15 inch ten spoke alloys tyre size??

[pkw2704]

ok so toying with getting some new rubber for the car,have uniroyal 195/45/15 on at the moment ,my questions is ,tyres in this size seem more expensive with less choice.Can you fit 195/50/15 tyres or will this size cause issues with fit or catching the clams ?

[East Kent AR]

I have 195/45/15 on the standard Caterham 10 spoke wheels. I tried 195/50/15 and it fouled the front wheel bracket that holds the carbon fibre arch.

I am not sure what the answer is, as I will eventually have that bridge to cross, as I have a spare set of tyres and wheels.

Piers

[pkw2704]

Oh dear that's not good news,could it be adjusted/bent out of the way? my very rough calculations make the 50 series around 10mm(5mm top 5mm bottom) bigger.Just found some Accelera 651 tyres that seem ok and was going to go for them

[aerobod - near CYYC]

It will depend on the profile of the tyre in many cases. I originally had very square-shouldered CR500s in 195/45-15 tyres on my R400D road wheels, had to swap to 195/50-15 due to availability, the Bridgestone RE-71R tyres I put on are a bit more round-shouldered and just clear the inner part of the stay and leave about 5mm to the outer lip of the carbon fibre wings. The overall diameter of the RE-71Rs at 576mm is about 20mm more than the CR500s were.

[pkw2704]

Understand James, the ones i fancied seem more track semi slick, but still a legal road tyre. Accelera 651, not sure if they are any good?

[aerobod - near CYYC]

The Accelera 651s seem to get decent reviews in many cases online. They do look like the RE-71Rs in term of shoulder roundness and are the same class of tyre (200 treadwear max performance summer tyre), they even have the same basic tread pattern.

I have a friendly tyre fitter that is quite happy to test fit tyres and take them back at no charge if they don't fit properly.

I would see if you can get those or similar tyres such as the Toyo R888R, Yokohama AD08RS and Avon ZZS test fitted by a more bespoke tyre fitter who is willing to spend the time to check the fit.

[pkw2704]

cheers James, is the shoulder roundness good or a bad thing? the toyo and yoko you mentioned were on my list ,it was purely the acceleras came at a good price

[aerobod - near CYYC]

From a clearance perspective, a slight round shoulder helps with both the wing clearance and inner part of the wing stay, you are talking millimetres here. I have about 5mm clearance in both cases with my 195/50-15 RE-71Rs, but don't lose too much in tread width compared with any other similar 195/50-15 tyre.

I'm running Nankang AR-1 185/60-13 front and 235/45-13 rear track tyres which are smaller diameter than the 15" road tyres, in 195/50-15 size they would probably rub due to the more square shoulder profile.

[John Vine]

My experience is pretty much the same as James (#4).  I moved from 195/45-15 CR500s to 195/50-15 ZZSs on my R400D 10-spoke anthracites.  The ZZS is more round shouldered - sufficiently so to just fit within the wingstays.

JV

[pkw2704]

well we'll soon find out if they fit ,ordered today !!

[pkw2704]

well they are on and fit no rubbing issues ,good clearance at the front due to rounded shoulders.

[Peter Wright]

Looking Good.  I'm going to give these some serious thought.

[East Kent AR]

What is the effect on the speedometer from going from 45 to 50 section tyres?

Piers

[Garry7]

Hi Piers,

I went from CR500s 195/45/15 to Nankang NS2R's in 195/50/15. Had to bend one wing stay slightly (by hand) but otherwise fitted ok. Speedo went from slightly over reading to just about spot on when compared to my GPS.

Best

Garry

[Mechanical Moz]

https://www.willtheyfit.com/index.php?width=195&aspect=45&diameter=15&wheelwidth=6&offset=50&width2=195&aspect2=50&wheel_size=15&wheel_width=6&offset2=50

This calculator shows the speedo error, a 3.39% reduction in indicated speed going from 45 to 50 section.

[East Kent AR]

Very interesting Gary and they are half the price of Avon ZZS 195/50/15.

Did you notice any grip/cornering difference?

regards

Piers

[Garry7]

Hi Piers, not really, no, still grippy enough for me at the speeds I go at  

Best

Garry 

[John Vine]

Re #13 and #15:

Don't forget that, if you have one of Caerbont’s Electronic Programmable speedos (2004 on), you can correct the error by editing the 6-digit pulse code.  For info, see Part C of this Guide.

JV