Wheels /tyres (yup laugh if you feel you must..)

[RogW]

I am well aware that I am more than likely to be opening myself up for criticism, ridicule, made a laughing stock of etc (a trait which sadly seems so prevalent on this site currently...)

 

I recently posted a thread on ChitChat asking for thoughts suggestions for my HPC Vauxhall - the result of which and after some careful thought and CONSIDERABLE searching on here - I have decided to change the wheels and tyres (currently 16 inch with associated tyres that have consistency of concrete)

 

I also posted a follow up thread asking for clarification on a couple of things (with hindsight, I something I regret doing due to the stupid comments coming back - eg - "My advice would be to go for the round ones. The square ones save on handbrake wear but it makes life difficult when trying to set up a consistent ride height" - MY HOW WE ALL LAUGHED at that comment... . (Leads me to question why I bothered to renew my membership a few weeks ago... A thought I suspect I am not alone in having)

 

If its POSSIBLE on here - I would like some straight forward advice - I make NO PRETENCE about being no more than a mechanical numpty - the same as I was when I joined the club over 10 years ago.

 

Simple question - If I replace the current 16" wheels with 13"s - my thoughts are 6" wide fronts and 7' wide rears with Comp Minators (probably from George Polley, who seems to be highly thought of), with 185 55 13 on the front; 205 55 13 rears, offset OT23 (?Is this the correct offset?) Simply - will this fit without any issues, reworking/lowering of suspension; fouling of body (car has clams [yup take the p**s if you feel you are soooo much greater than everyone just by having some other lump of plastic/carbon stuck over your wheels...]). Will it effect the speedo readings and if so by how much? (is that possible to work out? And if it does would it effect the MOT testing?)

 

Tyres - I err between 888s and 021s - car has approx 190ish HP (and needs to go on a rolling road to sort - another issue I would like some plain advice on - if that is again possible here).

 

Pretty simple questions I know - none which have not been asked before - for which I apologise - all I would like is some straight forward answers.

 

Kind regards etc.

[Grubbster]

Hi Roger - I hope I can answer a few of your questions.

 

Firstly you need to compare the diameter or circumference of your old and proposed new tyres to understand what the difference in ride height will be and whether the speedo will read much differently. About a quarter of the way down this page is a little calculator that will enable you to do this. Obviously if your car ends up much lower you can expect that you may need to raise the ride height.

 

Regarding offset - I don't know the answer but on the site above there is a good explanation of what it is so maybe that will help.

 

 

R888's are a great dry weather tyre for road and track (this is what I use at the moment), A021's would be better in the wet though (but not quite so good in the dry) so depends on your use.

 

Rolling roads - not sure what your question is but the basics are that you can get a power run for £30 - £50 ish depending on where you go, but if you want the car mapped while on the rolling road this can take a few hours and cost in the region of £300 (probably plus or minus £150 depending on where, type of ecu, problems etc). I used Emerald and their price list is online here

 

 

It's only taken four and a half years - I have started my website at last! Early days yet . . .

 

Edited by - Grubbster on 24 Jan 2008 23:08:53

[Casbar]

Caterham 6 x 13 rims have a 24mm offset.. if you go to 7"or wider you might find that they foul on the front wing stays.. So 6 inch front and 7 rear should be ok, I run that combination....

 

Simple question - If I replace the current 16" wheels with 13"s - my thoughts are 6" wide fronts and 7' wide rears with Comp Minators (probably from George Polley, who seems to be highly thought of), with 185 55 13 on the front; 205 55 13 rears, offset OT23 (?Is this the correct offset?)

 

George Polley will be able to advise on offsets, but this should be ok. I did have to grind off some of the de-dion tube with 7inch rears, but nothing major and it only took a few mins...

 

Simply - will this fit without any issues, reworking/lowering of suspension; fouling of body (car has clams [yup take the p**s if you feel you are soooo much greater than everyone just by having some other lump of plastic/carbon stuck over your wheels...]). Will it effect the speedo readings and if so by how much? (is that possible to work out? And if it does would it effect the MOT testing?)

 

Different rolling circumph will effect speedo reading, best to check against a measured mile to see how far it is out. Or fit a bike speedo. It will not effect MOT as it is not tested.

 

Tyres - I err between 888s and 021s - car has approx 190ish HP (and needs to go on a rolling road to sort - another issue I would like some plain advice on - if that is again possible here).

