Tyre Profiles

[Danny S]

Apologies if this has been asked before. which i imagine it has but can't find a sufficient answer.

I currently have 45 profile tyres fitted to my astra.

Its time to change them and i noticed in the book 50 profiles are recommended.

The ride at the minute is pretty harsh but the handling is pretty good for an Astra.

If i go to the recommended 50 profile tyres, will i notice much in the way of handling? I've read the car may feel a little more "spongey" ?

Thanks in advance
Daniel

[RichardD]

It is a small percentage difference, so I wouldn't worry about it or think it would make much noticable change.

[Simbu]

IfF your car was designed with 50 profiles and currently has 45's on it then the speedo will be slightly inaccurate, so fitting 50's again will resolve this.

[jarnold88]

I'm no expert but it will depend on how hard your side walls are, you wouldn't believe the difference a good set of tires make, originally on my car I had 195/55/R15 tire which was a Pirelli P6000 - a good tire I thought, in all weather conditions it gave good feel and had good grip, when it came for a change I had 195/50/R15 Pirelli P5000 Drago's on it, terrible tire! Not as much feel for the road, hardly any dry weather grip, slightly better wet grip, but definately not recommended! After those horrid tires I got 195/50/R15 Uniroyal Rainsport 2 tires on and they transformed the car, bag and bags of grip in all weather conditions, more feel for the road than any tire I have used before, only thing is...they have extremely soft side walls, so unless the tire pressures are perfect they were very squashy, I found I was doing my pressures once or twice a week just to make sure I had the best out of them.

So to summarise it really depends on the side walls of your tire, a larger side wall will generally give you more feel, but with the rainsport 2 being so soft they give more feel at 50 than the P6000 did at 55.

Hope this helps

J

[Danny S]

Thanks a lot for the advice!


I know the speedo is out at the minute, it is one of the main reasons i am asking asides from handling. Currently the diameter is about 5% out

If it has implications on my tyre, could it also affect my gearing ?

Thanks for the tyre advice J! appreciated



ETA- While i'm here, wheres a good place to get a tyre plugged? I have one of the original 50 profile tyres in the garage, its near enough brand new but has a nail in the tread and loses air.

Thanks
Danny

[varsas]

It will affect the gearing. Assuming the tyre width (and wheel size!) stays the same, a 50 profile tyre will be bigger (have a larger rolling radius) then a 45 profile one...so the car will travel further for each turn of the engine then it currently thinks it does. It also means it'll reach a higher real (not indicated) speed in each gear, but acceleration will be lowered.

http://www.etyres.co.uk/tyre-size-calculator.htm

Edited by varsas on Wednesday 9th June 10:54

[alfa pint]

A 50% profile tyre will hardly give you a 'spongy' ride! It will improve the ride marginally, but it's really only 65% and above profile that the tyre acts a bit like a suspension component.

As also posted above, the tyre choice makes a huge difference and what works well for one chassis is completely wrong for another - Pirelli P6000 tyres being a case in point; they're probably the worse tyres possible for my car, but standard fit on some saabs and jags.

[Danny S]

Thanks lads


Do you all stick to manufacturers advice on tyres then?

I've heard good things about Toyo Proxes, i will ask on the Astra OC for advice on which tyre to go for (unless theres an owner reading now)

[HellDiver]

If it's the 205-50-16 on a Mk4 Astra, then there'll be no problems with ride compared to the 45 profiles. I ran mine with a 55mm front lower, had no problems at all.

I went through lots of tyres on my Mk4(same tyre size), and the best two tyres I ran were the Bridgestone RE050 and the Lassa Impetus 2. The now discontinued Bridgestone RE720 was good too.

Edited by HellDiver on Wednesday 9th June 11:13

[dylan0451]

the proxes T1r is about £30 a corner from camskill in 195/50 r15 at the moment which is fantastic value considering some ditch finders are going for more

after coming from yoko parada's the T1r does feel like it's walking about on the tread blocks, abit akin to a nail brush :-s hopefully they'll settle when they're a bit more worn, though they're pretty good in the wet compared with the yoko's

i hear they wear fast, and i've noticed shoulder scrub wear after 2 weeks of having them on my car. for the price i couldn't grumble if they only lasted 8k or so

ETA just realised this is not the size you're after at all

Edited by dylan0451 on Wednesday 9th June 11:19

[Danny S]

dylan0451 said:

the proxes T1r is about £30 a corner from camskill in 195/50 r15 at the moment which is fantastic value considering some ditch finders are going for more

after coming from yoko parada's the T1r does feel like it's walking about on the tread blocks, abit akin to a nail brush :-s hopefully they'll settle when they're a bit more worn, though they're pretty good in the wet compared with the yoko's

i hear they wear fast, and i've noticed shoulder scrub wear after 2 weeks of having them on my car. for the price i couldn't grumble if they only lasted 8k or so

ETA just realised this is not the size you're after at all

Edited by dylan0451 on Wednesday 9th June 11:19

Lol, thanks anyway mate

Does ETA mean "edited to add" ?

The recommended tyre size is 205/50/16 for me

[dylan0451]

Danny S said:

Lol, thanks anyway mate

Does ETA mean "edited to add" ?

The recommended tyre size is 205/50/16 for me

no probs! i assume thats what it means, i didn't ask through fear of being labelled old or not 'down with the kids' or whatever tomfoolery housie language they speak now

you could always go for something like 215/45/16 if you're after more grip, while keeping the rolling radius close. a few % is the difference between new and worn, plus different manufacturers measure the sidewall from diifferent points, or so it seems, so you could find yourself with 2 identical tyre sizes from different manufacturers that are in fact, different sizes!