Version 5 is here!

What started as a quick update to include the new AF Clo5e ratio 5-speed gearbox soon turned into a full revamp and upgrade.

First of all I’ve cleaned up the look of the visualiser. It’s bigger on the page so it should be a little clearer and less claustrophobic.

The inputs now run across the top – work left to right filling in the inputs. It’s possible to do this without a dyno sheet by using your arse-dyno (see this post for a rough explanation).

I’ve added columns in the visualiser to show the RPM drop between 3rd and 4th, and 4th and 5th gear. If you’ve got a very peaky motor, you’ll want to avoid setups with excessive drops otherwise you’ll drop out of the power in the next gear. You’ll also notice that the drop increases as RPM increases, therefore underlining the need for peaky, high revving motors to have close ratios. On the flip side, lower revving, torquey motors will be nicer to ride with wider ratios which the motor can exploit.

If you scroll further down the visualiser you’ll find some additional tables showing:

  • Graphical comparisons on Final Drive ratios, Ratio Jumps between gears and Maximum Speed
  • Tables to show the Final Drive ratios in top gear for the gearboxes selected, and every other possible combination of sprocket/crown wheel available.

I welcome feedback and suggestions, so use the comments if you want something explained or would like something included in the future. I’d also love to hear how you use the visualiser and how it’s helped you.

You can download the latest version of the visualiser here.


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New 4-Speed CR Gearbox from Casa Performance

Casa Performance has introduced a new 4-speed close ratio gearbox for Series 1, 2, 3 GP / DL or Serveta scooters. Ratios were chosen by Vittorio Tessera in order to provide a close ratio gearbox at a lower price point than the Cyclone 5-speed.

The gearbox was designed and developed specifically for the Casa Lambretta Racing Team and used during their victorious 2015 ESC Championship season.

The gearbox ratios are configured differently to most on the market. Generally close ratio boxes reduce the jump between the highest gears, which helps relatively older low-powered, gear-challenged engines pull higher speeds without dropping out of the power. The CASA gearbox has a very “long” 2nd gear (more like two and a half) and then a fairly normal 3rd and 4th. The result is likely to be a gearbox that is very useable in 2nd and 3rd whilst retaining a 4th that would still give a good top end – i.e. think like a twisty circuit with a long straight where more benefit is realised in the twisty section. This could also translate well to riding around town and city centres.

Your local Casa dealer can be found here

Model this gearbox against others here

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Vespa anyone?

A recent email from Simon Stevens prompted me to dust off the Vespa Gearbox Visualiser I started 4 years ago.

I dug out the small frame data provided by Wayne Miller, entered the data and tidied up the UI and here we are.

Large frames and small frames get seperate visualisers and you can switch between the two by clicking the scooter at the top right.

This is version 1.00, so there may be bugs, and there’s bound to be gearboxes and primary drives missing, so let me know what needs fixing or adding in the comments section below

Version 1.00 of the Vespa Gearbox Visualiser can be downloaded here


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Gori RV4S

The Gori RV4S 4-Speed code ratio gearbox has now been added to the visualiser.

The Gori website details the thinking behind the ratios on this gearbox as well as some detail on the production process.

This sport gearbox was designed and developed by Gori Elaborazioni and entirely manufactured in Italy by Micozzi Ingranaggi [Macerata]. RV4S is the state of the art solution to enjoy maximum engine torque no matter what is the tuning configuration of your Lambretta. RV4S is made of a robust alloy of of nickel-chromium-molybdenum 18 nc 05 and it is specially treated with a process of carburizing and quenching. Gearwheels are at least as thick as the original ones. RV4S is a very precise and robust product at an affordable price.

RV4S was specifically designed to achieve the best possible performance ratio at any times and in any gear, thanks to the fact that torque is more prompt and available at higher revs.

First gear is rather elastic while the other gears are very tight to each other, which allows to ride uphill hairpins in first gear and then enjoy the very tight second gear for quicker output. When shifting, the decline of revolutions is very limited, thus allowing the best possible progression with no significant loss of power. As a matter of fact, our road tests confirmed that the best performance is obtained on uphill riding and on combined cycles.

RV4S can be fitted both on tuned and on standard Lambretta engines. Transmission is easily mountable and fits the standard selector (which doesn’t even need to be replaced).
For lovers of technical values we will be glad to provide the graphs of some of our tests with different pinions with different number of teeth. Our applications show that the decline in the number of revs when shifting is very limited: percentages range between 22% and 18%.

More detail and photos on the Gori website

UK distribution appears to be through Cambridge Lambretta with a retail price of £425

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Deposits being taken on new MB-5 gearbox

Mark Broadhurst announces a commercial development of his original bespoke MB designed 5 speed gearboxes from 2007.

Ratios have been tweaked to work on standard, mildly tuned or full race engines for one up or two up riding and rated up to 100hp.

Mark states that the steel grade out performs the normal metal as used in F1 and high spec engines, and are UK made by a top racing gearbox manufacturer.

Retail price will be around £1100 with deposits now being taken.

Link to the story on MB Scooters Facebook page

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New: Custom Gearboxes Return

Version 4.10 of the Lambretta Gearbox Visualiser sees the ability to model custom gearboxes return.

Bigger and better than before, you can now build and store as many as 27 different configurations for endless hours of nurdom.

To use the custom function, click the “Custom Box Builder” link at the bottom of the Visualiser. You can then give your gearbox a name, and spec the gears you want to use. When you’re done, click the link to go back to the Visualiser and then find your new gearbox under the usual drop down boxes for gearboxes (they’re at the bottom.)

This facility is only available in Excel xlsx format and is available from the download page.

Have fun…


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Lambretta Gearbox Visualiser: Version 4.01

The Lambretta Gearbox Visualiser is an Excel spreadsheet that can help you to choose the exact gear ratios and sprocket combinations to suit your Lambretta’s engine characteristics and riding style. Every ratio and every combination of optional gear available is now built into the new version of the Visualiser.

I’d done quite a bit of work trying different formats and layouts as well as additional tools since the last version, but in the end I’ve decided to keep it simple. Some of the other reasons for keeping this version simple was the screen resolution that many people appear to use (small), the range of OS and Excel versions and postings on forums from people baffled with what the Visualiser was trying to tell them.

So simple (relatively) it is, and that is why the ‘custom gearbox’ feature has gone and some of the other geeky new features weren’t included. I’m still mulling over a (paid) Pro version, and these and other features will surface if I go ahead.

Some of the new features are not supported in the older .xls format, and therefore this version is in the newer .xlsx format for Excel. For those that do not have software to support this, the previous version of the Visualiser has been updated to include all new gearboxes including the Cyclone5 and options

So, major changes in the new version are:

  • Inclusion of the fantastic new range of 5 -speed boxes from Rimini Lambretta Centre – You have BOTH versions and EVERY combination of alternative ratio.
  • 4-speed boxes from DRT Denis
  • Extra granularity to show the stages in the RPM range where power increases as well as where it peaks
  • Visibility of the RPM values where the engine is not making any significant power (off the boil)
  • A button to browse through the gearboxes as an alternative to the drop-down menu.
  • Extra descriptions and keys to help you understand what this all means and what values to enter
  • Recommendations to use chain adjusters rather than stretched chains for some sprocket and crown wheel combinations

Enjoy, and please leave a comment if you like it or have feedback. You’re welcome to link to this site, and using will help me keep track of referrers.



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