Discussion
Hey guys. Just wondering if any of u have put 18" wheels on your chim? If so have you had any probs? I was told by an obvious idiot of a manufacturer that 245/40/18 wheels would fit on my chim and when i came to fit them the damn things wouldnt fit on the front. I know that the chims come with staggered 16s on the back and 15s on the front but again i was told this wouldnt be a problem. Should i swap the fronts for 17" (if they'll let me) or attempt cutting the sills/arches?? 
This has been discussed quite a bit, but with regard to fitting 18's yes, it is possible and no your ride does not deteriorate horrendously, nor does it make the car worse to drive....
245/40's won't fit on the front, neither will 235/40's......I think I fitted some 225/35's (what ever the Tuscan has on the fronts) the later cars (Tuscan, T350 etc)were fitted with 18's so I see no reason not to fit them on a Chimaera.
Cutting the arches/inner wings is a bit of a none starter if you have a look at the structure you'll see what I mean, it would be very difficult to make a nice job of it!
245/40's won't fit on the front, neither will 235/40's......I think I fitted some 225/35's (what ever the Tuscan has on the fronts) the later cars (Tuscan, T350 etc)were fitted with 18's so I see no reason not to fit them on a Chimaera.
Cutting the arches/inner wings is a bit of a none starter if you have a look at the structure you'll see what I mean, it would be very difficult to make a nice job of it!
I`ve got 17 front and 18 rear the car handles so much better there are different offsets on the front wheels to the back, elite`s in rainham essex do a couple of different styles from about £700 ish upwards, its not recomended to put 17 all round or 18 all round , dont buy wheels what need spacer to fit them,
neejah said:
245/40's won't fit on the front, neither will 235/40's......I think I fitted some 225/35's (what ever the Tuscan has on the fronts) the later cars (Tuscan, T350 etc)were fitted with 18's so I see no reason not to fit them on a Chimaera.
Not wishing for a debate on this one but the comparison you make is not reasonable. The chassis on the Tuscan's & T350 are not the same as the Chimaera and the suspension is significantly different. It is a fact that lateral movement of the tyre wall is what prevents bump steer and tramlining. If you reduce the available lateral movement by reducing sidewall height or selecting stiffer sidewall tyres then you will increase the amount of lateral transition to the rim. The issue is simple. If there is not enough sideway movement provided by the tyre wall then the tyre will drag the rim to follow the tyre. This then transmits the rotation to the other front wheel. This affect is creates tramlining and bump steer. What I am saying is that if you decrease lateral movement you increase the level and likelihood of tramlining and bump steer. tvrbob said:
neejah said:
245/40's won't fit on the front, neither will 235/40's......I think I fitted some 225/35's (what ever the Tuscan has on the fronts) the later cars (Tuscan, T350 etc)were fitted with 18's so I see no reason not to fit them on a Chimaera.
Not wishing for a debate on this one...
) I did this back in 2000 before wheel changes were popular and the 'nay-sayers' predicted I would ruin the handling of the car but this didn't happen. It did however allow me to fit 315mm front discs and 300mm rears followed up with Nitron adjustable dampers 
all round a nice package. Obviously chap needs to maintain the rolling radius of the standard wheels to ensure they fit and Steve Heath has a handy tyre size calculator on his web site. But I would stress again bigger wheels do not ruin the ride of Griff's and Chim(p)'s. 
Rich... also more herewww.greenbear.org.uk
Dont think I agree with all that, just to add fuel to the fire
Many of the newer cars were supplied with 16" wheels, the 18" were upgrades. The specs for rubber on the 16" are very close to the Chim/Griffs (hence the factory spider wheel upgrade, and 16" fronts on later Grimaeras). I'm pretty sure even the 18" correct spiders are more suitable for the chassis than a lot of afternarket 17" which have been fitted ~ incorrect centreline / spacers ... The only great difference is that cerbs use fronts all-round.
The chassis will feel different if you change tyre brands, it is pretty adjustable. It is not to say any wheel will not fit, just that you may have to alter some other settings to accomodate it. The 18" spiders give a harder ride on the newer TVR's but most owners are aware of this; IMO the biggest drawback is fear of damaging the wheels on 'road craters'.
Dave
Many of the newer cars were supplied with 16" wheels, the 18" were upgrades. The specs for rubber on the 16" are very close to the Chim/Griffs (hence the factory spider wheel upgrade, and 16" fronts on later Grimaeras). I'm pretty sure even the 18" correct spiders are more suitable for the chassis than a lot of afternarket 17" which have been fitted ~ incorrect centreline / spacers ... The only great difference is that cerbs use fronts all-round.
The chassis will feel different if you change tyre brands, it is pretty adjustable. It is not to say any wheel will not fit, just that you may have to alter some other settings to accomodate it. The 18" spiders give a harder ride on the newer TVR's but most owners are aware of this; IMO the biggest drawback is fear of damaging the wheels on 'road craters'.
Dave
richb your car look better for the wheels i had 500 wheels on my chim i hated them, it took a while to find other wheels, mine feels so much better through the country lanes and were i live there are at least 5 miles of them in every direction , so sharkytvr if you want bigger wheel get them it make`s the car look much better you wont regret it.
