Yokohama tyres the facts / part 2

[mrequipe]

[tonybsa2008]

The tyre widths in thes pics look legal-just,what width are thes rims?Would like to see a vernier in these pics as well.

[richard]

The tyre looks on a narrow rim or not on a rim. Plus you cannot see were the rule is on the tyre, as I said the rim size will make a big difference, they are just to wide. Also as the tyre wears down the tread on the road will increase, They maybe just a small bit bigger but they are outside the rules of the club, if you have a 501cc engine in a 500 cc race it is to big and cannot race same as with the tyres in the classic club

[steve reilly]

The CRMC Sidecar eligibility rules have been updated and are in the process of being published on the website, as far as I am aware the tyre width limit test has been strengthened up to reflect actual racing conditions and the 5.5" contact width is to be measured with the machine fully laden including crew and the tyre pumped up to racing pressure.

Maybe Mike could arrange with Ian to carry the test out under the controlled conditions of Mikes workshop on the build table, this would then put this one to bed once and for all (maybe).

[mrequipe]

It doesnt bother me either way, I was trying to show what bullsh t people put about.

[wingnut]

It doesn't bother me either cos I race F1, but I was in Mikes workshop when these pictures were taken and can confirm the tyres were on rims,5.5 front,6 rear, and pressured correctly. So the pictures before you are as Mike says "the facts"
Steve the idea of measuring fully laden, is there a minimum weight for the crew?,

[tintop]

There are two versions of the AO48 13" - 175/50/13 & 175/60/13. Which one was used in the photos Mike?? Over here the 60 on a 13X6 would be acceptable, but the 50 likely not.

[steve reilly]

Hi Mike,
No minimum weight but then no maximum either, as us classic racers are usually "more mature in age and body weight" a lightish crew might be 13 stone driver and 11.5 stone passenger we do have some rather heavier crews and a few lighter one's !!!!!!!!!!!!!!!!!!!!!!!!!!!!, rather than testing individual bikes/crews I think it would be much better for the CRMC to carryout the test in controlled conditions and the tyre will either be in or out, if it fits the rules with an average crew but then goes over with a heavy crew then the heavy crew already have a handicap which an extra couple of mm of rubber is not going to overcome I think

all the best Steve

[richard]

look on steve's bikes for sale under classics, check the front yoko on the b.m.w and tell me that worn tyre is not over 5.5 inches

[Eddy Wright]

One of the tyres is an Avon. The other a Yokohama. That is the only difference. That's is it !

[Vicky Cooke]

Ian Johnson - can we clarify please? Are the Yokos allowed or not? Far too many if buts and maybes going on........

[petercaughlin]

Seems simple enough put down acceptable tyre size in black and white easily policed at scruting( Tech inspection? ( Yeah right?@#;**&$)
check numbers,if it don`t match, Ce la Vie or Merde!!!

[den etheridge]

Machine TEST fully laden with Crew, I suggest Phil the Pirate and BUDDA

[Eddy Wright]

Now then Dennis you need to behave yourself. This is a serious matter. They are those on here will lynch you.

[lang]

Just a thought, would not the easy and best answer to this problem be to rule that radial tyres are not eligable for classic sidecar racing.
They are certainly not in period, or apperance with classic bikes.
A top british chassis builder recently built himself a 10" wheel BSA outfit, and refused to fit yokohama radial tyres, he said (quote) they look like fork lift truck tyres.
I recently saw a radial tyre fitted to the rear of a 16" wheel outfit, they were certainly not available in the period. The first radial motorcycle tyres were not readily available until 1986.
The other advantage of such a rule change would be the elimination of the potentialy dangerous practice of mixing radial and cross ply tyres,
(a road going sidecar outfit will not pass an MOT test with a mix of tyres)
No doubt some expert will reply to this post saying that Fred Bloggs used Michelin X , or Charlie Farley used Pirelli Cinturato radial tyres in the period.
The point is, it was not the norm.
Any argument about radials being a cost saving factor is totally irrelevant.