Technical wheel hub
- Thread starter andrew t
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Technical wheel hub
jimbro1000
Established member
The short answer is you can't - until a few years ago Fiat didn't do 4x100, only 4x98. The grande punto changes this as it is a collaborative effort with GM. However this does mean you can at least source genuine Fiat parts - problem is they won't fit.
If you must have 4x100 you can either get the wheels modified (the central spigot needs attention as this is what centers and locates the wheel, not the bolts, use special bolts (again attention to the spigot is needed) or you can modify the hubs (still need to check the spigot) but then you need to source suitable discs. In the long run the cheap (modified hub) option is to swap to floating discs as the modification to the disc is one off for each corner as the disc is separate from the disc hub (sometimes called a top hat). The initial cost is significant though, the other problem is that these tend to be competition only parts - if you need type approval (I have no idea about such things in Canada) then you really will struggle. Rewinding back a bit though - the GM based discs from the Grande Punto might do the job but you'd be looking at the entire brake assembly and how this fits to the hub. You'd also need to make sure it fits inside your wheels as the GP base spec has significantly bigger rims than the X1/9.
If you must have 4x100 you can either get the wheels modified (the central spigot needs attention as this is what centers and locates the wheel, not the bolts, use special bolts (again attention to the spigot is needed) or you can modify the hubs (still need to check the spigot) but then you need to source suitable discs. In the long run the cheap (modified hub) option is to swap to floating discs as the modification to the disc is one off for each corner as the disc is separate from the disc hub (sometimes called a top hat). The initial cost is significant though, the other problem is that these tend to be competition only parts - if you need type approval (I have no idea about such things in Canada) then you really will struggle. Rewinding back a bit though - the GM based discs from the Grande Punto might do the job but you'd be looking at the entire brake assembly and how this fits to the hub. You'd also need to make sure it fits inside your wheels as the GP base spec has significantly bigger rims than the X1/9.
jimbro1000
Established member
I should add that some of the USA based owners have tackled this before and last time I checked there wasn't a really satisfactory solution.
Modifying the hub to accept a 4x100 stud pattern isn't particularly difficult especially if you opt for a thicker stud/bolt. You just redrill the hub with a slightly offset pattern and retap but then you need to redrill the brake disc which is fine until your disc wears out (hence the idea of switching to top-hats).
Finding a suitable disc with the correct pattern, spigot hole and disc offset is another option but not one I fancy trying... then again the cost of low quantity fabrication in the USA is so low compared with here in the UK that is might actually be viable to get some made to suit - but then the top hat option still might be cheaper and you only need to do it once. If you go down that road then the option of upgrading the brakes also becomes possible. Wilwood brakes were popular on X1/9s for a bit and might still be a relatively cheap way of getting into vented discs (at the front at least) with 2, 4 or 6 pot options for proper grabbing power....
Modifying the hub to accept a 4x100 stud pattern isn't particularly difficult especially if you opt for a thicker stud/bolt. You just redrill the hub with a slightly offset pattern and retap but then you need to redrill the brake disc which is fine until your disc wears out (hence the idea of switching to top-hats).
Finding a suitable disc with the correct pattern, spigot hole and disc offset is another option but not one I fancy trying... then again the cost of low quantity fabrication in the USA is so low compared with here in the UK that is might actually be viable to get some made to suit - but then the top hat option still might be cheaper and you only need to do it once. If you go down that road then the option of upgrading the brakes also becomes possible. Wilwood brakes were popular on X1/9s for a bit and might still be a relatively cheap way of getting into vented discs (at the front at least) with 2, 4 or 6 pot options for proper grabbing power....
