Suspension bolts grade

[damdy-cash]

Hi guys, I would like to renew the suspension bolts on my 1992 DeDion S3. length etc. I have but the grades are not clear to me as it is mostly the old sfx or whatever marking. I think there are not alle the same, someone can help here based on the list below? Cheers Volker

qty/ dim./ Head/ Thread/ Length / position
2 3/8" Alen UNF 2 1/4"/ 55mm top wishbone upper/front
2 1/2" Hex UNF 3 1/2" / 87mm top wishbone upper/rear
4 1/2" Hex UNF 4" / 100mm bottom wishbone front and rear
2 1/2" Hex UNF 3 3/4" / 94mm A- frame front
1 1/2" Hex UNF 2 1/2" / 62mm A- frame rear
2 3/8" Hex UNF 3 1/4" / 82mm Dedion tracking arms front
2 1/2" Hex UNF 2 1/2" / 62mm Dedion tracking arms rear
2 1/2" Hex UNF 2 1/2" / 62mm rear damper top
2 1/2" Hex UNF 5 3/8" / 135mm rear damper bottom

[one eyed mick]

10.8 grade for all of them [imperial rates ]

[pikeyboy]

Grade 10.8 is a metric bolt high tensile grade.

Since your bolts are imperial you'll need grade 5 or 8. Grade 5 would be adequate for your needs, its the equivalent of a metric 8.8.


fyi see below

http://www.hi-tensilebolt.com.au/bolt-strength-gra...

[Purespeed]

May as well go to CC for these. You will get a all the correct sizes and tensiles plus they come in packs for different areas of the car. Last time I bought them I thought they were good value for money which makes a change from CC at times..

[fergus]

I don't think there are any bolts under tension in a 7s suspension? Almost all are in shear, in which case, the tensile rating is somewhat irrelevant.

[BertBert]

Are you sure fergus? Would not the sheer strength be related to the tensile strength? Hint: wikipedia tells me it is

The ultimate sheer strength of steel is 0.75 of the ultimate tensile strength.

https://en.wikipedia.org/wiki/Shear_strength
Bert

fergus said:

I don't think there are any bolts under tension in a 7s suspension? Almost all are in shear, in which case, the tensile rating is somewhat irrelevant.

[fergus]

BertBert said:

Are you sure fergus? Would not the sheer strength be related to the tensile strength? Hint: wikipedia tells me it is

The ultimate sheer strength of steel is 0.75 of the ultimate tensile strength.

https://en.wikipedia.org/wiki/Shear_strength
Bert

fergus said:

I don't think there are any bolts under tension in a 7s suspension? Almost all are in shear, in which case, the tensile rating is somewhat irrelevant.

It may tell you that if you replace the word "stress" with "strength". Unfortunately, the aforementioned are different measures.... (but they do both begin with 's' to be fair)

[one eyed mick]

Re above statements to much brains not enough inteligence To OP order the correct bolts from Caterham !!! they will probably empty your bank account but you may have a chance of getting the correct items

[Grumbly]

Grade 5 bolts will be fine for all those applications. They are specified to achieve an adequate bearing area in the chassis and will never get anywhere near their shear capacity, unless the car encounters something immoveable at speed. In which case bolt failure will be the least of your problems.

The ultimate solution is AN bolts which have far better dimensional and strength quality control, together with grip lengths move suitable to the application.

[damdy-cash]

Think I got the final answer.
See this bolt set https://caterhamparts.co.uk/hardware-packs/177-fas... have a close look and you see they say v grade ("old grade clasification") 10.9 on it.
Darren from parts told me he believes its grade 8 what actual is around 10.9 as well

Cheers Volker

[fergus]

Grumbly said:

Grade 5 bolts will be fine for all those applications. They are specified to achieve an adequate bearing area in the chassis and will never get anywhere near their shear capacity, unless the car encounters something immoveable at speed. In which case bolt failure will be the least of your problems.

[BertBert]

What are you on about Fergus?
I think you said that the tensile strength was immaterial as the bolts are in shear.
But presumably they have stresses on them use? In which case knowing how strong they are is not irrelevant?
Bert

fergus said:

It may tell you that if you replace the word "stress" with "strength". Unfortunately, the aforementioned are different measures.... (but they do both begin with 's' to be fair)

[fergus]

BertBert said:

What are you on about Fergus?
I think you said that the tensile strength was immaterial as the bolts are in shear.
But presumably they have stresses on them use? In which case knowing how strong they are is not irrelevant?
Bert

fergus said:

It may tell you that if you replace the word "stress" with "strength". Unfortunately, the aforementioned are different measures.... (but they do both begin with 's' to be fair)

I did say that *tensile* (in tension) strength was not specifically required in the application of bolts for Caterham suspension as all bolts are located such that the bolts are in shear, not in tension.

You then quoted a stat from wikipeadia, however, your reference should have referred to "stress" rather than "strength" as you mis-quoted.

I didn't say knowing how strong they were is irrelevant. As above, I was referring to the *tensile* strength rating as a guide to their suitability.

[mickrick]

Grumbly said:

Grade 5 bolts will be fine for all those applications. They are specified to achieve an adequate bearing area in the chassis and will never get anywhere near their shear capacity, unless the car encounters something immoveable at speed. In which case bolt failure will be the least of your problems.

The ultimate solution is AN bolts which have far better dimensional and strength quality control, together with grip lengths move suitable to the application.

This.
Trident supplies have a good stock of AN stuff.