In my personal opinion, no other items are the source of such controversy and conversation, as tyres. The FJ comes shod with a 120/70 front, in either 16" or 17" flavour. The rear is 150/80x16". This OEM rear tyre size, on what amounts, by today's standards, a very narrow rim; restricts tyre selection considerably. The advances in modern radial tyre construction, have required wider rim sizes. The result, is a wider, lower profile tyre, with greater sidewall support. I've tried two different rear wheels and tyres on my FJ now and both have been a major improvement over the standard item.
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FZR1000 Exup front wheel conversion. This mod gives the FJ comparable rims to most modern sportsbikes. Neil Butcher slotted the Exup wheel straight into his standard FJ forks. This requires 1mm bushings to be made, as the Exup has a 17mm front wheel spindle, the FJ's being 15mm. |
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Bob Shammas's ZX-7R front wheel conversion. This uses adaptor plates to enable mounting of the Tokico six-pots. Bob explains:- I used a '95 ZX-6R front wheel and '97 GSXR750 6-piston calipers. This bike is a whole new machine. I'm not kidding!! You won't believe how an FJ can handle with modern rolling stock. I can roll that thing over until all sort of things are scraping and it's very confidence inspiring. The bike is really nice for an every day ride, and I think I'll be doing some touring in the rockies with it this year. |
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Another front wheel option for earlier 16" model owners, are the ' banded out ' original wheels, from DEGET of Germany. This gives the option of fitting ' Fireblade ' tyres, whilst retaining the original early FJ wheels. |
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FZR1000 GENESIS rear wheel
conversion
- This is a 4.5"x18"
rim
and takes a 160/70x18" tyre. This
gives a superb ride, with great 'flickability'. I followed the
instructions from the
UKFJOC technical
magazine. I've taken the liberty of
scanning a copy of these. The bearings required are 6204's, the same
as most GSXR1100 Suzuki's. The job is pretty easy, although some
machining is needed. Note:- If you need
help with this conversion, please do not contact Phil Hacker at the
UKFJOC unless you are a member. Any
queries may be directed to me
FZR1000 EXUP rear wheel conversion - This is a 5.5"x17" rim and takes a 170/60x17" tyre. It gives a very 'planted', stable ride. I wouldn't in anyway say it's superior to the Genesis mod though, as this remains the more 'agile' option. The Exup wheel just 'looks right' and a whole host of tyre selections become possible, with the 17" tyre. To install this wheel and retain proper wheel alignment and chain clearance, it is necessary to modify the cushdrive assembly. Basically, the whole cushdrive has to sit 7mm deeper into the wheel. All parts are standard FJ (except the wheel of course).The following alterations are made to these components:-
Cushdrive Hub/Sprocket Carrier - Machine 5mm from the ends of the cushdrive dogs (those things that engage into the cush rubbers). Remove the outer rim (about 2.5mm) of the cushdrive hub. (Picture)
Cushdrive Bearing Spacer - Machine 7mm from the end that butts up to the L/H wheel bearing. This part of the spacer now measures 13mm instead of the OEM 20mm.
Cushdrive Housing (In Wheel) - Remove 5mm from the outer surface of the cushdrive vanes. As the the cushdrive is introduced into the wheel, removal of a small amount of metal is needed around the L/H wheel bearing housing. Use Plasticine pressed onto these areas, to highlight surfaces needing further easing. You have achieved the correct amount of clearance for the cushdrive, when the cushdrive bearing spacer, squarely meets the bearing, with no fouling by the cushdrive. (Picture)
Cushdrive Rubbers - Shave approx 5-7mm, from the outer surface.
Caliper Mounting Bracket - I used an Exup caliper bracket, which differs from the FJ. Start by removing 2mm from the inner face and 5mm from the outer. Some slight adjustment will be necessary after this, but it's easy to do.
