Always heard this is so?? What are the facts??
Will a car with 16"s accelerate faster than with 18"s??

 

If the rolling diameter of the wheel + tyre is smaller then yes as you have lowered the overall gearing.

 

I was told by several sources than even when keeping the rolling diameter the same, the flex in a higher series tyre (smaller wheel)
is also an aid in acceleration.

 

Yes also true, that's one of the reasons dragsters have heeeyoooowwwge profile tyres with soft side-walls. Though I'm not sure you would notice any difference between say a 16's and 18's keeping the outside dia. the same....

 

Changing the wheels may hurt the acceleration for a number of reasons;

• if the overall diameter is changed, then the gearing will alter.
• if the rotating inertia of the wheel is changed, then more or less energy will be required to speed it up/slow it down. Something similar is very noticable on the front wheel of motorcycles - large ones are harder to turn in than smaller ones.

The use of flexible sidewall tyres on drag racers is as much as anything to increase grip and for the gearing to vary with speed.

Duncan

 

Everything with cars is a trade off, you gain one thing, you loose something else!

Personally I think yes, there would actually be some difference but it would be so small you wouldn't notice it. It wouldn't stop me upgrading to bigger wheels!

Bob

 

If you look at some of the higher power scoobs being dragged in Aus (500+ bhp) most of them use 15" or 16" wheels and I don't think it's because they can't afford bigger ones!

These guys have been building drag racers for many years so they must have good reasons for not using bigger rims.

 

for dragging, you want as low pressure as possible as this increases the area of the contact patch. giving you more grip, you then want narrow wheels, as this makes the contact patch longer, giving you more longitudinal grip at the expense of lateral grip which isnt necessary on a dragster.

If you notice when dragsters boot it, the inertia of the tyres forces their diameter to swell enormously and the tyre width to narrow aswell, the air in the tyre gets heated enormously veru quickly causing the pressure to rise. you need to run low pressure int he first place for the tyres tobe able to cope with the pressure rise.

It is more difficult to run low pressure on a low profile tyre, as the sidewalls are not large enough to flew suuficiently, and you risk the rim resting on the ground at times.