 

Think I would go for 888's or CR500's, which is what I use. Infact I use slicks on the tracks and CR500's for a road/wet tyre. Changing wheel size will change ride height, so this will need to be sorted, you will need adjustable platforms, if you don't already have them.

 

Pretty simple questions I know - none which have not been asked before - for which I apologise - all I would like is some straight forward answers.

 

 

[DohNut]

 

From Polley site

A021 185/60 R13 558mm diameter = 1752mm circ

A021 205-60 R13 578mm diameter = 1815mm circ

 

ie the circumference of the big tyre is 3.5% larger than the smaller one.

To get a bit more perspective on that, if the bigger tyre started with 7mm of tread and wore down to 2mm tread, the circumference drops to 1783mm

ie the change is insignificant compared to the accuracy of the speedo.

 

N

[I reply to every thread]

You usually only get the de dion fouling problem with 8" rears & then with the latest Caterham design

[Graham King]

Roger, I am not sure either of the tyres you mention come in a 55 profile. Choice of tyre is a personal thing depending on your usage profile, but I run mine on 185/60 R13 R888's. I have used these in heavy rain and they were fine and in the dry they are fantastic, however if I was planning on using the car in all weathers (which I don't) then I would probably go for A021 as a better compromise.

 

I don't know if it is a consideration or not but Polley are a Yoko dealer so will probably supply tyres on wheels balanced and ready to go with A021 whereas R888's you will have to source and fit yourself.

 

I think you will be amazed how different the car feels on 13" wheels.

 

Have fun.

 

Graham.

 

R7 GPK

Superlight #85

[CageyH]

Bear in mind you may have to raise the suspension platforms if you go to 13" wheels to maintain the same ground clearance.

 

What tyres do you have fitted now? If we know what you have, it is possible to work out if there is any loss in ride height, and by how much.

 

As for tyre choice, if general all round use, A021's. If venturing on to track occasionally, probably R888's.

Offset - ET23 sounds about right, but George Polley knows what you need. (He did when I ordered mine).

 

Only dead fish go with the flow....!

[neilg]

Roger, the Toyos and the Yokos would not be available with 55 series profile...i think that is the preserve of the Avon cr500.

I've just changed from Avon 175/55-13 to Toyo R888 185/60-13 this morning in fact purely cos I fancied a change and a set of four cost me £ 265-00 fitted and balanced including VAT from Steve at Simply Tyres, Wellingborough.rather than the £400-00 CR500 's would have cost from CC.

Actually the ride height difference is quite marked from the Avons to the Toyos just between the two tyres. I think I am going to have to have my suspension re flat floored.

The weight difference between the Avon and Toyo when you have them in your hands without wheel is also quite marked, the toyo being heavier.

I could also tell the gearing was higher than before although i haven't yet worked out how much.

I think the general consensus on here is than the Yoko A021/ CR500 are the best rain tyres and good all round road use tyre whereas the Yoko 48 and Toyo R888 have better lateral grip on track and are not quite so capable in resisting aquaplaning through standing water.

I have 6 inch rims all round with adjustable Billies.

If you plump for the Toyos give Steve a ring on 07737741634 at Simply Tyres in Wellingborough. He did a great job for me this morning.

Whatever your choice it will be a damn site better on 13's than the 16's.

Cheers Neil

[Mike Molloy]

I just got a quote from Steve Polley for 7 x 13 KN Minators (ET24): £65+VAT each (plus P&P).

I think the 6 x 13 fronts are ET19.

Worth getting a quote for a package deal with your choice of Yokohamas. (A048 maybe?)

Email: steve at polleymotorsport dot co dot uk

 

Still think you should go the whole hog and search out a s/h set of Barnby mags. Be prepared for a jaw-dropping experience if you compare the weight with one of your 16" wheels... 😬

[Lotus Boy]

Roger - shame to hear you didn't get straight forward answers before.

 

I have a 94 HPC that wears 15" Prisoners for touring and 13" minilites for summer hooning. Currently they have A048's, far too twitchy so am switching to R888's for this year.

 

My 13"'s are 6 & 7 and yes the rears did foul the de dion ears but as mentioned it is very easy to grind off a couple of mm where it touches. Not had any probs since. When Caterham introduced the 8.5" rear SLR wheels they started making smaller ears for clearance reasons, not sure when this happened but suspect mid to late 90's(?).

