Airhead front brakes

Captain Black · May 1, 2016

I'm on a roll

So GSPD 100 and GS 80 Basic.

Many folk say the brakes are shite .. :nenau

Me ?

I just think of them as old technology and pull the lever harder, seems to work for the most part, that and a bit of forward planning.

So I'm fettilng a bit here and a bit there as I may go old school for theTT this year. :augie

Anyways ... Was going to change my DOT 4 for some fresh, and thought ey up what about stainless brake line on my single front pot ? :nenau

Would it make a marked difference ? It probably needs changing through age anyways..

Anyone done it ? What type of line did you use ? :nenau

ChasF · May 1, 2016

Not having to pull so hard means you have more feel which iI find makes the whole experience a lot less testng

http://www.bmwboxersupplies.com/brakedisc-320mm-p-32.html

Captain Black · May 1, 2016

ChasF said:
Not having to pull so hard means you have more feel which iI find makes the whole experience a lot less testng

http://www.bmwboxersupplies.com/brakedisc-320mm-p-32.html

Thanks Chas, want to try and keep the bike OE.

Call me old fashioned ...

Gyp · May 1, 2016

Err... If you go for stainless it won't be OE.

Live a little

Sent from my Nexus 6 using Tapatalk

solidstate100 · May 1, 2016

I have upgraded my G/S to Goodrich stainless flexi, HE 320 brake disc, carbon ceramic pads and a master cylinder and caliper rebuild, and the difference between the 30 year old OE is night and day.

Like you I was going to keep it OE but using the bike daily in modern traffic just wasnt doing it - I nearly had 3 or 4 proper serious rear end crashes where there just wasnt enough stopping power in those emergency situations - no amount of forward planning or anticipation was enough.

Kenny · May 1, 2016

It's a wonder they haven't all been written off by now then !

Beemerboff · May 2, 2016

Last test I read in Bike mag new SS lines made little difference even when replacing shagged out 15 year old OEM lines.

What made the big difference was getting a decent master cylinder / lever set up. Harder on airhead as you have to change the switch too, but the best/ cheapest way to go if you need the power.

For some reason BMW usually stuffed up the master cylinder ratio by a long way, and having your existing set up sleeved down to 11 mm makes a decent difference to most bikes. Moto Guzzi used an 11mm with a twin disk set up with two 50mm GS style calipers and it worked reasonably well. No problems with lever movement if you take a little care to reduce the free play when fitting the new MC.

BMW ALSO fitted perches with short levers with little leverage too, modern levers have a mechanical advantage somewhere between 17 and 20, most BMW are around 8 or 9.

The disks fitted to 21 '' wheels are too small as well, so you loose more leverage here, and oversize disks help a lot.

There are much better pads around today than OEM, most HH pads will be a big improvement, and they actually get better as they heat up, so the small pads in the OEM calipers can work better than larger twin or triple piston jobs with larger pads which dont heat up enough.
My G/S has a 11 mm MC, modern rubber line, OEM caliper, 320 mm disk and Armstrong HH pads and I have no trouble locking the front wheel.
My GS has a 12 mm MC, SS line, Toxico 6 piston caliper, and HH pads working on the standard disk. It doesn't work as well as the G/S set up so I am speaking from hands on experience!

Captain Black · May 2, 2016

Beemerboff said:
Last test I read in Bike mag new SS lines made little difference even when replacing shagged out 15 year old OEM lines.

What made the big difference was getting a decent master cylinder / lever set up. Harder on airhead as you have to change the switch too, but the best/ cheapest way to go if you need the power.

For some reason BMW usually stuffed up the master cylinder ratio by a long way, and having your existing set up sleeved down to 11 mm makes a decent difference to most bikes. Moto Guzzi used an 11mm with a twin disk set up with two 50mm GS style calipers and it worked reasonably well. No problems with lever movement if you take a little care to reduce the free play when fitting the new MC.

