Discussion
Did you buy the Chim for looks or for driving? 18" front wheels cause significant bumpsteer and tramlining. 18" rims at the rear cause the car to loose the nice progressive oversteer so the car ends up snapping into spin rather than drifting. If you just use the car for cruzin then 18" wheels will be fine but if you want to drive on country roads then I would advise against it. These characteristics can't be dialled out by suspension adjustment because they are both associated with lateral flexibility.
Owners who have tried this tend to agree that 17" is as big as you should go. Anymore and the enjoyment of driving is lost for the sake of making the car look better.
Bigger rims because they look good is dangerously close to the definition of Max Power
Owners who have tried this tend to agree that 17" is as big as you should go. Anymore and the enjoyment of driving is lost for the sake of making the car look better.
Bigger rims because they look good is dangerously close to the definition of Max Power
Edited by tvrbob on Sunday 23 December 09:41
Bob, I'll bow to your superior knowledge here as I know nowt about it.
Are 18 at rear and 17 at front so bad? There seems to be a few cars nowadays with this sort of set up. Would SP go to the trouble of getting wheels made in these sizes if they were cack?
Like I say I'm only asking as I don't know
Are 18 at rear and 17 at front so bad? There seems to be a few cars nowadays with this sort of set up. Would SP go to the trouble of getting wheels made in these sizes if they were cack?
Like I say I'm only asking as I don't know
ray_von said:
Are 18 at rear and 17 at front so bad?
Hi Ray, people get away with this. I guess it depends how you use the car and what tyres are fitted. The important thing is to maintain as much lateral (side to side) movement at the road contact patch as you can. For the front this allows the tyre tread to follow ruts and white lines without dragging the car. It also absorbs ruts that when cornering hard would cause the tyre to bounce thus causing bumpsteer. The rears need a little flexibility to allow the tyre to tuck under when steering hard. This progressively reduces the contact patch which in turn allows the car to slowly develop oversteer. Without this progressiveness the rear simply breaks away causing a spin that can't easily be controlled. There's a contradiction here though. If lap time is important to you then bigger rear rims will be better because you can maintain a bigger contact patch. The down side is that when you loose it you loose it big time. I think 17" fronts and 18" rears matched to a soft wall tyre like Toyo T1-R's will be OK. The fronts however have smaller overall diameter than the rears so 18" front rims will remove too much of that vital lateral flexibility.I guess it's where you draw the line. I like a car that drives well and looks good. There are times when we have to compromise one for the other. IMO 18" at the front is too much compromise. Mine has 16" spiders all round and I'm happy with how it looks. The Spiders allow wider tyres too which I find keeps the car planted on the road. That matched to adjustable suspension and brakes split 85/15 front to rear sets me up nicely for both country roads and track. I do need to alter suspension setting and front tow-in when I'm on the track though.
Edited by tvrbob on Sunday 23 December 10:21
Amen to the above. The tyre is very much part of your overall suspension in terms of compliance. It's all about matching the gar to the car's needs really - if you have some soggy VAG product, it will - on balance - probably benefit from the extra sharpness offered by a bigger wheel/lower aspect ratio tyre combination despite the technical disadvantages (more unsprung/rotating weight, less give in the tyres means suspension bushes and bearing get a harder life). With a TVR however the very last thing you want to do is to remove the progression offered by lower/stiffer tyre sidewalls - it's not like they need any help to suddendly break away in unfavourable conditions! You'll get an (even) higher level of outright grip, but the transition between grip and 'backwards into hedge' will be a lot more sudden (for the same reason I tend to abstain from the really hardcore, dry grip/track biased tyres for a roadgoing TVR in favour of more 'benign' UHP designs offering more compliance and wet grip, like Dunlop SP9000, Toyos et al), and stay with the standard 205/225 sizes which give better steering feel, give less hairy wet weather characteristics and more progressive breakaway at the limit. If the rest of the suspension is sorted properly, you can still get a lot of dry grip and traction out of relatively narrow tyres - see the last Marcoses which ran 225 section tyres with 400+ bhp and similar weight to TVRs!
Personally I'd go no further than a 16/17" combo using Toyos which indeed have a softer sidewall than the OE Bridgestones - the main benefit being that you can fit bigger brakes if needed.
Personally I'd go no further than a 16/17" combo using Toyos which indeed have a softer sidewall than the OE Bridgestones - the main benefit being that you can fit bigger brakes if needed.
Edited by 900T-R on Sunday 23 December 10:33
900T-R said:
Personally I'd go no further than a 16/17" combo using Toyos which indeed have a softer sidewall than the OE Bridgestones - the main benefit being that you can fit bigger brakes if needed.
Et voila...
17" Team Dynamics Motorsport wheels with 205x40 ZR 17 on the front and 225 x 45 ZR 17 Toyo T1-Rs on the rear. And Wilwood 300mm brakes. That's me at Prescott this year. And it goes round corners and stops just luvverly.
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