smallframe rear brake conversion I did
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05 PX, 80P200, 63Li150, to many others
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Location: New Orleans, LA
Sat Jun 22, 2019 7:19 am quote
I am rebuilding my friend's smallie. Just a seal job, but while the engine was out and we were fussing with a few items I started thinking about the similarities of the rear brake set up to a P and wondered if there was a conversion to use the T5 brake cable. SIP makes this conversion for the P, if you don't know what I'm talking about check it out.

https://www.sip-scootershop.com/en/products/conversion+kit+brake+cable_j50015000

I love this kit. I've put it on several P's and its the best mod for 25 bucks! Anyway, the big difference in the smallframe is the rear brake lever in the hub. There was nothing I could find for the smallframe so I ordered the kit and a SIP made smallie lever. I measured, cut, and welded. Sorry for the lack of pics but I got it all installed last night. Looks great, works perfectly. No more struggling to get the tension on the cable right.

Just thought I'd share.

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IMG_0467.jpg

Veni, Vidi, Posti
74 50s x2 78 P200 84 Cosa 58 AllState 68 Sprint 80 50special + projects
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Sat Jun 22, 2019 7:41 am quote
That's great!
Molto Verboso
Joined: 26 Oct 2015
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Sat Jun 22, 2019 11:26 am quote
Thumbs up JoeP! Iíve done that conversion to 4 of my Pís. I had also been wanting to figure out a way to do it on my PK as well. Now that you gave me direction, this will be my next mod to my smally.
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1974VLB 1979VSX 1974V9A
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Sat Jun 22, 2019 3:23 pm quote
Lambretta style.
Molto Verboso
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Sat Jun 22, 2019 3:51 pm quote
PureDrivenSnow wrote:
Lambretta style.
Yes, except for 50% of the Lambrettas, the rear brake is about 50% functional about 50% of the time. The T5 cable conversion is legit 100% of the time every time.
Molto Verboso
Joined: 26 Oct 2015
Posts: 1570

Sat Jun 22, 2019 9:29 pm quote
Joe, which replacement rear lever did you use? It looks like your scoot might have the early 4 bolt brake drum(?), but it almost looks like the SIP lever that you used to cut down is the PK version?

PV version- https://www.sip-scootershop.com/en/products/brake+cam+sip+rear+for+vespa+_78366000

PK version- https://www.sip-scootershop.com/en/products/brake+cam+sip+rear+for+vespa+_21593700


I did a quick mock up of a T5 brake drum arm on my PKXL last winter, but it didnít look like it would line up very well. I think I might have a couple of those T5 cable kits in my shop. If so, and if I get some time tomorrow, Iíll take a second look at making the conversion happen.
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74 Super, 75 Super, PX project, LML off-roader and new to 2018, '66 Blue Badge Smallframe
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Sun Jun 23, 2019 4:01 am quote
Nice.
Hooked
05 PX, 80P200, 63Li150, to many others
Joined: 02 Dec 2008
Posts: 386
Location: New Orleans, LA
Sun Jun 23, 2019 2:12 pm quote
https://www.sip-scootershop.com/en/products/brake+cam+sip+rear+for+vespa+_21593700

This was the brake lever I used. Lines up perfect. With the wheel on the threaded end of the cable sits fairly close to the inside of the rim but totally works.
Molto Verboso
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Posts: 1570

Sun Jun 23, 2019 2:56 pm quote
JoeP wrote:
https://www.sip-scootershop.com/en/products/brake+cam+sip+rear+for+vespa+_21593700

This was the brake lever I used. Lines up perfect. With the wheel on the threaded end of the cable sits fairly close to the inside of the rim but totally works.
Well, that would be the PK version that you used then. I just searched my parts shelves, and i did find a couple T5 cable kits (and the T5 lever arm) that i have (gathering dust of course)! I'm hoping to get around to doing your coversion sometime this week. I think most people don't know just how much more easy (and quicker) it makes it to remove the engine from the frame when using a T5 rear brake cable.
Hooked
05 PX, 80P200, 63Li150, to many others
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Location: New Orleans, LA
Sun Jun 23, 2019 3:22 pm quote
Pic with the rim and tire.

