Street tires

[enrikerace]

Hello

Which size of street tire would replace the slicks used on FST-FV better?
I am using the OEM bug wheels (15"x4") I think the stock tires are 155 80 r15 .

Thanks

[rgu]

Sorry

US FST's mostly use excellent Hoosier R60a Tire in 13 inch sizes. The American Racer tire is also legal. Check out the Formula Vee Challenge or the Canadian FV1200 locations on this forum. Each of these group likes street tires and has long experience with them and could supply you with a recommendation. Also check FV in Australia as they actually use a 15 inch wheel.

[Rayzor]

Hi Guys
We in Australia have just had street tyres mandated (by the National Formula Vee body) purely on the basis of lower cost and longer life (and the kickbacks to the National body), with the hope this would grow Formula Vee.
I thought I would pass on my experiences.
On the face of it, going to a $750 Yokohama road tyres from $1400 Hoosier tyres seems smart.
But its not.
Firstly, the street tyres are around 3 kg per tyre heavier. This stresses front stub axles, so we expect them to break sooner than they already are. The cost of repairing the damage if it happens on the circuit will outweigh the cost savings, and that's only in dollar terms.
Also, steering racks are wearing out faster. More cost.
The tyres are a different size, in our case the rears are much smaller. So some cars may need to modify their chassis to get ride height, plus some extra for adjustability. Cost again. Some cars can simply be raised, but that reduces camber, which may affect handling badly, and reduces adjustability.
Our new road car tyres are also 40 mm wider, and as a result some cars won't fit into their trailers. So either a new trailer, or trailer tyres, are required. Cost again.
The heavier tyres are much harder, so the cars are much more twitchy to drive. This means you spend more effort simply keeping the car on the circuit than racing competitors and the circuit. In other words, you are not "racing" as much, which is what this is all about.
The heavier tyres mean that more engine power is required to overcome the inertia of the wheels/tyres, and therefore less engine power gets to the road to accelerate the cars.
So this, with the harder tread compound, makes our cars about two to three seconds slower at our two most raced circuits. In my experience, two to three seconds is an eternity slower. Its cruising.
So the twitchy handling and the slower laps times means - less fun.
However, all this does add up to the better handling cars being more affected, and so the cars on track are closer together. But, the twitchy handling adds up to less capacity to make passing moves, and so from my observations trackside, the "racing" was more processional, and when there was a pass down the inside out of greater desperation, the outside car would tend to be pushed off the circuit.
The flip side is that the cars do have more grip in the wet due to the deeper treads, but this is at the cost of much more spray being kicked up, again making it even harder to pass because you tend to stay further back.
In addition to the above, at our very first race meeting on the road car tyres, two competitors showed up with the treads buffed. That cost $178.
Buffed tyres are certainly faster, as proved by one competitor who used them in wet qualifying and came third, but used them again in the dry race and raced quickly to the front and won.
At the second race meeting, about six competitors had buffed tyres. All of them were at the front of the racing.
So now that buffed tyres are faster in the dry, and unbuffed tyres are faster in the wet, then you now need two sets of wheels and tyres. Cost again. Huge cost. Bigger trailer?
Buffing also reduces their life closer to about what a set of Hoosier may be. Another cost.
One competitor found that two of his tyres were buffed too far, and were then useless for racing. He had to pay for two new tyres, and doesn't know if he will get reimbursed.
Another complication is whether tyres should be "wedged buffed" inwards or outwards, radius buffed, or plane buffed. More cost.
This adds up to teams with more resources benefitting from all the new opportunities. But these thing don't change - the cars are slower, are not as much fun to drive, its harder to properly race wheel to wheel and corner to corner, and not only are the cost savings not there, but if you want to win, this will cost more hugely, unless you are a picnic racer and all you want to do is drive around and around and don't care how you go.
Formula Vee only has four gears, so it doesn't have a high top speed. We only have 60+ hp at the rear wheels, so we don't shoot out of corners. But the one great thing we always had was fast mid corner speed, equal to Formula Fords and even many wings and slicks cars. Road car tyres kick our greatest USP in the guts.
Would Usain Bolt run in steel cap safety boots?
After three races, our fields in New South Wales (the most populous state of Australia, and with the biggest Formula Vee fields) are down to the lowest in years.
Its not working.