This process probably sounds more complicated than it actually is. Once you have the components in front of you, it's pretty plain what's got to go where. I used a power file, to remove the metal from inside the wheel and to dress the cushdrive rubbers. I had the cushdrive machined, but with patience, this too could be done by hand. The cushdrive bearing spacer MUST be accurately machined to ensure proper spacing, otherwise the bearings would be preloaded when the rear wheel spindle is tightened (not good). When finished the whole lot will sit 7mm deeper into the cushdrive, as pictured.
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It is possible to fit a 180/55x17" tyre, however the tyre will run very close to the chain with the wheel properly centred. That said it can be done, as Neil Butcher's FJ shows. Incidentally Neil modified the sprocket mounting points, to gain more clearance. |
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GSXR1100 Suzuki rear wheel conversion - This is not one I've tried myself, but on paper (and if the accompanying picture is anything to go by) it's a very attractive option. This involves a 4.5"x 17" rear wheel from an 1988-89 model, including all brake components and cushdrive assmbley. The standard FJ wheel spindle is retained. Simply make two 5.5mm spacers (apparently 3 20mm ID washers will suffice) and fit one to each end on the spindle, to take up the slack between the swinging arm and bearing spacers. A strap then has to be fabricated (as pictured), to locate the front end of the torque arm. The Suzukis underslung caliper looks pretty trick eh! Thanks to Arnie Robbins for this one.
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Arnie Robbins FJ |
Mark Arliss' FJ |
Marks Again |
To further support how 'pretty' this mod is, here's Mark Arliss's baby, sporting the same set up.
ZX-7R Kawasaki rear wheel conversion - I've not too much information on this one, but I know it's reasonably straight forward. Below are some pictures of Bob Shammas' FJ1100 wearing what looks like a 180/55 BT56.
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Bob Shammas' FJ |
Bob's Again |
And Again |
And Again |
Bob explains:-
Anyway, as for the rear wheel, I chucked the sprocket carrier in the lathe and machined 0.220" off of the sprocket mounting face to move the chain closer to the tire and line up with the front. I used a 40 tooth sprocket, giving a net 1 tooth taller gearing since the 180 Battlax is actually shorter than the stock tire by about 1 tooth's worth (I needed this to control the wheelies with the 1314 motor's big torque). My wheel didn't come with the inner spacer so I cut down a KZ1000 spacer to the right size. Most likely if you had the stock one you wouldn't have to do anything to it. Then I just made spacers to center the wheel in the swingarm and a made a hanger to mount the '91 GSXR1100 caliper. For a brake arm stay I made a small bracket and bolted it in behind the shock linkage mount under the swingarm. That way there was no welding required.
It looks like a ZX11 wheel will be just as easy. A ZX-11 "C" front end will bolt on with minimal work also. The stems are the same diameter at the bottom, so the FJ stem can be pressed into the C model tree. Only the top clamp needs to be modified (bored). The D model is different. My turbo FJ will get this mod if I can ever take time out from riding my turbo EFI ZX-11, among other things.
HORST BLIM'S ABS WIDE RIM CONVERSION
Many FJer's have wanted to fit a wider rear wheel rim to their FJ's whilst retaining their ABS. Now it's no problem. Our old friend Horst Blim has done the necessary machining etc, to fit the 5.5" FZR rim to the ABS FJ.
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Horst can supply all parts necessary and can arrange shipping. Check out Horst's website at www.hbbike.de and don't worry Horst speaks good English too !
It is even possible to fit a 190/50x17"
into the standard FJ swing arm. Chris Pittick has ensured
correct wheel and chain alignment, by modifying the sprocket
carrier to run as close to the swingarm as possible. Even
the sprocket studs are shortened. The front sprocket is
spaced out also. Things are a bit tight for room on the
output shaft, with no room for a tab washer ! However, once
fixed with Studlock, he's had no problems (it was done in
1993).
Chris says that he uses Bridgestone BT56
190/50x17" tyres as they will fit without fouling. Many
other makes come up larger and things get too cosy !