IMG_0474.jpg

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Mon Jun 24, 2019 1:27 am quote
sweet.
Veni, Vidi, Posti
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Mon Jun 24, 2019 2:13 am quote
There's also a different adjuster nut that doesn't require a wrench.


Seen this on a T5, but don't know if it's stock.
Molto Verboso
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Mon Jun 24, 2019 11:33 am quote
V oodoo wrote:
There's also a different adjuster nut that doesn't require a wrench.


Seen this on a T5, but don't know if it's stock.
Hey Voodoo,
that thumb style knurled thumb turn knob actually came on the front T5's brake, and not the rear. I think the rear only got that hex head adjuster nut (it has a 10mm head). I think it would be more convenient to have that thumb screw in the rear. Maybe the reason Piaggio didn't use it there was because it's a likely area for corrosion? I haven't had any issues with turning that adjuster nut with my fingers, but i keep my scooters pretty darn clean. The front and rear brake cable threaded ends are different diameters, so it's not possible to use that front thumb screw (5mm) on the rear brake cable (6mm).

I did notice that the Piaggio cylindrical barrel and adjuster nut that slips on the rear cable is the same at the one that Honda uses on their older CB street bikes (same dimensions at on my sister's '81 CB400T Hawk), but for half the price. Maybe one of these days i'll come across a proper thumb turn adjuster nut (like the one in your pic), but for now, i havn't had the need for one.

I've tried using the rear brake thumb ajuster from off my Lammy, but the dimensions are all wrong. I suppose enough time on a lathe, and that Lammy nut would fit, but i'd rather find one that's ready to go.
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Thu Jun 27, 2019 12:02 pm quote
whodatschrome wrote:
V oodoo wrote:
There's also a different adjuster nut that doesn't require a wrench.


Seen this on a T5, but don't know if it's stock.
Hey Voodoo,
that thumb style knurled thumb turn knob actually came on the front T5's brake, and not the rear. I think the rear only got that hex head adjuster nut (it has a 10mm head). I think it would be more convenient to have that thumb screw in the rear. Maybe the reason Piaggio didn't use it there was because it's a likely area for corrosion? I haven't had any issues with turning that adjuster nut with my fingers, but i keep my scooters pretty darn clean. The front and rear brake cable threaded ends are different diameters, so it's not possible to use that front thumb screw (5mm) on the rear brake cable (6mm).

I did notice that the Piaggio cylindrical barrel and adjuster nut that slips on the rear cable is the same at the one that Honda uses on their older CB street bikes (same dimensions at on my sister's '81 CB400T Hawk), but for half the price. Maybe one of these days i'll come across a proper thumb turn adjuster nut (like the one in your pic), but for now, i havn't had the need for one.

I've tried using the rear brake thumb ajuster from off my Lammy, but the dimensions are all wrong. I suppose enough time on a lathe, and that Lammy nut would fit, but i'd rather find one that's ready to go.
I might need to eat my words a bit on that rear thumb turn adjuster Voodoo...turns out that I have one of them that is on one of my PXís. I canít remember if I swapped it off my T5, or if I got it from SIP. It the adjuster still looks a little shiny, so Iím just not sure. It looks like they are not available from SIP anymore, but I havenít checked around elsewhere.

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Last edited by whodatschrome on Thu Jun 27, 2019 12:07 pm; edited 2 times in total
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Thu Jun 27, 2019 12:07 pm quote
Those knurled knobs brake ride adjusters are pretty common. What is the thread size and pitch?
Molto Verboso
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Fri Jun 28, 2019 8:18 pm quote
JimVonBaden wrote:
Those knurled knobs brake ride adjusters are pretty common. What is the thread size and pitch?
Itís a 6Mx1. McMaster-Carr has them in the correct pitch, but I havenít checked to see if the dimensions will work. The outside diameter of the barrel needs to be a small enough diameter to fit between the brake arm. I green circled the area that Iím talking about.

https://www.mcmaster.com/90368a300

CC7DA600-1958-40FC-B456-D308B2F5B2F1.jpeg

Molto Verboso
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Fri Jun 28, 2019 8:26 pm quote
I got around to converting my Smallframe PK125XLís rear brake lever over to a T5 (thanks goes to JoeP). I decided to take a few pics since Joe didnít.

