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Hey guys, Tuning Fork (of mighty car mods fame) just shared this on his facebook page, it looked like an interesting concept which faded away long before I ever saw a set on the road and something I thought some here would be interested to see. I don't think they'd have too much longevity considering they look about as thick as space savers these days. JJD Twin Tyre wheels. Whilst searching I came across this madness...
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skinnylew
Club Retro Rides Member
Posts: 5,546
Club RR Member Number: 11
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Twin tyres on a car.skinnylew
@skinnylew
Club Retro Rides Member 11
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Love to see a side shot of the Esprit, the dish must be immense!
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Jun 27, 2016 15:44:55 GMT
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I note, for all the handling praise, it obviously never took off. Expense vs. Benefit I suppose.
It strikes me that all sorts of curse word would get caught up between the tyres?
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Jun 27, 2016 15:49:45 GMT
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If you want to add more tyres, the way to go?
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thebaron
Europe
Over the river, heading out of town
Posts: 1,636
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Jun 27, 2016 15:50:47 GMT
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Who's going to be the first here to bash some spacesavers together and get this look going again.
Those Speedlines on the promo shot are damn cool as well
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steveg
Posted a lot
Posts: 1,548
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Jun 27, 2016 16:14:58 GMT
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Found this by mistake. This was what I was looking for though. I found this company selling some nice wire wheels ready for the job as well but I don't think they will be cheap ! www.turrinowirewheels.com/steel-rims/
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Jun 27, 2016 19:56:52 GMT
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Found this by mistake. This was what I was looking for though. I found this company selling some nice wire wheels ready for the job as well but I don't think they will be cheap ! www.turrinowirewheels.com/steel-rims/The top one looks like a chopper & garden roller have bred!
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Jun 27, 2016 21:46:01 GMT
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Those wire wheels do look ace! I continued searching for more about the lotus and could only find this, "The idea was picked up in the Eighties by Jerry Juhan, whose Lotus Esprit was outdragged in the wet by a Citroen Deux Chevaux [2CV], prompting him to speculate that two narrow tyres would give better adhesion in poor conditions than a single wide one." It seems the very same guy (Jerry) may have had something to do with the downfall of Delorean as read on lotus forums "Interesting to note that 0203J was collected by a J. Juhan. I presume this was Jerry Juhan who was linked to GPD through which the missing £17.6 million from DeLorean was allegedly processed" I don't know, but presume the lotus pictured above is the one mentioned : 0203J
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Jun 27, 2016 22:10:30 GMT
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Personal account from the someone who's been using them since they came out.
"When tyres are fully inflated, the gap between them is about 0.25" and the overall width is about 9.5". I used to run equal tyre pressures of 22PSI all round until I discovered you could tweak the performance by making the inside 4 tyres a little higher in pressure by about 5psi or a bit more until you notice the difference and can deal with it. So I used to have the front inside ones at 26psi, the front outside ones at around 20 to 22psi. The rear inside ones at 32psi and the rear outside ones at 26psi. This was my optimum setting for great breaking and plenty of warning when cornering really hard on stiff suspension. I varied the pressure just a bit if/when I noticed a change in wear pattern or if I had to compensate when swapping front to back to even out the wear overall. When I get my car back on the road I want to try 125/90 on the rear with 125/85 on the front.
I had to adjust the toe-in so it's not so severe (around 2mm) as the original 15" tyres had far too severe toe-in of around 6mm. The camber and castor should really be made more precise for twins since they track better. There was a little wandering at about 160 to 180km/h but I felt quite safe even up to 240km/h which was the cars limit, although I think I might select a slightly tighter toe-in for those long country trips. My car was one of those that had a bit of slop in the camber area and I think I could have had better tyre wear had this been set properly.
I suppose an automatic toe-in adjustment for speed might prove useful to further improve stability, save tyre wear and reduce fuel consumption - anyone care to comment on this? If so then feel free to email me.
The good thing was I never had a problem with a flat stopping me getting anywhere - the flat could usually be pumped up with that sealer stuff and it would be OK. The handling change is noticeable when one of them goes flat but you can keep going for ages - like 500km without any trouble and the flat one is not damaged and can still be used when the puncture is repaired. I wouldn't recommend travelling this sort of distance with a flat, even with twintyres, but it goes to show that they do the job they're supposed to.
