Tyres - Again!

PostPost by: wparslow » Mon Nov 14, 2005 5:21 pm

Hello all. I have a quick question regarding the age old topic of what tyres one can fit to the standard alloys on a +2S 130. I want to go for 185/70 x 13 whic would more or less retain the rolling circumference of the standard 165/80s bit I am being advised that this might introduce some contact betwixt tyres and suspension.

Anyone out there been through this and feels they can advise? Also I know that Yokohama do a decent tyres in this size but there are also road/race Avons (CR6 I believe) that look the part but are bloody expensive - anyone tried the Avons?

Many, many thanks in advance for any help here.

Wayne
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PostPost by: rgh0 » Tue Nov 15, 2005 9:30 am

Depending on the exact tyre brand and dimensions you may struggle to get 185 section tyres to fit to the rear without fouling the rear spring platform unless you have fitted small diameter rear springs and platforms.

175 section tyres can generally be fitted but may require a little modification of the standard platform by grinding or hammering to fit tighter around the spring.

In general its best to aim for a soft sticky tyre rather than a wide one. I use 175/60 dunlops formula R tyres on my plus 2 with a little hammering modification to the outer edge of the platform. With most Lotus, the tyres go hard before they wear out from normal road use so the softer the better.

For a road car where you want to keep the original rolling radius Michelin XAS Formula France reproductions now available in Europe at least would be a good option

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PostPost by: wparslow » Tue Nov 15, 2005 10:58 am

Rohan - are yu the guy with the Yellow +2 with sexy tyres? If so, what are they - the 175/60s?

Wayne
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PostPost by: rgh0 » Tue Nov 15, 2005 12:53 pm

Yes - the yellow plus 2 is mine. The 175 /60 tyres with the sexy curvy tread pattern are Dunlop Formula R tyres. These are a soft compound road legal competition tyre. They are about 6 years old now and I am not sure if Dunlop make the same tyre tread pattern still. The recent Formula R tyres I have seen have a different pattern but they make several different versions so they may still be available but chck a pixture if you want that particular tread pattern.

They are comparable or better to the Yokohama A-032R S compound tyres I use on my competition Elan which I think are the benchmark for road legal radials for Elans. However not legal for historic racing in Australia so can only use on my plus 2. Only downside is they are little small in diameter if you do a lot of high speed cruising and dont have a 5 speed or at least a 3.55 diff fortunately my plus 2 has both and anyhow Australian speed limits are a maximum of 110kph except for the Northern Territory.

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PostPost by: wparslow » Tue Nov 15, 2005 1:08 pm

Thanks Rohan. I have a 130/5 but I do do a lot of highspeed road stuff so I wouldn't want to drop the rolling radius any if poossible - speedo already reads 10% slow on the standard rubber. Can't find a single place on the web with Formula R piks - including the Dunlop website. Car is at Paul Matty's right now so I am asking them to see how much hammer work may be required to get 185/70s under the arches without chafing.
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PostPost by: Hamish Coutts » Tue Nov 15, 2005 6:33 pm

Wayne,

I suspect that you will have to do some serious work to the spring seats if you are going to fit 185s. There is plenty of room under the arches for the tyres but it is the clearance to the spring that's the problem.

If you are very keen, the best solution is to fit smaller diameter spring seats and springs. As ever this 'don't come cheap' but if you want to go down that road the rear struts made by Spyder would do the job. With these, you can fit much narrower springs which would let you fit at least 185 tyres.
Spyder also sell 14inch minilites which would give you a better choice of tyres (they look kinda nice as well :) )

Regards,

Hamish.
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PostPost by: john-c-elan+2 » Tue Nov 15, 2005 8:57 pm

My S130 has the standard lotus ally wheels with 175/70 tyres, these present no fouling of anything ? Fairly common size so quite easy to get choice of brands. rgds jon
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PostPost by: wparslow » Wed Nov 16, 2005 9:31 am

I've thrown caution to the wind and bought 4 x 185/70 x 13 Yokohama A021-R tyres - they were a bargain on www.sca-racerally.co.uk - 39 quid each!

Matty's are going to see if they fit and I will report back once and for all when I know the result.

Thanks all for you replies - this is a great forum!

Wayne
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PostPost by: wparslow » Wed Jan 04, 2006 4:19 pm

A little cutting away at the insides of the front arches, light hammering at the top of the rear shocks and they fit fine, grip great and overall I'm very happy. Car does feel a little skittish over certain types of bumpy surfaces though.

So, just thought you'd all like to know you can get 185/70 x 13's on a +2S without too much trouble.

Wayne
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PostPost by: wparslow » Wed Jan 04, 2006 10:17 pm

Hi Rohan. My SPrint is nearing road readiness now and I note you have the competition Elan which looks to have chunky tyres. I have 13 x 5.5 Minilites going onto the Sprint - do you think I'll get 175/70 on them, and if so what sort of mods might be needed?

Thanks, and Happy New Year to you

Wayne
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PostPost by: rgh0 » Thu Jan 05, 2006 7:56 am

Wayne

I run 175/60 Yokohama A 032R on 5.5 inch rims on a standard body. Clearance is tight but OK. My suspension is about 15 mm lower than standard. If running at normal suspension height you should be able to fit taller 175/70's from most manufacturers provided the wheel offsets are right and you have the small diameter rear springs. Tyres vary quite a bit in diameter and width from the nominal specifications so you cant be definite and say all 175/70's will fit but I have seen quite a few fitted to Elans over the years.


For Elan handling it is more important to have a good stiff sidewall tyre with as soft as possible tread compound than it is to have the absolutely widest tyre you can fit.

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PostPost by: thor » Thu Jan 05, 2006 8:37 am

So,.... with my Spyder chassis and spax's, I've got 185/70s fitted, which to me look a bit too wide... I'm thinking of reverting to 165/80 for crisper handling, but HOW do I know if the sidewalls are stiff or not?=?? Any tips on good ones? And not Michelin as I don't like the French.,... :lol:
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PostPost by: rgh0 » Fri Jan 06, 2006 9:54 am

Thor

According to Keith tyre weight is a good approximation of side wall stiffness, The heavier the tyre the stiffer the sidewall. How good this is I dont know. Most of the truely sticky tyres ( eg "R" terminology Japanese Dunlop or Yokohama tyres) have good stiff sidewalls to ensure they can take advantage of their grip.

If your trying to sort through the general run of the mill tyres to find a good one, if you dont have any specific experience then going by weight is a best guess.

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PostPost by: type26owner » Fri Jan 06, 2006 4:02 pm

Rohan,
Got that info directly from a tire engineer after I wimpered in my best pitiful, pleading voice for help. :lol: I want one of those tire bibles they have. They cost $200 each year and are hard to get ahold of unless you're a paidup member of their association. One will come up on E-bay eventually, I hope. :?
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