stainless steel braided brake lines

[Tony Smith]

I took a punt a few weeks back and ordered a 1200mm braided stainless steel brake line from the well known Chinese purveyor of nearly everything - Banggood for my much maligned KLE500.

It arrived a couple of days ago and I am happy with it, not as cleaver as Venhill, but at $AU15 including postage, what the hey....

Another Chinese seller was flogging similar cables in lengths from 300mm to 2000mm starting at $US6 to $US15

Actually I have mildly misstated - I also bought a 400mm hose too - I'm planning to hook that up on a test rig and pump it up to 1000psi - seeing as hand and foot operated motorcycle brake lines never see the brght side of 500psi, if it takes 1000psi without popping - good enough for me and design rules be dammed!

(if the 400mm hose survives testing it will become the rear brake line on the KLE)

[mrclubike]

I ask because I checked with an outfit here in the states which sells Moto Guzzi parts at a MUCH lower price than seen elsewhere, and tried to order rebuild kits for my R65LS calipers, but was told "No, all our calipers are 38 mm so we can't help you."  The price difference was significant, like $14 vs $43.  The firm is found at MGcycle.com, I believe.

But you can fit a New complete Brembo F08 caliper from them
Then you have a 38mm caliper that is brand new and cheap to overhaul in the future
It is a direct fit no mods needed
That is what I did 

[Tony Smith]

If anyone is interested the Chinese sourced braided lines did not fail at 1,000psi. My mate with the test rig wanted to ramp up to failure point but I couldn't see that any worthwhile data would have been gleaned - I read once that bike hoses never see the bright side of 600psi.

Just as well they passed cause I'd already fitted the front one, I guess I'll go ahead and fit the rear now.

I do intend to watch them carefully but my thinking is that they have to be safer than 27 year old rubber hoses.

[Barry]

I did an experiment of sorts with a rubber hose to determine if they expand under pressure.

I had someone measure the outside diameter of the hose in several locations with digital caliper while I pulled as hard as possible on the brake lever with two hands, much harder than would be possible under actual braking.  I suppose it was two experiments as it also pressure tested the brake system.

No matter how hard I tried there was no measurable expansion of the rubber hose. It would have been much better to do this on a test rig under controlled conditions but it did make me question whether I really needed braided hoses. I know that brake hoses are a multi layer construction with the outer layer only really for abrasion resistance. I wonder if that is true of braided hoses as well as rubber, the real expansion resistance being a layer down surrounding the inner core.

[davidpdx]

  Yesterday I got my friend Bill to help me install my new Spiegler stainless steel braided brake hoses from the master cylinder to my front brakes and new high metal brake pads. These brake pads don't include nickel which is linked to cancer, who knew. It's almost like god didn't intend for us to inhale metal dust. I took the bike for a short ride after we bled the brakes (speed bleeder made it easy, thanks Rob) and I could tell that the brakes were improved but not as drastically as I had hoped. It takes a while for the new pads to seat in according to the package so I am hoping that they will continue to improve but we will see. Pretty easy job that took us altogether about two hours.

[mrclubike]

Have you checked your master cylinder bore size
It is stamped on the bottom of it
My bike had to big of a master cyl when I got it 

[davidpdx]

I will check. what size should it be?

[Tony Smith]

I will check. what size should it be?

If you have a single disc - 12mm, but if you have twin discs it should be 13mm.

BUT, these things are old now and the master cylinder may well have been re-sleeved. The only definitive way to be sure is to measure the bore. For example my wife particularly wanted a "round " master cylinder to keep her R65/80 "more original" (its got an R80 engne for God's sake!) Anyway, you couldn't buy a 13mm round master cylinder as they were becoming extinct at the time, so she bought a 12mm and I bored and sleeved it.

[tiggum]

Just as an example, my '83 R65LS (2 Brembo 36mm calipers) came originally with a 15 mm master cylinder, which was totally corrupted by years of sitting while still full of fluids.  I am replacing it with a NOS 14 mm master cylinder I bought from a friend.  I doubt that a change of 1 mm diameter will make too much difference (In this case, a slightly longer stroke of the lever and maybe replacing the pads sooner than one ordinarily would).

[wilcom]

I doubt that a change of 1 mm diameter will make too much difference

let us know......I'm betting you will feel quite the difference

[davidpdx]

I took a look this afternoon and it had 15 stamped on it. Maybe I am making this too simple but it seems like a larger master cylinder would put more pressure on the caliper stopping the bike quicker. No?    

[Tony Smith]

I took a look this afternoon and it had 15 stamped on it. Maybe I am making this too simple but it seems like a larger master cylinder would put more pressure on the caliper stopping the bike quicker. No?    

No.

In fact quite the reverse. Hydraulic ratios are a bit like gears - if you want high speed and less torque you have a larger gear driving a smaller gear. OTOH, if you want lower speed but higher torque you drive the bigger gear with the smaller.

So, smaller master cylinder will pump less fluid to the calipers, but will be able to raise a higher pressure in the brake line for a certain amount of applied grip from your hand.

My R65 that now wears a K100 front end has 38mm calipers and a 12mm master cylinder. I am aware of the power of the brakes and have adapted to them. I do not allow anyone else to ride that bike unless I talk to them about the front brakes and have confidence in their experience/skills.

For the record, I can lock up the front wheel (with a 100/90 tyre on it) with my little finger alone. If I was honest it is a bit dangerous as if I forget and grab a handful of brake in a panic I am going to be in a world of hurt.

[davidpdx]

Tony, Thanks for the explanation. I guess I will be in search of a 12mm master cylinder. I am not planning to do any stoppies but I would like it better if I could depend on my front brakes stopping me as quickly as possible.

[Matt Chapter]

I guess I will be in search of a 12mm master cylinder.

If a 15 mm was original equipment, going to a 12 mm would be too far.  If you've added a disc, then perhaps a 12 mm would be suitable.  If you want more brake pressure for the same amount of finger exertion, a 14 mm is probably more in line with what you want, bearing in mind that have some progression between "no braking" and "all braking" is nice.

I can't tell from your picture if you have dual discs or not, if you do, it may be worthwhile to see what the OEM configuration for a dual disc setup is.

[davidpdx]

I also wounder about how difficult it is to re-sleeve it down to a smaller size as I have a good working master cylinder now.