Stainless Steel Disc Bolts and Caliper Mounts

[minivin]

Evening people

I have been in contact with one of my stainless suppliers and they have stated that the socket buttons that would be needed for the disc mounts and the allen screws for the caliper mounts are grade 303 stainless steel which is a 30 ton tensile strength stainless.

The person at the company has been running 303 on his calipers and rear wheel axle for his ducati and suffered a catestrophic final drive chain failure recently where the rear chain snapped and wrapped itself around the rear wheel locking it solid, this left a 50 yards skid down the road but all that happened to the 303 axle was it bent slightly.

Front disc mounts are M8 1.25 pitch 25mm Button Heads and the Caliper Mounts for the front are M8 1.25 pitch 32mm Allen Screws with 24mm threaded portion.

For a front disc set that would be 10 screws £7 +P&P and for four caliper bolts for the front would come to £3 +P&P

If someone can confirm that 30 ton tensile is good enough for the use that we want of them (ABS pulsation has me thinking.....) then if anyone wants me to proceed with the above then let me know on email.

Robert Vincent

[stempy]

I'm in

[minivin]

ok stempy, if you can email me on minivin@ntlworld.com I can then send you my address for sending a cheque

I'm in

[Gats]

Rob, if 303 SS is the go for these, then I'm in too! I'll have to check the bolts on the KRS but I would hazard they are the same as our S. I'll send an email when I have checked in the next day or two.

Cheers,

[minivin]

no probs, with my ABS 03 S it's just an M8 bolt that is straight shanked i.e. no stepped portion.

Rob, if 303 SS is the go for these, then I'm in too! I'll have to check the bolts on the KRS but I would hazard they are the same as our S. I'll send an email when I have checked in the next day or two.

Cheers,

[Darth_1100S]

Rob - just me twopenneth, I may be wrong here but I thought the front calliper mounting bolts were M10. I've just had a quick look at mine and they certainly look like M10s. Also, again I may be geting mixed up with my 1100R but I'm sure they're the 1.5 pitch. I'll check 'em out tomorrow if nobody does it before.

Dave.

[minivin]

just checked the rear caliper bolts, they are M10 x 25mm with 1.5 course pitch, just going to check the fronts again myself!

Rob - just me twopenneth, I may be wrong here but I thought the front calliper mounting bolts were M10. I've just had a quick look at mine and they certainly look like M10s. Also, again I may be geting mixed up with my 1100R but I'm sure they're the 1.5 pitch. I'll check 'em out tomorrow if nobody does it before.

Dave.

[minivin]

yup, just confirmed on my bike that the fronts are M8 x 32mm and the rears are M10 x 25mm

So to summarise:

10 M8 x 25mm Button Head screws for both front brake disks £7 + P&P

4 M8 x 32mm Allen Hex Screws for both front brake calipers (check yours for size incase BMW done a "Honda" on us!) £3 + P&P

2 M10 x 25mm Allen Hex Screws for rear calliper, non-hugger (if you can supply size for hugger screw system I can get them made) £2.50 + P&P

[Darth_1100S]

Just took one of my caliper bolts out Rob, they're definately M10 1.5 pitch...hmm! I'm on Brembo Calipers, are yours the BMW type?

You're right it's probably best if we all check 'em before we order the buggers eh?

If you can get the rear hugger type bolts in S/S tho Rob then I'd be very interested in buying some from you. Mine are 1 3/8" long. If we can ascertain what's going on with the caliper mountings then I'd like some of them from you as well.

Keep us posted mate

Dave.

[minivin]

yup, mines a 52 registration february 2003 model with the bmw badged brembos. If you could do a length measurement in millimetres today and tell me which year your bike is I might be able to glean some info from one of the bmw agents and see when the transition was.

1 3/8", about 35mm in length which must mean they got about 5mm of grp and rest made up in a thick spacer I take it?

did you mean disc bolts in the last query, or just in general about the bw chaos that they have flung on us by changing hte caliper mounting arrangment

Just took one of my caliper bolts out Rob, they're definately M10 1.5 pitch...hmm! I'm on Brembo Calipers, are yours the BMW type?

You're right it's probably best if we all check 'em before we order the buggers eh?

If you can get the rear hugger type bolts in S/S tho Rob then I'd be very interested in buying some from you. Mine are 1 3/8" long. If we can ascertain what's going on with the caliper mountings then I'd like some of them from you as well.

Keep us posted mate

Dave.

[Darth_1100S]

Right Rob - got some measurements for you. My 'S' is a 99 on a T plate.

Rear caliper has the hugger type bolts fitted, these are M10 1.5 pitch. The thread length is 25mm with no plain shank. The hexagonal (spacer bit) is 17mm A/F and 35mm long. The tapped holes which mount the hugger are M6 and 22mm deep.

Front Caliper bolts are the same as the rear: M10 1.5 pitch x 25mm

Yep, I meant I'd like some disc bolts from you as well - I assume they will be the same no matter what brakes are fitted?

According to the workshop manual the disc bolts are fitted using Loctite 2701 (very strong) threadlock, so I guess they'll be bloody tight to get off. Probably require heating.

Anyway that should keep you out of mischief for a while!

Cheers - Dave

[minivin]

no probs with the M10's, I'll substitute the kit respectively for you.

I'll produce a CAD drawing for the hugger-orientated rear caliper bolt later and email it to my local company and se if they can do them, if not I know someone else who maybe able to help.

rear disk bolts are something that will be a future thought as I just looked at the bike and noticed the rear wheel has to come out to measure-up, maybe when the tyre needs replacing in a few thousand miles

my screws for the disc came out with only th lightest of effort, however even though loctite makes it a bugger to remove, it'll help to stop electrolytic corrossion taking hold which you really don't want!

Any news on the 400cc sizes you need?

[minivin]

duuuuh, just noticed my fatal comment above, initally I though the hugger went under the bolt, but of course it has M6 screws that go into a modified bolt to hold it on, therefore I wont be able to offer longer bolts at the same size as they're have to be made :s

I'll see about if we can get these made and how much the additional screws will come to, can someone tell me whether penny washers (large diameter washers) are used to spread the load on the hugger and what size they are if this is the case?

[Gats]

Rob, in the case of Pyramid huggers, I am under the impression the M6 countersunk screws are already SS (A2 grade most probably) and the matching washers look to be aluminium. I'll have to have a look when I get down to the garage in daylight.

[minivin]

ahhhh, countersunk, would this mean that the washer to go with the screw are counter-dished to suit the fastener?

Rob, in the case of Pyramid huggers, I am under the impression the M6 countersunk screws are already SS (A2 grade most probably) and the matching washers look to be aluminium. I'll have to have a look when I get down to the garage in daylight.