Running A048s backwards

[Shad]

My rear tyres always wear unevenly, in as much that the RL always wears faster than the RR (LSD + roundabouts I guess ). So to try and even out the wear I've swapped them around, but obviously this means they are now running backwards.

 

How badly does this affect their ability to clear water? They are down to around 1.8-2mm at the moment, and I'm at Silverstone on Tuesday where there looks like being a slim chance of rain. Normally I don't use the car in the wet, so it doesn't really matter which direction they run. I'll be replacing the tyres next Thursday anyway but if I do it now then I will have to do three track days and road miles on the new tyres, instead of two, which might be a stretch.

 

Any thoughts? Cheers

[Mcalvert]

Yokohama recommend that the front tyres on a rear wheel drive car be run "backwards" (can't put my hand on their leaflet to this effect immediately, but it has been posted here before), so I can't think there would be any problems. Only possible issue with doing anything other than recommended by the manufacturer could be in the case of an accident and insurance claim though - worth keeping in mind?

 

Michael.

[Pezky]

A number of people run front tyres the wrong way round as it helps with the braking.

 

Not sure running rear tyres like that though

[John Alston]

A long time ago George Polley told me the direction arrows on Yokohama's indicated the direction in which the tyre plys best resisted torque due to their lay-up method. Therefore, rears should only be fitted in the correct orientation as the torque applied to the tyyres comes from being driven under power. However, as the only torque applied to the front tyres is under braking, these should be fitted the reverse way round. This way all tyres are getting maximum use out of the tyre ply lay-up.

[CharlesElliott]

It is Avon that recommend CR500s are run in the direction of most torque. I'm not aware of Yoko or George recommending that for A048Rs, but I've never asked him.

 

I have run A048Rs backwards on a curcuit, but as they are bad in the wet anyway, you might need to be prepared to drive very slowly if it does rain!

[Claire Voyant]

George Polley told me the direction arrows on Yokohama's indicated the direction in which the tyre plys best resisted torque due to their lay-up method.

This is as I understand it for AO21, 32 and 48. Therefore, on the front it is OK because of the way the tyres react under braking.

For the minimal cost of swapping them over why not do it? Consider the cost of the trackday (plus the fuel, plus, plus) does the £10 or 20 to have the tyres swapped so that they are the right way round really make a difference (if it does, how can you afford the trackday - or a beer after a long, hot day on track).

[Shad]

Not sure where £10-20 comes into it, I can swap my wheels around myself

 

All I've done is swap left with right to try and avoid having the left wearing down onto the wear bars and into the crappy rubber before the right does. This business of which direction the tyre is designed to take torque seems plausible, but also a bit like a Paddock Myth to me. Citation needed?

 

As far as I know, direction arrows are there because the tread is directional and needs to run that way to clear water. Charles hit the nail on the head with that I'm thinking, which is that it probably makes a mediocre wet tyre a bit more mediocre

 

It would be interesting to do two timed runs back-to-back with the tyres facing each direction...

[Mick Day]

Yokohama did advise that their cross-ply slicks should be fitted with the front tyres running backwards for a RWD car. There were other options advised for FWD/AWD/motorcycle & sidecar as well.

 

The reason is as explained previously.

 

Some have extended this reasoning to treaded tyres but be prepared for much less grip in the wet.

[CharlesElliott]

I have raced in the wet on brand new 048Rs and I think they are rubbish then. Worn one backwards sound a nightmare 😬

 

Also, I believe that Avon's advice on running backwards is in the dry....

[Archie Procter]

Agree with Charles. The little water clearance you would get running them forwards would be lost completely, and Silverstone's surface is not exactly grippy in the wet at the best of times! In the dry I have run them both ways round and found it made bu99er all difference to lap times.

 

I haven't heard George recommend running the fronts backwards in the dry - and almost no Grads racers do, unless they're trying to balance wear and thus prolong the life of a race set (of which we are limited to 3 a season). However I will ask him when I see him next at one of our meetings.

[Shad]

Thanks all. I'll swap them back to run the right way if it rains, otherwise will leave them to try and even out the wear. As it happens, the forecast isn't so bad now

[SLR No.77]

otherwise will leave them to try and even out the wear

and

I'll be replacing the tyres next Thursday anyway

Am I missing something!!!! Track day tuesday, possibility of rain, new tyres on Thursday, and you're worried about getting more even wear? And you're prepared to compromise the structure of the tyre running it the wrong way round on track? Do I really need to state the bl€€ding obvious?

 

Stu.

[Shad]

Number one priority is having the most grip for the whole day. I tend to find once you get past the wear bars they aren't much good anymore, and since one is almost at the wear bars and the other is doing slightly better, I'm trying to reduce the stress on the more heavily worn tyre to get through the day. Yes ultimately I'm being cheap, but I don't have a bottomless pot of money with which to buy tyres (or anything else for that matter).

 

To be frank, I'm still not buying this business about my impending doom by using the tyres against the directional arrow. I will keep looking for some actual documentation from Yokohama to support this myth, but in the meantime you can pray for my safe passage to the after life if you like. If it was a safety critical feature then it would be written on the sidewall, probably alongside the warning about over-inflating.

 

The bottom line, with regards to my original question, is that using the tyres against the directional arrow in the wet is going to make a bad wet tyre completely useless, pretty much as I thought.

 

Beginning to wish I hadn't asked now

[A10ROX]

You could swap the tyres on the rims

This would result in even out the wear and being the correct rotation

which I think is what Rollbar was saying £5 a tyre?

 

An other point about running against the rotation indicated this may be an issue with insurance?