I have Gerry's bumper fixing kit which I am using to drill holes pre paint shop. I don't have overriders as they aren't available, which makes the job a little trickier. I also don't know when or if will use nudge bars. Gerry's front kit has 16mm tubes that reduce to M10 short threaded rods. The manual seems to suggest you don't use outer tubes (aluminium in original) or grommets. This would align with the 16mm mounting tube, not that that precludes aluminium tubes, but they would be quite wide. Do Hawk builders follow the manual, ie no grommets and no outer tubes on the front?
It would be very helpful if someone could tell me the distance between the mounting rods front and back so I can set this distance in the event that I do use nudge bars. For now I assume the mounting rods are level and parallel to an imaginary centre line. As you will appreciate this is all relevant to setting the correct size and location of the 8 holes pre paint shop!
Regards
Iain
Holes and bumper fixing kit
Re: Holes and bumper fixing kit
Iain,
Two things concern me in trying to drill the holes without the matching hardware.
How well are Gerry's overriders made with regards to continuity on dimensions and has he changed anything over the last 10 years?
Measuring mine the LH side spacing on the rear is slightly different to the RH side and the tubes not absolutely parallel !
Info you have requested is as follows measured on my 1999 Hawk but suggest you get some other dimensions to get an average.
Rear.
The mounting studs do have chrome tubes to cover and pass thro'' the bodywork without grommets. Tubes virtually size for size fit in the holes.
Tube O/D 15.0 to 15.25 mm
Distance between tubes ( not centreline of holes) 40.5 mm on LH and 43.0 mm on RH.
Front
Mounting bars do not have any cover tubes and again pass thr'o bodywork without grommets and are a size for size fit.
O/D of bars 16.0 / 16.1.
Distance between bars ( not centreline of holes) is 42.2 to 42.5mm
I can only suggest making the holes slightly undersize to finish off when you have the overriders. E.g giving yourself a 1-2 mm or more allowance to move the hole.Yes the hole might need a little bit of paint on its return edge but assuming you have a fibreglass body that isn't much of an issue.
Hope this assists.
Peter C
Two things concern me in trying to drill the holes without the matching hardware.
How well are Gerry's overriders made with regards to continuity on dimensions and has he changed anything over the last 10 years?
Measuring mine the LH side spacing on the rear is slightly different to the RH side and the tubes not absolutely parallel !
Info you have requested is as follows measured on my 1999 Hawk but suggest you get some other dimensions to get an average.
Rear.
The mounting studs do have chrome tubes to cover and pass thro'' the bodywork without grommets. Tubes virtually size for size fit in the holes.
Tube O/D 15.0 to 15.25 mm
Distance between tubes ( not centreline of holes) 40.5 mm on LH and 43.0 mm on RH.
Front
Mounting bars do not have any cover tubes and again pass thr'o bodywork without grommets and are a size for size fit.
O/D of bars 16.0 / 16.1.
Distance between bars ( not centreline of holes) is 42.2 to 42.5mm
I can only suggest making the holes slightly undersize to finish off when you have the overriders. E.g giving yourself a 1-2 mm or more allowance to move the hole.Yes the hole might need a little bit of paint on its return edge but assuming you have a fibreglass body that isn't much of an issue.
Hope this assists.
Peter C
Re: Holes and bumper fixing kit
Many thanks Peter, that's very helpful. Believe me I would love to have all the matching hardware but Gerry hasn't been able to supply this for several years. I'm more relaxed at the rear as the grommets give a fair degree of latitude. Measuring the distance between the centre of the front mount tubes it looks like 60mm and your measurements would suggest 58mm. I can work with this.
What would help is to know the distance between the tubes across the front and rear, ie so I can retrofit a nudge bar at a later date. None of this sits well with my OCD....but I don't know what else to do?
Iain
What would help is to know the distance between the tubes across the front and rear, ie so I can retrofit a nudge bar at a later date. None of this sits well with my OCD....but I don't know what else to do?
Iain
Re: Holes and bumper fixing kit
That's fantastic, thanks Alan.
I've done the front, that is relatively straightforward with the mounting kit, though I did have to bend the tubes to get everything aligned as I wanted. It it close to the 766mm across the front, certainly within tolerance. The rear measurements align with the markings on the body. Now I know this and it's the same 58mm between the rear tubes I have more confidence to finish this part of the pre-paint prep!
Thanks again
Iain
I've done the front, that is relatively straightforward with the mounting kit, though I did have to bend the tubes to get everything aligned as I wanted. It it close to the 766mm across the front, certainly within tolerance. The rear measurements align with the markings on the body. Now I know this and it's the same 58mm between the rear tubes I have more confidence to finish this part of the pre-paint prep!
Thanks again
Iain
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Paul Blore
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Re: Holes and bumper fixing kit
Just make sure the tubes are parallel with the line of the car looking from the side. Far too many have the tubes sagging down, especially at the front, which looks all wrong. Sorry, to anyone who has saggy tubes. 
