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I've just ordered some new tires (Heidenau K75 3.50-8") for my VBB and just want to double check if I should use the tire pressure recommended in the original manual or if things have changed in the last 40 years?

The manual says 15.6 psi on the front and 20 psi on the back (31.3 psi on the back if riding with two people) which seems kind of low. Any thoughts?

Also has anyone tried these tires? The reviews seem quite favourable.

soyachips:

I've just ordered some new tires (Heidenau K75 3.50-8") for my VBB and just want to double check if I should use the tire pressure recommended in the original manual or if things have changed in the last 40 years?

The manual says 15.6 psi on the front and 20 psi on the back (31.3 psi on the back if riding with two people) which seems kind of low. Any thoughts?

Also has anyone tried these tires? The reviews seem quite favourable.

 I would do 28 in the front and 30 or 32 in the back.Didn'T you get any information or suggested tyre pressures with them ?

I haven't received the tyres yet but on another forum I read that tyre pressure specifications are more about the maximum pressure you can pump the tyres up to without doing damage and that you're meant to go by what the scooter manufacturer recommends as it has more to do with weight, weight distribution, suspension, etc.

Your suggestion of running 28 on the front is a long way from what the manual says. Can you explain a bit more about why you'd do this?

I'd also be interested in what everyone else is doing.

 i go about 25 - 30

try a few difrent psi and see what works for you, its not a car so its more something, personal preferance 

joshzingzing:

 i go about 25 - 30

 

try a few difrent psi and see what works for you, its not a car so its more something, personal preferance 

On your rear, right? I go 30 rear, then top it up when it gets down to 26ish, and 18 front on my PX . . . Not far off what the manual says. Rear is better at 32ish with passenger . . .

I run 20 front and 25 rear, but they're 3.5 x 10" on a sprint.

The Dunlops on my LML suggest 35psi front and back.

captainpotato:

The Dunlops on my LML suggest 35psi front and back.

Don't be confused with what's on the sidewall of the tyre - that's not the recommended pressure for your machine, it's the maximum presuure recommended for the tyres.. If you run them at too high a pressure, you will have excessive wear in the centre, among other things...

Cap'n, I would suggest for your LML about 1.4 bar front (20 psi), 1.9 bar rear (27 - 28 psi). It would be slightly less for vintage large frame Vespas, which weigh less than the PX and LML, so Soyachips' VBB should be about the same as my Super on 1.3 bar front (18 - 19psi) and around 1.6 - 1.7 on the rear (23 - 25 psi). But do experiment and see what feels best.

(Handy conversion tool here: http://www.asknumbers.com/PressureConversion.aspx )

Good point. I haven't actualy checked to see what LML recommends.

I run them at the maximum generally because the ride feels better. It may increase the tyre wear, but I prefer the ride when the tyres are inflated to be pretty hard. I do drop them down a bit when it's wet, but the harder ride feels a lot more stable and the handling more consistent (and better) when the tyres are harder.

That's fair enough - over-inflated is better than under-inflated, anyway. It can also depend on the tyres themselves - for instance, Schwalbe Racemans have a much stiffer sidewall than Michelin S83s, so the S83s would be better with more air in them than you'd need to put in the Racemans.

 Stella LML in USA is 29psi front & rear ( disregard that i cant read properly its 22psi front 29psi rear )

20 up front and 30 rear is my starting point for 3.50 x 10 tyres on a Vespa.

Adjust as you need.

Classic Vespas are unbalanced towards the rear (rider and engine over the back wheel), hence the asymmetric pressures.

Captainpotato's method of 35 front and back would be too harsh and unbalanced for most riders.

Had my LML on the Southeastern Freeway tonight sitting on 95 with a decent crosswind, so it was certainly very twitchy (especially on the downhill curves), so I might try a lower pressure on the front. Having said this, it wasn't unrideable by any means.

According to the Stella owner's manual (for the LML), it should be 22psi on the front and 29psi on the rear (varies with temperature).

http://public.justinhileman.info/files/scooter/manuals/genuine/stella-owners-manual.pdf

If the recommended pressure is related to how much weight is over each wheel then it makes sense to have a lower pressure on the front. I guess they're trying to make the patch of tyre in contact with the road a similar size/shape on the front and back.

Thanks for the great feedback everyone, can't wait to get my tyres and try them out!

soyachips:

According to the Stella owner's manual (for the LML), it should be 22psi on the front and 29psi on the rear (varies with temperature).

http://public.justinhileman.info/files/scooter/manuals/genuine/stella-owners-manual.pdf

If the recommended pressure is related to how much weight is over each wheel then it makes sense to have a lower pressure on the front. I guess they're trying to make the patch of tyre in contact with the road a similar size/shape on the front and back.

Thanks for the great feedback everyone, can't wait to get my tyres and try them out!

  Thats correct i must learn to read properly