Gear Compatibility

Anything related to Lambrettas... ask tech questions, post helpful info, or just read and learn.
R_Andersen
registered user
Posts: 2
Joined: Fri Jul 13, 2018 4:32 am
ebay user ID: grandnat86
Main scooter: 1964 LI125
Contact:

Fri Jul 13, 2018 1:43 pm

Hi all, i have a '64 LI 125 and need to replace the gear cluster and 3rd gear but I'm having trouble finding parts.

Is it possible to replace the full set of 4 free gears and the gear cluster with a set from a different model Lambretta, such as an LI 150 gearset or something similar? These seem much more available and the gear ratios are similar.

I'm just not sure how interchangeable the gears are from the different models as long as I replace all of the gears together?

Thanks,
Rob

User avatar
Toddy
registered user
Posts: 4511
Joined: Sun Mar 08, 2009 12:01 am
Main scooter: Lambretta Series 1
Location: East Yorkshire
Contact:

Fri Jul 13, 2018 3:38 pm

Gear boxes are interchangeable but you may need to change sprockets to get the correct final drive below helps

http://www.afrayspeed.co.uk/pages/45-to ... -chart.xls
As my Dad used to say "Each to their own lad"

User avatar
HxPaul
registered user
Posts: 1015
Joined: Fri Dec 06, 2013 1:58 pm
ebay user ID: panhead_5
Main scooter: lambretta Li 150
Location: Halifax,Yorkshire
Contact:

Fri Jul 13, 2018 4:24 pm

If you change the cluster and the 4 gears,theres no problem.Some of the loose gears are interchangable,but not all.If you change the gearbox,stay with the cluster and 4 gears and you wont go wrong.

Minority
registered user
Posts: 682
Joined: Wed Feb 01, 2012 2:00 pm
Main scooter: Li230 S3
Location: Perth, Western Australia
Contact:

Sat Jul 14, 2018 11:31 am

Just be aware that the shimming may be different and that there is a considerable difference in the final drive ratio between the LI125 and the LI150. Dropping the front sprocket from 15 to 14 will give a closer match, but then you will have to consider using a pull down chain tensioner.

User avatar
leigh
registered user
Posts: 210
Joined: Wed Jan 07, 2009 12:55 pm
Location: Dorset
Contact:

Mon Jul 16, 2018 11:07 pm

Sure I have 125 cluster in my garage.

Leigh

johnny650
registered user
Posts: 236
Joined: Wed Oct 12, 2016 10:18 pm
Main scooter: lambretta 64 li 150 Special
Contact:

Sun Jul 22, 2018 9:53 am

thats a great chart calculator that toddy posted. I spend hours calculating different gear ratios . I think its a hang over from my cycling days when we only had 7-8 gears on a cassette and had to avoid big jumps between gears .

Something that has intrigued me is the 1x tooth difference you sometimes see between loose gear sets and their identical gear clusters (christmas tree ) of the various models .

if you compare first gear with its companion first gear of the gear cluster you see that first gear is either 50T or 51T right through the whole Lambretta model range (except TV models ).

If you look at the opposing gear on the gear cluster it can vary by 1x tooth . So you can have 50-11 on the Li150S Pacemaker for example and 50-10 on the Li125S and GP200 models !.?

There are examples of this throughout the gear ranges of all models so I presume that there is sufficient tolerance in the teeth geometry that you can go 1x tooth up or down when building your gear set from scratch.

If you look at the the Li150S pacemaker , the Li125 and the Li125S models you'll see that the 39T loose third gear will work with a gear cluster having a 17T , 16T and a 15T sprocket on the gear clusters interesting eh ?http://beedspeed.com/html-pages/Lambret ... oChart.htm

Fruitjuice
registered user
Posts: 202
Joined: Fri Jan 09, 2009 8:26 pm
Location: Gent, Belgium
Contact:

Wed Jul 25, 2018 10:41 am

johnny650 wrote:
Sun Jul 22, 2018 9:53 am
If you look at the opposing gear on the gear cluster it can vary by 1x tooth . So you can have 50-11 on the Li150S Pacemaker for example and 50-10 on the Li125S and GP200 models !.?

