Technical who put helium in my tyres?

[bulldog5046]

i just has my new rear tyres put on (205/40/17) and the rear end is all over the place to the point i almost cant control it under heavy breaking.

my front tyres are 215/45/17 so a fair bit bigger, i was desperate to get the rears changed as they were ruining my arches

unfortunatly the rear end is snaking all over the place under heavy breaking and sharp turning without the power on.

is this a side effect to having tyres that are too big on the front?

or is somthing more synister happening? only started today though :chin:

 

[GhostWKD]

_

 

[Hellcat]

Probably a mis-balance due to the extra force required to produce the same amount of braking on the front wheels.

The front wheel under braking is a type 3 lever with the pivot (hub) then the force (brake pad)) and the load (tyre against road).

With bigger tyres the load is further away from the pivot therefore requires more force at the brake to get the same force at the load point.

So how does that effect your car? Well you are braking harder to get the same stopping force on the front, but the rears being smaller are experiecing more braking force than usual. So in effect you have shifted the brake balance to the rear. Get same size tyres on the front and I think you'll find it balances itself again.

or..


your brake compensator valve is buggered.

 

[dave]

did they put right presures in them?

 

[bulldog5046]

ahhh, i see exactly what you mean Rob, wouldnt explain the floaty-ness not braking but it makes sence!

Dave, one of the first things i checked.

mind you these are the same P-Zero Nero's that killed the last marea so i'm pretty concerned!

 

[GhostWKD]

take it easy on new tyres then new tyres wont be much cop under heavy breaking etc they do need a slight wearing in period

 

[bulldog5046]

take it easy on new tyres then new tyres wont be much cop under heavy breaking etc they do need a slight wearing in period

also somthing i wondered, would like to get them on the front and give them a bit of stick.

 

[jug]

in effect you have shifted the brake balance to the rear.

:yeahthat:

 

[bulldog5046]

i had a little bit more about the point made Rob and yes the brake balance has gone to the rear, on top the pivot point has gained more leverage to make the back of the car lighter!

a simple test would be to fit 2 of my 195/55/15's to the front and see how she goes, unfortuantly i have been drinking now so cant test this.

 

[Hellcat]

i had a little bit more about the point made Rob and yes the brake balance has gone to the rear, on top the pivot point has gained more leverage to make the back of the car lighter!

a simple test would be to fit 2 of my 195/55/15's to the front and see how she goes, unfortuantly i have been drinking now so cant test this.

At quarter past 5?

 

[bulldog5046]

At quarter past 5?

i had the day off

 

[bulldog5046]

fitted 2 standard alloys to the front to test the theory and she handels fine

so, i cant be bothered to change it back or put all 4 standards on so i'm just going to look like a nonse till the weekend when i can have new tyres fitted

 

[jug]

i'm just going to look like a nonse till the weekend when i can have new tyres fitted

it'll take a lot more than tyres to stop you looking like a nonce

 

[Hellcat]

I've driven with a pair of coupe alloys on the front and standard tipo alloys on the rear. Got more attention than I wanted tbh.

Also driven with a pair of 14" steel wheels on the back of the Tipo and a pair of bright red space savers on the front. Poor tipo did look sorry for itself.

 

[bulldog5046]

nice! lol

well she is sorted now and she is attracting alot more attention with new shoes that she did before!

 

[Hellcat]

Not sat in a garage all dead she aint

Got some ribe bits now so if I ever get bored I can pop out to the garage and start taking apart the engine.

 

[bulldog5046]

shame you dont live closer, wouldnt mind helping!