LCGB Forums

The ability to post messages is restricted to LCGB members. Any questions contact us at lcgbadmin@googlemail.com

Tyre pressures

Technical help for Series one, two and three Lambrettas. Models include the Li, Li Special, TV, SX, GP, Serveta and API/SIL models

Re: Tyre pressures

Postby MickYork » Fri Aug 06, 2021 6:20 am

How accurate are the tyre pressure gauges ? I suspect the forecourt ones aren't calibrated and who knows the accuracy of shop bought ones. I've often inflated my tyre then double checked it within seconds and got a different reading :?
MickYork
 
Posts: 1476
Joined: Sun Jun 01, 2014 8:37 am

Re: Tyre pressures

Postby missing lynx » Fri Aug 06, 2021 9:21 am

I check them with a gauge, pump them up (if needed) then check them again. You always loose some air when you remove the the pump also remember if using a garage pump your tyres will be warm/hot so will read a higher psi
missing lynx
 
Posts: 863
Joined: Wed Nov 26, 2014 5:14 pm

Re: Tyre pressures

Postby Rich Oswald » Fri Aug 06, 2021 9:38 am

I use a digital pressure gauge and the readings are very similar to the dial one on my foot pump!

Rich'
User avatar
Rich Oswald
 
Posts: 8746
Joined: Fri May 30, 2014 3:30 pm
Location: Wiseman From The East (East Of The Pennines That Is)

Re: Tyre pressures

Postby coaster » Fri Aug 06, 2021 10:06 am

Goodf digital gauges have a 'zero' button which calibrates it to the abient atmospheric pressure. Inconsistenty reading are often due to getting a good seal as you hold it against the valve I find.
User avatar
coaster
 
Posts: 2647
Joined: Fri May 30, 2014 1:00 pm
Location: Norfolk, Flying 8 Balls

Re: Tyre pressures

Postby Warkton Tornado No.1 » Fri Aug 06, 2021 2:49 pm

Fast n Furious wrote:
Warkton Tornado No.1 wrote:
Fast n Furious wrote:The make and tyre rating also has an effect on the required pressure.
Tyres with stiffer side walls can generally use a little less pressure.
Continuous high speed riding will generate a lot of heat further raising the pressure. which can be a good thing in the right circumstances.
The question is arbitrary really because it all depends on the scope of use.
I limit my continuous high speed road riding to no more than about 20 miles a thrash, simply because the rear tyre gets to hand burning temperatures and needs to cool down before I dare go any further. ( I need a cig break anyway)
It's a slighly different situation on the race track because you accept the consequences that come with track racing. A bit more diligence is needed for the road IMO.

It's a very overlooked subject though. I'm constantly nudging my fellow club members about their obvious underinflated tyres. It's usually the first thing I notice as they pull into the pub carpark every week.
One of them recently ended up in hospital after a 50MPH front blowout left him sprawled across the A64. He was however riding a Vethspa so this may have had some bearing on the matter?


I have nothing significant to add to this long debate, but was wondering if you re-check the pressures when you make your enforced 'hand hot' stops?

For the record, are you running tubeless?

Just for completeness, when the BSSO approved tubeless rims for racing (which to me seems a no-brainer in not adopting) there were a number of top racers that resisted, choosing to continue with tubed tyres with the addition of a lining between tyre & tube made from cut up inner tubes. They still got punctures & I was not surprised. Rubber creeps & exasperates heat build up IMO.


I did once check the hot tyre pressures but it was years ago and I no longer recall what the increase was.
On my own machines I use the AF 3" tubeless rim on the rear with a 10/120/90 section tyre. (Modified engine casings, rear mudguard and rear of frame are needed). This tyre has only 3mm difference in diameter compared to the 12/120/70 setup I have on the front. The scoot therefore sits up 1" higher. Cornering is great fun, with zero exhaust groundings.
For giggles.... I used to park the bike up with a couple of bricks under the stand feet with the front wheel up against the pub wall. Start it up, drop it into 4th and rev it out and watch the cold rear tyre inrease in diameter by about 30mm :o :lol:
This is also a tetchy way of determining how good your rear wheel balance is, albeit a bit scarey when you find out that it's crap and tries jumping off the stand. :roll:


Thanks for that :D

There's usually a way around ground clearance issues, but I've never personally considered bigger wheel sizes. The SII rear damper length is always my first choice.

As for rims, I keep meaning to fir some Duro's to a set of alloy splits that Ressurection Scooters manufactured, but worried about sealing issues. I've bought some oversize 'O' ring cord to what was in them, so should pull my finger out :roll:

That said, some classic motorcycle racers used to use tubeless by sealing all the rim spoke holes with silicone & run with no retaining beads. I suppose that's no more unsafe than a tubed tyre......
Warkton Tornado No.1
 
Posts: 2112
Joined: Sun Jan 11, 2015 1:27 pm

Re: Tyre pressures

Postby Fast n Furious » Sat Aug 07, 2021 12:13 am

ooooooh. I could never have trusted that. Centrifugal force trying to rip the sealant from end of your spoke holes!!!! Squeeky bum time.
I hope it was a short lived practice? :o
User avatar
Fast n Furious
 
Posts: 1502
Joined: Sat Nov 19, 2016 3:56 am
Location: York

Previous

Return to Series 1, 2 & 3

Who is online

Users browsing this forum: No registered users and 32 guests