By having the tyre pressures as I set them up meant I had lots of warning in terms of feel when I pushed it hard into a corner with a very predictable and surprisingly safe drift when they eventuallydid let go. I used to have Pirelli singles on an older car - they were great for road holding but gave virtually no warning when they'd let go - could be quite dangerous if you've never put the car to it's limits. I think it would be worthwhile trying Pirelli's with those tyre pressure settings (if they made the same sizes - that is).
It's like anything I suppose, there are lots of people that proclaim their particular selection over others but, I'd likely stick with the twins for the safety at least. Going through puddles at speed on ordinary singles was always a worry - with the twins it's so much safer and precise.
My recommendation if you wish to try twin tyres on your own car for any length of time is to have the camber and castor checked as precisely as possible, I'd even have it done when sitting in the drivers seat so the checks account for the included weight of the driver. Otherwise you might find the normal cars settings could be out quite a bit and this will give you premature wear and might even make the stability appear worse. If you can get those camber/castor correction units then thats the best thing as the twin tyres seem to tolerate less negative camber and less toe in as well but, naturally a bit of experimentation can give improved results"
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Jun 27, 2016 22:17:21 GMT
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Jun 27, 2016 22:26:58 GMT
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Makes me wonder if this fella knew that tyres sold faster than cars, so the money that was supposed to go to lotus was going to be used to kickstart and push forward this tyre concept.
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qwerty
Club Retro Rides Member
Posts: 2,409
Club RR Member Number: 52
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Twin tyres on a car.qwerty
@qwerty
Club Retro Rides Member 52
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A few years ago there was a set of similar wheels for sale on here.
Tom
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I knew I'd seen these on the 2 face scirocco but I couldnt find any photos in my quick half arsed search. good job!
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MK2VR6
Posted a lot
Mk2 Golf GTi 90 Spec
Posts: 3,327
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Jun 28, 2016 11:14:21 GMT
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Something I've never heard of before, and a bizarre concept. I love the look of the twin rears on the 30's? sports car and didn't know that two-face Scirocco was continuing to evolve. I followed the car's development on a local VW forum for ages and it was interesting to watch it develop. Has the current owner come up with the twin-tyre setup?
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Jun 29, 2016 16:00:38 GMT
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Those wire wheels do look ace! I continued searching for more about the lotus and could only find this, "The idea was picked up in the Eighties by Jerry Juhan, whose Lotus Esprit was outdragged in the wet by a Citroen Deux Chevaux [2CV], prompting him to speculate that two narrow tyres would give better adhesion in poor conditions than a single wide one." It seems the very same guy (Jerry) may have had something to do with the downfall of Delorean as read on lotus forums "Interesting to note that 0203J was collected by a J. Juhan. I presume this was Jerry Juhan who was linked to GPD through which the missing £17.6 million from DeLorean was allegedly processed" I don't know, but presume the lotus pictured above is the one mentioned : 0203J You J Juhan had a pretty interesting life, Automotive sales in South America, Porsche Factory Driver, links to Swiss Banking, etc. Jaroslav "Jerry" Juhan
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Last Edit: Jun 29, 2016 16:01:45 GMT by MkX
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Jun 30, 2016 20:46:03 GMT
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I'm still finding more, here are a set of enkies that were apparently fitted to a 911 which show the valve for the inner tyre.
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Jun 30, 2016 20:50:13 GMT
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Would you believe, Goodyear have come up with a new concept which is pretty much the same as the JJD ones though instead of two separate tyres its one tyre but with two separate air chambers. "The groove improves fuel economy and tire noise. It is also designed to take large quantities of water and mud away from the tire's contact patch in wet conditions. Because it has less rubber, the tire is also lighter than conventional SUV tires"
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Jun 30, 2016 20:54:43 GMT
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I can't help but think even drag cars only really need twin tyres too looking at this image.
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Jun 30, 2016 21:55:37 GMT
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THAT TYRE MUST BE ABOUT NINE FEET TALL *n
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Top grammar tips! Bought = purchased. Brought = relocated Lose = misplace/opposite of win. Loose = your mum
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This article is very interesting! I work in the Australian automotive performance industry, and I asked one of my colleagues who has been with the company since the '80s working on both race cars and road cars. He remembered these twin-tyre wheels straight away, and had a good laugh about them. From his recollection, there was a lot of fanfare and then nothing much happened.
I do really like the concept, but I think it must have been ahead of it's time. If anything, twin tyres would be more useful now that cars have put on an extra 600kg plus!
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