[Rayzor]

I forgot to add that because the rear tyres are smaller, they result in higher revs of about 3% to 4%more often, and will hit max revs at a few tracks in Australia, where we might not, or only just, now.
Some people think this is not a problem at all, as if our engines could rev infinitely.
I can't see how higher revs will make our engines last for longer. That's another cost.
At one race meeting last year in Sydney, amongst all categories of around 200 cars, there were three engine blow ups. They were all Formula Vee engines.

[Rayzor]

And to make it worse, Hoosier dropped the price of their tyres after Yokohama were given the "contract", from $1420 to around $1,000, and also, Dunlop Formula Vee racing tyres came back on to the market with their respected tyres at $920. Another supplier, GiTi, has built racing tyres especially for Australia, and said they would sell them for $750.

[FVRacer21]

I was waiting to hear the results of this change.

The first thing that jumps out is the drop in prices and return to market. Hoosier might be due their recent buyout by Continental, but I wonder about Dunlop (owned by Goodyear) - do they also fit other cars and classes? Are you just hitting a production run?

I think the second thing is that if you start with street tires, you don't see what race tires can do and therefore you just get used to them. I assume the race tires are already at optimum tread depth and they are probably only good in the wet for a certain time? There are street times made to half tread depth, or are thinly disguised race tires - does not sound like you have these.

You may or may not see more breaking of spindles. They seem to be more affected by high cornering forces and age, not unsprung weight. A company in the US makes a spacer kit that stiffens the bearing assembly, so that is worth looking into (I think it is for king pin, do not know if it works for ball joint) but anyone running FV should be crack testing spindles on a regular bases - there are HD aftermarket spindles if allowed by your rules.

Many of these problems seem to be static - diameter, width, tread depth; that could have been foreseen up front. I hope the deal is short term so you can get back to where you were, or that Yokohama can step up and help in some way - does not hurt to ask....

Chris

[Rayzor]

Chris
Dunlop triggered this entire change in 2014 when they announced by surprise they would close their factory. We then went to Hoosiers, but after some time people were hurting from the cost of the Hoosiers (ignoring how they were hurting more from high engine costs, and poor parts availability) The National body ignored the high cost items, and pushed for new tyres, and despite the advice from two of our greatest racers at an official tyre test, favoured the Yokohamas.
We have made no progress to cut costs and improve parts availability, but we have gone to new tyres which are a fools paradise for cost saving and racing quality.
The Yokohamas are the ADO8R semi slick. Our particular tyre is basically made for Lancers and Holden Commodores, which weigh around 1500kg.
There are slightly lighter R rated tyres around - I know New Zealand changed from a heavier road car tyre to a lighter one at the beginning of last year, and I was told by one competitor that the new tyre was a revelation after years of racing on the heavier one - yes you are absolutely correct about getting used to a particular tyres.
Our National body, in one of the most inexplicable decisions, have signed a THREE year "contract" with Yokohama for these tyres. Apparently, even Yokohama are amazed that they were given this contract.
Dunlop have now apparently moved their tools to Portugal and are back in production.

[rgu]

just a brief comment on this issue:

"You may or may not see more breaking of spindles. They seem to be more affected by high cornering forces and age, not unsprung weight. A company in the US makes a spacer kit that stiffens the bearing assembly, so that is worth looking into (I think it is for king pin, do not know if it works for ball joint) but anyone running FV should be crack testing spindles on a regular bases - there are HD aftermarket spindles if allowed by your rules." Quoting Ray

The Australians use the same ball joint beam we do and our R60A Hoosiers generate much higher G-loads. I've seen data close to 2G's many places in multiple cars in certain kinds of corners. In the last ten years we have never seen anything like a cracked spindle. Running 1.12's at Nelson certainly provides a bump test. In fact even in truly bad crashes the spindle itself never broke.

Something else must be going on.

[Rayzor]

Chris
From my (poor) memory, we broke one or two ball joint spindles last year in our State, and one or two link pin spindles.
The link pin spindles are the more prone to break. What I failed to say was that our 1200 cars are sill running on Hoosiers for this year, but must change to Yokohamas for next year. Its the 1200 spindles we are more concerned about.
There was one high profile failure at our 2017 National Titles in Perth last October when an entire front corner - wheel and drum - off a 1200 link pin car broke off and bounced and rolled a long distance down a hill towards the pit complex in front of dozens of Formula Vee people from around Australia.
Perhaps the failures were simply age and road car abuse related. I guess my assertion is based on the "simple logic" of an additional 2.7kg per front corner from the new tyres must increase the risk of failure.