The triples came from GSXR 1100 K's for the first two while I went for an R6 triple on the latter.
The issue with the GSXR triples is that they have only a 35 mm offset.
This offset creates more trail compared to the OEM triple that measures approximately 51.5 mm.
Using a 17" wheel partially compensates for that as you will see below:
GS 1000 with 19" wheel OEM spec: Rake 27°, Trail 116 mm
Same with 17" wheel : Rake 27°, Trail 96 mm
Same with GSXR triple (35 mm offset) and 17" wheel: Rake 27°, Trail 113.7 mm
This is not bad compared to OEM but nowhere near modern bike standards.
With the R6 triple (40 mm offset) and the same rake the trail goes down to 108.1 mm
Last but not least using Vstrom DL 1000 triples ( thanks @chuck78) that has a 45 mm offset you get 102.5 mm of trail.
The good news is that all these triples have the same center to center spacing of the fork legs at 205 mm so that you can use complete front ends from eitheir a 1200 Bandit, a GSXR 11K, an R6 or even a Vstrom DL 1000.
You will however have to modify the lockstops for all of these triples and the bearings for the R6.
I haven't used the Vstrom triples yet so I'll keep you posted.
The formula to calculate the trail is:
T=R/tan alpha-D/sin alpha
T: Trail
R: radius of the front wheel
D: triple offset
Alpha : 63° ( 90-27)
All dimensions in mm
Note that I have kept the rake identical for all examples i.e. keeping the bike level despite the the fork changes to make the comparaisons worthwhile.
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