LCGB Forums

The ability to post messages is restricted to LCGB members. Any questions contact us at lcgbadmin@googlemail.com

Reverse pull brake

Need help with a tuning kit, how do you tune your scooter, which kit should I choose, and all general tuning and modifcations questions are for in here.

Reverse pull brake

Postby SlackerThePinstriper » Mon Aug 08, 2022 6:36 am

I'm juat about to send my front brake arm off for engraving, I intend to use it as a reverse pull.
Am I correct in thinking the arm gets flipped for reverse pull?

So from this
Image

To this?
Image
User avatar
SlackerThePinstriper
 
Posts: 838
Joined: Thu Jan 05, 2017 4:32 pm

Re: Reverse pull brake

Postby Storkfoot » Mon Aug 08, 2022 7:24 am

No, it stays the same way. Bottom photograph is right.
User avatar
Storkfoot
 
Posts: 2102
Joined: Fri May 30, 2014 8:59 pm
Location: Merseyside

Re: Reverse pull brake

Postby SlackerThePinstriper » Mon Aug 08, 2022 7:47 am

Storkfoot wrote:No, it stays the same way. Bottom photograph is right.


Nice one, cheers for that.

What does it involve then?
User avatar
SlackerThePinstriper
 
Posts: 838
Joined: Thu Jan 05, 2017 4:32 pm

Re: Reverse pull brake

Postby landybretta » Mon Aug 08, 2022 9:06 am

Is this for disc or drum brakes?
May be of interest.
viewtopic.php?f=22&t=11819
User avatar
landybretta
 
Posts: 730
Joined: Thu Jun 05, 2014 10:22 pm

Re: Reverse pull brake

Postby hullygully » Mon Aug 08, 2022 10:12 am

you could also use a clutch lever, longer than brake one, larger pivot 8-)
hullygully
 
Posts: 1970
Joined: Thu Jun 05, 2014 1:28 pm
Location: Hull

Re: Reverse pull brake

Postby SlackerThePinstriper » Mon Aug 08, 2022 10:55 am

landybretta wrote:Is this for disc or drum brakes?
May be of interest.
viewtopic.php?f=22&t=11819


Yeah it's drum, don't want to risk it being too sharp/dangerous.

Will just leave it I think
User avatar
SlackerThePinstriper
 
Posts: 838
Joined: Thu Jan 05, 2017 4:32 pm

Re: Reverse pull brake

Postby gaz_powell » Mon Aug 08, 2022 12:59 pm

http://www.ilambretta.co.uk/reverse.html

Im using reverse pull on drum on two bikes and like it. Will be doing the same on the new project
gaz_powell
 
Posts: 3074
Joined: Sat May 31, 2014 7:56 pm
Location: Hartlepool

Re: Reverse pull brake

Postby dickie » Mon Aug 08, 2022 5:21 pm

I'm a big fan of a reverse pull drum. WAY better than any other cable brake.

However, I have found that LI cams are better than GP type. The GP type give too much shoe movement for lever travel and make the brakes too harsh for me.

Using a longer lever like a clutch or better still, a late Spanish one will give more power and reduce the any harshness.
dickie
 
Posts: 1746
Joined: Thu Oct 02, 2014 12:32 pm
Location: Tyne and Wear

Re: Reverse pull brake

Postby tv175lambretta » Mon Aug 15, 2022 10:37 am

To point out the bleeding obvious...

The brake lever doesnt know whether it is being pulled from the right or pushed from the left. The brake mechansim itself is completely unchanged so isnt suddenly going to 'grab' more when used in reverse pull (ie push).

The only difference to changing to reverse pull is a more direct cable routing leading to lower cable friction and therefore a smoother more sensitive 'feel' for the brake, with less pulling effort needed on the handlebar brake lever.

If the shoes are worn out, and there is a risk of the cam locking, that's the same either way you route the cable.

But if you want to keep loads of friction in the cable route thats up to you. If you like to pull harder for less braking effort, then keep the original. Why not introduce a whole extra 360 degree loop in the cable if its better that way?!
User avatar
tv175lambretta
 
Posts: 22
Joined: Sat May 31, 2014 8:55 pm

Re: Reverse pull brake

Postby Warkton Tornado No.1 » Mon Aug 15, 2022 7:51 pm

tv175lambretta wrote:To point out the bleeding obvious...