First off, every P/PX/PK has the same rear cast aluminum brake pedal. So if youíre planning on converting any of those bikes over to a T5 brake cable, a notch will have to be cut into the pedal so that the cable can slip into it.

6C441DC1-5FCC-47A6-B3C9-026EA5280C06.jpeg

Molto Verboso
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Fri Jun 28, 2019 8:31 pm quote
The Smallframeís rear brake backing plate needs to be removed, then the hole that the brake cable adjuster nut screws into will need to be drilled out to a larger diameter.

EDABD3E8-3564-4742-8F59-2B4FE65979AD.jpeg



Last edited by whodatschrome on Sat Jun 29, 2019 11:44 am; edited 1 time in total
Molto Verboso
Joined: 26 Oct 2015
Posts: 1570

Fri Jun 28, 2019 8:35 pm quote
Get yourself a T5 rear brake arm, and measure twice and cut once. Weld the two together. The leftover pieces are in the picture.

D864C539-A8BB-43CC-B488-D74C10512DA4.jpeg

Molto Verboso
Joined: 26 Oct 2015
Posts: 1570

Fri Jun 28, 2019 8:39 pm quote
From a different angle you can see that I purposely welded the bracket offset about an 1/8Ē. Thatís so that there is a little more clearance between the lever and the wheel (when everything is assembled).

C9350166-9067-4F3C-AB6B-43638701DCA9.jpeg

Molto Verboso
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Fri Jun 28, 2019 8:42 pm quote
Here it is with the new welded up arm painted and installed back into the backing plate.

541E1E61-81F2-4EB3-A1A8-36842C7004E6.jpeg

Molto Verboso
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Fri Jun 28, 2019 8:47 pm quote
The most difficult part of the project was fishing the new T5 cable through the metal cable guide. The easiest way to do it would to be to remove both gear change cables, and pull them back through the guide, then fish the T5 cable through it, then reinstall both gear cables.

The threaded portion of the T5 cable might be too long, and rub against the wheel. If thatís the case, cut it down some. You can see that I marked it with a red paint pen.

D0417276-B74D-4897-A086-E812D698B2FD.jpeg

Molto Verboso
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Posts: 1570

Fri Jun 28, 2019 9:01 pm quote
And hereís an after pic with the threaded portion shortened up (also, if you have a keen eye, you can see that my PK came with the VMX6M cases!).

Overall the project is fairly simple. I probably wouldnít recommend doing it late at night when youíre tired, because it takes some thought when measuring.

Is there much benefit to this upgrade?...well, if you have all the parts, want a clean look, youíre comfortable with a welder, and want simple tool free brake adjustment, then I would say go for it.

8600463F-E30C-4AEB-AC79-D3719BB8A668.jpeg

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P125x (P200 Motor)
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Sat Jun 29, 2019 7:10 am quote
whodatschrome wrote:
JimVonBaden wrote:
Those knurled knobs brake ride adjusters are pretty common. What is the thread size and pitch?
Itís a 6Mx1. McMaster-Carr has them in the correct pitch, but I havenít checked to see if the dimensions will work. The outside diameter of the barrel needs to be a small enough diameter to fit between the brake arm. I green circled the area that Iím talking about.

https://www.mcmaster.com/90368a300
Perfect. Standard motorcycle size for drum rear brakes on small dirt bikes and older street bikes.
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Sat Jun 29, 2019 11:06 am quote
whodatschrome wrote:
And hereís an after pic with the threaded portion shortened up (also, if you have a keen eye, you can see that my PK came with the VMX6M cases!).

Overall the project is fairly simple. I probably wouldnít recommend doing it late at night when youíre tired, because it takes some thought when measuring.

