Tyres

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ANDYC8888
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Tyres

Post by ANDYC8888 » Thu Aug 24, 2017 11:38 am

Back to the age old issue of tyres.
My track bike is using a standard 4.50 wheel, and when it was on the road I had no problem running 160/60 tyres rather than the standard 150 set up.
Now I have switched to Pirrelli supercorsa SC2 which are track only tyres. A 160/60 seems to be pinched as if the 4.50 rim is too narrow for it, in fact it reduces the width down to 150mm from the true size of 165mm.
I have been in touch with Pirrelli and they sent me the chart which indicates that a 160/60 should be happy on a 4.50 or a 5.0 inch rim. This doesn't really help the present problem.
Has anyone out there had similar issues, or can shed some light on the subject?
Thanks in advance.

CB1pod70
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Re: Tyres

Post by CB1pod70 » Thu Aug 24, 2017 1:01 pm

Most people I know are racing 400s on Supercorsas with no issues.
They do appear to have a narrow profile compared to the Avon Extremes (also 160/60) which a few of us use and certainly feel a bit less forgiving but tip in quicker than the Avons. Personally I prefer the Avons (and they're cheaper too) but all the fast guys are running Supercorsas........

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Re: Tyres

Post by northernmonkey » Thu Aug 24, 2017 2:06 pm

Hi. I run spercorsa's on standard rims on my nc29 (and did on my rs250 as well). Fantastic tyre and can be bought cheaply as scrubs from the Thundersport supertwin boys who seem to change tyres constantly. £80 - £100 per pair is the going rate and you can normally pick up wets from the same source. Keep an eye on the date stamp.
The tyre does look a little 'pinched' but it is right and are suited to every circuit I've raced on (no stability issues).
Have fun.
Mark

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Re: Tyres

Post by ANDYC8888 » Sun Aug 27, 2017 12:07 pm

As it was one of those things that I knew would irritate me endlessly I decided to fit a 5 inch wheel. Quite straightforward really.
Although on saying that it was because I have a fair few CBR parts to choose from and try.
The standard set up with a 520 alloy sprocket but no disc tipped the scales at 12.60kg once I get the tyre swapped over next week I'll be able to see if there's much difference.

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Re: Tyres

Post by ANDYC8888 » Tue Aug 29, 2017 9:41 pm

The same set up with the 5 inch wheel weighs in at 13kgs. The tyre sits much better on this than the 4.5 wheel. The width is 163mm now.

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Re: Tyres

Post by northernmonkey » Sun Sep 03, 2017 9:26 am

Hi Andy. What bike was the 5 inch wheel off and was there much involved in swapping it? Was the Cush drive/sprocket carrier/ chain run the same?.

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Re: Tyres

Post by ANDYC8888 » Sun Sep 03, 2017 4:46 pm

Hi Mark,
It took a fair mixture of items but all of which are much cheaper and easier to source than nc29 bits.
The 5 inch wheel came from a CBR600F3 (94-98).
The sprocket carrier came from a CB500 (disc model)
Sprocket from Cb500 or SV650 depending on the use.
Caliper carrier from Cbr600f3
The sprocket carrier fits the wheel and uses CB500 cush drive rubbers. The sprocket can either be cb500 or due to the limited choice I went for the sv650 sprocket. This means that I had to reduce the size of the studs from m12 to m10 rather than enlarge the holes to suit the larger studs.
Fortunately once you remove the studs the threads left readily fit the m10 helicoil inserts which I considered to be a good result.
The standard disc fits fine however the disc is 10mm closer to the centre than on the standard wheel so the standard caliper carrier needs to be replaced with one from the cbr600f3 which is exactly 10mm wider than the original. Another stroke of luck is that the standard caliper fits straight on the carrier.
The standard spacer seemed to line everything up on the sprocket side.
The spacer between the disc side and the carrier needed to have one made to suit. Fortunately I have a lathe so it wasn't a problem. I can't remember the exact size but 14mm seems familiar. I may need to do some fine adjustments to align the sprocket once I get the gearbox in, but it measures up the same distance from the centre as the standard one did so it can't be that far away.
If you've got this far then anything else would be easy.
I have tried to cover everything but apologise if anything has been left out.

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Re: Tyres

Post by northernmonkey » Mon Sep 04, 2017 5:28 pm

Thanks Andy, and that a wide range of shopping you've done there to get that to fit.
I will have a look at that for a roadbike build I am planning over winter.

Mark

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Re: Tyres

Post by ANDYC8888 » Tue Sep 05, 2017 11:34 am

A minor point that came to me in a blinding flash of memory is that you will need to change the bearing and spacer from the CB500 sprocket carrier as it only runs a 17mm spindle. The memory didn't last long enough to tell me which one I used though. It may well have been the NC29 one, I'll check and get back to you on that one.


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