The brake lever doesnt know whether it is being pulled from the right or pushed from the left. The brake mechansim itself is completely unchanged so isnt suddenly going to 'grab' more when used in reverse pull (ie push).

The only difference to changing to reverse pull is a more direct cable routing leading to lower cable friction and therefore a smoother more sensitive 'feel' for the brake, with less pulling effort needed on the handlebar brake lever.

If the shoes are worn out, and there is a risk of the cam locking, that's the same either way you route the cable.

But if you want to keep loads of friction in the cable route thats up to you. If you like to pull harder for less braking effort, then keep the original. Why not introduce a whole extra 360 degree loop in the cable if its better that way?!


In any case, the preferred outer cables should be wound with a rectangular section wire, not round as is the case with speedo cables.

Besides the mechanical advantage pointed out, there is yet another advantage to the shorter, more direct reverse pull. It has been referred to as a 'servo' effect for want of a better term, but it is nothing of the kind. What actually occurs is that as the suspension compresses, the whole cable from where it exits the fork crown gets bent. This has the effect of pulling the coils of the outer cable slightly more apart on the larger radius side, which in turn means the inner cable is stretched within it even more.

For that reason, the reverse pull cable set up, whether disc or drum, is best assembled with as straight a run from crown to lever. It almost wants to be 'too short' to gain the best result though rebound of the suspension needs to be taken into account as that will result in the brake operating unintentionally when cresting hump back bridges or popping wheelies outside the local Wimpy....
Warkton Tornado No.1
 
Posts: 2112
Joined: Sun Jan 11, 2015 1:27 pm

Re: Reverse pull brake

Postby GExS » Fri Aug 19, 2022 3:02 am

On a related solution, I see Steelweasl the YouTuber that posts about Lambretta's, mostly good stuff, posted about putting a small pulley wheel near the hub lever to aid the braking. It looked to work on the video but I don’t quite understand the physics.
The best front brake set up I’ve ever had was using a reverse pull with a reshaped clutch level.
GExS
 
Posts: 50
Joined: Sat Aug 15, 2020 8:08 pm

Re: Reverse pull brake

Postby hullygully » Fri Aug 19, 2022 11:23 am

GExS wrote:On a related solution, I see Steelweasl the YouTuber that posts about Lambretta's, mostly good stuff, posted about putting a small pulley wheel near the hub lever to aid the braking. It looked to work on the video but I don’t quite understand the physics.
The best front brake set up I’ve ever had was using a reverse pull with a reshaped clutch level.

+1
hullygully
 
Posts: 1970
Joined: Thu Jun 05, 2014 1:28 pm
Location: Hull

Re: Reverse pull brake

Postby Warkton Tornado No.1 » Fri Aug 19, 2022 2:33 pm

GExS wrote:On a related solution, I see Steelweasl the YouTuber that posts about Lambretta's, mostly good stuff, posted about putting a small pulley wheel near the hub lever to aid the braking. It looked to work on the video but I don’t quite understand the physics.
The best front brake set up I’ve ever had was using a reverse pull with a reshaped clutch level.


I've seen most of his videos including the pulley. As front braking is the topic, he recently posted a video showing his solution to an overheating hydraulic caliper. I doubt that the racing lads have their fluid boil simply because they'll be using something like https://msdspds.castrol.com/bpglis/Fusi ... BGV7RW.pdf as I used to which completely eliminates fade.

What the pulley achieves in the video is halving the cable pull but it doubles the power from the 'bar lever. Theoretically it should endow the brake with more feel, but that has been discussed in this thread & fitting the longer crankcase cover clutch lever is a far easier option, if that is what is required. IMO the longer lever option completely overcomes the frictional losses of the pulley system & is not a complex solution by comparison.
Warkton Tornado No.1
 
Posts: 2112
Joined: Sun Jan 11, 2015 1:27 pm


Return to Tuning & Kits

Who is online

Users browsing this forum: No registered users and 12 guests