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Brake Link Front/Rear

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GC888 View Drop Down
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    Posted: 23 Oct 2017 at 16:24
My thoughts are currently to cut the front /back combination link. 

Reasoning - is it a bit of a 'gimmick' and when I have ridden a v50 previously I never liked the sensation/thought of the rear brake going on with the front. Generally good or bad habit there are situations where I just want the front by itself.       

So is this just a case of plumbing or more?

Leaver to both front discs, pedal to rear disk only. 

Who else has done this are there any issues? 

Thanks 


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stuv65 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote stuv65 Quote  Post ReplyReply Direct Link To This Post Posted: 23 Oct 2017 at 18:39
I find it quite handy to just use my foot to slow down and leave my throttle hand free.

I have replaced the brake pipes on my V65 (made my own - dead easy) but kept them linked.

I don't know if the front master cylinder is man enough to run two calipers and I don't know it just running one caliper from the rear master cylinder will make it too powerful.

Personally I wouldn't going to the effort & expense but entirely your choice :-)

I expect someone on this forum has unlinked their brakes and will be along shortly to comment.

ta
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Dodge View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Dodge Quote  Post ReplyReply Direct Link To This Post Posted: 23 Oct 2017 at 18:59
Linked brakes is the norm with cars. Rear wheel braking on any vehicle is not effective. The 75/25 system on Guzzi's gives you really powerfull braking. Use normal front brake (right hand) for most situations and if you have to slow down rapidly you can stomp on the rear brake and know that you are going to slow down as safely as possible.

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GC888 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote GC888 Quote  Post ReplyReply Direct Link To This Post Posted: 23 Oct 2017 at 19:50
stuv65 - the pipes being shot and needing replacement is a good reason I am considering changing the linkage.

Master cylinder... if its ok to go 75/25 front rear its good to go 50/50 front. However that asks a new question does it need two disks? As with the rear you can only squeeze so hard before it locks!!!  
Have run several bikes with just one disk that are similar weights (several with more power)

Dodge - Agree that rear wheel braking is not effective which is why I only use it to steady rather then slow, more often than not just letting it drag a gear works better. 

Stomping on the back gives me the shivers, I don't like high sides :-) 
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Mike H View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mike H Quote  Post ReplyReply Direct Link To This Post Posted: 23 Oct 2017 at 20:14
What model bike is it?

New designs having single disc often tend to have more powerful calipers e.g. 4 pistons, and longer bigger pads, so logically the old 2-piston ones would need 2 sets with 2 discs to get the same sort of braking power. That's my thinking anyway.



"Chicken nuggets don't dance on a Tuesday."
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Brian UK View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 23 Oct 2017 at 20:36

Firstly the linked brakes are definitely not a gimmick. They work extremely well, but were always rubbished by the UK press who had never seen anything like it before and therefore it must be rubbish.

Rant over.
 
But to delink the brakes - many have done it - you will have to increase the diameter of the front master cylinder, and probably decrease the diameter of the rear one.
 
You will also have to get new brake lines made up, you won't get anything off the shelf.
You could of course, get a set of hoses for the standard brakes from several suppliers.
Brian.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Hbhonda Quote  Post ReplyReply Direct Link To This Post Posted: 23 Oct 2017 at 22:13
My Honda cbf1000 has linked brakes, so if Hondasan does it then it's not a gimmick. Stick with it
Honda CBF 1000 2000 Cali EV (in bits)(not any more)
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GC888 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote GC888 Quote  Post ReplyReply Direct Link To This Post Posted: 24 Oct 2017 at 08:33
Still not sure - all my experience points to needing independent front and rear brakes. 
 
I'm into new brake lines anyway so thats not barrier. 

So who on here has actually delinked the brakes what issues were found or not?

Brian - hear what your saying; will look into disc diameter swept area and wight to check.   

Hbhonda - yes but Hondasan also sold cars with captive brake discs Wink

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Dukedesmo Quote  Post ReplyReply Direct Link To This Post Posted: 24 Oct 2017 at 09:32
I de-linked the brakes on my LM2 (Blasphemy, I know) as I couldn't get on with the front lever (1 disc only) not giving any decent stopping power plus, I wanted all my bikes the same as that's what I'm used to.

I can still use rear and front brakes together so I don't see any downside but now I've got a strong front brake - and given the age they are surprisingly good!

