Oh Bugger it rubs

[Twingowl]

Fitted new wheels today to my "oh please let me be a cup" RS

7 x 17's ET 38 running 205 40 17s, they fractionally touch plastic louvres under arch passenger side at front (which are not on drivers side in same place?) s'ok.

Problem seems to be drivers side rear arch, roughly 2 oclock position tyre is making contact with plastic inner; only coming off speed bumps and the odd pot hole.

HELP! Love these wheels, can I down size tyres to 195 40 17 or perhaps stiffen the rear (oops!) in some way.

Read various threads, Wheelbase stated the combo was ok. Have booked it for a geometry check just in case.

Drivers side only, is it me and my 80 odd kilos of pies haggis and coffee causing this interface?

 

[Chicken]

I'd wait for the geometry check and diet and see if there's any change :lol:

 

[yotah1]

You can go down to 195 tires as they are what is fitted to the RS Cup so...

 

[Twingowl]

I'd wait for the geometry check and diet and see if there's any change

Thinking exactly that, tis gonna be a long lean summer. :|

You can go down to 195 tires as they are what is fitted to the RS Cup so...

Granted, ET 55 offset on the cup though so.......?

 

[singlespeed]

I suspected 205/40/17 would rub with an offset less than et43. Hence mentioning it in the sticky post of which wheels work.

Going down to 195/40/17 will give you some clearance and should be fine unless your fully loaded up

 

[MovingShadow]

I feel like a retard but I still haven't figured out what exactly ET values are.

 

[singlespeed]

I feel like a retard but I still haven't figured out what exactly ET values are.

if you take a 7" wide wheel rim, like the cup alloy. The center line between the bead seats will be 3.5" from each seat if the hub attachment face was on the centerline, it would be ET0... Cup alloys are a high offset at ET55, meaning the hub face is 55mm outwawds from the center(yes metric and imperial units). So the cupalloys are recessed into the wheel arch

Going from a cup alloy et55 to a different alloy of et35 would mean the new one pokes out 20mm more.

Hows that?

 

[maggi200]

Good explanation neil, as we have come to expect

The hub face from the centre of the wheel expressed in mm is how I remember reading it. It was confusing at first but once I bothered to follow it through jn my head how you showed it, I understood it

 

[Twingowl]

You are a splendid and well informed bunch of humans, so at risk of sounding like a moron.......

Arch gap is same front and rear, front wheels turned to full lock clearly protrude from under arch, yet do not rub.
Seems like front suspension has less travel than rear (bump stops?)
:| Is there no way to modify suspension to ensure that rear works within similar tolerances to front?

 

[Ollie133cup]

So everyone knows ET20 is flush with the arch on a 7" alloy:

 

[MovingShadow]

I had to read Neil's explanation a couple of times, saying it out loud.

But I kinda understand now.. it's just the english explanation that made me have a brain fart when I first read it (not that my English is anything but bad.. if I say so myself)

 

[singlespeed]

I had to read Neil's explanation a couple of times, saying it out loud.

But I kinda understand now.. it's just the english explanation that made me have a brain fart when I first read it (not that my English is anything but bad.. if I say so myself)

your English is good enough to make me embarased for me only speaking English and a few words of French/German

 

[MovingShadow]

I owe that to The Simpsons (no joke). When I was young, I came home and it was allways first the simpsons and then homework.

Which resulted in making my parents drop their jaw to the ground when I was 12 years old and ordered my own food when we were on a roadtrip in the US, Florida.

 

[singlespeed]

So everyone knows ET20 is flush with the arch on a 7" alloy:

Are you sure yours are ET20?

Hanging a plumb line verticaly down from the outside edge of the wheel arches gives me a 14mm gap between the line and the outside rim of my wheel rim. Thats a 7" ET43, so I make that as ET29 would have the wheel rim flush with the top of the arch. I know the 2118's are rally rims, but surely the Zenders don't have razor thin rims to the wheel being 9mm thinner.

You are a splendid and well informed bunch of humans, so at risk of sounding like a moron.......

Arch gap is same front and rear, front wheels turned to full lock clearly protrude from under arch, yet do not rub.
Seems like front suspension has less travel than rear (bump stops?)
:| Is there no way to modify suspension to ensure that rear works within similar tolerances to front?

Bearing in mind the return lip (the part which curls back inwards) on the front arch extention is bout 16mm deep, your loosing some clearance... However, the rear return lip blends into the existing rear arch (if you feel the top of the arch, then go forwards, it becomes wider), meaning the return lip is somewhere around 26mm thick.

Hence the rears are more likely to rub with a load in the back, where as the fronts have may have some clearance at the top but rub on the front of the arch linner when on full lock.

 

[Ollie133cup]

Definatly ET20 Neil , When i got them i though i would of had to of extended the arches or ditch them but no the are flush at ET20.