BMW ALSO fitted perches with short levers with little leverage too, modern levers have a mechanical advantage somewhere between 17 and 20, most BMW are around 8 or 9.

The disks fitted to 21 '' wheels are too small as well, so you loose more leverage here, and oversize disks help a lot.

There are much better pads around today than OEM, most HH pads will be a big improvement, and they actually get better as they heat up, so the small pads in the OEM calipers can work better than larger twin or triple piston jobs with larger pads which dont heat up enough.
My G/S has a 11 mm MC, modern rubber line, OEM caliper, 320 mm disk and Armstrong HH pads and I have no trouble locking the front wheel.
My GS has a 12 mm MC, SS line, Toxico 6 piston caliper, and HH pads working on the standard disk. It doesn't work as well as the G/S set up so I am speaking from hands on experience!

That's interesting stuff .

I don't want to go to all the trouble and expense for what is an occasional ride. That said I might nail it over the mountain at the TT on it this year.

I'm tempted to go for a new SS brake line and new pads and see how I go. Even the brake bleed on set up may make a slight difference.,the lever does feel soft, but that's maybe against a mire modern set up, ie my GS1150A . If that is indeed classed as modern these days., :blast

ianboydsnr · May 2, 2016

Beemerboff said:
Last test I read in Bike mag new SS lines made little difference even when replacing shagged out 15 year old OEM lines.

What made the big difference was getting a decent master cylinder / lever set up. Harder on airhead as you have to change the switch too, but the best/ cheapest way to go if you need the power.

For some reason BMW usually stuffed up the master cylinder ratio by a long way, and having your existing set up sleeved down to 11 mm makes a decent difference to most bikes. Moto Guzzi used an 11mm with a twin disk set up with two 50mm GS style calipers and it worked reasonably well. No problems with lever movement if you take a little care to reduce the free play when fitting the new MC.

BMW ALSO fitted perches with short levers with little leverage too, modern levers have a mechanical advantage somewhere between 17 and 20, most BMW are around 8 or 9.

The disks fitted to 21 '' wheels are too small as well, so you loose more leverage here, and oversize disks help a lot.

There are much better pads around today than OEM, most HH pads will be a big improvement, and they actually get better as they heat up, so the small pads in the OEM calipers can work better than larger twin or triple piston jobs with larger pads which dont heat up enough.
My G/S has a 11 mm MC, modern rubber line, OEM caliper, 320 mm disk and Armstrong HH pads and I have no trouble locking the front wheel.
My GS has a 12 mm MC, SS line, Toxico 6 piston caliper, and HH pads working on the standard disk. It doesn't work as well as the G/S set up so I am speaking from hands on experience!

I thought the master cylinders on old guzzis only operated the right front,

I use a Yamaha ybr125 master on my front LM2, works great, the left is linked to the back brake.

Myke Rocks · May 2, 2016

Captain Black said:
Anyways ... Was going to change my DOT 4 for some fresh, and thought ey up what about stainless brake line on my single front pot ?

Would it make a marked difference ? It probably needs changing through age anyways..

Yes, it would make a marked difference - Brake even worse.
The reason is difficult to understand, but logical.
The original brake pipes are supposedly rubber, and when you squeeze the lever, they bulge slightly.
The stainless ones do not do this.
The effect of the bulging is to act in an manner which may be interpreted in one of two ways:
Way 1. The bulging effectively improves the poor mechanical advantage already referred to in other posts.
Way 2. It acts as a servo effect.
Take it either way, but either way, a stainless hose with the existing master cylinder will make your already extremely heavy brake even heavier.
Myke

Beemerboff · May 3, 2016

My G/S came with a twin pot caliper fitted and the original as a spare. The twin pot had stock pads, and it was also managing to draw air without leaking enough to be noticable.

When I finally found the problem I replaced it with the original single pot with HH pads.

