Modern Vespa

I'm sure this topic has been covered many times by now, but I don't know if this particular measurement is out there, because I ran into a problem upgrading my headlight bulb to LED and I thought I would share my research.

Most of the LED bulbs nowadays I found are quite compact and don't have additional modules, and are pretty close to identical measurements of a regular bulb. The first one I purchased from Auxito though was too wide in the heatsink section to fit through the hole in the headlight housing. The diameter of the regular bulb is 25 mm whereas the one I purchased was 28 mm.

The next one I bought I was impatient and didn't want to wait for the seller to provide me the exact measurements, so I just eyeballed it by making sure the heatsink section isn't much wider than the light section above it and it worked.

The bulb from Zethors doesn't have as many reviews as the first one, but I'm happy with it so far. Hopefully it lasts. There aren't that many sellers that sell a single bulb…

EDIT: I should also add that because the section that plugs into the wiring harness is almost identical to the stock bulb's, I did not have to modify the rubber boot around the harness at all!

I hope this helps someone else. 😃

So, you're saying the Zethors bulb pictured is the one that fits in the LX150's 25mm slot, and you like the result?

If so…you didn't really say that.

I don't understand the purpose of the question mark in the diagram.

Yes on all counts! 😃 Sorry for the confusion.

I edited the OP and uploaded a new photo. The one with the "?" was what I had sent to a seller asking for the heatsink width measurement, so they could tell what I was after.

Here is the link https://www.amazon.ca/Zethors-H4-motorcycle-Brightness-Conversion/dp/B0D4YNL95T/aps%2C64&sr=8-5&th=1

This one by AUTOONE should also work if the seller's measurements are accurate. they told me the width of the heatsink is 0.98" / 24.9 mm. this brand's bulbs have more reviews with slightly higher rating. I didn't buy it because they got back to me after I got impatient and just bought the other one before I had heard back. The measurement is actually listed in the product description also, but I had missed it.

https://www.amazon.ca/dp/B0C5922RPF

The only Zethors H4 LED bulb listed in US Amazon is different - it has a cooling fan.

On amazon.com you guys have a lot more selection than we do in Canada. I would say without measurements provided, buying one that is where the heat sink section looks like the same width as the plug section below the adapter, would be pretty safe.

Although a pair, this one should work and the price is reasonable for a pair:

https://www.amazon.com/FANTELI-H4-34000LM-Super-Bright/dp/B0CWHC9152/

Or these: https://www.amazon.com/MIFMIA-9003-LED-Bulb-Beam/dp/B0CMT2RQ93/