Fitting tyre protectors - drilling size for fastening holes

[stevenkeyte]

The front suspension road spring damper cup on my car doesn't have the pre-drilled holes for fitting the tyre protectors, would the tapping drill size for the screw be OK to use, i.e. M6 dome headed screw drill hole size 5mm and the M7 flat headed screw drill hole size 6.1mm, would this be OK given that the screws supplied with the kit are thread cutting screws, I presume so, but would like confirmation if anyone has done this,

Steve

[steve-45]

I thought mine was the only one without the pre-drilled holes ....

[stevenkeyte]

Originally Posted by steve-45

I thought mine was the only one without the pre-drilled holes ....

Apparently not!

Steve

[T-Cut]

Originally Posted by stevenkeyte

would the tapping drill size for the screw be OK to use, i.e. M6 dome headed screw drill hole size 5mm and the M7 flat headed screw drill hole size 6.1mm, would this be OK

I would say that will be near enough. If you need the absolute sizes, check out the self-tapping drill sizes online. Self-tappers seem to be graded numerically like wood screws, rather than by thread diameter in millimetres. It also takes account of the substrate hardness and thickness, which doesn't figure for normal thread cutting.

TC

[Yorkshire GOC]

Am thinking about getting tyer protectors fitted - have heard conflicting views as to whether they are worth fitting or not?

[stevenkeyte]

Originally Posted by T-Cut

I would say that will be near enough. If you need the absolute sizes, check out the self-tapping drill sizes online. Self-tappers seem to be graded numerically like wood screws, rather than by thread diameter in millimetres. It also takes account of the substrate hardness and thickness, which doesn't figure for normal thread cutting.

TC

Yes, I found a chart which gave the tapping drill size for thread cutting screws and the drill sizes are pretty close to the standard tapping drill sizes of which I'm familiar,

Steve

[T-Cut]

Originally Posted by Yorkshire GOC

Am thinking about getting tyer protectors fitted - have heard conflicting views as to whether they are worth fitting or not?

For what they cost, what reason is there not to?
Because the odd fracture wasn't contained by the protector it doesn't mean they aren't a cost effective safety measure. I've never read of anyone suggesting they should not be fitted.

TC

[roverbarmy]

Originally Posted by stevenkeyte

The front suspension road spring damper cup on my car doesn't have the pre-drilled holes for fitting the tyre protectors

Steve

Make sure that you clean all around the area with a wire brush as the holes can get blocked with grime over the years. Easily missed. One should be tapped and the other uses a self tapping bolt if I remember correctly.
Senility setting in, the old memory aint what it used to be!

[Bolin]

Originally Posted by T-Cut

For what they cost, what reason is there not to?
Because the odd fracture wasn't contained by the protector it doesn't mean they aren't a cost effective safety measure. I've never read of anyone suggesting they should not be fitted.

TC

I've had one spring fail and take out the tyre despite the protector and now a second spring fail and seemingly the protector has saved the tyre this time.

A lot cheaper than a new tyre, and as my second failed on the move, a lot safer too.

[hortonds]

I didn't like the self tapper. It seems fairly flimsy (and the last thing I want is for it to rattle off while I'm driving), so I put a stainless steel bolt and nylock nut on mine.