46 replies to this topic

[TheStotts]

The 10.9 is the recommended upgrade, the 12.9 have a higher torsional shear but lower lateral shear.

Sadly not in stock but will order another batch soon.

Would you be concerned that 12.9s are not fit for purpose, Cliffie I tend to drive quite slowly on the road but enjoy a good blast on track now and then

[Vespa]

Are there recommended torque settings for the 10.9 bolts or is it just a case of do them up tight?

68Nm + threadlock

68Nm?? I was told 90Nm.... Hmmmm what to do now, replace them again??

[techieboy]

Are there recommended torque settings for the 10.9 bolts or is it just a case of do them up tight?

68Nm + threadlock

68Nm?? I was told 90Nm.... Hmmmm what to do now, replace them again??

That's according to the Lotus service bulletin but not sure whether that's the Bible, so to speak.

[slindborg]

The 10.9 is the recommended upgrade, the 12.9 have a higher torsional shear but lower lateral shear.

Sadly not in stock but will order another batch soon.

Would you be concerned that 12.9s are not fit for purpose, Cliffie I tend to drive quite slowly on the road but enjoy a good blast on track now and then

I'd not run any suspension component with 12.9's fitted..... imho more of a risk than running poorly torqued up 8.8's

[Vespa]

So with the 10.9's having a higher tensile strength it should be ok to torque to 90Nm?

[Whiteboy]

So with the 10.9's having a higher tensile strength it should be ok to torque to 90Nm?

I was told torque to 68nm.

Steve

[slindborg]

So with the 10.9's having a higher tensile strength it should be ok to torque to 90Nm?

get them out and replace + torque the the RIGHT figure.

[Vespa]

But is 68Nm the correct torque for the uprated bolts?

[techieboy]

Yes. 68Nm.

[Vespa]

Bollocks I best get back on to cliffie then!

[TheStotts]

The 10.9 is the recommended upgrade, the 12.9 have a higher torsional shear but lower lateral shear.

Sadly not in stock but will order another batch soon.

Would you be concerned that 12.9s are not fit for purpose, Cliffie I tend to drive quite slowly on the road but enjoy a good blast on track now and then

I'd not run any suspension component with 12.9's fitted..... imho more of a risk than running poorly torqued up 8.8's

Thanks for your opinion Although it's really not what I wanted to hear

Before I question Steve's expertise does anyone else have an opinion on 12.9s? I'm sure he said that they purchased a bulk load of 12.9s for use on Elise type cars including his time attack car. I can't see me ever having the balls, let alone the talent, to drive my car like that

[FLD]

No idea on 12.9's but you should also consider swapping the camber shims when doing the HCB's. The oe ones with one hole and one slot are quite soft and have a habit of almost extruding out at the slot end resulting in a loss of the torque setting on the bolt. I've got my suspension in bits at the mo and both front sides have done this and the bolts had a slight wobble in them. Lotus supply a hardened camber shim with holes both ends that is supposed to stop this problem. I suspect this was the cause of my HCB failure last year. I'll put some pictures up when I can be ar5sed and if my camera will do justice to the problem.

[SteveA]

I've had 12.9's on my car for three years, do a fair bit of tracking on sticky tyres and have never had any problems. Has anyone actually heard of a failure on 12.9's or is this just another bit of hearsay?

[Mike (Cliffie)]

What this needs is an engineers opinion. I supply the 10.9 bolts as that is the Lotus spec upgrade. When I looked into this first time out, I was advised 12.9 would not be a good bet as the bolts are subjected to a side loading when on track on sticky tyres and the 12.9 are more prone to shearing when subjected to side loads whereas the 10.9 would have more flex. Saying that SteveA runs the 12.9 and he doesn't hang about on track. I will continue to only supply the 10.9 even though 12.9 are cheaper and available in the UK off the shelf whereas I have to order in the 10.9 from Europe.

