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lotus62

hub redrilling to 4 x 100

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Hi, I need 4x100 on my spitfire hub's  what is the best way of doing this, I was thinking to tap the 12.5mm holes with m14x1.5 ,  glue a (green loctite) piece of a treated rod into it and redrill .  or if I mill a 12.5mm hole next to the old hole (creating a sort of longhole) I have just 60% meat left over around the new knurl so I don't feel comfy with this.  anyone done this before?   thanks, Rick

 

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For the front you can buy alloy hubs from the likes of Merlin Motorsport that are drilled 4 x 100.

At the rear, unless you have long shafts I’d suggest using PCD adapters as the extra width is useful. Look for adapters to suit MGF and TR7

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Nick, I have the alloy ones with 4x100 but want to make them in steel as well, I read that the bearings can come loose due to heat (and start spinning) the hub's are on my banks europa  with 220bhp so better safe then sorry. ...   

 

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Hi Rick,

 not sure if I understand what you are doing but if you fill the existing hole with a stud (trim flat) and lock it in (loctite or peening) you could then drill your new hole next to it (with the overlap).

This would give you 100% metal contact and would be pretty strong.

 

Roger

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14 hours ago, lotus62 said:

Nick, I have the alloy ones with 4x100 but want to make them in steel as well, I read that the bearings can come loose due to heat (and start spinning) the hub's are on my banks europa  with 220bhp so better safe then sorry. ...   

Ok, so you are only worried about the front ones?

It is true that bearing races coming loose can be an issue with alloy hubs due to their greater expansion coefficient.  The races need to be a very tight fit when cold so as not to come loose when heated by lots of enthusiastic braking.  Vented discs can help your wheel bearings stay in......

However, I would say that this is what Loctite "bearing fit is for.  Also,  a spinning bearing race is a much more benign mode of failure than loosing a wheel because studs have pulled through........

There are also these special stub axle/wheel bearing conversions available (Classic Driving Developments for one, but there are others) which use similar alloy hubs and I'm pretty sure they come with different PCD options.

Edit: also meant to say that the standard hubs appear to be some form of cast iron rather than steel so strength margins are less and welding not an option (not that you were proposing that anyway)

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14 hours ago, lotus62 said:

but want to make them in steel as well, I read that the bearings can come loose due to heat (and start spinning)

re this problem in alloy hubs, has anyone thought of pinning the outer of the bearing so it just cant rotate?  if you drilled in from the side of the hub in-line with the centre of the outer bearing case, tapped the hole, put a dimple mark in the outer case (or actually a slot across it) then you could screw in a grub screw that would locate in the dimple/slot (no need to tighten on the outer) and this should firmly locate and stop rotation, rather like locating a die in a holder!

alan

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Hi Alan,

             I don;t think you woud be able to drill into the outer race. But you could grind a flat on it.

 

Roger

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@ Nick, yes it is just the front one's, the rears are cast iron.  with steel I meant iron.  would have been nice if they are steel....  

@Alan, something to think about but the outer shell is thin so not much meat to drill in.  

@ Roger, thats how I wanted to do it, tap into the existing hole, close it and redrill or mill the new hole.  btw I have drilled in the outer shell of an bearing, use a full carbide drill bit works very easy.

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4 hours ago, RogerH said:

Hi Alan,

             I don;t think you woud be able to drill into the outer race. But you could grind a flat on it.

 

Roger

actually a much better and quick solution, only needs to be a tiny flat or groove and a grub screw would hold it perfectly there is only going to be tiny torque in play

alan

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