Modern Vespa

On the MP3 400 the recommended psi. for the tires is 26.1 fronts and 33.4 rear for one passenger, and 33.4 fronts and 40.6 rear. What should I do if i am constantly changing between on and two passenger? Any recomendations? Thanks in advance.

Split the difference...?

I'm in kinda the same situation. When the weather is warm I take the bike and I drop my daughter off at school (she's the envy of 3rd grade) then head off to work. I set my tires about in the middle, so I shoot for 30 in the fronts and 35 in the back.

Some things make sense, others don't. This is one that doesn't. I ride my wife pillion every now and then and the tire pressure remains the same. I would go nuts if I deflated and inflated the tires every time someone got on or off my scooter.
willmw has the best solution: Split the difference if you are that concerned.

hey gptraveler, I'm jumping in on your thread here.

I read on the front Vin# plate of my MP3 250 that the front tires should be 29 and rear tire 40. I see there are many opinions on tire pressure. Well I thought I'd fill them as such. I just received my new Accu-Gage tire gauge in the mail that I bought. I love it. And I went to the gas station to fill up. Well the front tires were no problem. But the back tire, well......I guess I just realized there is no way in hell that I can get air in the rear tire using one of these: and lately most of the gas stations I've been checking have these kind. So currently I'm riding 29psi on both front tires and 34psi on the rear tire. Is that ok for now? I'm hoping I'm ok with those numbers. I never had this problem with my ET4. I had read on here that the rear MP3 tire is difficult to get to and YEAH it sure is! I wanted to try 29/40 but that is my next step. I'm going to need to find a portable pump or gas station that has a different air attachment. And yes, I hate when we have to pay for air. As always, I appreciate any advice from you fine folks.

Hey, hope this helps. I picked up one almost identical to this one for around $10 at Wal-Mart. It(and this one) have a right angle nozzle so that you can easily get it into the tire on the 250. It plugs into a 12V adaptor. I bought it after putting in a 12V(which is very,very easy mod for the 250) on the 250, but now I can still use it for my 500. Below is the link for the air compressor followed by the link to the 12V tutorial I made up for my first mod on here:

http://www.jcwhitney.com/INTERDYNAMICS-12-VOLT-PORTABLE-AIR-COMPRESSOR/GP_2010166_N_111+600017719+720000100_10101.jcw

https://modernvespa.com/forum/topic31215?highlight=12v

I agree, that gas station hose is not going to fit the rear tire of the MP3 250, a 400 or 500 perhaps, but not the 250. Luthorhuss has a good alternative but you would need a 12v socket installed. If you park your bike in a garage, then invest in a small compressor and fill your tires when needed. Make sure you buy a chuck that fits at an angle. I got one with a guage attached to the hose, this way if I pump more air than needed, there's a release button that will bring it down to the pressure desired.