Support Team Shaun_E Posted October 20, 2008 Support Team Share Posted October 20, 2008 I have decided for next year to go with the following Kumho tyre combination for sprints and hillclimbs: Front 215/50R13 Rear 235/45R13 Kumho recommend 8" wide rims for the 215s and 9" wide rims for the 235s. However most of the people who run this combination of tyres have 7.5" front and 8.5" rear - is there any reason for this (apart from not having to change the rear wheel width from standard with MB wheels)? Why move to 7.5" front and not 8"? I have decided to buy Image Billet 4 wheels as they have powder coated aluminium centres which will be lower maintenance than the MB magnesium wheels. People who know me will realise that is an important factor! I therefore have the luxury of starting from scratch with the sizing and offset. I will be fititng wider front wings but with the existing stays so will need to keep the inner edge of the wheel in the same postion relative to the wingstay. I have measured the backdepth (hub face to inner rim edge) at 111mm - does that sound right? Could someone measure theirs for me please. I intend to keep the same backdepth on the new wheels which will therefore have all the additional width on the outside - the offset will change significantly but will this cause any problems? On the rears I also intend to keep the (139mm) backdepth the same to prevent any possible fouling problems - it looks like there should be enough room under the arches. Can anyone forsee any problems there? Cheers, Shaun Yellow SL #32 - member of Drowned Rat Racing Edited by - Shaun_E on 20 Oct 2008 17:11:06 Link to comment Share on other sites More sharing options...
rgrigsby Posted October 20, 2008 Share Posted October 20, 2008 As one of the people who changed wheels last year I'll hold my hands up to just following the herd and getting 1" added to the outside of my Barnby rims which I believe is was the majority of people did. This seems to be fine with 215's on although as you say the recomendation is 8". Cheers Rob G www.SpeedySeven.com Link to comment Share on other sites More sharing options...
Adrian Williams Posted October 20, 2008 Share Posted October 20, 2008 Shaun, standard MB sizes are as follows: Front 5" inner with 1.5" outer = 6.5" overall Rear 6" inner with 2.5" outer = 8.5" overall At the front I went with a standard inner 5" with a 2.5" outer to get to 7.5". This gets over any wing stay issues on the inside and gives you an equal track front and rear into the bargain. The 215's fit nicely on the 7.5" rim so I didn't see the need to go to 8" fronts. A 6" inner at the rear is very close to the arb drop links if you have the over slung bar. A change to the under slung version is relatively cheap as the drop links and clamps are the same as the over slung as long as you have the mounting holes in the lower chassis member. If not an adjustable Freestyle jobbie will solve it. Adrian Link to comment Share on other sites More sharing options...
Leadership Team Mcalvert Posted October 20, 2008 Leadership Team Share Posted October 20, 2008 Shaun Michael Link to comment Share on other sites More sharing options...
Mark Durrant Posted October 20, 2008 Share Posted October 20, 2008 Michael What wheels will you be using next season Mark D Comp Sec Link to comment Share on other sites More sharing options...
Simon.Rogers1 Posted October 20, 2008 Share Posted October 20, 2008 I think the reason for just going to 7.5 front was largely the ease of just changing the outer of an MB rim. 7.5 is within the recomended range of the 215. 8 being optimum. Link to comment Share on other sites More sharing options...
Mike Biddle Posted October 20, 2008 Share Posted October 20, 2008 Shaun, I have those wheels on my car (red centres) and you are correct in saying they are low maintenance, very easy to keep clean with a quick wash. They are verly light too, top quality stuff. Link to comment Share on other sites More sharing options...
Support Team Shaun_E Posted October 20, 2008 Author Support Team Share Posted October 20, 2008 When do your new wheels arrive Michael? I guess I'll go the tried and tested route then and stick to a 7.5"/8.5" combo. Yellow SL #32 - member of Drowned Rat Racing Link to comment Share on other sites More sharing options...
Adrian Williams Posted October 20, 2008 Share Posted October 20, 2008 Shaun, I've measured the front offset as 113mm from the rear hub face to the outside of the inner rim. I can't measure to the inside of the inner rim as the tyres are still on. Adrian Link to comment Share on other sites More sharing options...
Support Team Shaun_E Posted October 20, 2008 Author Support Team Share Posted October 20, 2008 Adrian - thanks - that is close enough to the 111mm I've measured to convince me I haven't made an 🙆🏻 of it. I meant the outer edge of the inner rim IYSWIM. I will go ahead and order tomorrow. Mike - I thought I'd seen them on another car. Good to know they really are low maintenance. I will be getting the centres powder coated and both inner and outer anodized. Yellow SL #32 - member of Drowned Rat Racing Edited by - Shaun_E on 20 Oct 2008 21:58:25 Link to comment Share on other sites More sharing options...
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