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CR500 to ZZS


Black Hole

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My CR500 tires are aged out and I need to replace them on my 7 SV. My car has 195/45-15 CR500 and the ZZS that has superseded them is available in a 195/50-15. My issue is clearance. I knew one of my cycle wings is very close to the tire (about 4mm) but when I was looking at the options to fix that I noticed my cycle wing stay is also very close to the tire. The wing I could shim but the stay is a trickier issue. Out of curiosity I looked at Caterham parts and note that they list certain stays as being for use with the ZZS/ZZR tires. So they must have made a slight change to account for the wheel diameter change (from 21.69 to 23.08 per Avon website). Has anyone made the switch between the tires and did you have clearance issues?

 

I did a feeble attempt to flex the stay with the cycle wing still on to see if it would bend but it seemed fairly stiff. If that does not work I would likely heat it and try to bend it and I could buy new stays if i bugger them up as they are not too expensive.

 

20_02_02_jPhone_185.jpg 20_02_02_jPhone_186.jpg 20_02_02_jPhone_188.jpg

Edited by Black Hole
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The wingstays and fenders "float" with the tire.

 

As long as there is any clearance at all, it shouldn't be an issue. Like motorcycle front and rear fenders which float with the suspension.

 

I switched from Avon and while I'm not happy with the sizes they worked for now be773b8ee25e49d6ec29fbcfcb6af4cc.jpg27af0c75de309ca4e44bd702a624c39e.jpg

 

Sent from my Pixel 3a XL using Tapatalk

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I use Avon ZZS on my silver CSR in 15 inch wheel size and they originally were on CR500. Just bolted on with no clearance issues. Not much help as it is a CSR not a SV. I also have the ZZS on 13 inch wheels on my 420R but as that was from the beginning I suspect it had the special stays you refer to from original build.

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The wingstays and fenders "float" with the tire.

 

As long as there is any clearance at all, it shouldn't be an issue.

 

Thank, I know they move with the tire and that is why the clearance with the CR500 is tight but not an issue. The wild card is when I go to the larger tire I may run out of clearance

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I use Avon ZZS on my silver CSR in 15 inch wheel size and they originally were on CR500. Just bolted on with no clearance issues.

 

Hopefully I will have the same experience. I will likely order them in the next week or two from Roger Krause. I will get them to fit somehow, just a matter of bolt on or have to make some modifications.

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The other wild card, I have discovered, is that with very minimal tire/fender clearance, wind pressure at high speeds will shove the fender onto the tire and cause significant rubbing. My efforts at bending the stays were minimally successful. I had more luck with imaginative shimming (as long as aesthetics aren't a concern, and on my Cat, they are not:)). Even then, I have trouble fitting a 13x185/60 on the front.

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My new tires are 185/60r13 that are picturer above with the tight fit.

 

The previous original R500 had a much more tollerant fit. Don't remember their size. But ill trying to order the same matching set as original again.

 

Rears are a bigger problem. 245s are being very hard to find for the rear. And the current side wall at 45 makes them look very small in the arches and definitely much small than the 60 front.

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I thought the CSR used 245 rears, but the S3/SV used 215? Does that significant difference in front & rear width result in a lot of understeer?

 

-John

 

Not with Vlad - he usually exits backwards. :jester:

 

Current standard sizes for a S3/SV are 6 wide or 8 wide. CSR standard rear was 8.5 for my silver CSR. You can get 9 wide rears for a CSR and they do exist for a SV or S3 even though not standard. Vlad's set up is fairly common.

 

I run a stagger set up on the 420 - 6x13 front and 8x13 rear - works quite well. If I was below 200hp I would go a square set up for wheel widths.

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You might also think about trimming off some of the excess bolt length. I did so, not for the tires, but for using tire bonnets (straps) which caught on the bolts, between the tire and fender.

 

The ZZS are larger diameter so I may need to do it for tire clearance. I don’t trailer my car so I don’t have the strap issue. Instead I got to drive 250 miles home from NJMP with dodgy brakes.

Edited by Black Hole
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Not with Vlad - he usually exits backwards. :jester:

 

Current standard sizes for a S3/SV are 6 wide or 8 wide. CSR standard rear was 8.5 for my silver CSR. You can get 9 wide rears for a CSR and they do exist for a SV or S3 even though not standard. Vlad's set up is fairly common.

 

I run a stagger set up on the 420 - 6x13 front and 8x13 rear - works quite well. If I was below 200hp I would go a square set up for wheel widths.

