What tyres and wheels do you use?
Discussion
Basically the above on your Seven. I have a Tiger Cat E1 and getting the power down is a bitch. Plus i want something more sticky for the corners. I have been suggested to that Toyo R888's are good but also that i should maybe think about a 13" wheel.
Currently have 15" 185 x 60
Cheers
D
Currently have 15" 185 x 60
Cheers
D
You may find that part of your problem is the TigetCat itself. The rear suspension, being Sierra semi-trailing arms, gives huge unsprung weight for a 'Seven' type vehicle and traction is one of the things that suffers as a result.
The lighter your rear wheel/tyre combination, the better, so there may be some (traction) advantage in using 13" wheels.
Playing around with the rear damper settings might help a little bit, too, but to be honest it is partly a limitation of the design that you can't do much about (unless you get into a major re-design of the rear suspension, with custom, lightweight parts).
The lighter your rear wheel/tyre combination, the better, so there may be some (traction) advantage in using 13" wheels.
Playing around with the rear damper settings might help a little bit, too, but to be honest it is partly a limitation of the design that you can't do much about (unless you get into a major re-design of the rear suspension, with custom, lightweight parts).
My experience on my track Westfield:
I've had Avon ACB10's, Avon CR500's, Avon Zv1, Yoko A032SS.
ZV1's are on a set of 15" rims i use for wets.
The others are 13".
ACb10's are easily the most grippy, very light (2kg per tyre less than the Yokos), scary in the wet, expensive & as they are crossplies need the camber to be adjusted.
CR500's are almost as grippy as ACb10's, just as light, better in the wet, very expensive.
AO32SS almost as grippy as CR500, better ride & turn in (60 profile vs 50 on CR500's), same as CR500 in wet, least expensive.
I've had Avon ACB10's, Avon CR500's, Avon Zv1, Yoko A032SS.
ZV1's are on a set of 15" rims i use for wets.
The others are 13".
ACb10's are easily the most grippy, very light (2kg per tyre less than the Yokos), scary in the wet, expensive & as they are crossplies need the camber to be adjusted.
CR500's are almost as grippy as ACb10's, just as light, better in the wet, very expensive.
AO32SS almost as grippy as CR500, better ride & turn in (60 profile vs 50 on CR500's), same as CR500 in wet, least expensive.
I used to compete in sprints and hillclimbs, (heavily modified MG Midget, actually an Arkley special, so almost a kit car!), and everyone in my class ran on Yoko A032R SS compound. GOOD TYRE, and suprisingly good in the wet. Interestingly the A048's were available then, but nobody switched. Don't know about now though, stopped competing 3 yrs ago, but the A032's are seriously good alround tyres.
DamienCBR said:
Basically the above on your Seven. I have a Tiger Cat E1 and getting the power down is a bitch. Plus i want something more sticky for the corners. I have been suggested to that Toyo R888's are good but also that i should maybe think about a 13" wheel.
Currently have 15" 185 x 60
Cheers
D
Currently have 15" 185 x 60
Cheers
D
Softer springs will help, dual rate maybe if you can stomach the expense?
Think about an anti-roll bar if there isn't one already, and as already suggested, damper settings. Tendency is to set them higher than you need.
Have you tried experimenting with tyre pressures? For a lightweight car on fairly large tyres which are rated for far heavier cars than a Seven, you can probably lower the pressures further than you might think.
Seem to remember Ian Gray at STM using 17psi on his race car, then looking like he'd swallowed a goldfish when he realised he'd given away a trick of the trade. Fortunately for him I'm not racing against him...
Do think that 13s are the way ahead, too. 15" wheels look good but they're heavy and the tyre sidewalls will be overly stiff for the weight acting on them.
And I just can't believe the number of 7s you see for sale with 17" alloys on them. What are people thinking?
One other thought, hard to check though. Is the same wheel breaking away every time? If so, check the corner weights and try to equalise them with you aboard (or two-up if that's your normal load case).
May get a lot more traction simply by not allowing one wheel to be significantly less loaded than the other.
Corner weighting gauge is over £100 but you'd probably pay that for a corner weighting session at a preparation company.
May get a lot more traction simply by not allowing one wheel to be significantly less loaded than the other.
Corner weighting gauge is over £100 but you'd probably pay that for a corner weighting session at a preparation company.
Preferably both 
I've seen cars with open diffs leave twin black lines from a standing start, because they were correctly set up. Very critical though, and not a lot of use in a low speed, WOT corner exit situation.
I really wouldn't like to be having traction issues in 3rd in the dry though. Oh, no, wait - I do... Too-stiff springs and 18" rims I'm afraid. Fortunately I've got a slip diff, I dread to think what it'd be like otherwise.
I've seen cars with open diffs leave twin black lines from a standing start, because they were correctly set up. Very critical though, and not a lot of use in a low speed, WOT corner exit situation.
I really wouldn't like to be having traction issues in 3rd in the dry though. Oh, no, wait - I do... Too-stiff springs and 18" rims I'm afraid. Fortunately I've got a slip diff, I dread to think what it'd be like otherwise.
FNG said:
Preferably both
My last post was slightly tongue-in-cheek! A limited slip diff will mask traction problems to some extent, but a full corner weighting and geo session will benefit traction, handling and braking & is probably the best money you can spend on any performance car.
Sort your geometry and corner weights first and only then think about whether you need stickier tyres or slippy diffs to help put the power down.
Sam_68 said:
My last post was slightly tongue-in-cheek!I know
I hadn't thought of it and should know better 
:grouphug:
Anyway setup first, but I'd be interested to know what tyre pressures the OP is running cos a high pressure plus low profile tyre certainly won't help.
