Member Contributer CornerCarver Posted January 26, 2014 Author Member Contributer Share Posted January 26, 2014 I've spent hours researching offsets and trail numbers and reading Race Tech's Motorcycle Suspension Bible. The data shows most of the best handling bikes have around a 30mm offset with high 90s to low 100s trail values (CBRs, GSXRs, R1s... early R1s and RC51s are exceptions) and rakes of 23* to 24*; this was also confirmed by a reliable suspension expert. The stock 5th gen VFR chassis geometry doesn't cut it for this application... and it wasn't designed too. No fault, no grandiose claims that I can engineer better than Honda. Just me attacking a challenge to take something I love and adapt it to a new, more specific application. Based on this, and some more expert input, I'm going to shoot for an initial set-up of 30mm offset, around 102mm trail, and ~24* rake on my 5th gen track bike. My '09 ZX14 50/54 USD forks are scheduled for delivery tomorrow... so I can start the measuring and wrenching and stop the jabbering!!! Build thread to follow... To modify your rake to work within the design parameters of above mentioned GSXR/CBR are you going to cut your headstock from the frame and weld it back at that desired 24* angle? If not, perhaps an eccentric in the steering stem mount will allow for enough rake correction. Quote Link to comment Share on other sites More sharing options...
Member Contributer Rush2112 Posted January 27, 2014 Member Contributer Share Posted January 27, 2014 I've spent hours researching offsets and trail numbers and reading Race Tech's Motorcycle Suspension Bible. The data shows most of the best handling bikes have around a 30mm offset with high 90s to low 100s trail values (CBRs, GSXRs, R1s... early R1s and RC51s are exceptions) and rakes of 23* to 24*; this was also confirmed by a reliable suspension expert. The stock 5th gen VFR chassis geometry doesn't cut it for this application... and it wasn't designed too. No fault, no grandiose claims that I can engineer better than Honda. Just me attacking a challenge to take something I love and adapt it to a new, more specific application. Based on this, and some more expert input, I'm going to shoot for an initial set-up of 30mm offset, around 102mm trail, and ~24* rake on my 5th gen track bike. My '09 ZX14 50/54 USD forks are scheduled for delivery tomorrow... so I can start the measuring and wrenching and stop the jabbering!!! Build thread to follow... To modify your rake to work within the design parameters of above mentioned GSXR/CBR are you going to cut your headstock from the frame and weld it back at that desired 24* angle? If not, perhaps an eccentric in the steering stem mount will allow for enough rake correction. I'm hoping with a little elevation of rear ride height, and possibly lowering the front a little, I want to see what kind of rake I can achieve... I'm hoping to get down from the stock 25.5* to close to 24*. I can calculate and spreadsheet it to death, but until I have the parts assembled and start tweaking it is all theoretical. I'm not currently looking at cutting and re-welding the frame... that is kinda outside the scope and budget of my modest attempt :) For me, it will be easier to tell what can be achieved when I have a rolling chassis... i uncrated my engine and swapped the lower cushion for a 6th gen today... the real fun starts next weekend... temperatures permitting, I don't have a heating solution for my 2 car garage. Quote Link to comment Share on other sites More sharing options...
Member Contributer CornerCarver Posted January 27, 2014 Author Member Contributer Share Posted January 27, 2014 I recommend a couple of 1000 Watt halogen work lamps for garage heating. Quote Link to comment Share on other sites More sharing options...
Member Contributer Rush2112 Posted January 27, 2014 Member Contributer Share Posted January 27, 2014 I recommend a couple of 1000 Watt halogen work lamps for garage heating. ? Nice! Kill two birds with one lamp... heat and illuminate :D Quote Link to comment Share on other sites More sharing options...
Member Contributer Switchblade Posted January 27, 2014 Member Contributer Share Posted January 27, 2014 I recommend a couple of 1000 Watt halogen work lamps for garage heating. � And plenty of Band-Aids .... Quote Link to comment Share on other sites More sharing options...
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