There are examples of this throughout the gear ranges of all models so I presume that there is sufficient tolerance in the teeth geometry that you can go 1x tooth up or down when building your gear set from scratch.
?http://beedspeed.com/html-pages/Lambret ... oChart.htm
So basically if I have an Italian Li150 gearbox I should be able to replace the loose 37T third gear with a 387T one from a late Indian GP200 or Vijay Super GP150 to reduce the gap between third and fourth.... interesting...
Life shouldn't be a journey to the grave with the intention of arriving safely in a pretty, well preserved body, but rather to skid in broadside, in a cloud of smoke, thoroughly used up, totally worn out, loudly proclaiming: "WOW, WHAT A RIDE"

Minority
registered user
Posts: 682
Joined: Wed Feb 01, 2012 2:00 pm
Main scooter: Li230 S3
Location: Perth, Western Australia
Contact:

Wed Jul 25, 2018 11:02 am

Fruitjuice wrote:
Wed Jul 25, 2018 10:41 am
johnny650 wrote:
Sun Jul 22, 2018 9:53 am
If you look at the opposing gear on the gear cluster it can vary by 1x tooth . So you can have 50-11 on the Li150S Pacemaker for example and 50-10 on the Li125S and GP200 models !.?

There are examples of this throughout the gear ranges of all models so I presume that there is sufficient tolerance in the teeth geometry that you can go 1x tooth up or down when building your gear set from scratch.
?http://beedspeed.com/html-pages/Lambret ... oChart.htm
So basically if I have an Italian Li150 gearbox I should be able to replace the loose 37T third gear with a 387T one from a late Indian GP200 or Vijay Super GP150 to reduce the gap between third and fourth.... interesting...
I think that's a very dangerous assumption to make. It's not just number of teeth, but diameters etc that come into play when matching gears to clusters.

johnny650
registered user
Posts: 236
Joined: Wed Oct 12, 2016 10:18 pm
Main scooter: lambretta 64 li 150 Special
Contact:

Wed Jul 25, 2018 8:57 pm

Minority wrote:
Wed Jul 25, 2018 11:02 am
Fruitjuice wrote:
Wed Jul 25, 2018 10:41 am
johnny650 wrote:
Sun Jul 22, 2018 9:53 am
If you look at the opposing gear on the gear cluster it can vary by 1x tooth . So you can have 50-11 on the Li150S Pacemaker for example and 50-10 on the Li125S and GP200 models !.?

There are examples of this throughout the gear ranges of all models so I presume that there is sufficient tolerance in the teeth geometry that you can go 1x tooth up or down when building your gear set from scratch.
?http://beedspeed.com/html-pages/Lambret ... oChart.htm
So basically if I have an Italian Li150 gearbox I should be able to replace the loose 37T third gear with a 387T one from a late Indian GP200 or Vijay Super GP150 to reduce the gap between third and fourth.... interesting...
I think that's a very dangerous assumption to make. It's not just number of teeth, but diameters etc that come into play when matching gears to clusters.
thats an interesting assertion .........

What evidence, if any, do you have to support that assumption ? ;)

User avatar
Doom Patrol
registered user
Posts: 2234
Joined: Wed Jan 07, 2009 5:03 pm
Main scooter: Lambretta GP 150 going on 200
Location: Second star on the right and straight on till morning
Contact:

Wed Jul 25, 2018 9:42 pm

I once heard about someone who fitted the 3rd gear from a Spanish LI in an Italian gearbox. It apparently jammed owing to the fact that the Spanish gear was thicker.

Post Reply Previous topicNext topic
  • Information
  • Who is online

    Users browsing this forum: No registered users and 10 guests