Terence Posted October 16, 2017 Share Posted October 16, 2017 My Seven has 6in front and 7in rear wheels. They are currently shod with inherited 185/60 (F) and 215/50 ® tyres which will soon need replacing.I have looked on-line, and spoken to my normal tyre fitter and am no wiser. Can anyone tell me what width/profile tyres are suitable for fitting to these two wheels, and what the optimum size would be best for road use (with perhaps a track day or two as well).Does wider mean better? Will profile height affect the speedometer reading dramatically?I would also be grateful for advice on which tyres I should consider, as I am now having to learn a great deal about owning and driving a Caterham that wasn't necessary previously with lesser vehicles!Thank you. Link to comment Share on other sites More sharing options...
K7 VCT Posted October 16, 2017 Share Posted October 16, 2017 Check on line tyre guides for rim with. Says 205-215 is ideal for 7inch rim width. I run nankang ns2r on 6 inch rims- 185-60-13. They don't make a wider one I'm afraid. Link to comment Share on other sites More sharing options...
Terence Posted October 16, 2017 Author Share Posted October 16, 2017 Thank you, I will certainly look at the Nankang NS2R for the front. I haven't found a tyre supplier that asks for rim width, so I will look again! Link to comment Share on other sites More sharing options...
Terence Posted October 16, 2017 Author Share Posted October 16, 2017 Thank you again, K7!As you suggested, I have now found an on-line calculator:http://www.tyresizecalculator.com/tyre-wheel-calculators/tyre-size-for-rim-size-width-calculatorand this has answered that part of my questions.Now I would be grateful for advice on whether wider is better!I have a 2011 Supersport and know little about how tyre width affects handling for fast road, occasional track driving. Link to comment Share on other sites More sharing options...
Toby S Posted October 16, 2017 Share Posted October 16, 2017 Consider Toyo R888R 185/60 front 205/60 on the rears - should balance the car quite well and neutralise natural oversteer a bit - the previous owner of my 1400 Supersport ran this size combination on 13 x 6 inch rims with Yokohama AO48's (no longer available) and swore by it. These are road legal track day tyres though so don't expect huge mileage nor the best wet grip although huge grip in the dry - really depends how much driving you do in the rain and how much grip you want. Link to comment Share on other sites More sharing options...
Terence Posted October 17, 2017 Author Share Posted October 17, 2017 Thank you, Toby, As I live in the rain shadow of Dartmoor, I was looking more for wet grip, but I will try the Toyos on my set of Apollos for (dry) track days. Luckily, with the two sets of wheels I can go for both, as I do not want to stop using the Seven even if it is wet! Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted October 17, 2017 Member Share Posted October 17, 2017 I was just about to ask the first two key questions: how important is wet grip, and where do you want to drive it. Which leaves:Does wider mean better? How much power do you have?Will profile height affect the speedometer reading dramatically?You can get that from those calculators. But which sort of speedometer do you have? If it's electronic it's very easy to recalibrate.JonathanPS: For my vanilla 1800 K I chose identical wheels so that I can carry a spare. And because caring about the looks is way down my priorities. Link to comment Share on other sites More sharing options...
elie boone Posted October 17, 2017 Share Posted October 17, 2017 For excellent wet grip use Avon CR28 Sport Link to comment Share on other sites More sharing options...
Terence Posted October 17, 2017 Author Share Posted October 17, 2017 Thank you, Jonathan and Elie. I have a 2011 140bhp Supersport. I have found the speedometer calculation page from the suggestion by K7 above, and that profile height changes will have acceptable impact on my 13 in wheels.I would like to be able to afford the Avon CR28 Sport but a quick look at prices indicate that I would have to pay twice as much as for ZZS tyres, which have also been recommended.I am still not sure about the relative advantage of wider rear rims though. I understand that wider means more grip, but is that extra grip important just in fast road use? Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted October 17, 2017 Member Share Posted October 17, 2017 I understand that wider means more grip, but is that extra grip important just in fast road use?It's often asserted around here that there's a power threshold for 7s above which 6"/7" or 6"/8" works out better than 6"/6". IIRC 140 bhp is below it.JonathanPS: I'm deliberately avoiding the general question, but if anyone insists... Link to comment Share on other sites More sharing options...
Terence Posted October 17, 2017 Author Share Posted October 17, 2017 Thank you, Jonathan, I didn't find anything in the library or on the site. Perhaps I am using the wrong search terms- it won't be the first time! Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted October 17, 2017 Member Share Posted October 17, 2017 Were you using the built-in search tool or something like Google? I find the latter much more effective: try the second link in my signature.Jonathan Link to comment Share on other sites More sharing options...
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