Softening sidewalls delberately

[vitnagetrouble]

Hi - was watching some trials cars recently and some cars appeared to have much greater tyre footprints than others, even though they were the same type of car, wearing the same make, type and size of tyre, running the same pressure and bearing similar mass on them.

Made me wonder if the sidewalls of a tyre can be softened in order to get this greater footprint and if so, how do they do it ?

One person said they simply heated the side of the tyre up with a blowtorch - but surely that would stiffen it due to increasing the amount of vulcanisation ?

Any input much appreciated !

Thanks.

[LandRoverManiac]

vitnagetrouble said:

Hi - was watching some trials cars recently and some cars appeared to have much greater tyre footprints than others, even though they were the same type of car, wearing the same make, type and size of tyre, running the same pressure and bearing similar mass on them.

Made me wonder if the sidewalls of a tyre can be softened in order to get this greater footprint and if so, how do they do it ?

One person said they simply heated the side of the tyre up with a blowtorch - but surely that would stiffen it due to increasing the amount of vulcanisation ?

Any input much appreciated !

Thanks.

Never personally heard of people blow-torching their tyres (well - not intentionally). Though my knowledge of tyres/rubber dynamics is limited, I wouldn't have thought subjecting the sidewalls to heat would be any more effective than simply doing what everyone else does and lowering the tyre pressure until you get the flotation you need for the terrain in question.

The only advantage would be maybe making the rubber a bit 'stickier' - but that would be an advantage if you were heating the tread of the tyre which contacts the ground rather than the sidewall. If anything, heating the tyre by any considerable margin would cause the air inside to also heat up, expanding and giving you an artificially higher tyre pressure (thus a smaller footprint).

[brrapp]

Why wouldn't you just drop a bit of pressure? I've done it on trials bikes, trials landrovers, and occasionally on the road for a short period of time for increased traction in ice/snow conditions.

[vitnagetrouble]

Hi - thanks for replying, but note I said the pressures were the same. In fact, everything was the same, only the footprint was different, because one car clearly had softer sidewalls than the other even though the tyres were same type, age, size etc.

How did they get the sidewalls softer ?

[brrapp]

vitnagetrouble said:

How did they get the sidewalls softer ?

Was it deliberate? Maybe just a lot of use at lower pressure in the past which will have 'worn them in'.

[fat80b]

vitnagetrouble said:

How did they get the sidewalls softer ?

I would still have guessed it was pressures but you can buy tyre softener (not that I have ever used it or know what it would do to a sidewall)

http://www.demon-tweeks.co.uk/motorsport/tyre-trea...

[PhillipM]

Are they new carcasses or edge-to-edge remoulds?

Might not be the same tyre if the latter.
I have, a long time ago, seen people shaving the inside of the tyre right up to, and between, the reinforcement cords with a flap disc, but most tyres these days don't have any excess rubber there anyway.

I guess by the same pressures this is something that's checked independently prior to a run?
If so I'd be looking more for how they're dropping air after measuring...

[vitnagetrouble]

New - I have replace tyres like.for.lome, new for.old and they appear more.flexible giving a bigger footprint.
Am aware it's possible.to give a pressure reading which is way higher than the pressure in the tyre but no idea how it's done. I'd sooner not cheat anyway.