To my surprise the stopping power was a big improvement on the twin pot.
The lever is solid, with not a lot of feel but the power is great.
Disk brakes are linear, the harder you squeeze the more stopping power, so the smaller pads dont loose much as your force is concentrated on a smaller area and the pressure between the pad and the disk increases in direct proportion to the decreased area.
They will get hotter, of course, which might be a problem with obsolete organic pads which loose power as they heat up, but new sintered pads like HH types actually improve as they get hotter, and as they start off better anyway they end up a long way in front.

There was a time when most hot sport bikes had big six piston calipers, but they are now the exception, and much smaller two pots rule, probably for this reason.

Brake lines are a bit like progressive springs,most folks that fit them seem to get the result they want, folks that test them on a rig usually get a completely different result.

oldnfat · May 3, 2016

Well, I have been down the route of stainless steel and ceramic pads with a recondition MC. Made a bit of difference but not much. The issue as has been said is the ratio of wheel size to disc. The only way to really overcome this is go for the larger disc conversion.

I to wanted to keep the bike as original as possible but in the end decided that keeping my face OEM took a higher priority.

solidstate100 · May 3, 2016

oldnfat said:
I to wanted to keep the bike as original as possible but in the end decided that keeping my face OEM took a higher priority.

Which is the main reason I carried out the various upgrades that I did.

Just as an experiment, (see Myke Rocks post above) I have this very evening refitted my OEM rubber hose just to revisit what the difference is, stainless verses rubber. (i have the disc upgrade and ceramic pad thing going on)

I shall report back in a day or so once I have had a ride out

airhead_eire · May 4, 2016

oldnfat said:
.....................but in the end decided that keeping my face OEM took a higher priority.

Brilliant !!

Ogmios · May 4, 2016

Captain Black said:
...
So GSPD 100 and GS 80 Basic.

Many folk say the brakes are shite ..

Me ?

I just think of them as old technology and pull the lever harder, seems to work for the most part, that and a bit of forward planning.
...

I agree with you.
I know - i'm surprised too. :blast

Anyhow,
i cant be this nice for long, so - to derail your thread; :green gri

Dear collective,
If i "unlink" my Guzzi brakes* - can i get away with just that - new brake lines and no fecking about with new different size master cylinder? :nenau

*i.e: front brake lever = one front disc. "rear" brake pedal = one front disc + the rear disc.

Thang queue in advance.

cookie · May 4, 2016

You're supposed to use a smaller master cylinder on the front, but many people don't bother and say it's fine as is. I have no direct experience.

Ogmios · May 4, 2016

Cookie,

Thank you.
That's what i thought - and it would be hard to find a smaller master cylinder than what's fitted now anyhow.

chrisshrops · May 4, 2016

the front brake setup is cack on the gs i would put a better caliber on if I were you.
on my rt i have a pair of 1200t 4 pots with stainless hoses rebuilt the stock master cylinder, the result is great feel and lots of stopping power ,you never know when you need to stop in a hurry mate

cookie · May 4, 2016

Ogmios said:
Cookie,

Thank you.
That's what i thought - and it would be hard to find a smaller master cylinder than what's fitted now anyhow.

oops, sorry - that should have read LARGER master cylinder as it will have more fluid to push around with two calipers :blast

people used to use the unit from ducatis and laverdas to maintain originality, but they will all be long gone now. new, oblong units are available.

what i said about people just using the existing caliper is true though. must be worth connecting it and trying before spending out on a new M/C i'd have thought.

ianboydsnr · May 4, 2016

cookie said:
oops, sorry - that should have read LARGER master cylinder as it will have more fluid to push around with two calipers

people used to use the unit from ducatis and laverdas to maintain originality, but they will all be long gone now. new, oblong units are available.

what i said about people just using the existing caliper is true though. must be worth connecting it and trying before spending out on a new M/C i'd have thought.

It should work fine,

I converted my single disc R80RT to twin disc using the original master cylinder and it worked much better, with plenty of feel and only a little more travel.

Airhead front brakes

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