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VFR400R (NC-30) 17" Wheel Options
Although the stock front wheel on both the NC30 and the NC35 is a near-standard (these-days) 17" x 3.5" six spoke ENKEI alloy wheel taking a 120/60VR-17 tire, the NC30 (unlike the NC35) is cursed with an 18" x 4.5" rear wheel that takes a 150/60VR-18 tire. Apart from looking a bit strange to some (particularly in white), there are fewer choices of sticky road and race tires available in the 18" size—especially in the United States.
The obvious solution is to fit the 17" x 4.5" NC35 rear wheel to the NC30, but there are a few problems associated with this otherwise straight swap: (i) finding a used NC35 wheel can be a challenge—and it ain't going to be cheap when you do; (ii) changing wheel diameter alters the ride height at the rear, and the stock NC30 rear shock does not have any kind of a ride height adjuster; and (iii) the NC35 wheel is still only 4.5" wide (which just won't cut it down at the Wonderburger anymore... <g>) Although (ii) is an inevitable consequence of fitting a 17" rear wheel to a bike designed for an 18" rear wheel, there are other solutions available.
One such solution may be to fit an NTV650 (RC31) 5.25" Marchesini racing wheel, which might fit without modification or with only minor modification—the best thing to do here would be to check out some of the many Hawk GT-related sites for more on this. (The Hawk GT guys are pretty hardcore—and they've got to be if they want to achieve anything near as nice as a box-stock NC30 or NC35! <GD&R>)
The VSource.org-endorsed solution is to fit a 17" x 5" '94-'97 VFR750F (RC36) rear wheel to the NC30's axle assembly (part number 2 in the diagram above). This is a solution that requires machining of the axle assembly by a competent machine shop both to fit the four wheel studs and to cut down the locating flange on the NC30 axle assembly. A 17" x 5" VFR750F wheel and most 160/60VR-17 tires fit, but fitting anything larger causes tire-chain interference. Even with the 5" wheel, provision must be made to space the sprockets outwards by about 1/16". This is done by flipping the rear sprocket over (it has an offset) and fitting the front sprocket with a large flat washer as a spacer. However, tires of the same "sidewall size" from different manufacturers are often physically different sizes, so clearance should be tested or verified before fitting. A 170/60ZR-17 Metzeler ME-Z2 fitted onto a '90-'93 VFR750F (RC36) 17" x 5.5" wheel, for example, measures 175mm in width, while a 160/60ZR-17 Dunlop D207 fitted onto a 5" VFR750F wheel measures 176mm in width. Not surprisingly, diameters also vary considerably!
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This is a picture of the modified NC30 axle assembly and kit. |
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This is a head-on shot that clearly shows the different bolt circles used by the VFR750 and NC30 hubs. |  |
This is a shot of a '94-'97 VFR750F rear wheel with the modified NC30 rear hub. |  |
This is a shot of the rear of a '94-'97 VFR750F rear wheel with the modified NC30 rear hub. |
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This is a picture of the modified hub fitted to the VSource.org NC30. |
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This is a picture of a VFR750F rear wheel fitted to the VSource.org NC30. |
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Close-up of the VSource.org NC30 rear wheel. |
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Right hand side view of the VSource.org NC30. |
VFR750F rear wheels are much more plentiful than NC35 wheels—and the 5" ones are in less demand than the 5.5" ones that allow the fitment of the 180/70ZR-17 tires everybody seems to want on their '94-'97 VFR750F (or CBR900RR with single-sided swing arm conversion...). And because the 17" x 5" wheel size is the same as the popular CBR600F3 (PC-25), etc., any kind of tire you could possibly want can now be used, but, the ride height is still altered—and unfortunately it's altered in the wrong direction (down) for performance or racing.
There are a few possible solutions to the ride height problem. First, one can do what the RC30 guys did when they went to fit 17" racing wheels to their race bikes: install a special shock linkage which compensates for the smaller rear wheel. There may actually be a similar HRC part for the NC30, but it is not listed in the '92 VFR400R HRC Set-up Manual, and it would likely be rather pricey even if you could find one. There also may be a German maker of a similar, lengthened cushion connecting rod (linkage) for the NC30 which is a copy of this elusive HRC part. In addition, there is a Japanese aftermarket lower shock assembly that includes a revised cushion arm in addition to a lengthened connecting rod; there are some photos of it (with the OEM parts on the left) here.
A more practical solution may be to get a new rear shock custom built to be an additional 15mm longer than the stock Showa rear shock. The Penske 8981 remote reservoir rear shock is adjustable for pre-load, ride height, rebound and compression damping, and it is an elegant and high quality solution to the hide-height problem that provides the added benefit of being a custom built and user rebuildable racing shock. A picture of the NC30 Penske (on the left) next to the stock NC30 shock is here. Note that the Penske in the photo is adjusted to its minumum length (it can be adjusted 10-12mm), and it is still about 5mm longer than the stock Showa.
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