OK, so I'm still working through the whole Tubeless-tires-on-the-Bonnie thing.
Now I know there are folks here on the board who are much more knowledgeable and experienced than me on motorcycle modifications.
So here's my question:
According to the information on Triumph Twin Power (which seems to have a lot of comprehensive data on Triumphs) the factory wheel/tire sizes on my 2002 Bonnie are as follows:
Front: 19" x 2.5" spoked wheel, running a 100/90/19 front tire. Using the formula 100/90/19 (100mm x .90 to get sidewall height, x 2 sidewalls / 25.4 mm to convert to inches = 7.09" sidewalls + 19" wheel) gives a nominal diameter of 26.08" for the front wheel.
Rear is a 17" x 3.5" wheel with a 130/80/17 tire.
For the rear wheel, a straight-up swap with a Bonneville SE would work since the rear wheel on the alloy-wheel SE is the same 17 x 3.5" mounting a 130/80/17 tire. So no change there.
For the front, though, a 17" SE wheel wouldn't work. The alloy front wheel on the SE is a 3" wheel where the Bonnie has a 2.5", so if I wanted to do that I'd have to swap out the forks and triple clamp from an SE as well.
BUT .... there is also the early (2003 - 2006 Speedmaster and the 2006 - 2008 (Carbureted) America. Both of those bikes had cast front wheels. According to TTP, front wheel on the Speedy and the America was an 18" x 2.5" = same width as the Bonnie wheel.
So, what I'm wondering is: Is there any reason I COULDN'T run a Speedmaster or America front wheel on the Bonnie? An 18" Speedmaster or America front wheel running 100/90/18 tires would be the same width as the tire on the Bonnie currently but would be 1" smaller in diameter (25.08"), or 1/2" smaller in radius. Ideally, I'd like a tire size of 100/100/18 to make up the size difference (25.87" nominal size, just about 1/4" smaller than the factory 100/90/19 tire) but I can't seem to find a tire in that size.
110/90/18 is available and would also be very close, size-wise at 25.7" nominal diameter, but when I look at how close the inner fender bolt is to the tire, I don't think it could accommodate another 5mm of tire width on each side (see attached photo.)
Now, the only additional complication is this: The Speedmaster had twin disc brakes while the Bonnie just has a single on the left side. If I used an America wheel, that should work since the America also only had a single disc. Or, could I run a Speedmaster front wheel and keep the brake disc on there as a spacer but just have no caliper (i.e. a "dead disc?") How involved would it be to plumb another caliper so I could run double discs up front?
So these are all the things that I've got bouncing around in my head. Those of you who have more experience modifying motorcycles, what have I NOT thought of or considered? What pitfalls are there when trying to fit a different size wheel to the front of a motorcycle?
Thanks in advance for any thoughts or guidance!
Martin
You received this message because you are subscribed to the Google Groups "EMRAT" group.
To unsubscribe from this group and stop receiving emails from it, send an email to
.
.
.
.
