suspension mounting bolts for ABS B12

[2harsh4me]

A Progressive 420 rear shock for my ABS equipped 1997 B1200 arrived in the mail today. In the instructions there is a note stating the following: 1997 Bandit 1200 with Anti-lock brakes (SAV) must order a bolt (Suzuki part #09103-10101) and nut (Suzuki part #08319-31107) for the lower mount.

Why wouldn't I be able to use the stock lower hardware? Any ideas?

[Red01]

No, not much experience here with the ABS model... but if the instructions say so, you'd probably be best off ordering them up.

[2harsh4me]

It appears that the '97 ABS equipped B12s have a slightly different lower mounting set up for the rear suspension - the lower mount on the stock shock is threaded to accept a bolt and no nut is needed to secure it. The Progressive 420 lower mount isn't threaded hence the need for a new bolt and nut to secure it in place. The bolt required (Suzuki part #09103-10101) is a 10x54 according to the Ron Aryers fiche. My local stealer doesn't stock this - any suggestions on regular hardware store stock that might be good to use? stainless? I'll be doing the actual install next week and will report back. CJ

[Red01]

Whatever the metric grade is that is equal or greater than an SAE Grade 5. Personally, I'd lean to something equal or greater than a Grade 8 equivalent. For something in that size & length, you may have to go to a bolt specialist, but I've never tried the hardware store for a metric bolt in that size range, so they may have it.

[Mini4x]

Don't use improper fastners..  especailly on things like suspensions and/or brakes.  Sometime a higher 'grade' is not nessicarily better.

Grade 5 bolts is some situations are "safer" and the equivalent grade 8, as they'll give (stretch) instead of snapping.

I'd just get them from Suzuki, it can't be that hard.

[Red01]

Mini4x: Don't use improper fastners..  especailly on things like suspensions and/or brakes.  Sometime a higher 'grade' is not nessicarily better.

Grade 5 bolts is some situations are "safer" and the equivalent grade 8, as they'll give (stretch) instead of snapping.

I'd just get them from Suzuki, it can't be that hard.

Sorry, gotta call on this urban legend!

A Grade 5 bolt will fail before a Grade 8 bolt stretches. There is nothing a Grade 5 bolt will do better than a Grade 8 - except cost you less to buy.

Let’s look at an example of where grade 5 and grade 8 bolts are subjected to single shear loads.
(The type which a shock mount bolt would be subjected to.)

Using a .250-inch diameter grade 8 fastener gives you the following shear capability:

A = Cross-sectional area of the fastener size (since bolt bodies/shanks have circular cross-sections, use area of a circle) = Pi x r2 where R (radius) = .250/2 = .125, therefore A = Pi x (.125)2 = .0491 square inches (in2)

Capability in shear = 91,000 lbs / in2 x .0491 in2 = 4468 lbs

Using the same .250-inch diameter grade 5 fastener results in the following:

Capability in shear = 75,000 lbs / in2 x .0491 in2 = 3683 lbs


Calculating the tensile (clamping) capability is not as easy as shear since the thinnest portion of the bolt is at the minor diameter of the threads (bottom of the thread “V”). So you need to know the nominal minor diameter of that particular fastener. That’s where military specification MIL-S-8879C comes in. It is titled “Screw threads, controlled radius root with increased minor diameter, general specification for”. It lists that and a lot more for almost all possible fasteners. MIL-S-8879C lists the nominal minor diameter of a .2500-28-UNF at .2065 inches. Calculate the A (area) of the cross-section:
A = Pi x r2 = Pi x (.2065/2)2 = .03349 in2

Grade 5 bolt capability in yield (stretch) = 92,000 lbs / in2 x .03349 in2 = 3081 lbs minimum
Grade 5 bolt capability in tension (failure) = 120,000 lbs / in2 x .03349 in2 = 4019 lbs minimum

Grade 8 bolt capability in yield (stretch) = 130,000 lbs / in2 x .03349 in2 = 4354 lbs minimum
Grade 8 bolt capability in tension (failure) = 150,000 lbs / in2 x .03349 in2 = 5024 lbs minimum
[/quote]