Slk 230 2000 tyre question

[peter001]

Metal Type:
Aluminium
Tyre Type:
All-Weather
Rim Width:
7.5J
Tyre Width:
225
Rim Diameter:
18 inches
Aspect Ratio:
40
Offset:
37
Load Index:
88
Number of Studs:
5
Speed Rating:
Y: max 186 mph
Stud Diameter:
112
Tyre Manufacturer:
Michelin
Rim Manufacturer:
--
Rim Structure:
Multi Piece
Manufacturer Part Number:
B66470600


I HAVE THE OPPORTUNITY OF PURCHASING THE ABOVE WHEELS AND TYRES. I BELIEVE THEY CAME OFF AN SLK 2004.
AT PRESENT MY FRONT TYRES ARE SMALLER THAN MY REAR TYRES. IS IT ADVISABLE TO PURCHASE THE ABOVE AS THEY ARE ALL THE SAME SIZE ?

MANY THANKS IN ADVANCE, PETER

 

[antijam]

Your present set-up is presumably 205/55 R16 on 7J ET37's on the front and 225/50 R16 on 8J ET30 wheels on the rear?

Fitting your potential purchase will increase the the overall diameter of your rears by 6mm. this is not a significant change so your overall gearing and speedo accuracy will be relatively unaffected.

The tyre width at the rear will be unchanged so the contact patch will also be unaffected - so no more rubber on the road for extra grip. The change in ET of the rears effectively maintains the track, so no problem there.

I have just removed a pair of 225/40 R18's on 8J ET30 rims from the front of my R170 SLK and these presented no clearance problems so a 7.5J rim should be OK.

If the wheels did come from an R171 SLK there should be no problem with bolt pitch, although I would check that the bolt length is the same.

The core question is really what you hope to achieve with the change?
The two main reasons for increasing wheel size seem to be either aesthetic - cartwheels shod with rubber bands look cool - or sharper handling resulting from a stiffer tyre sidewall.

In going from 16" to 18" wheels the price you pay for either of these 'improvements' will be a much harsher ride coupled with an often severe tendency to 'tramline'. I speak from experience, having just 'downgraded' my SLK from 18" wheels to original 16"s, the ride and tramlining being unacceptable with the larger wheels.

 

[peter001]

big thanks

Hi Alex,
thank you so much for your informative reply- very much appreciated.

kind regards

Peter

 

[Alex M Grieve]

Hi Alex,
thank you so much for your informative reply- very much appreciated.

kind regards

Peter

Hi Peter,

I can not tell a lie - "Antijam" did it - I was just expressing appreciation - I too thought it was jolly good.

 

[antijam]

Thank's for your appreciation Alex - and for the credit.

Referring back to your original query Peter, R170 SLK's were originally shod with either same size wheel/tyre combinations front and rear - usually 205/55 R16's on 7J rims, or with the differing front/rear combo that you currently have. There should really be no problem therefore in fitting the same size all round in a different wheel diameter.

 

[peter001]

Thank you to you both ! cheers