Newbie-Probable old question

[Bearmurray]

Hi folks

Thanks for all the great information on this site.

I am picking up a Jan 99 Chimaera this weekend (can`t wait) and was hoping at some point in the near future to replace the alloys and tyres. The stock alloys are o.k but I think the car looks better with a slightly bigger "spider like" alloy.

I understand the TVR alloys require a change to 5 nut configuration, Can anyone tell me what size I could get away with? (without fouling the arches or upsetting basic set-up) what tyre configs would be best? I plan to buy some bigger alloys with 4 nut arrangement.

Cheers folks

Bear

[tvrbob]

The 5 stud configuration from TVR is subject to a very long waiting list. I've been on it for over a year. As for rim size, 17" 7.5" is as big as you can go without compromising the ride. The chassis needs the sidewalls to flex in order to provide progressive cornering grip. These cars will snap away from you very quickly and you'll need as much warning as possible.

As you're new to this I'll give you the one major piece of advice. Decelerating and changing down to engine brake is something to be careful with. It's very easy to end up with too much rear wheel braking causing the car to swap ends.

Take it easy for the first 1000 miles while you get to feel the car and you'll be enjoying your new car for many years. They are twitchy in winter.

[bearmurray]

Thanks TVRBob!

Will definitely be trying to take it easy over winter! Will I be O.k with 17" all round? In your experience are there any tyres that have been worthwhile, was either planning on Toyo`s or Bridgestones.

Sorry for being a pain.

All the best

[trevorw]

Hi and Welcome,

This topic may be of some interest to you click me

[19560]

One major consideration is: are you thinking of two different pairs of wheels or four the same. The originals have different dias, widths and offsets. Really for a 245/40 or 255/40 at the rear you could do with an 8 or 9 inch rim respectively but for a 215/45 at the front you need a 7.5 or 8 inch rim.
There are a few other points:-
Assuming that you keep the roling radius the same then larger wheels will: Downside:- cost more, have more expensive tyres, perform worse in the wet, perform worse on bumpy roads, be more susceptible to tram lining, increase the weight of the car, increase the unsprung weight, produce a harsher ride, increase the rotating unsprung weight(second moment of inertia) and be more liable to scuffing on kerbs when parking. On the plus side they should:- prevent the tyre from distorting thus giving greater cornering grip in the dry and on smooth roads, be more direct giving greater steering feel, produce less heat and be better for long high speed journeys, and effectively increase the spring rates being an easy way to fine tune your springing rates from summer to winter if you swap back to the smaller wheels for winter and they should look good.

Also note that fitting lower section tyres with less sidewall flex can make the car more sensitive to suspension geometry changes. Lowering the car can adversely affect the handling by throwing the static geometry out, and giving you too much camber correction and bump steer.

[tvrbob]

Toyo's or Bridgestone's, well that has been debated so much it's hard to decipher a PH opinion. Toyo's have a problem in that they take up to 1000 miles to settle in during which time they are, well lets say challenging. Once they settle they are more gripy that Bridgestone's but don't last as long. Bridgestone's SO3 are too hard, Bridgestone SO3pp are OK but they are less progressive when cornering. Probably sidewall rigidity. Bridgestone SO2's are OK on the rear but too hard for the front. SO2pp are like rocking horse dodo but are the best alrounder.

No opinion here, just my view of current PH thinking.

[Corin Denton]

19560 said:

One major consideration is: are you thinking of two different pairs of wheels or four the same. The originals have different dias, widths and offsets. Really for a 245/40 or 255/40 at the rear you could do with an 8 or 9 inch rim respectively but for a 215/45 at the front you need a 7.5 or 8 inch rim. There are a few other points:- Assuming that you keep the roling radius the same then larger wheels will: Downside:- cost more, have more expensive tyres, perform worse in the wet, perform worse on bumpy roads, be more susceptible to tram lining, increase the weight of the car, increase the unsprung weight, produce a harsher ride, increase the rotating unsprung weight(second moment of inertia) and be more liable to scuffing on kerbs when parking. On the plus side they should:- prevent the tyre from distorting thus giving greater cornering grip in the dry and on smooth roads, be more direct giving greater steering feel, produce less heat and be better for long high speed journeys, and effectively increase the spring rates being an easy way to fine tune your springing rates from summer to winter if you swap back to the smaller wheels for winter and they should look good. Also note that fitting lower section tyres with less sidewall flex can make the car more sensitive to suspension geometry changes. Lowering the car can adversely affect the handling by throwing the static geometry out, and giving you too much camber correction and bump steer.

A lot of good information there, a couple of points though, if your car is currently on Bridgestones which most are then the sidewalls are very stiff anyway so if you drop the profile and change to something like the Toyo with a softer sidewall it will be comparable in flex, these tyres will also be cheaper in most cases.

I have changed to 17"s and I can definately recommend getting the geometry set up afterwards.

[19560]

Corin Denton said:

A couple of points though, if your car is currently on Bridgestones which most are then the sidewalls are very stiff anyway so if you drop the profile and change to something like the Toyo with a softer sidewall it will be comparable in flex, these tyres will also be cheaper in most cases.

Yes, although most people agree that SO3PPs are too stiff in the sidewall for TVRs anyway given that the favoured original tyres were SO1, SO2PP or Toyos; of course you may have wanted a stiffer tyre anyway.

[M@H]

19560 said:

Corin Denton said: A couple of points though, if your car is currently on Bridgestones which most are then the sidewalls are very stiff anyway so if you drop the profile and change to something like the Toyo with a softer sidewall it will be comparable in flex, these tyres will also be cheaper in most cases. Yes, although most people agree that SO3PPs are too stiff in the sidewall for TVRs anyway given that the favoured original tyres were SO1, SO2PP or Toyos; of course you may have wanted a stiffer tyre anyway.

The originals on my last one were RE71's ..boy did the SO2's seem solid after them ! The tyrefitter even commented on the huge difference..

[19560]

M@H said:

The originals on my last one were RE71's ..boy did the SO2's seem solid after them !

Yep, sounds correct. The SO2s were too stiff and widely disliked; there was much relief when they were replaced by what should have been called the SO3 but was actually called the SO2PP.

[M@H]

19560 said:

M@H said: The originals on my last one were RE71's ..boy did the SO2's seem solid after them ! Yep, sounds correct. The SO2s were too stiff and widely disliked; there was much relief when they were replaced by what should have been called the SO3 but was actually called the SO2PP.

..and I was talking about PP's too ! ..what were the straight SO2's like..!!

[shpub]

Bit like PPs but a lot cheaper...

[PetrolTed]

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