Is there much benefit to this upgrade?...well, if you have all the parts, want a clean look, youíre comfortable with a welder, and want simple tool free brake adjustment, then I would say go for it.
i am gonna do it soon, thanks for the tips and cheer
Veni, Vidi, Posti
74 Super, 75 Super, PX project, LML off-roader and new to 2018, '66 Blue Badge Smallframe
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Sat Jun 29, 2019 8:28 pm quote
Great tip!
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Sat Jun 29, 2019 9:09 pm quote
this can also be done on PX/LML? I would love the simplicity of this on my stella!
Molto Verboso
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Sat Jun 29, 2019 10:01 pm quote
swiss1939 wrote:
this can also be done on PX/LML? I would love the simplicity of this on my stella!
Yes, it's super easy on the P/PX/LML. No welding is required. Cut a notch on the brake pedal lever (so that the cable can slip into it), drill out the brake cable adjuster hole to a larger diameter, and Bob's your uncle. I have pictures of that conversion on my pink PK200 thread (wherever that thread is hiding).

You can also look halfway up the page on this thread. The picture that has the orange colored rim is a PX with a T5 brake cable conversion.
Molto Verboso
Joined: 26 Oct 2015
Posts: 1570

Fri Aug 09, 2019 9:55 pm quote
Well son of a gun...it looks like Scooter Center has a PK to T5 conversion cable and cam kit for about $40 USD. If time were money, i could have bought a few of these kits for the amount of time i have into converting mine. https://www.scooter-center.com/en/3331260kt/brake-cable-set-scooter-center-vespa-pk-s/xl/xl2-conversion-to-adjustable-brake-cable-with-thread?number=3331260KT

Or if you already have a T5 cable and just need the conversion cam. https://www.scooter-center.com/en/3331260/rear-brake-arm-with-brake-cam-scooter-center-pk-s/xl/xl2-adjustable
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Sat Aug 10, 2019 12:42 am quote
whodatschrome wrote:
The most difficult part of the project was fishing the new T5 cable through the metal cable guide. The easiest way to do it would to be to remove both gear change cables, and pull them back through the guide, then fish the T5 cable through it, then reinstall both gear cables.

The threaded portion of the T5 cable might be too long, and rub against the wheel. If thatís the case, cut it down some. You can see that I marked it with a red paint pen.
That looks pretty good, but it would be ideal if the black bracket was bit shorter so that the cable goes straight in line.
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Sat Aug 10, 2019 7:08 am quote
nomadinsiam wrote:
whodatschrome wrote:
The most difficult part of the project was fishing the new T5 cable through the metal cable guide. The easiest way to do it would to be to remove both gear change cables, and pull them back through the guide, then fish the T5 cable through it, then reinstall both gear cables.

The threaded portion of the T5 cable might be too long, and rub against the wheel. If thatís the case, cut it down some. You can see that I marked it with a red paint pen.
That looks pretty good, but it would be ideal if the black bracket was bit shorter so that the cable goes straight in line.
I wanted to keep the brake lever cam (black bracket) the same length as the original, so that's why I didn't shorten it. In my picture, the cable isn't going in a straight line because the threaded portion of the brake cable is rubbing against the wheel rim. Once I shortened the threaded potion of the brake cable with a grinder, the brake cable lines up perfectly because the brake cable goes through a pivoting barrel. I suppose I should have taken a photo from a different angle to show how it all lines up in the end.
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Sat Aug 10, 2019 5:58 pm quote
whodatschrome wrote:
nomadinsiam wrote:
whodatschrome wrote:
The most difficult part of the project was fishing the new T5 cable through the metal cable guide. The easiest way to do it would to be to remove both gear change cables, and pull them back through the guide, then fish the T5 cable through it, then reinstall both gear cables.

The threaded portion of the T5 cable might be too long, and rub against the wheel. If thatís the case, cut it down some. You can see that I marked it with a red paint pen.
That looks pretty good, but it would be ideal if the black bracket was bit shorter so that the cable goes straight in line.
I wanted to keep the brake lever cam (black bracket) the same length as the original, so that's why I didn't shorten it. In my picture, the cable isn't going in a straight line because the threaded portion of the brake cable is rubbing against the wheel rim. Once I shortened the threaded potion of the brake cable with a grinder, the brake cable lines up perfectly because the brake cable goes through a pivoting barrel. I suppose I should have taken a photo from a different angle to show how it all lines up in the end.
I see what you mean now. That is a great idea as I have always dreaded dealing with rear cable adjustment on my smallframe.
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