Paul
Paul
Re: Holes and bumper fixing kit
Iain
My distance between overrider mountings as follows.
Centreline to centreline as best can be measured bearing in mind bodywork does prevent the tape being an absolute perfect straight line.
Rear- 807
Front - 777
Suggest Alan that you check your front dimension - is it a typo and your 766 should be 776?
I agree with Paul to make sure you don't make the front bumper tubes run downhill and give the car a drop snoop look.
Ref drilling the holes it is more important at the front to start with a small hole as you go thr'o a very curved part of the body. I think I started with a 3mm pilot hole to check that the centreline was in the correct place before opening it up large enough to accept a suitable round file. Then judicious filing and continual checking produced the correct sized hole.
Another suggestion is who lives near to Alain and could they lend their overriders for a day?
Peter C
My distance between overrider mountings as follows.
Centreline to centreline as best can be measured bearing in mind bodywork does prevent the tape being an absolute perfect straight line.
Rear- 807
Front - 777
Suggest Alan that you check your front dimension - is it a typo and your 766 should be 776?
I agree with Paul to make sure you don't make the front bumper tubes run downhill and give the car a drop snoop look.
Ref drilling the holes it is more important at the front to start with a small hole as you go thr'o a very curved part of the body. I think I started with a 3mm pilot hole to check that the centreline was in the correct place before opening it up large enough to accept a suitable round file. Then judicious filing and continual checking produced the correct sized hole.
Another suggestion is who lives near to Alain and could they lend their overriders for a day?
Peter C
Re: Holes and bumper fixing kit
Many thanks Alan and Peter that is just the data I need.
The distance between my centre points on the front is 772mm. It would not be difficult to extend this if that is what the nudge bar requires. I was initially concerned to ensure the rods are parallel to an imaginary centre line as said. The curvature of the body makes this a little difficult to ascertain but with a longer piece of 16mm tube it is quite east to see. To achieve this the spacing needs to be narrower, I see Alan's car doesn't have a nudge bar? If you look at a plan view of a car with a complete bumper set up it looks to me that the whole is designed to be a curve, ie the over riders actually point outwards. Not sure this looks good without a nudge bar. Of course for those doing what I am doing with all hardware none of this is relevant, you just assemble and that's that. Quite fascinating when you research this without hardware.
The Hawk front mounting kit doesn't give that much latitude to have droopy mounts. The tolerance is more to ensure all is level. I too have seen Cobras with droopy bars and I suspect it's because some overriders are designed to be vertical and there is no difference beetween front and back. This is wrong of course, but you need different angles on the welded in mount plates front and rear. Some just have M10 nuts welded to the over rider, hence they are the same, therein lies the problem.
Regards
Iain
The distance between my centre points on the front is 772mm. It would not be difficult to extend this if that is what the nudge bar requires. I was initially concerned to ensure the rods are parallel to an imaginary centre line as said. The curvature of the body makes this a little difficult to ascertain but with a longer piece of 16mm tube it is quite east to see. To achieve this the spacing needs to be narrower, I see Alan's car doesn't have a nudge bar? If you look at a plan view of a car with a complete bumper set up it looks to me that the whole is designed to be a curve, ie the over riders actually point outwards. Not sure this looks good without a nudge bar. Of course for those doing what I am doing with all hardware none of this is relevant, you just assemble and that's that. Quite fascinating when you research this without hardware.
The Hawk front mounting kit doesn't give that much latitude to have droopy mounts. The tolerance is more to ensure all is level. I too have seen Cobras with droopy bars and I suspect it's because some overriders are designed to be vertical and there is no difference beetween front and back. This is wrong of course, but you need different angles on the welded in mount plates front and rear. Some just have M10 nuts welded to the over rider, hence they are the same, therein lies the problem.
Regards
Iain
Re: Holes and bumper fixing kit
Thus it goes to show that there might be differences in the manufacture of parts. In this case if the twin tubes for the overrider bars to slide into are not truly parallel to their their base plate ( and I don't remember checking that aspect ) then it would be easy for the center distances to be different. We are only talking 5mm per side.
I can now see that the overrider position is slightly different on each side relative to the grill opening. Clearly not noticed during the build or since until measuring it now.
You will of course be positioning the holes to suit the mounting tubes.
I should point out that neither Alan nor myself have bumper hoops only overriders!
Bumper hoops would create a specific need to get the mounting centerline distance more accurate.
So you need someone with bumper hoops to give you the dimension to compare.
Peter C
I can now see that the overrider position is slightly different on each side relative to the grill opening. Clearly not noticed during the build or since until measuring it now.
You will of course be positioning the holes to suit the mounting tubes.
I should point out that neither Alan nor myself have bumper hoops only overriders!
Bumper hoops would create a specific need to get the mounting centerline distance more accurate.
So you need someone with bumper hoops to give you the dimension to compare.
Peter C