Anyone know WHY from front center bore was reduced?

dalefield said:

From the S4 on, the front center bore was reduced from 60 to 58mm. The 60 makes sense as it was a legacy from from the Supra, but does anyone know why Lotus switched to a 58mm center bore for the front hubs from the S4 forward?

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Yes - I'm curious too - I just ordered factory OEM hubs from the UK so my 88 can use these S4s wheels with 58mm center. Didn't want to bore the wheels out (to maintain the mechanical integrity) and didn't want to machine the 60 mm hubs.

It does seems odd to remove 2mm - so minor. And it's only the front - not the rear (remains at 60mm).

Maybe the smaller bore size on the wheel made them stronger? Just grasping for straws.

To prevent people from switching wheels front to rear.

Vulcan Grey said:

To prevent people from switching wheels front to rear.

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I've heard that before, but I find it hard to believe that is the real story.

I think it is more likely a new parts sourcing manufacturer was the rewal reason.

the original Stephens setup used Toyots spindles and hubs. Those parts probably were drying up and lotus made a change as they were going away from the toyota brakes, too. With Lotus being such a small volume manufacturer, finding already prioduced hub was more cost effective than having a small run of custom hubs made.

this is just a guess though......

the real reason may be no reason at all.... after all, these cars are British. :UK:

QuadCam said:

the real reason may be no reason at all.... after all, these cars are British. :UK:

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This has my vote.rotfl

QuadCam said:

the original Stephens setup used Toyots spindles and hubs. Those parts probably were drying up and lotus made a change as they were going away from the toyota brakes, too. With Lotus being such a small volume manufacturer, finding already prioduced hub was more cost effective than having a small run of custom hubs made.

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The hubs on the S4 (pre-Brembo brakes) are identical to the SE hubs, except for the 58mm spigot. The hub is not a Toyota part, and I'm fairly certain the spindle isn't, either.

I'm pretty sure it was just to prevent numpties from putting the wheels on wrong.

It could also be that they were moving to the larger brakes, and didn't want anybody trying to stick the old wheels over the larger brakes...

Sanj said:

The hubs on the S4 (pre-Brembo brakes) are identical to the SE hubs, except for the 58mm spigot. The hub is not a Toyota part....

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I think this is "mostly" correct. However, I'm under the impression that the hub is identical to the Supra's in many respects, but rather than having 4 studs for the Mk2 Supra wheels, the face of the hub is drilled to receive the 5 bolts of the Esprit. The back of hub, for instance, where the rotor attaches, I think is identical, as obviously, is the rotor itself.

FWIW, I think it's just coincidence that the front and rear were both 60mm at the time. Toyota (front) and Renault (rear) were both using 60mm in contemporary designs. That makes me think the theory about keeping people from switching wheels may be on target. Sometimes, manufacturers will use different hub bores front and rear to prevent this. My guess is that Lotus didn't mean to have them the same by design...it just worked out that way because Lotus' suppliers used the same hub bore. Just guessing, but makes sense.