One other point to add - best place to save weight on any car is the wheels. Reduce rotational inertia, improve sprung:unsprung weight ratio and therefore ride quality, give potential for softer springs, probably shorten the overall gearing while you're about it, improve steering feel, get a more progressive breakaway at the grip limit ... if you possibly can, go for 13s.
The 13" route sounds like a good possibility. Can anyone recommend any websites?
Also what sort of affect will this have on my ground clearance? There is a spead bump at the bottom of my road that does touch the bottom of the car at the moment, will it be worse with smaller wheels?
Maybe 14" might be better. Remember this is for road use, maybe a track day in the summer, but road hooning at the weekends.
Thanks for all the help guys
D
Also what sort of affect will this have on my ground clearance? There is a spead bump at the bottom of my road that does touch the bottom of the car at the moment, will it be worse with smaller wheels?
Maybe 14" might be better. Remember this is for road use, maybe a track day in the summer, but road hooning at the weekends.
Thanks for all the help guys
D
Damiencbr said:
Also what sort of affect will this have on my ground clearance? There is a spead bump at the bottom of my road that does touch the bottom of the car at the moment, will it be worse with smaller wheels?
Look up the specifications of your existing tyres and proposed tyres on the manufacturer's website (or any manufacturer's website for tyres of the same size). They should quote a figure for 'static laden radius' in each case. The difference between the two is the change in your ground clearance.
It depends on tyre profile as well as wheel diameter... very low profile (eg. 35 section) tyres on 15" wheels might have a very similar static laden radius to taller profile (eg. 60 section) tyres on 13" wheels, but yes, chances are that your ground clearance will be slightly reduced.
Also remember that the car will look quite different with smaller wheels... you don't want to spend a grand on new wheels and tyres only to find that you can't live with the appearance, having been used to seeing a set of big rims filling the arches.
Overall diameter will be less, so you'd need to raise the ride height to at least the current distance. Easy done on the coilovers but you'll need to adjust camber and if you can, make sure you're getting negligible bump steer. Rack realignment required, direction and amount you move it depends whether the wheels are toeing in or out in bump travel. Trust to a motorsport prep company if unsure.
Possibility that you'd need different front arches or reposition them (great big air gap between leading edge of the arch and the tyre not helping your drag factor).
I'd try and stick with 13" rims if you are going to change. You may not really notice very much difference moving to 14" (or at least, you could achieve largely the same effect by getting lighter 15" rims and stickier tyres, and leaving your suspension setup largely alone).
Plus, 13" trackday tyres are a lot easier to find both new and secondhand. 14" tyres aren't going to be a lot cheaper than 15" ones, if at all, and the range of makers and compounds is more limited especially if looking at trackday compounds.
You can even use FRenault front slicks on a 8x13 rim if you really want to go mad - they're very cheap from some of the top teams, who get shot of their tyres after every qually or race once the initial sweet spot is used up. Plenty of useable life left in them if you're not bothered that they've given up the last half-second of grip already.
First place I'd look for 13" RWD-Ford-fitment alloys is the back of Motorsport News. Well, a few years ago there certainly were plenty of Mk2 Escort breakers who had enough wheels to choke a hippo at any given time. Otherwise, there's just about always some old rally rims on ebay from Revolution. Compomotive, Minilite & Superlite also do your PCD and offsets, it's probably still their stock-in-trade!
Possibility that you'd need different front arches or reposition them (great big air gap between leading edge of the arch and the tyre not helping your drag factor).
I'd try and stick with 13" rims if you are going to change. You may not really notice very much difference moving to 14" (or at least, you could achieve largely the same effect by getting lighter 15" rims and stickier tyres, and leaving your suspension setup largely alone).
Plus, 13" trackday tyres are a lot easier to find both new and secondhand. 14" tyres aren't going to be a lot cheaper than 15" ones, if at all, and the range of makers and compounds is more limited especially if looking at trackday compounds.
You can even use FRenault front slicks on a 8x13 rim if you really want to go mad - they're very cheap from some of the top teams, who get shot of their tyres after every qually or race once the initial sweet spot is used up. Plenty of useable life left in them if you're not bothered that they've given up the last half-second of grip already.
First place I'd look for 13" RWD-Ford-fitment alloys is the back of Motorsport News. Well, a few years ago there certainly were plenty of Mk2 Escort breakers who had enough wheels to choke a hippo at any given time. Otherwise, there's just about always some old rally rims on ebay from Revolution. Compomotive, Minilite & Superlite also do your PCD and offsets, it's probably still their stock-in-trade!
FNG said:
Overall diameter will be less, so you'd need to raise the ride height to at least the current distance. Easy done on the coilovers but you'll need to adjust camber and if you can, make sure you're getting negligible bump steer. Rack realignment required, direction and amount you move it depends whether the wheels are toeing in or out in bump travel. Trust to a motorsport prep company if unsure.
I may be wrong (I'm not especially up on old Fords), but I don't think the rear suspension on the TigerCat is easily adjustable for toe and camber - it uses standard Sierra semi-trailing arm set-up.
In theory bump steer shouldn't be a problem. The arcs of the trackrods and the arcs of the suspension arms should have been designed to coincide throughout their range of movement, but in practice that might not be the case, so yes, it's worth checking (particularly if the car feels a bit directionally unstable after you've raised it).
Unfortunately the TigerCat, being very much a 'budget' kit, doesn't lend itself to easy adjustment of these sorts of suspension settings.
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