Wheel Spin

[russ123]

hi just wonder in if someone can help me with a question now i'm running 235/35/19 tires (toyo t1r's) i was saying to a mate about getting a fair bit of wheel spin at last track day he reckon's that i wouldn't be getting as much if i had 17's or 18's can anyone tell me if there is any truth in that? cheers

[joeyjoejoejuniorshabadoo]

smaller wheels will give you more sidewall and can provide more grip, but not as much as better tyres or better setup

[russ123]

smaller wheels will give you more sidewall and can provide more grip, but not as much as better tyres or better setup

so if they were the same tires 1 set beening 17's and 1 set beening 19's the 17's would grip more?

[Roy]

Nothing is ever perfect and everything is a compromise. Cars do three basic things and a mix of all at times. The accelerate, the corner and they brake. A tyre that is good at one may not be good at the others or even all three.

Generally more sideall will give you better longitudinal grip, braking and power down...but if you are trying to go through corners as well..... like I said, everythings is a compromise.

Frankly, a low profile 19" car should work perfectly fine if its a good quality tyre and your suspension is set up for it. If you have big, baggy side walls then you can generally run harder suspension as the tyre acts as a damper. If you have low profile tyres with no side wall then you need more compliance in your suspension

[GTSBoy]

Regardless of how the actual tyre itself performs, a 17" wheel and tyre will weight less than a 19" wheel and tyre of the same overall diameter. And the lower the wheel weight, the better the carw ill behave on the track (and on the road - even more so because the road has more bumps).

Something worth remembering is that the 19" version of a tyre is not the same tyre as the 17" version. If the 19" version has to have a much shorter sidewall in order to keep it down to the same overall diameter, then they may need quite different sidewall construction. Regardless of the details of the construction, the 19" sidewall will have to be much stiffer in order to keep the rim off the road, and that lack of compliance will hurt some aspects of the tyre's performance. As noted by Roy, above. On a really really smooth track it might be reasonably pleasant in the corners (a stiff sidewall generally giving good grip but with the risk of not offering much warning of when it's going to let go) - but you'd still expect the lack of sidewall give to cost you in longitudinal grip and hence lead to more wheelspin.

The short version? People often prefer 17" wheels for track use over 18" wheels. That leaves 19" wheels out in the cold.

[jjman]

smaller wheels will give you more sidewall and can provide more grip, but not as much as better tyres or better setup

Agreed, essentially this

tho dont run out and buy 17's n new rubber if that is what you are thinking. Go for setup first. Second- Upgrade the tyres if you are chasing more grip and even get a tyre with a bigger sidewall to counter the effects related to the above comment about sidewalls and grip.

last resort would be lashing out on new size rims n tyres in the pursuit of grip.

i cant remember which episode it was but im prety sure top gear or some review show ran a car round the test track with the 'optional 20" rims' and then with the standard 18's or 19's. The 20's were way slower and more of a handful to control the car on...

there is a reason F1 cars have sidewalls that are Huuuuuuge...

[djr81]

You have to differentiate between tyres/rims that contribute to what some perceive as looks and those that function well. The 20" HSV rims do neither IMHO. Bit like the cars themselves.

As someone who uses 17" the reason is not because I believe them to be better than their 18" counterparts. They arent. The reason is that they are cheaper - about $500 a set cheaper for R compounds.

R compounds, relative to road tyres, have very stiff sidewalls. Tyres with too low air pressure on the other hand, dont. A drag tyre is the extreme example. The sidewals are designed to give and thereby provide good traction.

Oh and for what it is worth that if you have a proper rim/tyre package the rim is lighter than the tyre.