I will shortly be changing the tyres on my 100 HP ,
22000 miles and still loads of tread but wearing on inside edges .
And with winter on the way I think its better safe than sorry to change the 4 tyres , So I'm thinking of upping the tyres from 195/45/15 to 195/55/15 . as anybody tried this?
,any constructive comments appreciated . Raising tyre wall more for the sake of comfort than anything else .

there's this chap in Athens who went to 50's.

http://onehundredhp.com/?p=98

There was also a thread a while back about the effect changing the size had on the speedo readings. The 50 would make the speedo read slower but I think someone else reckoned the 50 would just about balance out the optimistic reading. A 55 would I think put you very much the wrong side.

Try this site
http://www.kouki.co.uk/utilities/visual-tyre-size-calculator?wscr=1024x768
a 55 would mean at 30 you are doing 32.1 (assuming speedo was dead accurate)

mtsw said:

I will shortly be changing the tyres on my 100 HP ,
22000 miles and still loads of tread but wearing on inside edges .
And with winter on the way I think its better safe than sorry to change the 4 tyres , So I'm thinking of upping the tyres from 195/45/15 to 195/55/15 . as anybody tried this?
,any constructive comments appreciated . Raising tyre wall more for the sake of comfort than anything else .

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That would result in a 7% difference and generally it's reccomended to keep it at 2.5-3% so I would say it's not a good idea.

Why would you want to do this? Just don't understand. It will add significantly to the rolling radius, it's a quirky tyre size that has limited choice of tyres (my ITR uses this size).

Why not just use the standard size? Trouble is you'd do well to find a tyre with a softer sidewalls than the F1's. Suppose you could go to a 50 profile as there is as lot of choice in this size. Though i wouldn't reccomend going to a 55 profile.

I run 195/50/15 winter tyres without any problems, but that's only because nobody makes a 195/45/15 winter pattern - I wouldn't run that size all the time however.

If you want ride comfort get a different car. The 100HP springs and dampers are so stiff for such a short and narrow car, and a lack of rear anti roll bar compounds this. Increasing tyre profile isn't going to transform the 100HP into a comfortable car.

Just IMO.

Ben

As others have said, have you considered a change of tyre rather than size? Toyo Proxes are supposed to very good; to pass on a bit of hearsay from a work colleague (so I won't vouch it's true!) he is on his second set on his Civic and reckons the sidewalls are far more forgiving than the OEM Bridgestones. I know Andrew B went for 50s but 45s are listed as available here in the UK if you don't mind the extra expense. Gains may be marginal however given the suspension set-up.

Schwenck said:

Toyo Proxes are supposed to very good; to pass on a bit of hearsay from a work colleague (so I won't vouch it's true!) he is on his second set on his Civic and reckons the sidewalls are far more forgiving than the OEM Bridgestones.

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They are good....Bit noisier than the OEM F1s and very slightly less grippy in the wet....They haven't lasted quite as long though....

BenP said:

I wouldn't run that size all the time however.

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Why is that?

I quite like the idea of running 195/50/r15, but why didn't fiat fit them originally?

As per reply to " 16's on a 100hp "

Find a tyre with a 2 ply sidewall, you won't look back - makes all the difference in ride comfort, as for treadwear rates, don't get me started !!

As for increasing the profile size to a 50, yeah, good in theory but, you could end up spending money unnecessary hoping for an improvement in ride comfort, resulting in very little to no improvement.

P.S Forget 55's, that's just wrong... ( in terms of too bigger size for application, & just looking totally out of proportion )

pdtrewern said:

Why is that?

I quite like the idea of running 195/50/r15, but why didn't fiat fit them originally?

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Rolling radius would not be correct for their calculations I guess. Can't see any other reason.

Proxies are a bit of a budget tyre really.

Fair point. I think when mine are up for replacement (19,500miles on originals) I will go down the 50 profile route...

trackdayqueen said:

Proxies are a bit of a budget tyre really.

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What defines them as a budget tyre?

Pricewise, there's not a lot in it....

Blackcircles.com:

Yoko S-Drives - £44.97
Toyo T1R Proxies - £49.80
Goodyear F1s - £54.95

ThisBitterPill said:

What defines them as a budget tyre?

Pricewise, there's not a lot in it....

Blackcircles.com:

Yoko S-Drives - £44.97
Toyo T1R Proxies - £49.80
Goodyear F1s - £54.95

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Blackcircles have an offer on S-drives, which is where I got mine from, have seen them for £70 each elsewhere. Proxies tend to be a little bit cheaper than other comparable tyres.

There is nothing wrong with them, a bit soft in the sidewall. Have them on the front of my ITR (only because we are selling). Had them on there for a few months, they don't rate very well compared to the OEM integra tyre (RE010's) way too floppy on the sidewall really.

pdtrewern said:

Fair point. I think when mine are up for replacement (19,500miles on originals) I will go down the 50 profile route...

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Why though? You didn't seriously buy a 100hp for comfort and higher profile than spec wheels will just spoil things.

I know, it's the only thing that is just not quite right on the 100hp, taking just the edge off the jarring would make it complete..

And no, I dont want to change!! Its does everything else (esp handling) extremely well. Having said that, fitting new rubber (original size) would have slightly more rubber between wheel and road.. about 6mm if the old ones are worn...

I stuck two new tyres on the C4 on Thursday as they were approaching the TWI's and it was quite surprising how much the ride improved with a bit of extra rubber.
After an afternoon of trundling around with the sat nav checking the speedo on the 100 hp one side effect of a switch to 50's might be to make the speedo a bit more accurate.

Thought about Koni's as a permanent fix to ride comfort instead of changing the tyre size, after all there are insurance implications on both counts here.

Koni shockers will last far far longer than a set of fatter tyres.

There are a lot of good vehicles out there just crying out for Koni's, which can only improve the overall feel of the car.

pdtrewern said:

I know, it's the only thing that is just not quite right on the 100hp, taking just the edge off the jarring would make it complete..

And no, I dont want to change!! Its does everything else (esp handling) extremely well. Having said that, fitting new rubber (original size) would have slightly more rubber between wheel and road.. about 6mm if the old ones are worn...

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I'm not convinced going up a profile half size is going to give you what you are looking for. The problem lies in the rear suspension.