Edited by pk500 on Monday 5th February 18:53
Well i still have standard wheels and get a huge amount of tramlining and this is with softer sidewall Toyo's. I'll soon be getting new wheels (17"fr/18"rr) once i decide on a set i like and i seriously doubt they will make the ride any worse. I think i will revert to a 225 rear tyre - the tramlining got significantly worse when i put 245 rears on my 400.
I've never been a believer that the TVR's suspension set up spefically for their wheels and that changing this would destroy everything! BIg car companies spend fortunes on suspension setup; some like Porsche, Ferrari etc even get racers to develop their setups. There is no way TVR could have done this on their budget - there was probably some testing to get a car that feel about right, but far from optimum.
I've never been a believer that the TVR's suspension set up spefically for their wheels and that changing this would destroy everything! BIg car companies spend fortunes on suspension setup; some like Porsche, Ferrari etc even get racers to develop their setups. There is no way TVR could have done this on their budget - there was probably some testing to get a car that feel about right, but far from optimum.
jsr said:
Well i still have standard wheels and get a huge amount of tramlining and this is with softer sidewall Toyo's.
Are you sure it's tramlining? Toyo's are renowned for their good match to the standard chim/griff set up. Perhaps you are driving on 'book' tyre pressures. If so it'll not be tramlining, it'll be a result of too much lateral flexing. The standard set-up needs higher tyre pressures to compensate for the softer Toyo sidewalls. It could also be too much play in your steering. In the end you'll put your big wheels on because you want to. You should Google the words 'tramlining' and 'bump steer' before making your choice though. Edited by tvrbob on Monday 5th February 23:08
AHA juts found the tyre combination for mine. Fronts 215/45 17 Rears 235/40 17 shod with TOYO Proxies. Superb turn in, no tram lining. Nice ride. You've got to admit the standard 15/16 wheels can look a bit small in those big curvey arches?
Edited by tvrchutney on Monday 5th February 23:46
15/16 do look too small. I put the five stud upgrade on mine. The reason was partly aesthetic and partly to move brake balance to the front to improve track performance. The 16" spiders look nicer IMO and the tyres go up in width from 205/225 to 225/245 resulting in better dry traction and less understeer on initial turn in. I can't do a real comparison because I changed from SO2pp's to Toyo T1-S at the same time and the Toyo's are known to be a different feel to the stiffer SO2pp. Just to clarify my words above. Tramlining and bump steer are functions of the front wheels. 17"/18" would be no problem IMO. Edited by tvrbob on Tuesday 6th February 07:27
tvrbob said:
15/16 do look too small. I put the five stud upgrade on mine. The reason was partly aesthetic and partly to move brake balance to the front to improve track performance. The 16" spiders look nicer IMO and the tyres go up in width from 205/225 to 225/245 resulting in better dry traction and less understeer on initial turn in. I can't do a real comparison because I changed from SO2pp's to Toyo T1-S at the same time and the Toyo's are known to be a different feel to the stiffer SO2pp. Just to clarify my words above. Tramlining and bump steer are functions of the front wheels. 17"/18" would be no problem IMO. Edited by tvrbob on Tuesday 6th February 07:27
Bob, Without getting into a "debate" with you on this, with regard to Chim/Griff suspension, yes they are softer as standard than Tuscan, T350 etc but the chassis geometry is not that far apart.
I actually had my name down for the factory upgrade kit, but had a look at a car with them fitted and decided that they looked too small (all IMHO), which is why I went for the 18's. I would suggest that unless you have driven a Chim/Griff with the wheel and tyre combinations which have been talked about that you are not in a position to comment on the performance. As you have stated in a previous post, stiffness of a tyre wall can have dramatic effects on bump steer and tramlining so you need to ensure that you're comparing apples with apples.
neejah said:
I would suggest that unless you have driven a Chim/Griff with the wheel and tyre combinations which have been talked about that you are not in a position to comment on the performance. As you have stated in a previous post, stiffness of a tyre wall can have dramatic effects on bump steer and tramlining so you need to ensure that you're comparing apples with apples.
I agree, I'm not responding from an 'experience' point of view but the relationship between tyre wall height and available lateral movement between tread and rim is well known. As is the mechanism that causes tramlineing and bump steer. It seems reasonable then to say that the smaller the sidewall (on the front) the greater the level of tramlining and bump steer. I back that up with a conversation I had with Neill Anderson when I was specifying my wheel and brake upgrade. His opinion is robust; he designed the Chim/Griff chassis. He suggested that (and I paraphrase) 18's are too big; they cause instability on country roads and on rough surface roads. Probably OK on the track but may result in uncontrollable breakaway over steer because the rear sideways flexing is what generates the 'progressiveness' and allows the driver time to manage over steer. Take that progressiveness away and the car is likely to snap into a spin without any warning. As a track driver that enjoys a bit of sideway action I took heed of this warning.Neill was a great fellow and I had a number of useful conversations with him when I 'designed' my wheel & brake upgrade. At the time he was experimenting with the Cerbera running gear fitted to his Griff and he thought my arrangement of 17" fronts and 18" rears would work well. I later had lunch with him at Bedford and we spoke some more and I was able to tell him he was correct. Personally (for what it's worth) I reckon tyre pressures can have as much effect on handling, tramlining and tail break-away as an extra inch on the rim size.
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