Slick tyre skimming?

[Zico]

I was talking to a Kiwi friend of mine who was telling me about his buddy who races an old classic of some description..

When he fitted his new slicks he would run them for 20 miles or so until the beads had settled in the rim, remove them, centre them on a lathe and skim them somehow (hot knife?) so that they were perfectly round. I was thinking He may have confused it with tyre buffing, but he seemed quite adamant.

I'd never heard of this before.. Is this a normal required procedure for using slicks?

[phoenix]

Originally Posted by Zico

I was talking to a Kiwi friend of mine who was telling me about his buddy who races an old classic of some description..

When he fitted his new slicks he would run them for 20 miles or so until the beads had settled in the rim, remove them, centre them on a lathe and skim them somehow (hot knife?) so that they were perfectly round. I was thinking He may have confused it with tyre buffing, but he seemed quite adamant.

I'd never heard of this before.. Is this a normal required procedure for using slicks?

Definitely, no....

[MaxxUK]

Not normal but I have heard of it being done, probably more commonly known as tyre-shaving. Not only do they do it to ensure a perfectly round tyre but they also have been known to "shave" camber into the tyre where it is not available from the suspension itself.

Maxx

[jonners]

i believe that something different to tyre shaving is being discussed here.

I've never seen this anywhere other than speed events but it is quite common to see all four wheels off over the lunch break and for slicks to be attached with surforms [spelling??] and soapy water. Nothing very scientific in the technique - the finish looks quite rough once they've all finished.

I use very soft cut slicks for hillclimbing and just can't be bothered with that sort of thing but then again I haven't yet gone as fast on slicks as I did on Yokohamas...

Am told it's absolutely essential - the purpose is to clean off the rubbery marbles and stuff - bear in mind that the slicks are very soft in speed events so look very messed up quite quickly.

Some of the hillclimbers on the hillclimbing forum could probably explain in better detail.

[phoenix]

Jonners, I think that cleaning up tyres, as some do in hill climbing, is quite different from shaving brand new slicks to make sure the are 'round' as was the proposition in the first question in this thread.

Buffing/shaving treaded road tyres is also quite different from 'shaving' slicks but is common practice in events where treaded road tyres have to be used in a race series or class.

If shaving tyres to add camber (one post up) takes place, then I admit I have never heard of it being done either.

[Notso Swift]

Originally Posted by phoenix

Jonners, I think that cleaning up tyres, as some do in hill climbing, is quite different from shaving brand new slicks to make sure the are 'round' as was the proposition in the first question in this thread.

Buffing/shaving treaded road tyres is also quite different from 'shaving' slicks but is common practice in events where treaded road tyres have to be used in a race series or class.

If shaving tyres to add camber (one post up) takes place, then I admit I have never heard of it being done either.

I remember it being done in the early 90's for our National Production Car Championship where I was crewing. THey were not allowed to use R tyres as a cost saving measure, but it ended costing more as people tried everything and this was one thing (the rules allowed 1mm min tread, but the edges could be worn, so people shaved the inner edge down to nothing ) Tyres then became one use.
They changed the rules the next year

[R59]

I thought the best treatment was to have them pre-baked

[RPD Motorsport]

...sounds like the kind of practice someone may have done once and gone a bit better and is now absolutely convinced that this helps... In practice it is the number of heat cycles that effects a tyres hardening prosess, and the more cycles the harder they get. So it makes no sence to put them through an unnessacery heat cycle- theres a reason top teams run new rubber (slicks wise) out of the box!
There is also little use making a tyre 'round' when cold as tyres all have spots where the cords are imperfect somehow. So when a tyre heats up and softens you will find it changes shape slightly anyway, in general it is held more round by the centrapetal force. This is how we can have Formula renaults/F3s etc get a punture at the start of a strait and not know until they slow down.
We have done lont of roling road , track and 7-post rig testing on tyre preperation and you are much better keeping them in the dark and getting them perfectly ballanced.
In reality I think your friend is wasting their time, spend yours elsewhere on the car!

[kallievan]

Hi Guys,

Newbie.

I read with interest the different views and expriences on racing tyres. But how about road-going ones?

In South Africa (okay, maybe 'only in Africa!' :-) some years ago (okay, some decades ago) when wheel vibration became an issue on our new super-smooth highways for certain makes (read 'Cortinas' such as I had ) a service was available to restore the roundness of the tyre. Apparently, this worked a treat, CAR magazine reported. This skimming or grinding process lost you some surface but you gained a smooth ride.

Now back to the present. My wife's just bought a very low mileage Mini Cooper the tyres of which the previous owner or someone else on his behalf had seriously flat-spotted, causing a rhythmic rumble you wouldn't believe. I swopped the tyres back/front because evidently that hadn't been done yet in 26000 km, but this made the noise worse - now definitely transferred to the front. I'd imagine about 80% tread life remains. It would be ideal to have them skimmed or ground or rounded, I feel, instead of replacing them.

Any recommendations? Thanks for your time

And congrats on a great forum.

Kallievan

[graham bahr]

just fit some new tyres,

if they are old they will be past there best anyway skimmed or not

[tristancliffe]

Jesus! It's hard enough to flat spot a racing tyre at anything less than 80mph, let alone a road tyre at road speeds. Is it even possible? I once locked up at 120mph and got a tiny tiny flat spot (far less energy than in F1), but it was gone about 100 yards later.

[Steve Fox]

Originally Posted by kallievan

Hi Guys,

Newbie.

I read with interest the different views and expriences on racing tyres. But how about road-going ones?

In South Africa (okay, maybe 'only in Africa!' :-) some years ago (okay, some decades ago) when wheel vibration became an issue on our new super-smooth highways for certain makes (read 'Cortinas' such as I had ) a service was available to restore the roundness of the tyre. Apparently, this worked a treat, CAR magazine reported. This skimming or grinding process lost you some surface but you gained a smooth ride.

Now back to the present. My wife's just bought a very low mileage Mini Cooper the tyres of which the previous owner or someone else on his behalf had seriously flat-spotted, causing a rhythmic rumble you wouldn't believe. I swopped the tyres back/front because evidently that hadn't been done yet in 26000 km, but this made the noise worse - now definitely transferred to the front. I'd imagine about 80% tread life remains. It would be ideal to have them skimmed or ground or rounded, I feel, instead of replacing them.

Any recommendations? Thanks for your time

And congrats on a great forum.

Kallievan

Put 'em on the front, switch the traction control off and give it some doughnuts, they will be round in a jiffy

[Al Weyman]

Its easy to flat spot a road tyre at least on my heavy cars in fact I have to be careful not to and part the reason I would imagine is simply they dont grip as well as a slick so lock upinstead of slowing you down. I have enough expensive flat spotted Dunlop Formula R's to prove the point! Mind you I have some serious brakes on the thing!

[Notso Swift]

On a road car I would have thought ou of round is more likely from storage than flat spotting

Anyway yet you can buff a tyre to remove the flat spot

And I am with Al, sedands on R tyres, flat spots are not that uncommon at all

[midgetman]

Shaving slicks between races is pretty common in Cadet karting. Dads are there with hot air guns and paint strippers, chiselling off. Not done in TKM so I don't know why the Cadet racers do it.