How sensitive are T cars to wheel offset?
Discussion
3mm spacers on my 2004 Tuscan with 18” spiders made a world of difference. The 2000 Tuscan with 18” spiders made some difference but not as much. (Bump steer and turn in)….
Having spoken to Dom at length and other experts who have done the research and know the cars inside out (all the specs and variations), I’d say just to go with their advice/specs.
Having spoken to Dom at length and other experts who have done the research and know the cars inside out (all the specs and variations), I’d say just to go with their advice/specs.
MPETT said:
3mm spacers on my 2004 Tuscan with 18” spiders made a world of difference. The 2000 Tuscan with 18” spiders made some difference but not as much. (Bump steer and turn in)….
Having spoken to Dom at length and other experts who have done the research and know the cars inside out (all the specs and variations), I’d say just to go with their advice/specs.
That's interesting as it should be the other way round with the Tuscan. The later cars were updated to work with the 18s.Having spoken to Dom at length and other experts who have done the research and know the cars inside out (all the specs and variations), I’d say just to go with their advice/specs.
Q. does anyone know if the early Tamora's ever run the Mk1 top wishbone (I have picked the picture from another thread that I really do not want to drag people into discussing, as it is a question about a wishbone change that takes place in 2001). A@
Edited by Adrian@ on Thursday 1st February 11:53
Adrian@ said:
Q. does anyone know if the early Tamora's ever run the Mk1 top wishbone (I have picked the picture from another thread that I really do not want to drag people into discussing, as it is a question about a wishbone change that takes place in 2001). A@
The KPI change came in before the Tamora started production, so early Tamoras would have had the non curved but longer top wishbone, ie the middle of 3 versions from the Tuscan.Edited by Adrian@ on Thursday 1st February 11:53
Basil Brush said:
The KPI change came in before the Tamora started production, so early Tamoras would have had the non curved but longer top wishbone, ie the middle of 3 versions from the Tuscan.
You have thrown me a curved ball ...with an additional version wishbone! I am collecting parts to do a four corner rebuild and rather than have parts off the car for a time, I was hoping to have parts refurbished ready to swap on.
Many thanks, I need to get this 100% right, (it is a 2003 car, but I am was hoping to work with part from various sorces) as I don't have a handling issue. A@
Lateish reply re offsets. Stock 18" spiders on T-Cars had allegedly compromised front offset ie an extra 3mm inboard , presumedly for arch clearance (on some T-Cars ie T350C/T ) so it is claimed (cant recall where) that taking 3mm off the front offset improves steering/bumpsteer etc (ie ET40 instead of ET43). on 8.5" front rims that may lead to arch clearance issues for some cars (as the wheel will be further out by 3mm). The rear offset is to ensure optimum chassis /arch clearances so you can play with that to some degree . Bolas spiders and other wheels made by that vendor can (or used to be) obtained in custom offsets. I fitted a set of bolas to my T350 in 19" as the lack of decent 18" tyres in matched make/model was getting smaller for the range of tyre sizes that fitted (without body mods etc) , I ended up with ET40 offset (if memory is working) in 9.5" rear and 8.5" front (though would have preferred 8" front it wasn't made in the style I chose) So if you try to stick to the ET40 for the front (and no wider than 8.5 max & 225 tyre then you should be ok with fitting and have the supposed best offset for front steering . I'd avoid doing it with spacers as the TVR hubs have very small center lips so small spacers will overlap that leaving wheel centering to be entirely reliant on the nut chamfers and not the hubs/wheel center bore interface .
Adrian@ said:
Basil Brush said:
The KPI change came in before the Tamora started production, so early Tamoras would have had the non curved but longer top wishbone, ie the middle of 3 versions from the Tuscan.
You have thrown me a curved ball ...with an additional version wishbone! I am collecting parts to do a four corner rebuild and rather than have parts off the car for a time, I was hoping to have parts refurbished ready to swap on.
Many thanks, I need to get this 100% right, (it is a 2003 car, but I am was hoping to work with part from various sorces) as I don't have a handling issue. A@
Just noticed the update to this thread, Having just read the original thread about the SP12s it seems to confirm that the 18 inch Spiders didn’t fit properly in the first place. Therefore using Spiders as a reference point to correctly size 17 inch wheels isn’t going to work. Instead I should be using the SP12 numbers which seem to be the same as those mentioned above. Given the potential for getting this wrong I’m reaching the point where I can’t be bothered to source 17s. Perhaps a better way to improve ride quality is to try and find a set of SP12s and switch my Nitrons for something softer. At least I’m then dealing with known quantities rather than having to cross my fingers.
I’m afraid I can’t add anything of value when it comes to the technical side, but if your motivation behind this is mainly ride quality then I’d agree and say ditch the Nitrons straight away. I’ve never had a TVR that rides well with them, I really can’t understand why people rate them.
The terminology used and misinformation on this topic, not so much in this thread, will mislead those not familiar.
Anyone reading and thinking there is a magic bullet, erase that thought. example, bump steer and kick back are confused so often.
The adjustments for a road car I have made (apart from tyre pressure/offset/damper) is,
To keep the side walls of the tyres vertical, not stretched, on the rims. Think what a stretched tyre does when loaded sideways Vs one that can flex slightly. Can reduce tramlining and the twitchy feel that scares a lot of people. Choice number 1
Get the camber correct to spec, like 4 wheel alignment, mark the top position (wishbone Vs ball joint) and try moving it in and out, both sides the same, be brave. Choice number 2
Swap the two shims about on the top ball joint, make thinner ones for finer adjustment, you can make it feel lazy if that is what you want, I want it pointy. (Caster) Choice number 3
If you don't want to do this then leave it alone.
Anyone reading and thinking there is a magic bullet, erase that thought. example, bump steer and kick back are confused so often.
The adjustments for a road car I have made (apart from tyre pressure/offset/damper) is,
To keep the side walls of the tyres vertical, not stretched, on the rims. Think what a stretched tyre does when loaded sideways Vs one that can flex slightly. Can reduce tramlining and the twitchy feel that scares a lot of people. Choice number 1
Get the camber correct to spec, like 4 wheel alignment, mark the top position (wishbone Vs ball joint) and try moving it in and out, both sides the same, be brave. Choice number 2
Swap the two shims about on the top ball joint, make thinner ones for finer adjustment, you can make it feel lazy if that is what you want, I want it pointy. (Caster) Choice number 3
If you don't want to do this then leave it alone.
robsco said:
I’m afraid I can’t add anything of value when it comes to the technical side, but if your motivation behind this is mainly ride quality then I’d agree and say ditch the Nitrons straight away. I’ve never had a TVR that rides well with them, I really can’t understand why people rate them.
I had them on my car for about 20 years and they were miles better in every way, including comfort, than the standard kit the car came with. Maybe if you go with a more track biased kit then comfort may suffer?Gassing Station | Tamora, T350 & Sagaris | Top of Page | What's New | My Stuff