To do it I needed a larger front master cylinder, I fitted a Brembo RCS15 (15mm) which is perfect for the job and at the rear I needed a smaller master cylinder and found a smaller (12mm) version of the same Brembo unit as fitted to various Ducati etc. of the era. Custom brake lines and a full overhaul; new pistons (old ones were corroded), seals and pads and the brakes are now very good indeed.


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Brian UK View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 24 Oct 2017 at 10:27
That's about what others have done.
 
It's all about the ratio between the master cylinder cross sectional area and the total area of the calliper pistons. If you add another calliper then that ratio is not going to be right, the same happens if you remove a calliper.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ken-Guzzibear Quote  Post ReplyReply Direct Link To This Post Posted: 24 Oct 2017 at 12:10
I can see the point of de linking on a sporty bike IF you are taking it on track days BUT the system was revolutionary in the 70's. A while ago when I was an instructor, before ABS on bikes, My fellow instructors and 2 Police riders decided to test it on a controlled off road area.
the area was used for CBT's we put marker cones and against other bikes got up to 30 then 40 and finally 50 mph hit the brakes at the cones marked the stop.
OK there was maybe a slight fluctuation in reaction times BUT the 2 Police riders were so impressed they begged a shot on the V1000 ....

The V1000 was stopping a whole bike length quicker with All brakes , just rear ones more than a bike length and just front only it was up to half a bike length longer EXCEPT at the 40 mph where one guy lifted his rear wheel "foul" was yelled ....control issue, but he was a full bike length on fronts only ...... this WAS in the 1980's
I do know Nick's V50 out braked Annies Virago due to linked brakes ....The V1000 is similar to the T3 and other Tourer/Cruisers from Guzzi, nowadays the ABS etc is way better but from my own experience the linked system allows shorter stopping distances, greater control and less dive ......your bike your choice IF you find braking lacking fit new braided hoses, change fluid , reverse bleed the system ans older Brembo calipers can trap air behind them, then fit good Ferodo or EBC pads .....
The Older i Get, The Better I Was
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Post Options Post Options   Thanks (0) Thanks(0)   Quote iansoady Quote  Post ReplyReply Direct Link To This Post Posted: 24 Oct 2017 at 12:19
There's a lot about this on Guzziology and all makes sense.

To start with, braking effort is not 75/25 as there is no proportional valve in the system. The only thing affecting front / rear ratio is the slightly different disc diameter which will make no more than a 10% difference. All 3 calipers are identical.

I don't now, and didn't when I had a V50 in the 80s, like the wooden front brake so have sourced a Honda Silverwing master cylinder which has an 11mm bore as opposed to the 12.7mm (1/2") which is standard. My V50 has the handlebar mounted master cylinder. With this change I would expect to use the footbrake (still linked) for everyday slowing but have an effective front brake to add to it when I want it.

Other changes I'm considering are different pads but I can find no data on friction coefficients of different pads. Anybody?
Ian
1982 V50
1952 Norton ES2
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 24 Oct 2017 at 12:42
Some of the later big block models do have proportioning valves, but don't think they ever bothered with the small block.
 
I have to say on my Spada III which did have a proportioning valve, I was never that impressed with the linked brake, but the single front was amazing.
Brian.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote GC888 Quote  Post ReplyReply Direct Link To This Post Posted: 24 Oct 2017 at 20:04
Originally posted by Ken-Guzzibear Ken-Guzzibear wrote:

I can see the point of de linking on a sporty bike IF you are taking it on track days. 

Originally posted by Dukedesmo Dukedesmo wrote:

I wanted all my bikes the same as that's what I'm used to.


I think this sums up my feelings quite well 
  1. wanting everything to be the same.
  2. if I ever over cook a corner I want independent control of both brakes.  
In a straight line I am sure that the system will work better at stopping me sooner.

Useful info on piston sizes as the cost in not prohibitive I may give the combined system a go before going indy if I can't get on with it.

Thanks again 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Dodge Quote  Post ReplyReply Direct Link To This Post Posted: 24 Oct 2017 at 21:16

I definitely recall reading somewhere that the foot braking on my LM3 was 75/25. Plus, the front left pads (rear brake operated) wore far quicker than the rear pads which, to me, indicates that the braking effort is front loaded. There was a certain learning curve with the LM braking but overall I felt that the stopping power was very controlled. I never managed to lock the rear wheel even on a fairly hairy deceleration into Creg ny baa with a fallen rider sliding down the road in front of me.

 

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