[iVXT]

What this needs is an engineers opinion. I supply the 10.9 bolts as that is the Lotus spec upgrade.

When I looked into this first time out, I was advised 12.9 would not be a good bet as the bolts are subjected to a side loading when on track on sticky tyres and the 12.9 are more prone to shearing when subjected to side loads whereas the 10.9 would have more flex.

Saying that SteveA runs the 12.9 and he doesn't hang about on track.


I will continue to only supply the 10.9 even though 12.9 are cheaper and available in the UK off the shelf whereas I have to order in the 10.9 from Europe.

Cliffie could you supply the uprated camber shims FLD recommended along with uprated 10.9 bolts as a kit?

Thanks a lot.

[Mike (Cliffie)]

What this needs is an engineers opinion. I supply the 10.9 bolts as that is the Lotus spec upgrade.

When I looked into this first time out, I was advised 12.9 would not be a good bet as the bolts are subjected to a side loading when on track on sticky tyres and the 12.9 are more prone to shearing when subjected to side loads whereas the 10.9 would have more flex.

Saying that SteveA runs the 12.9 and he doesn't hang about on track.


I will continue to only supply the 10.9 even though 12.9 are cheaper and available in the UK off the shelf whereas I have to order in the 10.9 from Europe.

Cliffie could you supply the uprated camber shims FLD recommended along with uprated 10.9 bolts as a kit?

Thanks a lot.

As Geary from Elise Parts supplies the camber shims, I wouldn't get involved. Don't want to go encroaching on his business.

[TheStotts]

No idea on 12.9's but you should also consider swapping the camber shims when doing the HCB's. The oe ones with one hole and one slot are quite soft and have a habit of almost extruding out at the slot end resulting in a loss of the torque setting on the bolt. I've got my suspension in bits at the mo and both front sides have done this and the bolts had a slight wobble in them. Lotus supply a hardened camber shim with holes both ends that is supposed to stop this problem.

I suspect this was the cause of my HCB failure last year. I'll put some pictures up when I can be ar5sed and if my camera will do justice to the problem.

Would like to see pics for future reference

I've had 12.9's on my car for three years, do a fair bit of tracking on sticky tyres and have never had any problems.

Has anyone actually heard of a failure on 12.9's or is this just another bit of hearsay?

Thanks Steve

Reassuring to know that others have run 12.9s without issues. I’m still running standard wheels and tyres and drive like a fanny so fingers crossed they will be fine

What this needs is an engineers opinion. I supply the 10.9 bolts as that is the Lotus spec upgrade.

When I looked into this first time out, I was advised 12.9 would not be a good bet as the bolts are subjected to a side loading when on track on sticky tyres and the 12.9 are more prone to shearing when subjected to side loads whereas the 10.9 would have more flex.

Saying that SteveA runs the 12.9 and he doesn't hang about on track.

I will continue to only supply the 10.9 even though 12.9 are cheaper and available in the UK off the shelf whereas I have to order in the 10.9 from Europe.

Thanks Cliffie

Out of my depth with all this engineering business to be honest. Know the physics behind it but have no ideal how to apply it in the real world... bloody physicists, eh?

I’ll stick with the 12.9s for now but ask Steve G to keep a close on eye them on future visits

[Mike (Cliffie)]

Yes. 68Nm.

Lotus told me 90Nm on the 10.9 and 68Mn on the 8.8.

This needs further clarification I feel.

Vespa, sorry for the short reply to your PM, I was still at work but wanted to get a fast response to you, you have another PM

[techieboy]

My search skills sadly fail me Somewhere I've got a pdf copy of the Lotus Service Bulletin 2004/08 that details the upgraded 10.9 bolts and the 68Nm/50Lb-Ft torque setting for them (up from 45Nm of the 8.8 bolts). Will carry on searching for it. 90Nm sounds like a big increase for one step up in grade of bolt.

[techieboy]

Closest I can currently find is this - check the camber shims section at the bottom of the page.