 

I haven't adjusted the ride height yet and although it does noticably sit lower on 13"'s I've not encountered any problems to date. As the car will wear the 13"'s more of the time I am going to get it flat floored for these so it is properly set up.

 

Oh yeah and I have flares too so you'll have no issues there...and yes I am a fan of them too and don't care what others think!

 

To finish my ramblings - you won't regret fitting the 13"'s and sticking better rubber (185/60 and 205/60 is what you need to fit) will transform the car. Keep the 16"s as spare or do what I do. I have Yoko A539 on the Prisoners which are ideal (well I think) for long distance touring such as the Swiss Trip as you will be prepared for all weathers, you won't wear them out quickly and switching back to 16"'s will give you a bit of useful ground clearance should you need it.

 

Hope all or some of this helps

 

Dave

[F355GTS]

Roger

 

Oddly unlike Aves I've had no problem with 8" fouling the dedion but the 7" did, I've machined the ear/ ear bracket to clear

 

I'd definitely go for the A021R's for general road use over the 888's if you ever intend to see any standing water

 

On the Rolling road I would not recommend running the 21's (Road & Race and Polley's recommend you do not use an race tyre) I had two virtually new 21's fail on the RR caused by them getting too hot and when brought to rest they delaminated where in contact with the rollers

 

Mark

[philwaters]

That's interesting Mark, my 032's got pretty warm at Emerald last year, but didn't suffer - but then they had gone off a couple of year before then!! and I've got loads less power then you

Got the R888's fitted this afternoon and they feel like chewing gum in comparison to the old 032's. Can't wait to try them.

£256 for 185x60x13" fronts and 205x60x13" rears... fitted in 45mins to Bracknell Tyre & Battery.

 

Phil Waters

[RogW]

Brilliant help guys - THANKYOU

 

Looks like it will have to be 60 profile rather than 55 - and 021's I think. (I guess anything will be better than the Mich "Pileups" that it has at the moment).

 

Looking forward to the results!

 

Time to get the credit card out me thinks!

 

Be prepared for some other total numpty questions coming to space soon!!!

 

Kind regards

 

Rog

[nickh7]

Consider the roads you drive on, round here in South Yorks the surface is poor and sumps can suffer if you run to low, I find the 14" a very good compromise and yes 13" offer better balance but I cant risk the sump. Yes I know you can set you ride height to offset the smaller wheels but

 

Go for 048rs soft front medium rears- simply stunning

 

 

PS Rog dont forget to make sure you ask for the round ones

 

 

Its Yellow And Black and Makes me 😬here

[Slipper man]

The cheap 021's are 70 profile I think, and are (IIRC) the same diameter as the 16 in tyres.

[combine]

I've been advised to get 6x14'' wheels if changing from 'HPC' wheels as there will be a very large gap between tyre and mudguards , its up to you though ! 😬 Probably a good idea to check ground clearance with new wheel sizes too as my car is low enough already , serious damage will result if it gets lower !

 

Edited by - combine on 25 Jan 2008 19:22:14

[Gambo]

My HPC came originally with 16" wheels. If you go to 13", you will indeed have a large gap between the tyre and cycle arch. If you have Clams then you will not notice this difference so much. Really, reguarding the cycle arch tyres gap, it will be a personal prefernce whether you like it, or you could simple buy 13" arch stays and new arches.I won't bother with the other questions as evrybody else has covered them.

 

RED 2.0 HPC 230BHP here

[k.russell]

Roger, another for George Polley, went for 6's and 7's on my HPC after innitially having the 16's with goodyear eagles, then 6's allround with 021r,these were very good, but think the 048s i have on now are the best so far. fwiw i did fit adjustable shocks to set the car up how i wanted it, ride height etc. i do have gaps under the front arches but if you have clams then this isnt a problem. A close freind also has a HPC with same combination of wheels & tyres and has remained on the OE bilstein fixed length shocks and had no problems. I did have to file the de - dion slightly at the egde of the ear to clear the inside of the 7" rims. pics of my HPC here

 

kevin R

black-ali HPC

 

 

 

Edited by - k.russell on 25 Jan 2008 19:43:02

[Dickie Normuss]

Lighten up, I was only having some fun. If you hadn't have been so quick to close the thread you would have got the replies as above in time.

 

Apologies for having upset you.

 

VX HPC - Loud and proud here

Watch out, whatever hits the fan will not be distributed evenly