance, camera at mid bike height, importing it into a cad or vector graphic program and anlalyisng it. .
Step 2. Use my new calculator ... there's a screenshot of it attached to this reply below the pictures and a downloadable version attached to my next reply.
Note .. this only works if the triple T has zero rake itself and neither it nor the forks are bent in any way
Also for a 500 four a one degree change in rake translates to a quarter inch change in trail ... so if using a bubble protractor it needs to be able to measure to say within 0.5 degrees and the bike will need to be on a perfectly level surface
SteveD CB500K0:
I've added .xls and .xlsx file types to the "allowed" list Ewan. Nobody has ever tried it before!
Steve
Ewan 500 K1:
--- Quote from: SteveD CB500F on September 03, 2013, 10:03:58 AM ---I've added .xls and .xlsx file types to the "allowed" list Ewan. Nobody has ever tried it before!
Steve
--- End quote ---
cheers Steve , calculator link at foot of this reply
Ewan 500 K1:
Have had it confirmed that stock fork offset is 45mm
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