 

476.jpg

 

I'm 99% certain the staggered setup is stock on SLR packages but square setup was available as well and came on other trims throughout the years. The 245's the came off the back were from 2001 which is also the year of the car. I'm certain there were stock.

 

With that said I've never spun the car! From what I can still recollect out of the ton of different experiences over the adventurous period of tracks last year my car tends to understeer and I'm happy with that. Sway bar is in the back is likely in the middle setting too.

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Staggered is stock; I'm just surprised by the delta. 185/245 is more extreme with my ass-engined car. Even the 620R -- which by all accounts is reasonably powerful -- only has a 185/215 stagger.

 

-John

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...my car tends to understeer and I'm happy with that. Sway bar is in the back is likely in the middle setting too.

 

I suspect the reason for that is your car was corner weighted for 2 people in it and you track with just one on board.

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  • 4 weeks later...

I got my ZZS and had them mounted and as expected they do have some minor clearance issues. The good news is they do not interfere with the stay, which was one concern based on their larger size and minimal clearance, but they do rub (lightly) on one fender The tire tech said they were a real bitch to get on the rims.

 

 

20_03_07_Caterham 7_001.jpg [ATTACH=CONFIG]16660[/ATTACH] [ATTACH=CONFIG]16661[/ATTACH] 20_03_07_Caterham 7_012.jpg

 

So the question is what is the best tactic to solve this problem. I can try and bend the wing stay (cold or heated), I did a test try a while ago and it seems pretty stiff.

 

I could move the wing to outboard as it is not centered and I think that would work. i would have to deal with the holes in the fiberglass.

 

The final solution would be to buy the new stays as they note on the Caterham Parts website that they are for ZZS/R tires. I suspect I would have a hole alignment issue with the wing holes so I would probably be just as easy to move the wing on the existing stay.

 

Its unusually warm (a nice balmy 44 deg F at the moment) in the NE so I will probably try the cold bend and if that works I exercise the car. I assume these tires have minimal grip at these temperatures!

20_03_07_Caterham 7_005.jpg

Edited by Black Hole
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Avon ZZS are fine for grip at freezing or below - I use them in track days in the UK at that temp. Just be smooth with throttle application and be more cautious of brake application as I find they lock up very very easily. Still plenty of grip for cornering.

 

Why not reposition the wing. You don't need bolts for affixing wing to stay. Most common way is Sikaflex 292i and big heads. Refer photos in post #16.

https://www.lotus7.club/forum/techtalk/which-sikaflex-252-or-552-or-fixing-bigheads-cf-cycle-wings?page=1

 

No bolts needed. If you need to reposition then you cut it off, remove old adhesive and start again. Its how I do my CSR.

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Avon ZZS are fine for grip at freezing or below

 

Why not reposition the wing. You don't need bolts for affixing wing to stay. Most common way is Sikaflex 292i and big heads. Refer photos in post #16.

https://www.lotus7.club/forum/techtalk/which-sikaflex-252-or-552-or-fixing-bigheads-cf-cycle-wings?page=1

 

 

Good to know on the cold temps. The P Zero I had were abysmal in cold weather. Have not really tested my Micheline 4S at a cold temp.

 

Thanks for the reminder on big heads. I had thought of the zip tie / bonding solution before and that may be the best solution. Amazon has the adhesive, is there a US supplier for the fasteners?

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Good to know on the cold temps.

 

Still take care - there is not as much grip as on a dry warm day. I find braking is the biggest issue - you get wheel lock up quite easily. If you need proof my 3 way video comparison posted this week was on Avon ZZS. It was freezing temps plus moist conditions. Cornering grip surprisingly decent for the conditions.

 

 

Yes googling "bigheads" could produce some unwanted results....

 

The website is here

https://www.bighead.co.uk/bighead-solutions/extended-range/

 

The one people use is 32mm square tyrap.

 

As a distributor, they will probably only sell in silly bulk quantities so I would try Ebay to buy four for your purposes. Even if it is UK Ebay, the postage for four won't be too bad.

 

Singles available here in UK

https://www.ecfibreglasssupplies.co.uk/product/cable-tyrap-stainless-steel

They ship internationally if you call.

 

 

Some additional information on using them and prep guidance

https://www.lotus7.club/forum/chitchat/bigheads

https://www.lotus7.club/forum/techtalk/bigheads-0

Edited by Croc
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Yes googling "bigheads" could produce some unwanted results....

 

 

Thankfully my web search only found the company and no collateral damage

 

 

The one people use is 32mm square tyrap.

 

Perfect, I was perusing the options and needed this info

 

Off to eBay to see what I can find as there does not seem to be anyone retailing them in the US

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